Joined Nov 2001
17K Posts | 773+
Ely, England
jetting a bike is a relentless task, usually done with no guidance or help. owners stop the moment that they feel thay have them running "OK". I met this American that actually wanted to test and give honest feedback.
probably only the 20th person in the 580 kits we've sold. I liked him that much, I sent him a new design to test with spares etc for free. He runs a KTM but the results have always been similar for the KTMs and Husabergs.
now incase you think they are totally different. they are NOT. at the end of this I expect his jetting will be the same even for a 380 Husaberg. 380-650 the jetting is down to the owner. and this one is good!
the new needle is near the bottom if you want to cut this top lot out. any questions....you're more than welcome!
read on then;
JETTING KITS. I HAVE NOW SOLD 580 JETTING KITS OF WHICH 50% ARE NOW FOR KTMSs. THAT NEEDLE DESIGN HAS BEEN SUPERCEDED AS OF TODAY. ONLY ONE PERSON HAS TRIED THE NEW NEEDLE SO HERE GOES. FIRSTLY WITH THE OUTGOING NEEDLE.
SO FOR THOSE WITH THIS ONE ALREADY, HERE IS WHAT HE SAID;
"Hot starting is instant and low end punch seem good.
So the pilot circuit seems good now.
As far as the choke circuit. I removed the jet from the carb and it was marked 85.
I drilled it out with a .95 mm bit and reinstalled it.
The bike started a little bit better when cold and when using the choke with a warm engine the idle was slowed a bit after using the choke more than a moment or two.
So I took it out again and drilled it to 1.15 mm.
Now it finally started quickly when cold and the engine would start to stumble after 20 or 30 seconds of use.
So I think the choke is good now. (I wonder if the choke circuit is a bit dirty and is causing the need for such a large jet)
I added your spacer to the AP diaphragm and overall it seemed fine but with no AP after 1/2 throttle or so it lost some punch.
So I took the spacer off the diaphragm post and drilled out the leak jet path with a .5 mm drill bit.
Now the roll on was more brilliant than ever and I had some AP going from 1/2 to 3/4 throttle quickly so I was happy.
So I think the AP is better now.
So now with the roll on a leaner from the reduced AP when I got to wide open throttle it was a bit flat.
So I suppose I should move from the 165 down to the 162 as you already told me to do. (many months ago)
I wanted to let you know that I took your advice on the choke and it worked out well."
AFTER ADVICE FROM MYSELF WE HAD;
You were right that the 115 choke is a bit much on a warm day.
It was 73 yesterday and the motor started to load up after 20 sec or so.
I pulled the hot start with the choke on for another 10 secs to have a nice high engine speed and after that the bike would idle with no choke.(not smooth but it didn't die before I put my left glove on)
I was running 165 main clip 7 so I decided to try 162 and it pulled better at wide open throttle.
So since leaner is better I then tried clip 6.
It really smoothed out the bike at small throttle openings. (I didn't realize it was surging)
Now I can tell surging vs motor vibrations.
Its almost fuel injected now.
I did lose a bit of pull after 1/2 throttle so I then tried a needle shim to give me clip 6 & 1/2.
Now the small throttle surging was still good and the pull above 1/2 throttle was improved.
I appreciate all of your support.
BE MINDFUL THAT HE USES THE TERM APJ FOR THE PAJ AT THIS POINT. ALTHOUGH I PULL HIM UP ON IT HE DOES IT QUITE OFTEN.
MORE ADVICE AND WE HAVE THIS;
Yesterday I did some high speed runs. 162 main. Clip 6.5. The bike is geared a little short so it will only run 93-94 with me on it. 17/45 with a 17” rear tire. Over run seems good. If I close the throttle a bit it slows it doesn’t speed up. The power did not fade after 20-25 secs at top speed. The AP is too much as I come out of a tight corner but at a higher engine speed it feels nice. I may increase the leak jet size from 50 to 55 or 60.
It still had some surging so I closed the pilot screw and the surge was better. I can reach it while riding (I have long arms). Closing the pilot screw would kill the bike at idle. Closing would also cause exhaust popping on closed throttle.
Today it was hotter 79 F and I moved the clip leaner to see if was too rich as you suspected. First I tried clip 5.5 and then 4.5 and the surging was gone. It was hot enough today that the pilot screw would not kill the bike. Low loping idle but still running. In fact the bike would start with no choke. It would die soon after though.
So as you suspected the needle needed lowering and the pilot circuit is a bit rich as well. I’m not sure what pilot and air pilot that you sent to me. (Which are installed in the bike)
So what’s next? one more clip leaner? Lean the pilot or increase the air pilot a bit?
AFTER MORE ADVICE WE HAVE;
Happy Easter. I hope you are doing well. I’m not in any hurry for a reply so please take your time.
My bike is a 2004 KTM 625. I ride at about 900ft. It has a 41mm FCR MX with bolt on Belmouth. It has hot start and coast enricher. I stretched the spring in the enricher years ago to keep it from causing surging.
You were thinking that the air box was restrictive. I’m using the stock exhaust. To run a hotter cam you have to have an open exhaust. So what I’m trying to say I’m sure it does not breathe as well as a Husaberg.
I’m running 162 main on clip 7. I am still using AP with the short post diaphragm and .5 mm hole for a leak jet.
I removed the pilot from the carb to see what you sent me. It was a 40 so I assume you sent a 75 PAJ but I didn’t pull that out yet. I put in a 38 pilot. The bike likes .5 turns out with the 38.
I think that the surging is better with the 38. It only has trouble at a specific rpm at a specific throttle opening (5% or so).
Closing the fuel screw does not kill the engine.
I did check the ACV diaphragm and it looked good.
Maybe the needle jet is worn. It has more than 200 hours on the motor and the owners manual says that the needle jet may need to be changed after 200 or so.
What’s next - Change the PAJ to a 60? Replace the needle jet? Leave it alone and ride it?
I SENT SOME PARTS OUT TO HIM AND SO WE CONTINUE;
625 KTM again from the states.
I'm running 38 pilot, Not sure about the APJ but most likely larger than a 60. (I have ordered a 60).
Clip 6, 162 main and a drilled out starter jet to 110.
Bike starts OK at 65F and ran for 30 sec before engine slowed down.(bike still required 10 sec to start so I think I need this much choke- I know when it gets hot it will be too much choke)
If my pilot fuel screw is .5 turns out.
I'm happy with the bike. I just have a surge at a specific rpm 3000? and specific throttle opening 5%?
As far as installing the 60 APJ.
If I install a smaller APJ won't that enrich the idle mixture?
But I'm only .5 turns out?
If I close the pilot fuel screw it does not kill the engine unless the temperature outside is 75 F or more.
Should I try the 60APJ? or try 35 pilot.
Or is the needle jet worn and letting extra fuel into the engine?
Or should I just stop and leave it alone.
LUCKILY WHEN YOU GUESS RIGHT, PEOPLE FOLLOW YOU'RE ADVICE. WHEN YOU DON'T GET IT AND GUESS WRONG, IT ISN'T A LACK OF KNOWLEDGE JUST MISUNDERSTANDING WHAT PEOPLE SAY. THEN IT GETS EVEN HARDER TO ADVISE....
I watched your videos on YouTube and on Facebook. It’s nice to put a face with a name. Or at least your mustache and your voice. Maybe you have Scandinavian ancestors. That’s why you like your Husaberg!
I was using 162 main, 155 MAJ, clip six, 35 pilot, 60 APJ with .6mm leak jet path.
First I tried 160 main and it seemed very similar to 162. Maybe a little weaker at power peak or over rev. Dealer didn’t have a 158 so I tried 155.
155 main.
Bike was fine but weaker above 1/2 throttle. Seemed to need more throttle to carry the same speed as 160/162. I think it had a little more snap moving through 1/4 throttle. Fuel screw became sensitive like you thought. Closed would kill it quickly as well. Idle was poor until 1.5 turns out. Idle picked up even more speed going to 2.5 turns out. Flat spot just before it comes on the needle like you thought.
So I went back to 160 to test more.
160 main. Sometimes the fuel screw would kill it and sometimes not. It liked about .75 turns out. Very rideable just doesn’t pull as hard at WOT. Long uphill road I tried 95% throttle and wide open back and forth. It seems like it ran a little better with the needle in the way. This was near power peak not over rev. I did get some light popping on closed throttle over run. Maybe i should try a 180 MAJ? So I can lower the main? As I think back with 162 and 155 MAJ it seemed like it would rev so far it blow itself up. It didn’t feel that way tonight.
My dealer ordered a iridium plug for me so I’ll have it this week.
I don’t have a 45 APJ to try yet.
I may have to try 162, then 160 then 158 in the same afternoon.
AND NOW, THE NEW NEEDLE
I was able to try the needle tonight. The pull is definitely stronger at 3/4 throttle. Now WOT feels less impressive so I’ll have to try the 160 main again.
One curious thing though. It started and ran without choke. Is the straight portion supposed to be the same as my old needle? I should put a caliper to them to confirm. What is the target needle root diameter? Maybe the old one was a little fat and this new one is a bit skinny but both are still in spec. Did the same shop make them? On the same grinding machine?
So I’ll have to put the 32.5 pilot in place after all. So the homework starts again.
I wanted to thank you for all the time you have spent helping my bike run better and better.
AND;
I installed a iridium plug as you recommended. The smallest APJ I could get was a 52. I also installed a new jet nozzle. Once I put the new nozzle in the bike I was so happy I stopped testing. (The bike finally always stalls immediately when I close the pilot screw)
35 pilot
52 APJ
Your needle on clip 7
162 main
200 MAJ
(I went back to the 200 to see how the bike ran with a new nozzle-it ran so well and never put the 180 back in - I know it would make the over rev much better but the bike has so much power I don’t need the over rev on the street)
I have new chain and sprockets ready to on. I was waiting to finish the last few miles on the rear tire before swapping the sprockets at the same time. I bought rear sprocket with three teeth less to gear it up a little faster.
What would you like me to try?
THEN;
Thanks for double checking on the base diameter.
I rode on Sunday night and the bike did not need choke. I suppose lifting the slide to remove the needle and also to remove the needle holding screw (it got caught in the slide mechanism ) gave the bike just the right amount of fuel to vaporize for an easy cold start.
Also the 162 main was not too rich as it was 5 degrees Fahrenheit cooler than Friday. But since it’s on the edge I need to go to 160.
NOW HE IS REALLY ENJOYING IT! NO NEED TO ASK HIM IF HE'LL EVER TEST IT. SO SEE BELOW;
I hope you are having a good summer. The only negative for me is that we have storms that pop up and surprise us from time to time.
I had some energy late this afternoon so I did some testing.
I was running-
35 pilot
52 PAJ
New needle C7
162 main
200 MAJ
Peak was sometimes weak depending on the weather and I had no over rev but everything else was very strong.
Changed PAJ from 52 to 50.
Kept 35 pilot
Kept needle on C7
Moved main down to 155.
Installed 155 MAJ.
1/4 throttle was dramatically improved and moving thru 1/2 and 3/4 was really strong as well. Peak power was a little better than previous setup. Over rev was better and complemented the peak. (Both were good but not outstanding)
The only trouble seemed to be a miss at steady state 1/8 throttle. Turning the fuel screw out didn’t seem to help. It was a similar feeling to when I had the needle too lean a few months ago. (Clip 3 and 4)
I could smell the exhaust like it was hot when I pulled into the garage. Also the Engine cases seemed hotter to the touch.
The 50 PAJ and the 155 MAJ should have both enriched the mixture. (What you have taught me) I guess the 155 main is a bit small and starving the needle?
Try 158 main? Clip 8? 38 pilot?
AFTER SOME SUGGESTIONS;
You were right it was rich!
I rode almost an hour using clip 6. I had to turn the idle up just a touch. Steady state 1/8 throttle miss was almost gone. Low rpm (lugging the engine) was more possible than ever before. The nice pull at 1/4 was still there just a bit softer. 1/2 and 3/4 were good. Peak power and over rev were strong. (It had thunder stormed and was a bit cooler) Maybe I can lower the main and get 1/8 even better? Or the lower main might allow to go back to clip 7 for improved performance. You had thought I could get down to a 155. The new needle has let that happen easily! The only negative seems like the engine would rather be up shifted. It seems to be unhappy or unsettled just a bit to spin at 5500 or 6000 RPM and hold steady.
Your thoughts? Lower the main until the bike is weaker at peak? You don’t really know until you over do it right?
OUT WITH THE FAMILY, MUST BE AN AMERICAN THING;
Thanks for the excellent reply! Your comments on each of my statements is easier for me to understand.
My family rode 80 miles tonight. Both my wife and son have bikes.
Earlier you thought I tried the 32.5 pilot. But I have not tried it yet. I did change the MAJ, main and PAJ. And after reporting in you recommended clip 6 - so after that we stand four changes.
The miss at 1/8 was worse tonight. I think the rain the other day cooled the engine some. After running the engine hard (90+ mph) the miss remains even after closing the pilot screw. It seems metronomic in nature like a good jazz drummer (da-dada-da-dada) it does worsen as the screw is opened but it doesn’t get much worse. The bike does pop while riding with the pilot screw closed. The miss is not horrible just a bit annoying.
I’ll purchase the lower mains tomorrow and test them over the weekend.
Thanks again for the clear direction to try lower the main. “***** country” - that’s funny. Not politically correct but funny.
IS THE NEEDLE A SUCCESS THOUGH?;
The needle is definitely a success.
OFF WE GO AGAIN - THINGS ARE COMING GOOD;
Recap-
35 pilot
50 PAJ
The new needle on clip 6
Was running 155 main.
My dealer had to order a 150,148 and 145 for me. I asked for 152 but he messed up. He agreed this is uncharted territory - he’s never put thIs small of a main in a big bike.
I put the 150 in last night but it was a bit late to ride. Two nice elderly ladies live right beside me. (Don’t want to keep them up)
This morning ran the bike. The 150 was definitely an improvement. The miss at 1/8 throttle was almost gone. Everything seemed like more power. The engine idled better.
Swapped in the 148 and again things are better. Vibration thru the bars was less. The pull at 1/4 and 1/3 improved. Feels fuel injected. The miss at 1/8 is gone or as close to gone as I can tell at this point. The RPM range that the engine will accept is wider than it has ever been.
Last week I was able to get a new rear tire, chain and sprockets mounted. I did take 3 teeth off of the rear sprocket.
I need to try the 145 Main next. I think it will take it (as you like to say)
HELL! THERE'S NO STOPPING THE GUY. THIS IS 2-3 DAYS LATER;
It was cooler today and I ran the 145 main. Probably 75 degrees or so. It’s easier to wheelie! Pull from 1/4 and on was better! The usable rpm has been extended again. It will pull down low almost as well as a fuel injected bike and it turned as fast as I world want it to turn.
I had wondered if we could get the pull that the 162 Main / 200 MAJ had. It seems very similar now. Maybe a 142 will match it?
The pilot screw had to be out at least 1 turn to get rid of the slight popping. As we are peeling this onion back one layer at a time the engine is now making new sounds. With the Pilot Screw closed of course it popped but at .5 it did this light pop like a race car on over run.
I can let the bike go down to idle in gear with very little coughing or sputtering. This has never happened before.
Peak was great and blended well with over rev. The 155 MAJ is close because I really wouldn’t want to rev it much more. I honestly think we are at the limit of the camshaft, air box and exhaust now. (In order to use the hotter factory camshaft you need an open exhaust or you loose power)
Explain to me about a 45 PAJ. It would reduce the total amount of flow in the pilot circuit right? (The straw is smaller that we are using for this creamy soup)
But it would enrich the flow in that circuit right? Same suction with less air coming in right?
1/8 throttle is nearly perfect now. But I would think as the weather cools I would need a larger main and then 1/8 would show up again. It’s a good time to get it perfect right? No time like the present.
I need to reduce the accelerator pump further. It doesn’t pull as strong if I twist the throttle too fast. I’ve been lazy and haven’t done it yet.
So I need to order a 45 APJ if I can find one and still push further and order a 142 and 140 main. Or I could wait for weather to cool down thru September and see how long the 145 works.
NOW WE HAVE TO WORK OUT HOW TO MOVE FORWARDS AND ALSO TO UNDESTAND WHAT IS HAPPENING IN THERE;
Thanks for the gentle correction on the PAJ mistake and also the excellent explanation about going lean on the pilot circuit at higher revs.
With that in mind I need to clarify my explanation.
The miss I have been having at 1/8 throttle was at low revs.
It's like I am following a tractor but instead of a gear too low I'm nearly a gear too high.
Just barely holding the throttle open steady I would have a miss.
Going from clip 7 to 6 helped. Leaning the main from 155 down to 145 also helped.
Leaning it always helped so that is why I was confused about the 45 PAJ.
Because the 45 PAJ should enrich that circuit (more at higher revs - but richen it nevertheless)
So do I need to try the 32.5 pilot? I'm only 1 turn out with the 35 (to get rid of the popping)
Maybe a needle with a larger base diameter?
Today I drilled out the leak jet path to further reduce the AP.
I didn't get it put back together yet so it may be a good time to try the 32.5 pilot while the bowl is off.
I hope I'm not driving you crazy.
INTO ACTION THEN. A RED LETTER DAY AS I DON'T LIKE THE APJ AT ALL AND HAD BEEN ASKING HIM TO WORK WITHOUT IT, SO;
I hope things are well for you.
I drilled the leak jet path to reduce the pump further. I also swapped to the 32.5 Pilot. (I was able to order a 45 PAJ today)
It took a bit longer to catch and start. It also took longer for the engine to begin to load up while using the choke. It was colder natured and took longer to warm up as well. Response was a bit softer but it pulled well. I can imagine the 45 PAJ could strengthen the power right before the needle taper begins. (But it was fine)
Peak and over rev were both good. I totally agree to try a 165 or 145 MAJ to make sure the 155 is the best we can get.
I was able to get the high rev lean surging at 5% throttle like you described. I also have hanging idle. When slowing the engine braking is weak. Also when coasting and closing the throttle the idle hangs up just a moment. It took about 2-2.5 turns out to stop any exhaust popping.
I think next is to install the 45 PAJ. I may try a 145 MAJ when I put the 45 PAJ in the carb. The only way I can know if the main air jet is correct is to change it right? You never know unless you make it better or worse right?
Bonus - one more test before sending the email.
I also ran it briefly with no AP. I think it ran a bit better. C6 is enough fuel. The AP must be pushing it a bit rich. Which I had suspected because rolling the throttle quickly didn’t pull as well as a slower application of throttle. (When the AP was active)
CLOSING IN;
I’ll leave the pump off until everything else is settled. Then I’ll go back and see if that bit of a hit can be felt.
Yes changing the jetting every ride and pushing the limit is a bit crazy. (365 day jetting sounds good to me) It’s good to know that you are pulling me back to reality. Since I am thee tester, I shouldn’t disappoint my instructor! It’s easy to overdo or under do things in this life.
You sent the 32.5 so I must test it! (and the bowl was off the carb anyway) Also now I really know what a lean pilot and hanging idle feel like. And since I now have a problem, I will be able to feel how much the 45 PAJ fixes it.
My bike wouldn’t start with the 85 starter jet. I had to drill it out. I went too far (over 100!) but it starts every time! I look forward to it starting on cold days easily at least. I’ll record the time that it takes to load up once I get the 35/45 back in it. I think I’ll try 32.5 / 45 and report in to you first.
I will edit this and add on to it to the end so please don't "quote me"!! yes it is hard to read it all but for those in the thick of it it will be helpful!
NOTE FROM 8TH OCTOBER.
HE NOW HAS THE PROBLEM THAT IT IS NOW NO LONGER THE SWELTERING HEAT OF SUMMER BUT THE COOL AIR OF 'THE AUTUMN' THE FALL. THE JETTING MUST NOW GO UP AGAIN. WHAT LOOKED LIKE THE LEANEST JETTING EVER MAY BE CORRECT IN THE SUMMER SUN BUT HE NEEDS 12-MONTH JETTING.
cheers
Taffy
probably only the 20th person in the 580 kits we've sold. I liked him that much, I sent him a new design to test with spares etc for free. He runs a KTM but the results have always been similar for the KTMs and Husabergs.
now incase you think they are totally different. they are NOT. at the end of this I expect his jetting will be the same even for a 380 Husaberg. 380-650 the jetting is down to the owner. and this one is good!
the new needle is near the bottom if you want to cut this top lot out. any questions....you're more than welcome!
read on then;
JETTING KITS. I HAVE NOW SOLD 580 JETTING KITS OF WHICH 50% ARE NOW FOR KTMSs. THAT NEEDLE DESIGN HAS BEEN SUPERCEDED AS OF TODAY. ONLY ONE PERSON HAS TRIED THE NEW NEEDLE SO HERE GOES. FIRSTLY WITH THE OUTGOING NEEDLE.
SO FOR THOSE WITH THIS ONE ALREADY, HERE IS WHAT HE SAID;
"Hot starting is instant and low end punch seem good.
So the pilot circuit seems good now.
As far as the choke circuit. I removed the jet from the carb and it was marked 85.
I drilled it out with a .95 mm bit and reinstalled it.
The bike started a little bit better when cold and when using the choke with a warm engine the idle was slowed a bit after using the choke more than a moment or two.
So I took it out again and drilled it to 1.15 mm.
Now it finally started quickly when cold and the engine would start to stumble after 20 or 30 seconds of use.
So I think the choke is good now. (I wonder if the choke circuit is a bit dirty and is causing the need for such a large jet)
I added your spacer to the AP diaphragm and overall it seemed fine but with no AP after 1/2 throttle or so it lost some punch.
So I took the spacer off the diaphragm post and drilled out the leak jet path with a .5 mm drill bit.
Now the roll on was more brilliant than ever and I had some AP going from 1/2 to 3/4 throttle quickly so I was happy.
So I think the AP is better now.
So now with the roll on a leaner from the reduced AP when I got to wide open throttle it was a bit flat.
So I suppose I should move from the 165 down to the 162 as you already told me to do. (many months ago)
I wanted to let you know that I took your advice on the choke and it worked out well."
AFTER ADVICE FROM MYSELF WE HAD;
You were right that the 115 choke is a bit much on a warm day.
It was 73 yesterday and the motor started to load up after 20 sec or so.
I pulled the hot start with the choke on for another 10 secs to have a nice high engine speed and after that the bike would idle with no choke.(not smooth but it didn't die before I put my left glove on)
I was running 165 main clip 7 so I decided to try 162 and it pulled better at wide open throttle.
So since leaner is better I then tried clip 6.
It really smoothed out the bike at small throttle openings. (I didn't realize it was surging)
Now I can tell surging vs motor vibrations.
Its almost fuel injected now.
I did lose a bit of pull after 1/2 throttle so I then tried a needle shim to give me clip 6 & 1/2.
Now the small throttle surging was still good and the pull above 1/2 throttle was improved.
I appreciate all of your support.
BE MINDFUL THAT HE USES THE TERM APJ FOR THE PAJ AT THIS POINT. ALTHOUGH I PULL HIM UP ON IT HE DOES IT QUITE OFTEN.
MORE ADVICE AND WE HAVE THIS;
Yesterday I did some high speed runs. 162 main. Clip 6.5. The bike is geared a little short so it will only run 93-94 with me on it. 17/45 with a 17” rear tire. Over run seems good. If I close the throttle a bit it slows it doesn’t speed up. The power did not fade after 20-25 secs at top speed. The AP is too much as I come out of a tight corner but at a higher engine speed it feels nice. I may increase the leak jet size from 50 to 55 or 60.
It still had some surging so I closed the pilot screw and the surge was better. I can reach it while riding (I have long arms). Closing the pilot screw would kill the bike at idle. Closing would also cause exhaust popping on closed throttle.
Today it was hotter 79 F and I moved the clip leaner to see if was too rich as you suspected. First I tried clip 5.5 and then 4.5 and the surging was gone. It was hot enough today that the pilot screw would not kill the bike. Low loping idle but still running. In fact the bike would start with no choke. It would die soon after though.
So as you suspected the needle needed lowering and the pilot circuit is a bit rich as well. I’m not sure what pilot and air pilot that you sent to me. (Which are installed in the bike)
So what’s next? one more clip leaner? Lean the pilot or increase the air pilot a bit?
AFTER MORE ADVICE WE HAVE;
Happy Easter. I hope you are doing well. I’m not in any hurry for a reply so please take your time.
My bike is a 2004 KTM 625. I ride at about 900ft. It has a 41mm FCR MX with bolt on Belmouth. It has hot start and coast enricher. I stretched the spring in the enricher years ago to keep it from causing surging.
You were thinking that the air box was restrictive. I’m using the stock exhaust. To run a hotter cam you have to have an open exhaust. So what I’m trying to say I’m sure it does not breathe as well as a Husaberg.
I’m running 162 main on clip 7. I am still using AP with the short post diaphragm and .5 mm hole for a leak jet.
I removed the pilot from the carb to see what you sent me. It was a 40 so I assume you sent a 75 PAJ but I didn’t pull that out yet. I put in a 38 pilot. The bike likes .5 turns out with the 38.
I think that the surging is better with the 38. It only has trouble at a specific rpm at a specific throttle opening (5% or so).
Closing the fuel screw does not kill the engine.
I did check the ACV diaphragm and it looked good.
Maybe the needle jet is worn. It has more than 200 hours on the motor and the owners manual says that the needle jet may need to be changed after 200 or so.
What’s next - Change the PAJ to a 60? Replace the needle jet? Leave it alone and ride it?
I SENT SOME PARTS OUT TO HIM AND SO WE CONTINUE;
625 KTM again from the states.
I'm running 38 pilot, Not sure about the APJ but most likely larger than a 60. (I have ordered a 60).
Clip 6, 162 main and a drilled out starter jet to 110.
Bike starts OK at 65F and ran for 30 sec before engine slowed down.(bike still required 10 sec to start so I think I need this much choke- I know when it gets hot it will be too much choke)
If my pilot fuel screw is .5 turns out.
I'm happy with the bike. I just have a surge at a specific rpm 3000? and specific throttle opening 5%?
As far as installing the 60 APJ.
If I install a smaller APJ won't that enrich the idle mixture?
But I'm only .5 turns out?
If I close the pilot fuel screw it does not kill the engine unless the temperature outside is 75 F or more.
Should I try the 60APJ? or try 35 pilot.
Or is the needle jet worn and letting extra fuel into the engine?
Or should I just stop and leave it alone.
LUCKILY WHEN YOU GUESS RIGHT, PEOPLE FOLLOW YOU'RE ADVICE. WHEN YOU DON'T GET IT AND GUESS WRONG, IT ISN'T A LACK OF KNOWLEDGE JUST MISUNDERSTANDING WHAT PEOPLE SAY. THEN IT GETS EVEN HARDER TO ADVISE....
I watched your videos on YouTube and on Facebook. It’s nice to put a face with a name. Or at least your mustache and your voice. Maybe you have Scandinavian ancestors. That’s why you like your Husaberg!
I was using 162 main, 155 MAJ, clip six, 35 pilot, 60 APJ with .6mm leak jet path.
First I tried 160 main and it seemed very similar to 162. Maybe a little weaker at power peak or over rev. Dealer didn’t have a 158 so I tried 155.
155 main.
Bike was fine but weaker above 1/2 throttle. Seemed to need more throttle to carry the same speed as 160/162. I think it had a little more snap moving through 1/4 throttle. Fuel screw became sensitive like you thought. Closed would kill it quickly as well. Idle was poor until 1.5 turns out. Idle picked up even more speed going to 2.5 turns out. Flat spot just before it comes on the needle like you thought.
So I went back to 160 to test more.
160 main. Sometimes the fuel screw would kill it and sometimes not. It liked about .75 turns out. Very rideable just doesn’t pull as hard at WOT. Long uphill road I tried 95% throttle and wide open back and forth. It seems like it ran a little better with the needle in the way. This was near power peak not over rev. I did get some light popping on closed throttle over run. Maybe i should try a 180 MAJ? So I can lower the main? As I think back with 162 and 155 MAJ it seemed like it would rev so far it blow itself up. It didn’t feel that way tonight.
My dealer ordered a iridium plug for me so I’ll have it this week.
I don’t have a 45 APJ to try yet.
I may have to try 162, then 160 then 158 in the same afternoon.
AND NOW, THE NEW NEEDLE
I was able to try the needle tonight. The pull is definitely stronger at 3/4 throttle. Now WOT feels less impressive so I’ll have to try the 160 main again.
One curious thing though. It started and ran without choke. Is the straight portion supposed to be the same as my old needle? I should put a caliper to them to confirm. What is the target needle root diameter? Maybe the old one was a little fat and this new one is a bit skinny but both are still in spec. Did the same shop make them? On the same grinding machine?
So I’ll have to put the 32.5 pilot in place after all. So the homework starts again.
I wanted to thank you for all the time you have spent helping my bike run better and better.
AND;
I installed a iridium plug as you recommended. The smallest APJ I could get was a 52. I also installed a new jet nozzle. Once I put the new nozzle in the bike I was so happy I stopped testing. (The bike finally always stalls immediately when I close the pilot screw)
35 pilot
52 APJ
Your needle on clip 7
162 main
200 MAJ
(I went back to the 200 to see how the bike ran with a new nozzle-it ran so well and never put the 180 back in - I know it would make the over rev much better but the bike has so much power I don’t need the over rev on the street)
I have new chain and sprockets ready to on. I was waiting to finish the last few miles on the rear tire before swapping the sprockets at the same time. I bought rear sprocket with three teeth less to gear it up a little faster.
What would you like me to try?
THEN;
Thanks for double checking on the base diameter.
I rode on Sunday night and the bike did not need choke. I suppose lifting the slide to remove the needle and also to remove the needle holding screw (it got caught in the slide mechanism ) gave the bike just the right amount of fuel to vaporize for an easy cold start.
Also the 162 main was not too rich as it was 5 degrees Fahrenheit cooler than Friday. But since it’s on the edge I need to go to 160.
NOW HE IS REALLY ENJOYING IT! NO NEED TO ASK HIM IF HE'LL EVER TEST IT. SO SEE BELOW;
I hope you are having a good summer. The only negative for me is that we have storms that pop up and surprise us from time to time.
I had some energy late this afternoon so I did some testing.
I was running-
35 pilot
52 PAJ
New needle C7
162 main
200 MAJ
Peak was sometimes weak depending on the weather and I had no over rev but everything else was very strong.
Changed PAJ from 52 to 50.
Kept 35 pilot
Kept needle on C7
Moved main down to 155.
Installed 155 MAJ.
1/4 throttle was dramatically improved and moving thru 1/2 and 3/4 was really strong as well. Peak power was a little better than previous setup. Over rev was better and complemented the peak. (Both were good but not outstanding)
The only trouble seemed to be a miss at steady state 1/8 throttle. Turning the fuel screw out didn’t seem to help. It was a similar feeling to when I had the needle too lean a few months ago. (Clip 3 and 4)
I could smell the exhaust like it was hot when I pulled into the garage. Also the Engine cases seemed hotter to the touch.
The 50 PAJ and the 155 MAJ should have both enriched the mixture. (What you have taught me) I guess the 155 main is a bit small and starving the needle?
Try 158 main? Clip 8? 38 pilot?
AFTER SOME SUGGESTIONS;
You were right it was rich!
I rode almost an hour using clip 6. I had to turn the idle up just a touch. Steady state 1/8 throttle miss was almost gone. Low rpm (lugging the engine) was more possible than ever before. The nice pull at 1/4 was still there just a bit softer. 1/2 and 3/4 were good. Peak power and over rev were strong. (It had thunder stormed and was a bit cooler) Maybe I can lower the main and get 1/8 even better? Or the lower main might allow to go back to clip 7 for improved performance. You had thought I could get down to a 155. The new needle has let that happen easily! The only negative seems like the engine would rather be up shifted. It seems to be unhappy or unsettled just a bit to spin at 5500 or 6000 RPM and hold steady.
Your thoughts? Lower the main until the bike is weaker at peak? You don’t really know until you over do it right?
OUT WITH THE FAMILY, MUST BE AN AMERICAN THING;
Thanks for the excellent reply! Your comments on each of my statements is easier for me to understand.
My family rode 80 miles tonight. Both my wife and son have bikes.
Earlier you thought I tried the 32.5 pilot. But I have not tried it yet. I did change the MAJ, main and PAJ. And after reporting in you recommended clip 6 - so after that we stand four changes.
The miss at 1/8 was worse tonight. I think the rain the other day cooled the engine some. After running the engine hard (90+ mph) the miss remains even after closing the pilot screw. It seems metronomic in nature like a good jazz drummer (da-dada-da-dada) it does worsen as the screw is opened but it doesn’t get much worse. The bike does pop while riding with the pilot screw closed. The miss is not horrible just a bit annoying.
I’ll purchase the lower mains tomorrow and test them over the weekend.
Thanks again for the clear direction to try lower the main. “***** country” - that’s funny. Not politically correct but funny.
IS THE NEEDLE A SUCCESS THOUGH?;
The needle is definitely a success.
OFF WE GO AGAIN - THINGS ARE COMING GOOD;
Recap-
35 pilot
50 PAJ
The new needle on clip 6
Was running 155 main.
My dealer had to order a 150,148 and 145 for me. I asked for 152 but he messed up. He agreed this is uncharted territory - he’s never put thIs small of a main in a big bike.
I put the 150 in last night but it was a bit late to ride. Two nice elderly ladies live right beside me. (Don’t want to keep them up)
This morning ran the bike. The 150 was definitely an improvement. The miss at 1/8 throttle was almost gone. Everything seemed like more power. The engine idled better.
Swapped in the 148 and again things are better. Vibration thru the bars was less. The pull at 1/4 and 1/3 improved. Feels fuel injected. The miss at 1/8 is gone or as close to gone as I can tell at this point. The RPM range that the engine will accept is wider than it has ever been.
Last week I was able to get a new rear tire, chain and sprockets mounted. I did take 3 teeth off of the rear sprocket.
I need to try the 145 Main next. I think it will take it (as you like to say)
HELL! THERE'S NO STOPPING THE GUY. THIS IS 2-3 DAYS LATER;
It was cooler today and I ran the 145 main. Probably 75 degrees or so. It’s easier to wheelie! Pull from 1/4 and on was better! The usable rpm has been extended again. It will pull down low almost as well as a fuel injected bike and it turned as fast as I world want it to turn.
I had wondered if we could get the pull that the 162 Main / 200 MAJ had. It seems very similar now. Maybe a 142 will match it?
The pilot screw had to be out at least 1 turn to get rid of the slight popping. As we are peeling this onion back one layer at a time the engine is now making new sounds. With the Pilot Screw closed of course it popped but at .5 it did this light pop like a race car on over run.
I can let the bike go down to idle in gear with very little coughing or sputtering. This has never happened before.
Peak was great and blended well with over rev. The 155 MAJ is close because I really wouldn’t want to rev it much more. I honestly think we are at the limit of the camshaft, air box and exhaust now. (In order to use the hotter factory camshaft you need an open exhaust or you loose power)
Explain to me about a 45 PAJ. It would reduce the total amount of flow in the pilot circuit right? (The straw is smaller that we are using for this creamy soup)
But it would enrich the flow in that circuit right? Same suction with less air coming in right?
1/8 throttle is nearly perfect now. But I would think as the weather cools I would need a larger main and then 1/8 would show up again. It’s a good time to get it perfect right? No time like the present.
I need to reduce the accelerator pump further. It doesn’t pull as strong if I twist the throttle too fast. I’ve been lazy and haven’t done it yet.
So I need to order a 45 APJ if I can find one and still push further and order a 142 and 140 main. Or I could wait for weather to cool down thru September and see how long the 145 works.
NOW WE HAVE TO WORK OUT HOW TO MOVE FORWARDS AND ALSO TO UNDESTAND WHAT IS HAPPENING IN THERE;
Thanks for the gentle correction on the PAJ mistake and also the excellent explanation about going lean on the pilot circuit at higher revs.
With that in mind I need to clarify my explanation.
The miss I have been having at 1/8 throttle was at low revs.
It's like I am following a tractor but instead of a gear too low I'm nearly a gear too high.
Just barely holding the throttle open steady I would have a miss.
Going from clip 7 to 6 helped. Leaning the main from 155 down to 145 also helped.
Leaning it always helped so that is why I was confused about the 45 PAJ.
Because the 45 PAJ should enrich that circuit (more at higher revs - but richen it nevertheless)
So do I need to try the 32.5 pilot? I'm only 1 turn out with the 35 (to get rid of the popping)
Maybe a needle with a larger base diameter?
Today I drilled out the leak jet path to further reduce the AP.
I didn't get it put back together yet so it may be a good time to try the 32.5 pilot while the bowl is off.
I hope I'm not driving you crazy.
INTO ACTION THEN. A RED LETTER DAY AS I DON'T LIKE THE APJ AT ALL AND HAD BEEN ASKING HIM TO WORK WITHOUT IT, SO;
I hope things are well for you.
I drilled the leak jet path to reduce the pump further. I also swapped to the 32.5 Pilot. (I was able to order a 45 PAJ today)
It took a bit longer to catch and start. It also took longer for the engine to begin to load up while using the choke. It was colder natured and took longer to warm up as well. Response was a bit softer but it pulled well. I can imagine the 45 PAJ could strengthen the power right before the needle taper begins. (But it was fine)
Peak and over rev were both good. I totally agree to try a 165 or 145 MAJ to make sure the 155 is the best we can get.
I was able to get the high rev lean surging at 5% throttle like you described. I also have hanging idle. When slowing the engine braking is weak. Also when coasting and closing the throttle the idle hangs up just a moment. It took about 2-2.5 turns out to stop any exhaust popping.
I think next is to install the 45 PAJ. I may try a 145 MAJ when I put the 45 PAJ in the carb. The only way I can know if the main air jet is correct is to change it right? You never know unless you make it better or worse right?
Bonus - one more test before sending the email.
I also ran it briefly with no AP. I think it ran a bit better. C6 is enough fuel. The AP must be pushing it a bit rich. Which I had suspected because rolling the throttle quickly didn’t pull as well as a slower application of throttle. (When the AP was active)
CLOSING IN;
I’ll leave the pump off until everything else is settled. Then I’ll go back and see if that bit of a hit can be felt.
Yes changing the jetting every ride and pushing the limit is a bit crazy. (365 day jetting sounds good to me) It’s good to know that you are pulling me back to reality. Since I am thee tester, I shouldn’t disappoint my instructor! It’s easy to overdo or under do things in this life.
You sent the 32.5 so I must test it! (and the bowl was off the carb anyway) Also now I really know what a lean pilot and hanging idle feel like. And since I now have a problem, I will be able to feel how much the 45 PAJ fixes it.
My bike wouldn’t start with the 85 starter jet. I had to drill it out. I went too far (over 100!) but it starts every time! I look forward to it starting on cold days easily at least. I’ll record the time that it takes to load up once I get the 35/45 back in it. I think I’ll try 32.5 / 45 and report in to you first.
I will edit this and add on to it to the end so please don't "quote me"!! yes it is hard to read it all but for those in the thick of it it will be helpful!
NOTE FROM 8TH OCTOBER.
HE NOW HAS THE PROBLEM THAT IT IS NOW NO LONGER THE SWELTERING HEAT OF SUMMER BUT THE COOL AIR OF 'THE AUTUMN' THE FALL. THE JETTING MUST NOW GO UP AGAIN. WHAT LOOKED LIKE THE LEANEST JETTING EVER MAY BE CORRECT IN THE SUMMER SUN BUT HE NEEDS 12-MONTH JETTING.
cheers
Taffy
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