Jetting / fuel concerns.

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goatman

Joined
Sep 26, 2007
Messages
25
Location
Groote, N.T.
Hello all - I live in a remote area of Australia where due to fuel sniffing concerns in the communities they have banned fuel which contain aromatics. The colourless alternative named Opal, is apparently 90 octane at most and unsuitable for anything high performance. I have a sneaky deal going though with the airport and buy avgas from them, the blue type. My bike is a 2005 Fs650e, 2000 k's on it, 32 hrs. I am currently mixing the two fuels at around 3.5 ltrs of avgas with 6.5 ltrs of opal, adding a litre of toluene ( to make around a tank of fuel ). This all comes from reading various and many threads on this site. It doesn't like too much avgas - surges , nor too little - preignition I thinks. It seems to run fine when I get it right. does anyone see something wrong with this ?

Also , it has always popped and farted on a trailing throttle , and I have tried to contact Lineweaver to buy his needle and jets , without success. Now I have just put an Akro slip-on on it and the popping is terrible. Is there something I should do whilst trying to track down Lineweaver ? Thanks for your time.
 
fuel

hey Goatman
what octane rating is the ave gas ?
i have used the Green stuff 110 octane and most of the time it was the pilot jet that needed to go up a size or 3
I have also mixed av-gas methanol and acetone and that was awesome but needed jetting allover.
If i could get ave gas now i would run it strait no mixing just sort the pilot jet

Cheers Matt
 
RE: fuel

Thanks Matt
I have tried full Avgas (unknown octane - used for small prop planes ) But it seemed to be shuddering , lurching, and with the concerns of the main bearings I haven't tried again. Also the avgas isn't an endless supply, more a favour I don't want to push too far. But you reckon change the pilot jet to ease the popping hey ? The toluene I use as this Opal fuel is gumming up in fuel systems and the toluene is good for that as well as for octane. I hope mixing the three doesn't do damage. I know it hates that opal by itself. Thanks for the help.
 
I am not fuel expert but I was always under the impression that avgas was a slow burning fuel designed for, among things steady rpm at around 2400 - this made it far from ideal in fast spinning engines so mixing was recommended.

I used to read some stuff by Rich Rohrich and even exchanged a few emails with him years ago - in my opinion he knows his way around fuel

Here is a link I found on the topic, though it is slanted towards 2 strokes...

http://forums.everything2stroke.com/art ... oline.html

Cheers

Mark
 
Yes , I had read here that slow burning was an issue and that to make it work (100% avgas) you had to change the timing considerably. It definately didn't like it ! Even if I mix it 60-40 it seems to lurch. I was more worried about the unknown to me opal fuel and its effect. There are reports of rubber hardening and gumming . I hope the avgas and toluene remedies this but I am not sure. It does make jetting a problem . Does anyone think that I should still get the Lineweaver kit ? It does seem to be rough down low and also a bit flat up top. I will take off the carb tomorrow and see what I have now. Orangeberg sold it first so it may have something non - standard. Thanks again.
While I'm here - is there a recommended place to buy blue pastics ( headlight and shrouds ) ? Cheers!
 
Chilledspode - I actually hadn't read the link you listed before my last post - sorry. Thanks, that is the best thing I've read about avgas yet. It does explain the slightly dissapointing performance. I've also got a 900ss Ducati here with twin 41fcr carbs and it seems to struggle with the upper revs. There was one guy there - a two stroke plane pilot , who said he found poor response and lost top end revs until he 'leaned the mains and set the needle down a notch'. I tried lifting the needle before which didn't seem to help, so tomorrow I'll drop the needle a notch and check out the mains size. And I'll read up on how to adjust that screw at the bottom of the carb. The popping with this Akro is embarrasing. Thanks.
 
The "blue" avgas that you are getting is 100 octane low lead or 100LL as it is known. It should be marked on the pump that is dispensing it.

And toluene can be extremely destructive to the rubber, and synthetic rubber in your carb, I think anything above 10 or 15% of this is going to get you into trouble.

I may have overlooked it, but, I haven't seen in your posts what jetting you are currently running.

The popping on decel is caused either by a lean condition, or by leaks in your exhaust system. The lean condition can be cured with a thinner needle straight, richer pilot, or by raising the needle.

Is race gas available in your area? I think you are going to have to nail down a particular fuel, and stick with it and then jet accordingly.

What does your plug look like?

Get back to us on what jet's and needle you are running and let's go from there.
 
Hello -I've found a needle marked as OBEKR - it's not standard is it ? The mains is a 160 . But what is weird is the plug which has a fairly clean yet yellowish ceramic area and a black soot mark around only half of the circumference . It looks strange - like a flow is going past it leaving the back half clean. Any ideas ?

Something else - I had bought a pipe from England on Ebay, payed for start of November last. Didn't arrive , so after 4 months bought the Akro slip on. Yesterday the pipe from England arrived after a 5 month journey. I have two pipes now. The other is a full FP system with stainless end pipe. The headers are quite a lot larger than standard and Am assuming the rear to be 60mm, over the Akro's 50mm. Has anyone got an opinion on the two ?
I know this is novice - the pilot jet must be inside the bowl right ? Thanks.
 
goatman said:
Hello -I've found a needle marked as OBEKR - it's not standard is it ? The mains is a 160 . But what is weird is the plug which has a fairly clean yet yellowish ceramic area and a black soot mark around only half of the circumference . It looks strange - like a flow is going past it leaving the back half clean. Any ideas ?

Something else - I had bought a pipe from England on Ebay, payed for start of November last. Didn't arrive , so after 4 months bought the Akro slip on. Yesterday the pipe from England arrived after a 5 month journey. I have two pipes now. The other is a full FP system with stainless end pipe. The headers are quite a lot larger than standard and Am assuming the rear to be 60mm, over the Akro's 50mm. Has anyone got an opinion on the two ?
I know this is novice - the pilot jet must be inside the bowl right ? Thanks.
Click to expand...

The pilot jet is in a recess on the engine side of the main. Pull it and see what the number is. The EKR and 160 main sound about right, although the needle might be a tad rich.

Better yet, download the owners manual, and repair manual from the husaberg.se for free, and have a look at where everything is.

The black area on the plug probably occured when you started it and only let it run a short time, without really riding it, or just riding slowly when you got back to the truck. The true reading is the yellowish color further down inside the plug. And by the sounds of it, it looks as though it's pretty close. But, get back to us on the pilot jet, and fms position.

What have you come up with as far as a consistent fuel supply?
 
hello - where I live is a remote island where there is only one fuel pump , and it has only this Opal rubbish. It's also against the rules to barge any other fuel in, which is why I'm stuck with trying to make a decent fuel out of what I can fid - I'm not doing it for performance.

I've found the pilot is size 38 and the screw in the bottom of the carb was only out just over half a turn. So I will order a couple of bigger pilots and see how I go. Does anyone recomend a needle other than the one I have now or Lineweavers ? Oh, and what is the FMS ? Thanks !
 
goatman said:
hello - where I live is a remote island where there is only one fuel pump , and it has only this Opal rubbish. It's also against the rules to barge any other fuel in, which is why I'm stuck with trying to make a decent fuel out of what I can fid - I'm not doing it for performance.

I've found the pilot is size 38 and the screw in the bottom of the carb was only out just over half a turn. So I will order a couple of bigger pilots and see how I go. Does anyone recomend a needle other than the one I have now or Lineweavers ? Oh, and what is the FMS ? Thanks !
Click to expand...

Too bad about the fuel situation. If you can, see if you can secure Av Gas by the drum (as in 55 gallons)and you won't have to sneak about, as I'm assuming that you have an air field on the island. Then you can jet for it and be done with it, as the fuel supply will then be consistent and not at the mercy of political agenda's.

The FMS is the little screw on the bottom of the carb towards the engine side of the float bowl. FMS stand for fuel metering screw.
 
so where is groote? northern territory in australia?

the plug will be black on one side due to oil i think.

i wouldn't blame the plug or guess jetting from viewing it.

i suggest you try the FMS out at 1.5 turns and try half a turn either way. the 38PJ is fine and there's a heep of us here running it. the needle is fine possibly a little rich on tickover.

the PJ is beside the MJ and so is the choke jet. the holy trinity all in a line abreast!

160-165MJ will do. needle must be tested to suit.

regards

Taffy
 
Carburation / fuel concerns

For anyone willing to experiment with carb replacement I ran across this working (?) EFI website, http://www.microsquirt.info/, which lists MC usage in it's forums. You would have to be willing to due a lot of fabrication and experimenting but this might be a frontier worth exploring. :idea: J2u
 
RE: Carburation / fuel concerns

Thanks again - Groote Eylandt is in the gulf at the top of Australia , east of Darwin - mine manganese here. It's a big island which is pristine beside the small area they mine, heaps of riding, lots of crocodiles !! Two people have been eaten here that I know of, one a couple of years ago. Two weeks ago a miner got really drunk on rum and swam out to a croc trap as two crocs were swimming nearby. The cops came and shot at the crocs enough to scare them away. The miner came in and was really angry at the cops for endangering the crocs. He got sent from the lease . Made the papers .
Just finished putting the FP system on and dropped the needle one. Set Fms as per Taffy's suggestion - will adjust later. I love this Fp pipe with the big headers, looks beefy and well made - English ? Pitty the slip on is heavy , though lighter than standard. The Akro is much lighter but I can't fit it to the headers. Decisions!! Anyone got the FP in titanium for sale ? Thanks again for the help.
 
RE: Carburation / fuel concerns

I have to admire your persistance under those conditions of fuel supply. Bear in mind that all usual recommendations of carb settings assume gasoline quality with normal distillation curves and vapor pressure. By using avgas for upgrading octane, you'll have to "blend your own" to get the other specs. right. I'd use butane or propane to increase vapor pressure and initial boiling point because you are probably not getting the fuel to burn properly for the demands of your engine. You could also use NGL's (natural gas liquids) to accomplish the same thing. I know there is a huge natural gas production and processing facility on the Northwest Shelf and they condense a lot of NGL's from the gas they produce.

If you have to blend propane or butane, get assistance as it's a bit tricky and dangerous, but hey, you are obviously very resourceful!
 
RE: Carburation / fuel concerns

Hello - went for a ride today after dropping the needle one and turning out the fms to just over one and a half, though done in conjuction with switching to the full FP system -- much much betterer ! It is only popping a bit now , quite acceptable, and the bottom end is full and smooth. So, not doing things singularly, I don't know what is responsible for the improvement, though the jetting probably the main factor. Even so I love this pipe - sounds really deep and the headers are fat and snake around in two seperate pipes right to the first frame rail.

So butane, I've eyed some of that sitting in the storehouse, what is hard/ dangerous about blending it with avgas ? Do you mean as in to damage the motor or as in I might blow myself up ? Should I throw a litre in and see what happens ? Thanks for all the help !!
 
RE: Carburation / fuel concerns

i don't really know for sure but i would have said that 25/30% avgas is all you need. avgas slows the flame down and makes the bike run cooler. it does not add power. what it allows you to do is up the compression ratio FROM WHICH i said FROM WHICH you THEN THEN get more power!!!

so use the shyte they have and add a little AVGAS if any....

regards

Taffy
 
RE: Carburation / fuel concerns

Yes, that's about where it seems best. Am very happy with it now with the jetting sorted.

Thanks again!!
 
RE: Carburation / fuel concerns

Hey Goatman where did you get the the FP exhaust from as i whant one as well
cheers matt
 
RE: Carburation / fuel concerns

Matt - I bought it on ebay , England. It took five months to arrive, so if you ever do similar only use express post ! I gave up and bought an Akro slipon instead which is now sitting around. All the best .
 

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