Starters & Stators??

Incidently

BTW my bike has never started via the kick start system so good since I have owned it. And the plug colour was a beautiful brown colour after our ride on the w/end.

Scully, I just checked my valve travel with a small steel rule. It measures about 1mm.

As you may have read in the past, the decomp lobe protrudes out of the cam by 0.7 - 0.75mm, it actuates the exhaust valve momentarily while the piston is on the compression stroke. Its generally a pain to measure hence my suggestion to just measure the travel at the valve.

As I mentioned previously, remove the exhaust valve inspection cover and stator cover. With a 17mm socket, rotate the crank while watching the exhaust valve. When the timing marks on the flywheel are around 10 or 11 o'clock you will see the exhaust valve open and close over a fairly short duration. Its the travel in the valve you want to measure.
You can stand the end of a steel rule on the edge of the inspection hole opening to hold it steady.

Its a quick check and will hopefully rule one potential cause of your problem out.

Good luck.

Taffy said:

scully

your brother will have told you to connect one battery on to the other and that is -thankjfully - 12 volts. you don't wanna see 24 volts!

it gets ugly. but i get your drift and good luck. i hate electrics.

Taffy

Click to expand...

Yes I do want to see 24 volts, but only WHEN initially starting and only on the s/motor! If you place the other battery in the line that connects to the solenoid you get 24 volts at the starter only and 12 volts else where. I beleive I need to have a QUICK go at this to prove the theory that the motor isnt cranking fast enough? I wish I had a small 6 volt battery just to limit the potential damage.

twistthethrottle said:

Scully, I just checked my valve travel with a small steel rule. It measures about 1mm.

As you may have read in the past, the decomp lobe protrudes out of the cam by 0.7 - 0.75mm, it actuates the exhaust valve momentarily while the piston is on the compression stroke. Its generally a pain to measure hence my suggestion to just measure the travel at the valve.

As I mentioned previously, remove the exhaust valve inspection cover and stator cover. With a 17mm socket, rotate the crank while watching the exhaust valve. When the timing marks on the flywheel are around 10 or 11 o'clock you will see the exhaust valve open and close over a fairly short duration. Its the travel in the valve you want to measure.
You can stand the end of a steel rule on the edge of the inspection hole opening to hold it steady.

Its a quick check and will hopefully rule one potential cause of your problem out.

Good luck.

Click to expand...

I will try to give this a go B, thanks again.

Well it seems my brother does have a dial indicator, I will get it tomorrow.
Today I hooked up with 24 volts, and yes I got an excellent spark!!!!! But by the time I put the plug back in and tried to start it again( fired up once) the batteries were almost flat?????????? Took them out and had them load tested, and the newest one is buggered? So this might be the problem all along. When I was testing the spark size I measured the voltage across the starter and it got down to 1.2 volts?? "something wrong here"?? Well that new battery only lasted a year? So now I am trying to get a XTZ7S but one Battery shop says thet arent available to the public yet? And the other one say he could get a generic brand but none available at the moment?? Bad luck again?
So after all this crap the Berg MIGHT start off one battery now? I still think I may have a small problem with the auto decomp as I had to touch the lever in to get it to fire up ages ago?
I will get there eventually, I really would like to race in a pony express on Sunday.

Yuasa YTZ7S dimensions are 113mm X 79mm X 105mm so this means that it will not fit our Bergs?? As the old batteries are 71mm wide not 79mm? I suppose we need the 04 model battery box?

Scully said:

Yuasa YTZ7S dimensions are 113mm X 79mm X 105mm so this means that it will not fit our Bergs?? As the old batteries are 71mm wide not 79mm? I suppose we need the 04 model battery box?

Click to expand...

Scully, the YTZ7S drops straight in. I put one in my bike about 9 months ago. The battery dealer is correct, Yuasa don't bring the battery into Australia.

Your options are.
1) Buy the battery from your Husaberg dealer.
2) I have heard that the WR450 uses the same battery but they give it a proprietary part number. You could get the battery from a Yamaha dealer but to be sure, take your old battery along with you and compare the size.

Brian,
According to the Yuasa web site the WR450 ues a YTX5L-BS which is the same dimensions as my battery box. I wonder if your 03 Berg has a larger battery box or the dimensions of the battery on the web site are wrong?
It looks more and more like I have a decomp problem. I did get it to go twice this morning off the car but I had to get the manual decomp just perfect or it gets to much compression. What is involved with "fixing" the decomp mechanism? Does the head have to come off? I think the KTM's have a bolt and nut assy on the cam?
See ya

Sounds like the Yamaha battery won't fit. My battery box is the same as yours so it looks like your only option on the YTZ7S is the Berg dealer.

First check for the 1mm valve movement per the previous post, if it doesn't have the travel then...........

You don't need to remove the head. Its a matter of removing the valve cover (note where the different length bolts go) then undo the cam chain and lift the cam out. Very straight forward.

My cam chain had a joining link in it, don't know if this is standard but have a look as it makes the job very easy.
First you have to remove the mid section of the exhaust, then remove the centre bolt/spring on the cam chain tensioner and then unbolt the cam chain tensioner.

Mark the timing sprocket tooth that lines up with the joining link then carefully remove the link. While keping a little tension on the chain so it doesn't come of the bottom sprocket, I threaded some thin wire through the chain at each end and tied it to the bike.

To measure the decomp, rotate it so that it protrudes above the cam, it should protrude by at least 0.7mm.

If it is below 0.7mm you can probably get more out of it by adding a dab of weld to the inside of the arm where it contacts the cam. You should be able to see where the weld was placed originally as this is the normal procedure for adjusting the decomp. Aim for a lift of 0.75-0.8mm.
Please don't try for a higher lift as it wont work on the 02 model!!!

If the lobe is badly worn you should replace the decomp device, expect to pay around $125. Even with the new decomp you will probably have to add/grind weld to get the correct lift.

After the cam chain is refitted, to install the cam chain tensioner, leave the centre bolt/spring out. Lift the little pawl and push the tensioner all the way into the body. Then bolt the tension onto the head and then fit the centre bolt/spring.

When refitting the valve cover (after cleaning it up) use a thin silicon sealant such as white 3-Bond. Thick sealants like Silastic can prevent the cover seating all the way down reducing the grip on the cam bearings.

If I have forgotten something I am sure someone will let us know.

I hope this helps.

Twisty
You mentioned not to go over 0.8mm lobe height on the '02 model. What is the best height for the pre2001 bikes - aka a '98 600?

I'd also add to NOT use Loctite 515 Master Gasket, or any other anaerobic sealant like it, on gasket faces that you want to mate accurately such as the rocker cover. It always props the two surfaces 0.005" to 0.010" apart, preventing the bearings being locked in place correctly. I use Permatex Aviation No.4 - a bitumen-like gasket compound.

Thanks for that Brian, I will have to check it first with the dial indicator(I should get on the w/end) but I'd bet it is wrong. This is the only thing that is different due to wear that is preventing it from starting like it use to.
I think we are misunderstanding each other re; the battery? The Yamaha is suppose to have the YTX5 battery which is the same size as my batt box and the YTZ7S is 8mm to wide to fit in the box?? I have one battery dealer whom has ONE but they wont order it "special" so I have to wait until mid June?
ps, I use 3 bond on everything.

Well today I ripped out the radiator and exhaust valve cover and stuck the dial indicator on the valve, and guess what? I have the movement in the exhaust valve the size of a bees dic! So this is my problem!!!!
I then pulled the r/cover off and you can visibly see the wear mark on the cam. I also checked the size of the movement with kicking and manual decomp, both 30 thou, no wonder it wont bloody start.
I am only guessing but has anyone ever welded a tab on the bolt that holds the cam gear on where the decomp cam almost sits up against?? Would this be easier? ( know what I mean??)
This was all I had time to do before afternoon shift so I will get into it this week.
Thanks for the advice Brian.Have you had a chance to measure your battery for me yet?

Scully, glad to hear you are getting on top of the problem.

1) Trust me, the YTZ7S will fit. Don't worry about the extra 8mm.

2) Regarding the weld. My bike has 3 bolts. 2 hold the sprocket onto the cam, the third is the stop bolt for the decomp. The decomp rests against this bolt during normal running, ie while the decomp isn't engaged. If this is the bolt you are refering to, adding weld wont help.
When the engine is at rest, the decomp is engaged by the spring, at this point the inside curve of the decomp arm is resting against the cam. Its at this point where the inside of the arm touches the cam that you need to add weld.

If the lobe is badly worn its probably worth fitting a new one. I have heard of guys adding weld to the lobe but that makes me nervous. The lobe takes a pounding and you don't want a piece of weld breaking off and doing major damage just to save 120 odd bucks.

Good luck Dale, hope this helps.

Brad said:

Twisty
You mentioned not to go over 0.8mm lobe height on the '02 model. What is the best height for the pre2001 bikes - aka a '98 600?

Click to expand...

Brad,
Here is the background for comming up with the 0.8mm.

When it came time to replace my decomp I read the old threads here on UHE. A few of the guys were raving about the improved starting by increasing the autodecomp lift to 1mm so that is what I aimed for. (I actually had about 0.95mm)

When I fitted the decomp, the bike would usually start well but other times the engine would do half a turn and lock. What I found was that the cam follower bearing was smacking into the decomp lobe and rotating it back out of the way. In effect it was like have no autodecomp at all and the engine would just stop spinning on the compression stroke.

I couldn't understand why it had worked for the other guys so I started going through the gallery of guys that had gone for the 1mm lift. I found they all had pre 2001 bikes and from the pictures the lobe appeared to be more rounded.

Now I don't know when the decomp lobe profile actually changed but I do know that the new decomp lobe wont work properly when the lift gets somewhere above 0.9mm.

To answer your original question, I suspect your bike would work fine and possibly start better with the 1mm lift.

I think I mentioned it previously but the factory spec for the lift is 0.75mm

Guys,
Don't know if you have seen this in the gallery but check it out.

Autodecomp Pictures

They show the older style decomp cam lobe. I would like to know why they changed it as the older style looks a lot more durable.

Brian,

Thanks for the pic's and info.
I have had a closer look today before work, no con link in my chain.
I understand how the decomp works but the older model seems to be better thought out. I was refering to the other end of the decomp lobe, the one that sits up against the cam when in the "normal" not running position. I think something could be done on this end, like a thread tapped into it and a bolt so you could adjust the lift when wear occurs, if there is enough of it left? Or you could make a little cam that could bolt on underneath the bolt that holds the cam sprocket in place and the lobe could rest against it when in the normal position, I hope all this makes sense?
I dont know what to do with mine. Its a pain in the arse to get apart without a conlink and I dont know how effective a weld will be?

scully

i hear ya on the weld idea and you appear to be right. i bought a used cam off scoot about 6 months ago and i got the auto decomp with it. in the inside of the curved bit was a blob of weld-about 1mm wide and it was obvious that this was how someone had dealt with it.

my record is that i welded a blob on the actual lobe and then had it ground down and shaped. the trouble is that the contact point moves from the leading edge to the dome in the middle. so instead of the roller "keeping the decomps head down" and in the decomp position it allows it to roll back and it doesn't decomp anymore.

that's why you get a two-speed starter motor. so i have converted mine completely back to manual decomp and nothing else. so as you can guess i've no extra rotational mass. i will be in charge of when and if it starts-i hope!

another thing to remember that hasn't been mentioned (i did on this subject when doing the weld mod) is that if the auto decomp used to bump at the leading edge of the 'bump', by welding a lobe that looks like a humped back bridge you are infact making the bump back near the middle.

aha! i hear you say, so what! but that's about 40 degrees at the crankshaft. 40d and we should be working to within 5-10d of the orignal auto decomp. 40d? jeez!

working on it all today so i can let you know of the decomp, battery fit, the lot.

PS why a new thread? all the info is HERE!

Taffy

Yes Taff, you appear to be right also!
The reason why I was asking the question regarding moving the lobe around to be in a different "starting" position was because of the leading edge is worn away. And by welding a blob on it you could easily change the timing of it decomping.( it would be to earlier than 10 o'clock)
How did you make it manual decomp to electrical start?????
I dont particularly want to pay a $125+ for a new mechanism when there must be a better way of solving this.
I started another thread to get MORE input as I dont think as many people read the Electrical threads?

Taffffffffff, just to clear up something here.
On the left hand side of the cam sprocket is where you find the decomp cam funny shaped thing. Well where it sits "idle" it rests on the actual cam, well if you move it slightly towards the rear it lifts up the leading edge of the decomp lobe! So if this could have a different "idle" position, maybe by making a "stop" that connects to the bolt that holds the sprocket to the cam?? Comprade??????

iwa swith ya until the last coupla words aussie and then ya lost me! too many tubes methinks!

the inner curve of the decomp swing arm. weld there! that'll keep the front edge of the decomp up. not only that but that face will become broader as it wears and therefore LESS liable to wear.

as to manual decomp; well you should have had one cable from the back of the kickstart housing, then you have the one we are presently on about-the auto decomp and then finally you should have a cable from the magura juice clutch over the bars and down vertically to the right of the engine. here is a boomerang shaped piece of shiny metal that pivots in the head. the cable attaches to this and upon you pulling it a bar pushes the exhaust rocker arm down and stops the valves seating.

please go look at a workshop manual in the downloads or if you have your own.

i started the bike once today and have a little task to redo which i won't bore you with. i never make mistakes now remember that!!!!!!!!!!!!

fuller picture at a later date.

hope this helps and er....lay off the beer scully!

Taffy