teeth & pins



4 replies to this topic
  • Taffy

Posted August 12, 2000 - 12:13 PM

#1

i just had a sod of a time starting the bike, lost compression, kicked over like a two stroke. i've just looked at the cam timing ahead of changing it on holiday & found the camwheels weren't in line. i retarded the exhaust cam one tooth & now the difference is 12 pins & not 13. the camwheels now sit pretty much as per book-although both appear tilted slightly. at least they're (nearer)in unison. started first time. all i'd done was dry the plug & change the cam timing. could the cam timing really have altered just by kicking the bike over this morning?

tried to start the bike with trainers on & paid the price by flooding it i guess. i'm really fed up. H & H tomorrow, it's now 10.05pm & i've yet to load up. it least it just thrashed up & down the estate ok.

questions!
if the cams don't line up with the top of the head perfectly should they be in advance slightly (as i expect) & rocked slightly anti-clockwise- or not?
how many pins twixt marks before & after the yz timing change?
why have i lost that solid wall as i gently roll it over to TDC (which i can no longer find even)& yet it just rolled up the road ok?

going to give it a bloody good thrashing tomorrow with my stealy 10oz weight fitted but standard top end. will it go pop?

  • Clark_Mason

Posted August 12, 2000 - 12:48 PM

#2

Taffy

How old is you bike and does it have a few miles on it. If so the cam chain will strech and the marks will not be as perfect as they were when new, but they will not be far off.

With the piston a TDC as indicated by the mark in the timing window the intake cam punch mark at the 3 0'clock position should be vary close to lined up perfectly with the flat surface of the head while you push in the cam chain adjuster hole with you finger a to remove the slack KEEP IT AT TDC while doing this--it does take multi talent.

Now once this is perfect put a zip tie on the intake cam and chain so it cannot move and adjust the location of the exhaust cam sprocket. If there are 13 pins in between the top mark on each cam sprocket it is WR timing. If there are 12 pins between the top punch marks on each cam it is YZ timing.

Now bolt down the cam towers not forgetting the cam holding / alignment clips on the top of each cam sprockett bearing. put the cam chain tensioner in, activate the tensioner, and put the engine at TDC as indicated by the mark in the mag timing cover viewing hole. Look at the cam marks the intake 3 o'clock punch mark should be pretty damn close to dead level with the flat surface of the head. The exahust top cam timing mark should be 12 YZ or 13 WR pins away. If it is WR timing 13 pins then the 9 o'clock punch mark on the exhaust cam should be real close to even with the top of the head. If YZ timing 12 pins bwteen the top punch marks on the cam sprockets then the 9 o'clock punch mark on the exhaust cam will be slighly above the top of the head surface. Remove the ZIP TIE.

If you follow the above your compression should be just fine.

Hope this helps

Clark

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • MotoGreg

Posted August 12, 2000 - 03:34 PM

#3

Did you check the cam timing because of the loss of compression or did you do something to the cams and then it wouldn't start?

If you just had a loss of compression, it's probably just flooded. Did you just oil your air filter and then try and start it too soon? If so it's easy to flood and you'll be able to kick it over past TDC pretty easily.

------------------
MotoGreg - The voice of absurdity
'99 WR400 - 'Cause thumpers rule and two-strokes drool!
'92 GSXR 7/11 (But I wanna get a dope 916)
I might let you visit my photo album for $3 - ENTER AT YOUR OWN RISK - DANGER LURKS WITHIN

  • James_Dean

Posted August 12, 2000 - 08:21 PM

#4

Taffy,
I had the low compression symptom that Motogreg described. Kicked over like a 2-stroke like you said, was worried but compression came back starting it later. Hope all goes well.
James

  • Taffy

Posted August 13, 2000 - 10:08 AM

#5

three very well put together responses, thanks lads. clark, i've got to try & remember last night but here goes.

the lack of compression made me have a look at the cams; somebody once fell off their YZ & had the cams move so i thought i would check. if anything the exhaust cam was advanced as far as the marks went, the inlet was slightly retarded. so i decided to go to the 12 pins there & then by retarding the exhaust cam.

the bike is a Sept 99 with one day a weekend thrashing on it. hard practice & not much dualsport due to trying to get my skill level up.

on reflection the thing was just wet on the plug-no sneekers (as you call them) from now on.

so how did it go today?

yeeeehaaaaaa!!!

i passed all the usual suspects, beat my mate on his 250EXC for the first time & came in the top 15%. loads of compliments from friends on how well i was riding etc.

the track was a 4 1/2 mile course rock hard & covered in 1' deep long grass. the bike started first time & had it's compression "wall" back!

i could not believe the power. with the WR you do not have to be subtle but it took me 30 mins to learn how to control the power surge. wet long grass & a few graceful 270%'s & on my arse! in the afternoon though...

the flywheel weight (10oz stealy) was amazing! i was hitting walls of hardened dirt dropping the bike into troughs & gunning it & it didn't stall.

on my opening lap i normally stall it 6 or 7 times & i'm out of it. not today, you could do anything with it off tickover. both alterations were brilliant.

i would go as far as to say that every novice rider who stalls & falls a lot should fit one of these to help them.

James i know i'm dead lucky, the bike ran 168 MJ, 45 PJ, standard Exhaust, WB filter, standard needle setting & i think it wouldn't mind a 48 PJ-that's all i could feel.

what with the Clarke tank & Ceet seat i definately had a red letter day today.

oh! & JD i got the forks back from Gold valve uk & they were superb.

motogreg you must be claire voyant in disguise!




 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.