srx cam chain sprocket timing marks alignment query

[guest668]

hi i have just been putting cylinder head onto srx but have encountered a problem wiht the cam chain sprocket alignment marks.. After putting tension onto the camchain by putting finger through cam chain hole the alignment marks on the cam sprocket are meant to line up above the top of the cylinder head. However one side seems slightly raised to the other by about a mil...we have tried to correct this several times but it always ends up with one of the marks slightly raised higher than the other . I was wondering if anyone else has had same problem how critical is it ..could it be due to wear in the chain? i was looking in a xt600 manual i have and they say it must be aligned but then  they show a photo in which there marks are also tilted and not at an equal distance above top of cylinder head?  hope this makes sense any advice will be greatfully recieved.

ps all the other alignment marks line up ok just the horizontal marks on cam sproket that dont?

[Dick Scratcher]

Having done a fair bit of work on a 250RSA which sounds virtually the same design I would suspect a little cam-chain wear plus manufacturing engineering tolerances.

[guest668]

thanks for the reply so should i not worry to much about it and go for near as level as possible?

[guest668]

also just to check it is the dot on the cam shaft timingsprocket i should be checking against the mark on the crabkcase and not the T for top dead centre isnt it? the manual says the dot so ive been going with that but thought id better check just in case...thanks

[guest668]

heres a photo to illustrate problem

[attachment deleted by admin]

[Steve H]

It doesnt look far out, but I would have expected a stretched chain to move the timing in the opposite direction. Have you tried fitting the camchain tensioner and rotating the engine a few times, it maybe that the load exerted by just pushing the tensioner is insufficient.
Also did you use a Yamaha head gasket or a copy ?. If a thicker head gasket were used then the timing would move in the direction it has. 

[guest668]

we have tried adjusting it several times and it either sits like this or the same difference but on the opposite side i used genuine yamaha parts. Shoutl i set it up to er more towards intake side then? many thanks steve

[guest668]

also can anyone tell me if i should be setting the timing using the t mark on the crank or the dot...the manual says dot but i would have thought it would be the t?

[guest668]

oh and another thing do i need to readjust the cam tensioner before refitting it and how do i do this....is it just a case of loosening the nut on the tensioner

[Steve H]

oh and another thing do i need to readjust the cam tensioner before refitting it and how do i do this....is it just a case of loosening the nut on the tensioner

I would use a wooden rod or similar down the spark plug hole to determine TDC. I think the manual mentions the spot because in general, when building an engine, the flywheel and cover will not be fitted at this point of assembly.
In order to fit the tensioner, I would

• Remove the cap retaining the spring
• De-adjust the tensioner by releasing the ratchet
• Refit the tensioner body without the spring and cap
• Refit the spring and cap, this will tension the chain
• Rotate the engine several revolutions

[guest668]

thanks steve tried your suggestions and it looks like a stretched chain still...what is the procedure for changine the chain is it just a case of removing the alternator rotor or is it more involved...and where can i get a puuler from does it have to be the yamaha one?

[guest295]

On bikes I've had, T was for Time and the mark is for top. Yours may be different. The cam chain can be replaced without disturbing the bottom. Get a new one with split link, pop the old one with a chain splitter and attach it to the new one, pull on the old one until the new one comes up. Bob's yer proverbial. Takes half an hour.

[Steve H]

The alternator can be difficult to remove. I usually use an air hammer on the nut, you can use any puller which uses the three tapped holes in the flywheel (I think a mini flywheel puller works but dont quote me). I would also recommend leaving the camchain fitted whilst removing the alternator as its easy to damage casting that the camchain tensioner locates in.

[guest668]

thanks for the advice wil have a go at the alternator next week...my sons got a mini flywheel puller so will let you know how we get on....dont like the idea of split links on a camchain though !! will see how we get on.
THanks for all the advice

[Steve Lake]

It is possible that the cam chain sprocket on the crankshaft has moved.... as it is fitted using the hot/cold process, and there is no keyway for exact location.... never happened to me, but just a thought.