Think I might have slipped a tooth on my cam chain

[jonnyjameswalker]

Hello there, I have just recently bought a 2002 Firestorm, I thought I could hear the dreaded chain rattling and had already read up about this problem before, so I ordered some manual cct's and a Haynes manual, Im quite handy on the spanners, and am just looking for some reassurance about whats happened! I followed Haynes instructions, and have since been told that I should have found the TDC on each cylinder before replacing the cct! Now when Im holding a steady throttle at roughly 30mph 'ish in 2nd or 3rd and neither accelerating or decelerating the engine keeps misfiring until I change my throttle! I spoke to somebody and the said I could have slipped a tooth when i removed the old cct's, I have removed the rocker covers, and checked the timing marks, the rear is fine and all matches up perfectly, the front however, when the crank shaft is at TDC alignment, both of the cams are slightly out, i.e. not level with the top of the head, I think the chain might have slipped a tooth at the crank shaft end.

So....I assume this is my problem, can remove both camshafts, keep the chain tight and turn the engine through two rotations until its perfectly lined up at TDC again then re-align my cams? would this work? hope somebody can help :-)

[benny hedges]

yeh m8 the haynes is very misleading, youre not the first & wont be the last lol.
use the guide in the workshop knowledgebase on replacing tensioners.
follow it step by step to the letter.

it wont have slipped at the crank end... if it wasnt at the correct tdc position with the valves closed on the compression stroke then it will have jumped a tooth on the cam gear.
it is very important to differentiate between tdc on the exhaust stroke & tdc on the compression stroke, as on the exhaust stroke the exhaust valves will be open and the cams have spring tension trying to spin them back, which makes the chain jump the gear if the tensioner fails or you remove it to fit a new one.

recommend you remove BOTH cam covers to be 100% it is right before starting the engine again.
you need to set the correct tdc position then remove the cct, then remove one camshaft and jog the other round to the correct position, with tension on the non-tensioner side of the chain, then refit the cam you removed, in the correct position.
refit the tensioner, then rotate the crank to the correct tdc on the other cylinder and do the same.
chances are you timed it up 180 degrees out if you followed the haynes manual.
the gear marks dont always line up exactly with the head depending on chain wear, but there is a massive difference between chain wear and being a tooth out, so you will know when you check them.
it wont take you long.
dont take any shortcuts - there arent any lol!
good luck - post back when it's right!

[jonnyjameswalker]

Hi thanks for he reply, I have been riding the bike today and have only stripped the cam covers off so far, and stopped there til i got some advice, you say the marks on the cams might not align completely, both are about 5mm (not quite a full tooth) out from the cylinder head, this is why I thought I'd slipped a tooth at the bottom end, because if I were too move them around to the next tooth, it would be too far, if you understand me?

if its not the timing that is causing this new misfire, what could it be then as it only started to do it since I replaced the CCT's

[AMCQ46]

1 tooth is the same no mater it it is the cam or the crank, it is one chain link!

5mm sounds close enough, and the front is a bugger to see even with a mirror. sound like a chance that you distrurbed something else when you had teh tank off.

Vac hoses, or trapped a fuel line, or missing hose on teh airbox, or carb not seating ?

[benny hedges]

Vac hoses, or trapped a fuel line, or missing hose on teh airbox, or carb not seating ?

or forgot to clip the throttle sensor back on

i rode down the road on mine once after messing with it and forgot to do up the rubbers.... the carbs came completely off lol.
i wondered why it suddenly went loud and died on me