whilst changing the belts this happened... the mark on the r/h pulley was never totally on the casing mark, but i'm sure it wasn't this far off.. i've changed the belts many times before and never had an issue, but this time i'm pretty sure i heard a clunk when the 2nd belt came off(this cylinder). i've turned it over manually to make sure nothing hits anything else then tried it on the starter with the plugs out and there was no calamity. but the bike only ran on 1, so i'm guessing this has something to do with it... any thoughts on how to resolve this?
It definitely shouldn't be like that, the marks are not spot-on on mine but they're no more than 1/2 tooth out. If there's been any piston to valve contact under any sort of power (even the starter motor) then I'd be taking the head off to check for damage/bent valve.
Have those pulleys been off lately? The nuts look quite new. The pulley could have slipped off the key if it was dislodged as the pulley was fitted. Also, as an aside, the tensioner looks to have been tensioned clockwise. It should go anticlockwise so as to reduce the risk of the belt touching at the point between the pulleys. Whatever, I'd have the belt off and set it up again. If the pulleys have been off, I'd check the security and the keyways
i'm ok with taking the belt off an re doing it, but can i turn the pulley back to where it should be?? do i need to turn it clockwise or anti?? how will i know if it's in the right place?? just by turning over manually to make sure nothing touches or is there a better way?? i have never messed with desmo valves before
Start again with belt replacement procedure it looks like you didn't align the cam when putting the belt on. Some of the cams will rotate (vertical cylinder inlet cam from memory as per pic you took) when the belt is removed. There are a few guides on how to : heres one for reference. 916 Belt Change
That is indeed the cam that will spring one way or the other when trying to fit the belt, you can get a bracket thing that holds it whilst you fit the belt but either way you should double-check (and check again) that it is right before turning the engine and not 5 teeth out. OP doesn't sound too confident, it maybe time to take it to a pro before any serious damage is done (if not already)?...
Align the motor to its marks on the double pulley, then see where the cam mark is. I'd remove that belt and pulley and check the keyway. You can rotate the cams by hand so don't worry about that. The cams, if not in the correct place, will move around themselves when the belts are removed, so it's always best to check that hasn't happened when the new belts are fitted.
don't bring it here, just payd a "pro" to put a head on a bmw didn't time it correctly. at least two snapped valves. i am just managing to keep the heed. just.
You were very lucky that it turned over without a piston/valve interface because that could have been very expensive to sort. I suppose it depends which way it's out as to whether contact is made, but 5 teeth is a significant amount to be wrong by - buy a lottery ticket this week because with your luck you're bound to win.
