Top end Rebuild Finished now engine wont move

cafenoir

cafenoir

Cafe Noir
Assembled engine and used lots of assembly lube and the engine moved freely after back together.... with the engine installed on the bike I tried to put the starter back on and the engine was very difficult to turn over.... now cant get it to budge... any suggestions... I havent touched the valves if the valves are completely untuned and are shut on the exhaust stroke no matter what .... would this cause the engine to have to much compression... also I installed the points plate and it was pretty hard to get on .... Im baffled by the fact that I cant turn it over.
 
Can chain was off but held up with string and when I put it back together it initially moved freely ... I installed the cam sprocket while the timing was on the LT mark and the l in the can sprocket in the correct position
 
Is it in gear and the clutch plates are just slipping? Is the stator cover on? Is the stator on the case correctly?
 
No, the valves being shut would not cause too much compression for the engine to turn over, that is how they work... but should only be on the COMPRESSION stroke. What makes you think they are closed on the exhaust stroke?
If they are your cam timing is out. You say the engine turned free after assembly. Complete assembly?
But then turned hard when you tried to install the starter... what did you do between those two steps?
I would pull the spark plugs and remove the stator cover and put a wrench on the rotor bolt. Then gently try to turn it over by hand. If a valve is hitting a piston because the cam timing is out, you can bend / break things... BAD things.
 
Ok I installed the spark advance mechanism and points plate and In theory if I installed the cam incorrectly theoretically can't I just remove all necessary parts and then flip the cam so that it's on the right stroke ?
 
Not sure I am following your question... A crankshaft is stupid. It doesn't know if it is on TDC of compression stroke or exhaust stroke until you put the cam in. In 360 degrees of crankshaft rotation you only get 180 of camshaft rotation.
Make sence?
 
Yeah makes sense.... hopefully I can get this right without pulling the engine again .... wish me luck .... hopefully the valves didnt damage the piston...
 
If the camis 180 degrees out it would only make the bike not run. Valves should not be touching pistons when cam is 180 of. One tooth off would still be possible for some bikes, more then 1 will be problematic.
As the engine did turn when it was on the bench, i guess we can rule out cam/timing.

Few things to check;
is it in gear?
is the clutch properly adjusted?
did you do something other then just 'putting 'er in the frame?
 
it's not immediately obvious from your comments if the cam is incorrectly timed or if there's another problem. I'd start by checking cam timing and see if the valves and pistons have been intimate.

If that's OK, remove the starter and see if there's anything wrong there. Sounds like cam timing though.
 
I assumed that the bike did not slip into gear but never checked... if thats the case I will be a happy camper.... and it would make a lot of sense. hopefully this is the case... and no damage done guys.
 
cafenoir said:
I assumed that the bike did not slip into gear but never checked... if thats the case I will be a happy camper.... and it would make a lot of sense. hopefully this is the case... and no damage done guys.
Click to expand...

would be very stupid though :)
 
Re: Re: Top end Rebuild Finished now engine wont move

Bert Jan said:
would be very stupid though :)
Click to expand...

Hey, if it's the "free" stupid rather than the "expensive" stupid, that's cool.
 
Re: Re: Top end Rebuild Finished now engine wont move

Rich Ard said:
Hey, if it's the "free" stupid rather than the "expensive" stupid, that's cool.
Click to expand...

Yeah, i hate the expensive one too!
 
You must log in or register to reply here.

DTT Light or Dark

  • DTT Light

    • Spread the Love

    Back
    Top Bottom