Motor will not rotate freely after valve adjustment | GTAMotorcycle.com

Motor will not rotate freely after valve adjustment

mistersouthpaw

mistersouthpaw

Well-known member
So I have adjusted the valve clearances on my en500. I followed the manual and a step by step, rotated motor to tdc (denoted as position c), adjusted side one and then rotated the motor to position f and adjusted side two as stated in the manual and the walk through.

Before this the motor would fully rotate in either direction

After adjusting side two I wanted to just double check the clearances on side one and attempted to rotate the motor to c again and the motor would no longer fully rotate. It was able to see position c in the viewing window but the cam lobes were not facing up and the gear market indicators would not line up. The motor would then only rotate one half turn counter clockwise and one full turn clockwise and would lock. It would lock as if it could not be rotated further (as if I bolt had been threaded all the way in)

The motor has a zero balance crankshaft.

Any ideas?


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The rotation stops and locks at the exact same position in each direction. It does not seem as if there is a kink in the chain or something lodged in there that was dropped in.

@matt rain is stumped and says this is out of his league

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Did you turn the engine against its normal direction of rotation?

Bad, bad, bad. The tensioner for the timing chain is not designed to allow that. Always turn the engine in the normal direction of rotation so that you are not fighting the tensioner.

I think the EN500 engine is the same as the EX500 engine ... the tensioner is on the front of the engine and it spins "backwards".

Recheck the cam timing. The instructions are in the section on how to remove and install the camshafts. You may have made the timing chain jump a tooth.

Don't forget, if you remove the tensioner, you have to retract the tensioner and hold it retracted while bolting it to the engine, then let it go. I think that engine has a screw-type tensioner. You take a screw off the end then you turn a small flat-blade screwdriver inserted into the end while pushing the end of the tensioner in to retract it. You're supposed to use a special locking tool to hold it from (spring-loaded) spinning while re-installing it, but you can use the screwdriver for that, just hold it in place and don't let it spring out.
 
I definitely rotated it the wrong way. This seems like a job I should not attempt to fix myself

Thanks for the helpful response

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Brian P said:
Did you turn the engine against its normal direction of rotation?

Bad, bad, bad. The tensioner for the timing chain is not designed to allow that. Always turn the engine in the normal direction of rotation so that you are not fighting the tensioner.

I think the EN500 engine is the same as the EX500 engine ... the tensioner is on the front of the engine and it spins "backwards".

Recheck the cam timing. The instructions are in the section on how to remove and install the camshafts. You may have made the timing chain jump a tooth.

Don't forget, if you remove the tensioner, you have to retract the tensioner and hold it retracted while bolting it to the engine, then let it go. I think that engine has a screw-type tensioner. You take a screw off the end then you turn a small flat-blade screwdriver inserted into the end while pushing the end of the tensioner in to retract it. You're supposed to use a special locking tool to hold it from (spring-loaded) spinning while re-installing it, but you can use the screwdriver for that, just hold it in place and don't let it spring out.
Click to expand...

Edit: small dowel fell in.. Have to give a shoutout to Tom and cyclewerx for saving my ass on this one
 
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mistersouthpaw said:
I definitely rotated it the wrong way. This seems like a job I should not attempt to fix myself

Thanks for the helpful response

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Click to expand...

definitely not, a botched valve adjustment especially when you don't know exactly what you're doing can be very costly. I blew my engine having done something similar and it probably would have cost me a couple thousand bucks but I was lucky and my extended warranty saved my butt.
 
LoneRonin said:
definitely not, a botched valve adjustment especially when you don't know exactly what you're doing can be very costly. I blew my engine having done something similar and it probably would have cost me a couple thousand bucks but I was lucky and my extended warranty saved my butt.
Click to expand...

Yea.. Well it turns out that the timing was fine and a little dowel had fallen in the cam chain when I removed the valve cover. I was sure nothing had fallen in but it did. My guess is that it stuck it the valve cover and fell off as I was taking the cover off. Tom at Cyclewerx was able to get it out with a magnet.. It was touch and go for a bit there but all is good now lol

Had I not taken this photo id probably not noticed the dowel missing

bc832f68b835f3649afe1d8bf7edaf29.jpg
 
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i hope you no there is no need to remove the cams with an engine such as yours,
 
Your engine has screw-and-locknut clearance adjustment.

Quite a few other engines use a bucket-and-shim method with the shim trapped underneath between the bucket and the top of the valve. If you have to make a clearance adjustment, you have to change that shim to a different thickness, and the camshafts have to come out in order to do that.
 
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