Tight Timing Chain

crawford · 10-15-2017, 10:10 AM

Did you check old parts with new? There really shouldn't be a big difference between old and new it really sounds like there is a wrong part to me to be that tight.

GrouchyOle'Man · 10-15-2017, 01:56 PM

Hi Crawford, I suspected a timing issue with this engine as it was not drawing fuel out of the carburetor; so it had a no-start condition. I have installed a few new parts, but no new engine parts. Today I found a blue link on the timing chain that would not rotate as easily as all the other links and was kinked. I straightened it out. I do not know if the chain was ever tampered with. Everything is as I found it except the cylinder base gasket and head gasket which I replaced since I had the top end of the motor off. They were identical to the ones they replaced. Even after straightening out the blue link, the same situation exists. The inside cam bearing is above the journal it rides on about 1/2". Also, I cannot properly set the cam in correct timing position. It is always off by one tooth. Either side of the sprocket, I get the same result. Off one tooth and camshaft not seating. So, the only parts to compare OLD to NEW are the 2 gaskets and chain guides. I may opt for counting the links in the chain to see if one was previously removed to facilitate tightening up the chain. I do not know yet if a new chain will fix this. The gear on the crank the chain rides on is suspect also. I fear it is quite worn. This scoot has over 11K miles on it according to the odometer.
Again, this is with the automatic chain tensioner NOT installed. The old timing chain guides had some damage to them and I replaced them. I initially thought a piece of plastic off the bottom of the lower guide was stuck in the timing chain gear on the crankshaft, then I found the kink in the blue link. At any rate, the chain seems to be too short to properly reinstall.
So after trying to assemble the top of this engine numerous times without success; I guess my next step is to count the number of chain links in my timing chain and compare it to a new one. I just counted 45 links and the chain is about 11" long. I have seen new ones for sale that are exactly that size.

10-15-2017, 01:56 PM	#2
GrouchyOle'Man Join Date: Sep 2017 Location: NE Central Florida Posts: 37	Hi Crawford, I suspected a timing issue with this engine as it was not drawing fuel out of the carburetor; so it had a no-start condition. I have installed a few new parts, but no new engine parts. Today I found a blue link on the timing chain that would not rotate as easily as all the other links and was kinked. I straightened it out. I do not know if the chain was ever tampered with. Everything is as I found it except the cylinder base gasket and head gasket which I replaced since I had the top end of the motor off. They were identical to the ones they replaced. Even after straightening out the blue link, the same situation exists. The inside cam bearing is above the journal it rides on about 1/2". Also, I cannot properly set the cam in correct timing position. It is always off by one tooth. Either side of the sprocket, I get the same result. Off one tooth and camshaft not seating. So, the only parts to compare OLD to NEW are the 2 gaskets and chain guides. I may opt for counting the links in the chain to see if one was previously removed to facilitate tightening up the chain. I do not know yet if a new chain will fix this. The gear on the crank the chain rides on is suspect also. I fear it is quite worn. This scoot has over 11K miles on it according to the odometer. Again, this is with the automatic chain tensioner NOT installed. The old timing chain guides had some damage to them and I replaced them. I initially thought a piece of plastic off the bottom of the lower guide was stuck in the timing chain gear on the crankshaft, then I found the kink in the blue link. At any rate, the chain seems to be too short to properly reinstall. So after trying to assemble the top of this engine numerous times without success; I guess my next step is to count the number of chain links in my timing chain and compare it to a new one. I just counted 45 links and the chain is about 11" long. I have seen new ones for sale that are exactly that size. Last edited by GrouchyOle'Man; 10-15-2017 at 04:26 PM.
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