Drive chain not parallel with itself

[gearhead437]

Dear Fellow Motorheads-Although this is my second build, it has not been any easier than my first! I carefully mounted and aligned my engine to the frame, just as I carefully aligned and installed the driven rag mounted sprocket. The chain has a very slight twist coming out of the drive gear, so the bottom part of the chain is a few mm's out from the top part of the chain. I had to push the idler wheel in slightly while tightening to prevent the chain from riding the side of the driven sprocket and binding, as it was trying to jump off of the bottom of the driven gear-not good. I realize that some stretching will initially occur. I am wondering if , after initial stretching, if the idler wheel should be removed, along with enough links, to either not need an idler wheel or use the case mounted spring loaded idler assembly. TIA for any detailed reponses-Gearhead437

 

[GW's Motorized]

You could try shiming the mount

 

[darwin]

Sounds like your engine is tilted slightly to the right side from your post. Any pics, they help. Chains and sprockets need to be aligned no amount of stretch or wear will help. Need to fix the alignment issue.

 

[Chainlube]

Dear Fellow Motorheads-Although this is my second build, it has not been any easier than my first! I carefully mounted and aligned my engine to the frame, just as I carefully aligned and installed the driven rag mounted sprocket. The chain has a very slight twist coming out of the drive gear, so the bottom part of the chain is a few mm's out from the top part of the chain. I had to push the idler wheel in slightly while tightening to prevent the chain from riding the side of the driven sprocket and binding, as it was trying to jump off of the bottom of the driven gear-not good. I realize that some stretching will initially occur. I am wondering if , after initial stretching, if the idler wheel should be removed, along with enough links, to either not need an idler wheel or use the case mounted spring loaded idler assembly. TIA for any detailed reponses-Gearhead437

What is most likely happening is the idle pulley is causing the chain to move over and ride up on the side of the pulley wheel. If you get a big ole crescent wrench and close it on the tensioner arm, you can twist the arm so the pulley lines up with the chain's run to the rear wheel.

 

[gearhead437]

Dear Chainlube and fellow motorheads-That is a great idea! Darwin, I took your advice, loosened all of the engine mounts and pulled the engine over as far as it would go. I also ensured that the chain is not as tight. It's a little floppy now, and I'm wondering if I should install the chain cover spring loaded idler . The T type tension idler worked great on my Grubbee 49cc, but the spring had to be just right, or the chain flopped around too much. Not sure if I want to go that route yet. Have not started the engine up yet, as I wanted to get this alignment issue fixed or improved upon. It's much better now, but not perfect. Will keep everyone updated. The 415 chain is not as forgiving as the 410, and I'm wondering if it's required for a stock 66 cc 2 stroke. Does anyone know the Hp output of these stock 66 cc 2 stroke engines? (feel free to laff). UPDATE-Pedal chain has about 1.25" of slack and the engine chain has about 1" of slack, FYI. Will readjust after I ride it for a bit. As with my 49cc, I am more concerned with the chain staying on the sprockets more than anything else.-Gearhead437.

 

[GW's Motorized]

Can't wait to see tour bike finished! Keep up the good work

 

[gearhead437]

Thanx GW! Thankfully, the Pk80 engine mounts allow for at least 1/4" or so lateral adjustment. My chain is not completely parallel, but it's much better than it was. At least now it's not trying to jump off of the rear sprocket-Gearhead437