Keeps throwing the chain.

[Frank Bullitt]

I swapped my 6.5hp HF motor on my doodlebug I made sure the chain wasn't too loose. I got the clutch inline with the rear sprocket as close as I could eyeball it and verified with a straight edge. Everything looks good but it still throws the chain very easy. I barely make it out of the driveway before it tosses the chain.
Anyone have any suggestions to trouble shoot this?

 

[xdomhnallx]

Maybe give your back wheel a spin and check it your rear sprocket is bent. If not that, maybe just get a new chain. Guy at my local shop told me that you have to also make sure the chain is well oiled especialy if you are running an old chain. Other than that maybe just invest in a chain tesioner.

 

[Frank Bullitt]

It has a chain tensioner and the chain isn't really loose. Also the chain is brand new. I think it may look in line with the rear sprocket but maybe I need to drill some new mounting holes in the motor mount and move it a little bit. But I did use a square on the clutch and it really looked aligned with the rear sprocket.

 

[GTO]

Not lined up right.

 

[Frank Bullitt]

How do you line up yours? I used a carpenters square and set it on the clutch teeth and it lined right up with the rear sprocket. Maybe the motor shifted when I tightened it up? Or my alignment method wasn't accurate enough?

 

[LeviMan_2001]

i dobut it, my engine is a little off on my mini, and i just eyeballed it and it amazingly hasn't chucked a chain yet.

 

[Darvin Jahnke]

Are both shafts parallel in a horizontal plane? I f the chain keeps jumping something is out of alignment. Possible bent sprocket or twisted chain?

 

[Frank Bullitt]

Well today I went to work on it again. I cut new slots on the plate to move the motor back towards the right of the bike. I verified alignment with a carpenters square and some welding magnets by putting the short end of the square vertical on the back of the sprocket and the long end on the top of sprocket pointing toward the clutch. then I moved the engine to match and cut my slots. Using the square also helped me verify that the sprockets were parallel so it worked out pretty good. I put it all back together and a quick test and the chain didn't fly off. So a couple of laps around the block and it is working great.