chain skip

[raptorobbie]

our DRR has a brand new aftermarket chain, stock sprockets and stock tensioner. While doing work on the bike over the winter I noticed something was slipping in rear end - I though it was the sprocket hub jumping splines on the axle. I had to change the chain, and made it the same lenght as the stock one. At a harescrambe this past weekend I found out its actually the chain jumping teeth on the rear sprocket. Rear sprocket doesnt look that worn - should I just change it anyhow or is the problem more w/ the stock tensioner? As far as I know the rear end is tight and hasnt loosened the chain adjustment.


thanks!

[mmsoup]

Have the same problem on two of my Apex A-1 motors one is noticeably worse. Have a third motor that doesn't do it at all. The strongest motor of the three falls in the middle.
Thought the same thing you did. I weigh 205 and while testing it does it whenever I shower down on them. I just figured I need a lighter test pilot :)
Seriously, does anyone know what's going on there? Transmission on the worst of my three didn't show any unusual tooth wear and no bearing slop.........

[riding4fun]

My chain will only do that when its loose or when my big butt makes it sag too much. . Tighten up the tensioner a little more or the chain.

[raptorobbie]

yeah - exactly, my 200# butt makes it sag, loosens the chain and makes it skip bad under hard acceleratioin, but during the race, he came back and complained about it too. It might just be the new chain going thru its stretch and just needs adjusted.

[bulldogfallon]

It could chain stretch, proper chain tension adjustment and maybe the motor tweaking under acceleration.

We have a lower engine mount that keeps this from happening...one of local race dads makes them for everyone

[Coley'sdad#8]

yeah the chain pitch is measured from pin to pin and 428 chain pitch is .500 or 1/2" excessive will allow the chain to bunch up on the sprocket and not seat between the teeth which will let it jump over the teeth. keep a tensioner on it to keep it from jumping over. check the sprocket carefully and make sure the noiose and feel are not the chain trying to jump over the side of the sprocket from motor torque pulling sprocket alignment off and trying to derail chain.