Matt, my interceptor kart has a 530 on it and when I first set it up
it stretched constantly. I rigged up a spring loaded chain tensioner
you can see it in my pics on my group. This stopped the slipping and
I finally was able to remove it after a short time. I would also
change to at least a #40 chain. Your cart is probably heavy enough
with the driver and the torque added are to much causing the chain
to stretch. How do you have your cart geared? If it is set up for
top speed you could be putting to much stress on the chain while
taking off. If you try a smaller drive sprocket there will be less
stress on the chain to get the cart rolling. There are many
variables. I guess in my opinion a larger chain is certainly not
going to hurt your situation.

Randy
Custom 500cc kart
3203 Yerfdog
2004 Twister Hammerhead
http://autos.groups.yahoo.com/group/gokarts_and_minichoppers/

--- In offroadgokarts@yahoogroups.com, "Matt" <matt1ptkn1@y...>
wrote:
> I have a single seat kart, with a live axle, 18" rear tires, a
TAV30
> torque converter with the newer aluminum mounting plate and a 10
> tooth drive sprocket, #35 high performance kart chain, and a 5 HP
> Briggs engine with the governor removed. I have modified the
frame
> and it is solid. The axle does not shift sideways, and the frame
> does not flex. The engine does not rock or slide and the
sprockets
> are straight and in line. But the chain still jumps!!!! It will
> work great for a while, 10-20 mins or so; the kart has plenty of
> power and speed and I don't drive crazy, but then the chain
jumps. I
> believe it is stretching, because of everything I mentioned above,
> and after it jumps it is obviously a little looser. But it is a
> brand new high performance chain. Is it normal for chains to
stretch
> this much, and with only 5HP? I am thinking of making the switch
to
> #420 chain, but I would rather avoid spending the $$, and I am not
> positive that would cure this problem. I had this exact setup on
> another kart, using the exact same chain, and never had it jump
> once. I am at my wits end trying to figure out why exactly the
chain
> jumps, and how to cure it. I have never had this much chain
trouble
> before. Anyone else ever go through this or have any suggestions?