stage 6 cylinder studs breaking

[john willhoite]

Any suggestions?

I think it is cracking and then the nut backs off. Put a new nut on and barely tighten and the stud breaks the rest of the way off.

Its happend the last two races and both times its the same one.

We run engine ice and the large radiator.
We ran our last moto with it off. Just a little coolant blows out. The gasket and everything looks good.

http://i741.photobucket.com/albums/xx60/w6racing/IMG_0549.jpg

http://i741.photobucket.com/albums/xx60/w6racing/photo.jpg

[RCR_531]

G force has a stub kit to fix this but others may have it too. I seen it last night when I was on their site. Good luck

[john willhoite]

called them and they said they just have the stock studs.

[RCR_531]

what about a tractor supply store? they may have some harden studs that would work.

[john willhoite]

Ive looked all over, they are 8mm on one side and 6mm on the other side.

I wonder how important the unthreaded part is?

[RCR_531]

What about a hardend 6mm stud with a shelve that is 6mm inside and 8mm outside, then washer and nut it? You might need to find a machine shop to make them for you. Just an idea but hope you find something that helps

[fomospede]

considering where the stud is that is breaking
maybe your motor is flexing and the exhaust putting a bind on cylinder

a engine relocator might reduce the pressure put on the cylinder

we run a custom lowering setup and also run without a chain tensioner using a 400 ex chainguide

which allows less static power loss to the wheels

if it were me id leave it as seen in the pic
and slice the head pipe and let the tension off of it then reweld it and disassemble and clean interior of pipe for flow and reassemble and try it!

it is also possible that the case halves are shifting

[cik orange]

Add a bottom engine mount should relieve the stress

[Coley'sdad#8]

Yeah you have other problems causing the studs to fail, even on the small 6mm end of the stud even a grade 8.8 has approx.
116,000 psi tensile strength, look at the comparable stud sizes used on the larger engines, you have a bind issue somewhere.

[john willhoite]

The exhaust flange was hitting on the cylinder adapter plate. Ground a little off of the exhaust flange and it clears now.

We should know after 5 min of riding.
Will let you know after this weekend.

Thanks for all the suggestions.