BannedCR500Riders.com

Did you break them right in the bend? Where the tube gets smaller?
Those new rails are straight gnar kill !!!!!

Any pic's of the breaks Ray?

Gee, no doubler.....

I realise the engine mounts should have been a lot wider where they meet the frame rail. Rails stood up to 58hp engine for a good few months. They failed when we upped the HP.

are you sure it's not the headstay? i think i read another 450 broke in similar fashion not long ago. Everyone seemed to think it was the headstay?

I agree with bob. Those motor mounts are rather small. Kinda concentrates the load instead of spreading out load. On that note those billet ones should be bomb proof!!!!

my completly unprofessional opinion
i think its mostly the headstay, (motor mounts could use help too) while it is built nicely, it dosent provide enough front to back stiffness.... it works on a 450 cause the headstays go straight down, on the billet ones they go in then down on a 90, not the way any other headstay works on anything....
just by looking at it you can see its gonna flex forwards to back real easy, even being billet



now look how honda does it, straight down, not in 4 inches then a 90

seems to me that using the doubler has a few benefits. obviously it spreads the load wider but also your not putting all the weld heat directly onto the frame rail. hell i could be wrong though

The motor was only braced sideways when the first rails broke. We thought maybe headstays came loose. Which caused stay to brake and load frame rails with too much force. Rails held up fine for 6 months running standard engine. They broke on first outing with 80+hp engine.



When we rebuilt the the frame rails we braced it sideways and added an extra brace back to shocky tower. All bolts and nuts were installed with Lock Tight and closely monitored for loosening. The rails broke on second outing. The bike is used for beach racing only. It has not been jumped at all.

aparently you have too much power

Ha Ha 100hp, not enough we recon.

Where do you guys beach race ?

Grasstree near Sarina

I'm not saying it is the cause but I can't help but wonder if bending the tube in T6 condition played a part in the breaks. I do think the mounts should have been wider as you already said. Props to you for showing the busted rails and those billets look bad ass! May have a break some where else but it ain't going to be on the rails.

KE 336 wrote:Props to you for showing the busted rails...

Yup.... We cant make things better without knowing what isnt working.

Speed... not sure if I missed it somewhere in this post, but who made the pipe?

First Pipe was CPI.



Second pipe.

I think the abrupt shoulder on those mounts focus the torque in a small area. It seems as though the designs that match OEM work out the best-i have never seen anything like that with bikes that reused the stock bottom mounts.

nmdesertrider, Yeh I think you are right. The original mounts were pretty much a copy of Shanmans, from his PDF file. His mounts have been use on a lot of bikes with out issue.

Wow, I bet the raw piece of billet alone needed to make those rails cost a pretty penny!

Looks good though!

Sure hope you don't find the next weak point now!

Why the mismatch?