RFS crank spread issue?

[Orangeshirtdude]

A friend recently had a 2005 KTM 525 SMR die because of crank spread. This apparently happens to RFS engines used in supermoto applications on asphalt because the rear wheel doesn't spin up like on dirt. The cranks are not beefy enough to withstand sustained full load and distort, resulting in bearing failure. There is a simple fix involving welding and truing of the crank. Has anyone with a RFS-based Beta done this with their crank?

I hate the idea of dissembling a perfectly good engine, but I'm planning to have the crank welded and trued in the spring before putting the bike in supermoto trim, unless I find out that Beta addressed this already in their RFS engines.

[Haychip]

If you are going to do SM you need to do the crank. We do (did) it on our race bikes as well. Changing to ball bearings and crank mod. There are a few guys including myself that can do it for you. Or just send your crank to one of them if you want to do it yourself.

[Orangeshirtdude]

Thanks. I have a friend in northern NC who swears by a shop near him. I'm thinking what I'll do over the winter is pull the engine and haul it down one weekend along with my SMC in the truck so I can do some riding while I wait for the service.

[chasejj]

Send it to Travis at ThumperRacing. He can do the welding and balancing the crank including the counterbalancer so that it will feel like almost vibe free. Not many people can do the proprietary balancing they do. It is legendary in RFS circles. I regret not doing mine when I went to the 540.

[Orangeshirtdude]

Send it to Travis at ThumperRacing.

That name and affiliation comes up frequently.

[ChasM]

I had Travis at www.thumperracing.net build my '09 Beta RFS 570 engine (SMR 560 100mm cylinder) and it is as smooth as silk with balanced crank and counter balancer, crank conversion to ball bearings, angular contact bearings, 8/33 cam, etc.

[Orangeshirtdude]

I had Travis at www.thumperracing.net build my '09 Beta RFS 570 engine (SMR 560 100mm cylinder) and it is as smooth as silk with balanced crank and counter balancer, crank conversion to ball bearings, angular contact bearings, 8/33 cam, etc.

Yeah that's the straight dope, I'm told. My buddy is saying to drop in a big bore kit and all that, but I kinda like the 450 power and torque. I figure though while in it I might as well have the crank balanced, counter balancer added, ball bearings and the angular contact bearings. I'm after bomb-proof more than max performance.