Mainshaft roller bearing conversion

[SlOoT]

The ball-bearing needed to be replaced, but I did not have those bearings in stock. And then I took a look at the countershaft roller bearing and noticed the sizes were the same.

KTM actualy has this as an modification for their LC4 engines, all our LC4 engines have already been converted to a roller bearing. Coz the first part that fails on a LC4 engine (after 200-300 hours) is the ball-bearing behind the clutch leaving a big mess (cracked case).

I installed the bearing with special bearing lock-tite, it will never come out...

[Happyboy]

Sloot, are the problems with the LC4s mainly on the enduro and supermotos? I ask because of the speed and extended rpms they would have compared to a woods bike or a quad.

[cannondale27]

Does the mainshaft keep its original position? Not back more? Where did you get the spacer for the front. Looks like a worthwhile mod. Nice job.

[claas900]

How funny just the other night Tim and where talked about bearings. And we've never heard of that bearing going out. LOL

[SlOoT]

I have indeed never seen that bearing fail, however the one that was in there did not feel 100%.

The shaft stays in the original position. The spacer in front is the same as the spacers used in the swingarm for the axial bearings. I made the I.D. larger.

The LC4 bikes do not realy run at high RPMs. My street LC4 makes 5500RPM @ 60 mp/h.
The LC4 I used for MX racing did have that bearing fail (and cracked my case).

[wayneschofield]

I would inspect that regularly if I were you (at least until you know it's ok). It's a long while since I had a tranny to bits but it looks like the shift-sleeve thrust will be pushing on the ends of the rollers when you are shifting gears.

If the ball-race gives no trouble I think I'd rather I'd keep it.