SKF crank bearings.

Message

blaze#52 · #11 Post by **blaze#52** » Tue Jan 24, 2006 2:39 am

I am doing a motor now that it looks like the plastic cage on the flywheel side started to eat in to the engine case? anyone else, the stator was also trashed,like it had a lot of endplay. I have half of the diamond racing bearings in my motor, two seasons ago i ran ball bearings on both ends of the crank. then I last seaon i switched to a ball beaing on the flywheel and a two piece roller on the cam chain side, not failures ever, I like the ball bearing cause it eliminates the flywheel wanting to get in to the stator.

4strokemadman · #12 Post by **4strokemadman** » Tue Jan 24, 2006 3:54 pm

The reason we went with c4 clearance is for temperature variation. If you are never going to run your quad in really cold temperatures then you can probobly get away with a c3 clearance.

haydug · #13 Post by **haydug** » Tue Jan 24, 2006 6:52 pm

I was talking to Kevin at All Balls about the bearings. I honestly have no intention of getting them now, if something didn't work out, it's "hang" time, and I am basically sick of trying to upgrade these engines. I feel my bikes runs strong, is reliable, and that is all I need.

4strokemadman · #14 Post by **4strokemadman** » Tue Jan 24, 2006 7:10 pm

Here is some data for minimum C4 clearance at temperature:

20C .0023mm
150C .0513mm
-40C -.0203mm

wistech · #15 Post by **wistech** » Tue Jan 24, 2006 7:51 pm

Testing shows the C3 can survive in the cold climate. It would be a good idea to measure the races after pressing them on the crank just to be sure .

wistech · #16 Post by **wistech** » Tue Jan 24, 2006 7:59 pm

Thanks for the info 4stroke.
I will admit I have used the grossly underated ball bearing in an fx400 before the case mod came about. It was rated even less than the brass caged bearing. It never failed but the quad has less than 10 hours on it.

4strokemadman · #17 Post by **4strokemadman** » Tue Jan 24, 2006 8:03 pm

Whoa! thats cold for sure!
Don't forget I just gave the minimum clearances, so that would be a bearing bore on the low side of the tolerance and a crankshaft on the high end of its tolerance. So when you build an engine you may want to measure both then decide. This would be critical if the person is going to be riding in cold temps. The max clearances are as follows:

20C .0576mm
150C .1067mm
-40C .0349mm

In any case I think in most situations the c3 clearance would be fine...

wistech · #18 Post by **wistech** » Tue Jan 24, 2006 8:07 pm

Thanks

I sure wish the motors had a thermostat so cardboard in the radiator wouldnt be needed on these frosty runs.

4strokemadman · #19 Post by **4strokemadman** » Tue Jan 24, 2006 8:18 pm

Ha! Carboard works though!

Happyboy · #20 Post by **Happyboy** » Tue Jan 24, 2006 8:18 pm

dang thats cold!