Non bearing side cover motor

leoofc

Member
Time to jump start this blog. Yeah,yeah,yeah these motors are not supposed to run over 3600 RPM. But im sure lots of us have them on minibikes,fun karts etc. We run what we got. My question- how do we give these motors the best chance of survival? i would think quality synthetic oil as a start? How about drilling holes in the crank journals? A raingutter type system to drip oil on the top of the crank at the bearing? A couple of 6000rpm blasts on a minibike is all ill need. Its been done successfully. (so far!)
 
Been a while but if theres not a hole on top of the bushing side cover drill one.
Still probably last as long as the mini bike theres thousands running still .
 
More clearance for oil, dimpling can help, add'l oil hole on top of the bushing. All will help, but the simplest solution (and long term) is to replace the sidecover with a ball bearing one. Slip fit a bearing to the crank and you're good to go as much rpm and for as long as you desire.


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🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
33 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
More clearance for oil, dimpling can help, add'l oil hole on top of the bushing. All will help, but the simplest solution (and long term) is to replace the sidecover with a ball bearing one. Slip fit a bearing to the crank and you're good to go as much rpm and for as long as you desire.


-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
33 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
Is it really that simple to change? I thought the cranks might be different.shoulder radius.sideplay etc. I just sold a briggs dual bearing industrial motor on a minibike.
 
Yes, it is that simple. There are two different bearing sidecovers (lg bearing and sm bearing.) You will need the lg bearing so you can turn the bushing crank down to slip fit the bearing on your crank.
You set crank endplay with the various thickness sidecover gaskets available (.005, .009, .015, .020") or by stacking 2 gaskets.
 
More clearance for oil, dimpling can help, add'l oil hole on top of the bushing. All will help, but the simplest solution (and long term) is to replace the sidecover with a ball bearing one. Slip fit a bearing to the crank and you're good to go as much rpm and for as long as you desire.


-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
33 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
if the bearing is not press on it doing nothing
 
so b/s press them on because you have a low rpm with governor but racing you have to take them a part for maintenance so iam learned
 
There is no part number for the bearing being slip fit -- you can use the same bearing.
There IS, however, a 9 ball bearing that replaces the oem bearing/bushing stack on the older dual bearing cranks and also fits the newer cranks directly, that is legal.
Simply turn the crankshaft down in a lathe just enough to slip fit the bearing.
We're not just using the slip fit to ease in maintenance, but also for alignment.
We would use self-aligning bearings if they were legal.

Think about your rear axle and front hub bearings -- be thankful they are slip fit. Oh yea, and even before the inception of rear cassettes, we floated the rear bearings so that they wouldn't bind under chassis load and axle deflection.
 
See what I started! I guess its time to get out the machinists handbook.I would think a slip fit would be a hard push on maybe a tap with a wooden mallet. I would think a press fit would be at least a 25psi hydraulic push. Just guessing.
 
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