Help: Journal bearing replacement

cuong-nutz · February 27th, 2014, 04:39 PM

My crank journal bearings are measuring close to 0.038 mm using plastigage.

Should go up another size or just get new bearings of the same ones I currently have?

If I go up a size, which color/part number bearings do I get? I'm having trouble deciphering what is what and what to use.

I have a mark on the upper crankcase half which is a "0" with blue paint over it.
Then I have no markings on the crankshaft.
The journal bearings I took our painted yellow.

Now for the balancer:
I have no markings on both the balancer and crankcase half.
the bearings have are blue.
Which color bearings is one size bigger if I am out of spec?

Connecting rod:
No markings on rods or shaft
and no identifiable color on the rod bearings

The rod bearings are in spec: Maybe a hair larger than 0.038

dcj13 · February 27th, 2014, 05:57 PM

0.038 mm is just under 1.5 thousandths of an inch. Didn't check any specs or machine design handbooks, but that seems plenty tight (in other words, no need for thicker bearings). Are the bearings boogered up? If not, why not just reassemble with proper lubricant (assembly grease, perhaps) and call it good?

And how many miles can one have on a 4 year old bike?

mgentz · February 27th, 2014, 09:39 PM

@cuong-nutz you can call me if you want to go over this. Too much to type on my phone.

Based on your schedule, call me when you wake up.

February 27th, 2014, 04:39 PM	#1
cuong-nutz RIP Alex Name: Cuong Location: Houston, TX Join Date: Apr 2011 Motorcycle(s): '10 250r, '09 265r Posts: A lot. Blog Entries: 2	Help: Journal bearing replacement My crank journal bearings are measuring close to 0.038 mm using plastigage. Should go up another size or just get new bearings of the same ones I currently have? If I go up a size, which color/part number bearings do I get? I'm having trouble deciphering what is what and what to use. I have a mark on the upper crankcase half which is a "0" with blue paint over it. Then I have no markings on the crankshaft. The journal bearings I took our painted yellow. Now for the balancer: I have no markings on both the balancer and crankcase half. the bearings have are blue. Which color bearings is one size bigger if I am out of spec? Connecting rod: No markings on rods or shaft and no identifiable color on the rod bearings The rod bearings are in spec: Maybe a hair larger than 0.038 __________________________________________________ HalfFast Racing Team Serving Greater Houston Area Riders:WFO Riders MotoHouston HPC CMRA Ride Smart Fastline Lone Star Track Days

February 27th, 2014, 05:57 PM	#2
dcj13 Participant Name: Dave Location: South of Seattle Join Date: Oct 2012 Motorcycle(s): '94 K75 std Posts: Too much. MOTM - Aug '15	0.038 mm is just under 1.5 thousandths of an inch. Didn't check any specs or machine design handbooks, but that seems plenty tight (in other words, no need for thicker bearings). Are the bearings boogered up? If not, why not just reassemble with proper lubricant (assembly grease, perhaps) and call it good? And how many miles can one have on a 4 year old bike?
	1 out of 1 members found this post helpful.

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February 27th, 2014, 09:39 PM	#3
mgentz Board Member Name: ... Location: WI Join Date: Dec 2011 Motorcycle(s): 250R (street), 250R (dirt) Posts: A lot.	@cuong-nutz you can call me if you want to go over this. Too much to type on my phone. Based on your schedule, call me when you wake up.