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**tarzan** · 05-10-2009, 10:18 PM

I dont grind a crank unless it is scored,pitted,visually damaged,or out of tolerance.
Looking at your clearances,I dont think they are that bad.The one .0032 is a little over a half thousands out,but thats pretty small.
How do the bearings look.

**jfmerk** · 05-10-2009, 10:42 PM

The bearings look good... I have a couple pictures but I need to figure out how to post them.

**DiverRay** · 05-10-2009, 11:03 PM

To post a picture you need to use a "hosting" site like photobucket. There are threads on this, just do a search with "post photo".
If the crank has good journals that are NOT tapered, DO NOT grind! You will need to look at the "color" of the bearings installed, and go to a "tighter" bearing color. I don't remember what the color sequence is, but it IS in the manual. Just use plastigauge to check everything. If you have one on the "loose" side, you should still be OK. Just make sure it's only about 0.0025 MAX. It WILL run OK looser, but it will NOT last as long as it would otherwise....

**petejw** · 05-11-2009, 06:39 PM

Regarding grinding the cranks on our bikes,
there are no over size bearings available for these bikes
so grinding isnt an option.
With regards to the colour code of the bearing this was only relevant with a new crank,
with a used crank it was recomended using the thickest bearing(i think blue from memory)
as the other bearings when fitted were out of spec.
Theres a cpl of topics on here and the uk site about it.

**jfmerk** · 05-12-2009, 05:54 AM

Hey thanks for the tips. When I get a little time (probably tonight) I'll get some pictures posted.
I've got a few pics of the main bearings too. A few have a little pitting so I'd like to see what some of you think.

Jeff

**jfmerk** · 05-12-2009, 07:44 PM

Well if I did this right, I have a few shots of the crank journals a main bearings and con rod bearing. I will pick up some plastigage and see what that reveals for clearance. I have no experience with plastigage and I've heard it is very accurate and I've heard it's not so accurate. Can a bore gauge reach in deep enough for checking the inboard main bearings? I'll borrow one from work and find out, I know it has a fairly long stem.

All of the con rod bearings look like this.

The two main bearing pics represent the worst, all the others are in better condition.

Thanks for any comments on this pics and I'll look for other threads on the topic.

Jeff

**jfmerk** · 05-12-2009, 08:03 PM

Oh well, swing and a miss on the pics. More reading.

**jfmerk** · 05-12-2009, 08:32 PM

Got it!

**Shappers** · 05-12-2009, 11:35 PM

To my eye, the crankshaft journals looks good with no significant scoring. Just normal wear I would say.

The main bearings have picked up along the sides but the bottoms are smooth, from this it indicates to me that they are worn and the clearance is quite large. Those specks along the edges of the shells mean the oil hasn't been changed as regularly as it should.

If it was me I would bolt it back up with just a new set of main bearing shells. I would fit the thickest ones to compensate for the wear in the crankshaft. Thickest are the Blue ones.

The big end bearing clearance don't look so bad to me, I probably wouldn't change them unless they also have picked up some rubbish on them.

It becomes quite expensive if you need to change both main and big end bearings

You can mess about with plastigage measuring the clearances (I did), but at the end of the day if any of the parts are worn (like the crankshaft) then you will need to fit the thickest shells anyway to compensate for that wear.

**Thee_oddball** · 05-13-2009, 08:01 PM

shappers does the pitting on pic 2 and 3 matter? or is that just normal and acceptable wear?

thnx

**jfmerk** · 05-13-2009, 10:00 PM

Plastigage measurements

Since I've never used Plastigage I wanted to see how it works. My garage was right around 68-70 degrees; somewhere I read where thats important.

The con rod bearings all indicated < or = .002" which I was glad to see, I would estimate .0018" ~ .0020"

The mains from left to right did not fair as well: .002", .003", .003", .0027" and .002"

Shappers you were right about the wear. So I'll be looking for some "code blue" bearings.

Jeff

**Shappers** · 05-13-2009, 11:57 PM

Originally posted by Thee_oddball View Post

shappers does the pitting on pic 2 and 3 matter? or is that just normal and acceptable wear?

thnx

The pitting along the sides indicates that there has been debris in the oil which ends up getting stuck in the soft bearing shells. As the bottoms of the shells are clean it tends to suggest there are rather large clearances and the crankshaft has been "sitting" in the bottom of the shells.

I would change the shells just because "I was in there", the wear and the pitting makes it a no contest in my book.

Don't forget that the main bearing clearances are also directly responsible for the oil pressure in the engine. If your mains are within specifications then your top end is being pumped lots of fresh oil keeping it cool and lessening the wear on the camshafts and valves

**TADracer** · 05-14-2009, 07:45 AM

While you are down this far there is one other thing you should do. Remove the oil gallery stopper bolt on the right side of the motor case and make sure the gallery is clean all the way through. Shavings from factory machining has been known to reside in here. Also, in the two outside and the center main bearings you will see small orifice plugs that can be removed with a screw driver (they are visible in one of your pictures). These even out the oil flow to all the mains as the ones that do not have the orifice plugs get more oil flow since they supply the oiling to the connecting rods through the feed holes in the crank. Make sure all these are open and clean.

**Thee_oddball** · 05-14-2009, 07:47 AM

Originally posted by Shappers View Post

The pitting along the sides indicates that there has been debris in the oil which ends up getting stuck in the soft bearing shells. As the bottoms of the shells are clean it tends to suggest there are rather large clearances and the crankshaft has been "sitting" in the bottom of the shells.

I would change the shells just because "I was in there", the wear and the pitting makes it a no contest in my book.

Don't forget that the main bearing clearances are also directly responsible for the oil pressure in the engine. If your mains are within specifications then your top end is being pumped lots of fresh oil keeping it cool and lessening the wear on the camshafts and valves

thank you sir, very good info for future tear downs

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Connecting rod bearing clearance

Connecting rod bearing clearance

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