Engine bearing help

[trbig]

I have split the cases on my spare motor that was running well, but the tranny took a dump. I thought a shift fork had bent, but it looks like a piece in the shift drum broke. My camera battery is dead, but I will post a pic tomorrow for that question.

So on to my other problem... this motor was the only one I have installed on the bike that didn't have a slight "Knock" in the lower end. After splitting the cases, the crank bearings look exceptionally well... better than I have seen in any of the other 3 motors I have split. I thought about just replacing the bearings anyway while I'm in here, BUT.....several of the numbers stamped into the crank lobe are illegible for both the 5 crank and the 4 conrod numbers, and there are NO numbers stamped into the case??? I can see the color of a few of the bearings, but not all of them. So.....

What is the actual thickness of the bearings for each color? I know they are +.25mm to +1mm, but what's the actual thickness?

OR....

Do I just fix the tranny, put the 1179 top end from the other motor back in this one and button it up with the existing bearings??

Looking back on things, this is the 5th time I have had a motor in and out of this bike in a little over 2 years. I am sick and tired of working on it, and it's all been due to crank bearings except for this tranny problem.

Tod

[mro]

plastigage the bearings
in spec leave em
If not....

mro

[trbig]

I plastigauged the bearings and they are at the limits of in spec... so I am going to change them. I think I have them all figured out on the crank and then went to try to figure out the conrods....

WTF is this?!?



All of them have what appears to be "4 + 15" stamped on them. Anybody ever seen such a thing?? Of all the backup motors... I get the one that rode the friggin short bus to school... I think this motor was made on a Friday evening at quitting time.


As a bonus question...

I found this part when I was checking out the tranny and gears. I looked around at the case for an hour before I had a DUH moment. It appears to be made of cast metal, so I knew it wasn't a gear. First correct guess wins the dime I compared it to... just send a stamped self addressed envelope and it's yours!




Tod

[blue giant]

Tod,

I beleive they are stamped 4H5 ,same as mine.

[trbig]

OK... so what do you subtract from for the numbers stamped on the crank lobe?

Tod

[red bandit]

The part next to the dime is a piece of the friction clutch tang.

[blue giant]

Tod, you would subtract the number on the crank lobe from the number 5.

example: 5-2=3 so you would use a brown color coded bearing.

Use the same formula for the other 4 conrod bearings.

[trbig]

How do you get that they are all 5's? All the other conrods I have seen have had the actual numbers stamped on them to do that with.

Tod

[blue giant]

Originally posted by trbig
How do you get that they are all 5's? All the other conrods I have seen have had the actual numbers stamped on them to do that with.

Tod

Sorry Tod, Should be the number 4 you subtract from.

Paul

[trbig]

And...... DING DING DING!!!


Bandit wins the dime!!

I should have posted this pic when I started looking! lol. I would have been done sooner.




Tod

[blue giant]

Tod,

What are the 4 numbers on the end of the crank starting from top to bottom?

Paul

[trbig]

The numbers for the conrod on the crank lobe are all 2's... but I'm not understanding how you know that it's 4's on the rods?

Tod

[John]

Are there any numbers on the other side of the con rod? That's where it should be.

[blue giant]

Originally posted by trbig
The numbers for the conrod on the crank lobe are all 2's... but I'm not understanding how you know that it's 4's on the rods?

Tod

Not to sound like a wise ass but it's explained fairly clearly in the manual.
Do you have a manual?

[trbig]

I have a manual and I have read and done this all before. I understand the subtraction you do from the numbers on the crank. BUT, there has always been a 4 or a 5 stamped on the side of the rod, not "4H5". The manual states to subtract the number on the rod from the crank number... got that. You have determined that they are all 4's somehow on the rods and I was wondering how you came to that assesment.

The manual says there will be a 4,5, or 6 on the rod... nothing mentioned about 4H5.

Tod