camshaft bearing wear on valve cover

[Jim]

And you still need to find the source (reason) for all that damage. Three choices of the top of my head. Either it was run for an extended period without oil, the oil tube to the head is clogged or the oil pump has failed. That really need addressing before you rebuild it, or it'll just happen again.

 

[Jan_P]

Thank you. It's says 20,000 miles

Yes Sir Mr Jim was faster

So it can be a case of Low on Oil at some Point in time .I would check Piston Skirts -- And Bores
Don't ask how i Found Out --- please.
And check oil filters for metal. Magnet or so ..
Pictures on those and pictures of the cam can be one way getting an overview

 

[Its been a long time]

And you still need to find the source (reason) for all that damage. Three choices of the top of my head. Either it was run for an extended period without oil, the oil tube to the head is clogged or the oil pump has failed. That really need addressing before you rebuild it, or it'll just happen again.

Absolutely. The bit I suggested is the simple bit. There's a reason for what we see.

 

[Username]

I'll check for clogs and I'll check to see if the oil pump is working. Not sure why an oil pump would fail at this mileage.

 

[Jim]

I'll check for clogs and I'll check to see if the oil pump is working. Not sure why an oil pump would fail at this mileage.

The internal pump gears have been known to split in two.
Most common problem I'd guess is rebuilding the motor and forgetting to put the keyway pins in the drive gears. Seen that several times.

 

[Username]

I thought the Japanese made shit that lasted forever haha. I'll check it out and report back.

 

[Jim]

I thought the Japanese made shit that lasted forever haha.

Given proper lubrication... it will.

 

[Username]

Yes Sir Mr Jim was faster

So it can be a case of Low on Oil at some Point in time .I would check Piston Skirts -- And Bores
Don't ask how i Found Out --- please.
And check oil filters for metal. Magnet or so ..
Pictures on those and pictures of the cam can be one way getting an overview

What am I checking the pistons and skirts for? I'm planning on deglazing / honing if cylinders are in spec and putting new rings and pistons in. I'm having trouble measuring the cylinders but I'm sure I'll figure it out. Any one know how much honing the cylinders would take off in mm? I'll upload better photos of the cam and rocker arms today

 

[Jim]

There's a top end buildup thread in the TECH section. It has 2 videos concerning honing and measuring cylinder diameter.

 

[Username]

There's a top end buildup thread in the TECH section. It has 2 videos concerning honing and measuring cylinder diameter.

i looked it up. Thank you for posting that.

 

[Username]

Ok I may have needed my glasses

 

[Username]

More photos

 

[Username]

More photos

 

[Jim]

Cost wise... you might want to consider pickup up a used engine to rebuild.
Head and rocker box, cam, rockers and adjusters... valves too most likely... and you have no idea what damage is in the lower end. Cha-ching $$$

 

[Username]

Cost wise... you might want to consider pickup up a used engine to rebuild.
Head and rocker box, cam, rockers and adjusters... valves too most likely... and you have no idea what damage is in the lower end. Cha-ching $$$

Yea the only problem with that is running into the same thing. You don't know what's going on in there until you open it up. Luck of the draw I guess.

 

[Jan_P]

Yea the only problem with that is running into the same thing. You don't know what's going on in there until you open it up. Luck of the draw I guess.

Yes there is a risk .But It does not look good here .. I have opened one motor with 70 000 km that was a 5 on a scale to ten
And it was Hot rodded crashed twice and not particularly well taken care of Oil changes
This looks as a 3 -4
I am leaning Towards Jim s idea getting something else. Maybe for head parts only

Back in the early 70 ies friends Bought cheap bikes .And many never got them running that long
Lot of work and parts cost and at the end 50 Km was a stretch for some Oil leaking
A cam ca $ 100 Pistons $ 2 -- 300 Rebore Gaskets Seals adds up

This is not an exact science and it depends on your plans and skills .Perhaps You are into the Wrenching.
Just a feeling but It can be something to consider as JIm Says

 

[Its been a long time]

Yes there is a risk .But It does not look good here .. I have opened one motor with 70 000 km that was a 5 on a scale to ten
And it was Hot rodded crashed twice and not particularly well taken care of Oil changes
This looks as a 3 -4
I am leaning Towards Jim s idea getting something else. Maybe for head parts only

Back in the early 70 ies friends Bought cheap bikes .And many never got them running that long
Lot of work and parts cost and at the end 50 Km was a stretch for some Oil leaking
A cam ca $ 100 Pistons $ 2 -- 300 Rebore Gaskets Seals adds up

This is not an exact science and it depends on your plans and skills .Perhaps You are into the Wrenching.
Just a feeling but It can be something to consider as JIm Says

A bit of a lottery? There's nothing there that can't be recovered I would say. But that's only from the pictures shown here. I would want to understand the condition of the rest of the motor before committing to expensive repairs on worn valve gear. Eminently recoverable, but not cheap and the rest of the engine condition?

 

[Username]

A bit of a lottery? There's nothing there that can't be recovered I would say. But that's only from the pictures shown here. I would want to understand the condition of the rest of the motor before committing to expensive repairs on worn valve gear. Eminently recoverable, but not cheap and the rest of the engine condition?

Yes there is a risk .But It does not look good here .. I have opened one motor with 70 000 km that was a 5 on a scale to ten
And it was Hot rodded crashed twice and not particularly well taken care of Oil changes
This looks as a 3 -4
I am leaning Towards Jim s idea getting something else. Maybe for head parts only

Back in the early 70 ies friends Bought cheap bikes .And many never got them running that long
Lot of work and parts cost and at the end 50 Km was a stretch for some Oil leaking
A cam ca $ 100 Pistons $ 2 -- 300 Rebore Gaskets Seals adds up

This is not an exact science and it depends on your plans and skills .Perhaps You are into the Wrenching.
Just a feeling but It can be something to consider as JIm Says

My original plan was to install new cam chain. New piston and rings. Deglaze the cylinders. Now due to wear, I may just buy a used rocker box from eBay or just buy the rocker arms from Mike's xs. I can do most of the work myself. Just didn't want to open the bottom end. The connecting rods on the crank have almost no play in them. Like .75mm
The piston pins also have nearly no play when in the small end of the rods.

 

[Jim]

The rocker box and head are line bored as a set. They have matching numbers stamped into 'em. They need to be changed as a set or there's a very high probability the cam won't fit.
Most Ebayers are ignorant of this... or plain don't care... and sell 'em independently.
If you go the rebuild route on this engine, make sure you buy a matched set.

 

[Username]

The rocker box and head are line bored as a set. They have matching numbers stamped into 'em. They need to be changed as a set or there's a very high probability the cam won't fit.
Most Ebayers are ignorant of this... or plain don't care... and sell 'em independently.
If you go the rebuild route on this engine, make sure you buy a matched set.

Good to know. Two options I see here.
1- buy a really nice top end from eBay (good luck)
2- buy new rocker arms and use the current cam and cases. Use loctite for the bearing. And continue the work I planned on doing.
I have about $1500 for parts but this bike needs a lot and was missing some pricey items (carbs and exhaust) I also wanted to do the pma setup and no battery