How far gone is too far gone?

[MedicWild]

Hey everyone,
I am new here and in the process of my first XS build. I’ve been reading and learning from the form, and love all the amazing knowledge here. It’s been my goal to get my hands on a XS650 for years now and just landed two engines in a trade.

I just broke into the “cleaner” of the two and found literal debris sitting an along the piston heads and the valve case a caked up mess. I am hoping that media / vapor blasting will clean up the valves, but wondering if the pistons are even worth salvaging.

Any advice? All info appreciated and welcome.

Thanks!

 

[Jan_P]

There are inspection routines and dimensions in a service manual
I dont think the top shown on the picture makes it entirely impossible to reuse . I would try to Clean it
The skirts can have scratches if many miles on them

The cylinder can need a rebore and then the Pistons are out

 

[toglhot]

Carbon build,up is not an issue. Run an engine for a month and pistons will have a carbon build up, as will valves and combustion chambers.
The issue is whether or not they are scored on the skirts or worn undersize. Put a mike across the skirts and measure the bores, then measure the ring gap.
If you have a blasting cabinet, bead blast if not, just clean everything up by hand, carbon isn't that hard to get off, just don't score the top of the, pistons when scraping carbon off. The chambers are all steel, so pretty tough.
Be careful where you spend money and what parts you buy, fixing bikes is a money trap if you're not careful and start buying stuff that's not needed.

 

[motormike]

Carbon deposits on the piston head.. normal... same with valve areas of the head.. all can be cleaned... mic the cylinders.... pistons.. so long as they're not scorned.. possible to re use... just order new rings.. hone the cylinders... but over sized pistons shouldn't be an issue.... sump cover tells a story.. the screen filter is usually torn... double check the rod - crank bearings.... these are good engines.. and take a lot of abuse.....

 

[5twins]

To remove the carbon buildup and any old stuck on gaskets, you can use paint stripper. Soaking for 10 to 15 minutes will soften the carbon and old gaskets up so that minimal scraping will be required. It usually takes a couple applications to get it all off.

 

[MedicWild]

There are inspection routines and dimensions in a service manual
I dont think the top shown on the picture makes it entirely impossible to reuse . I would try to Clean it
The skirts can have scratches if many miles on them

The cylinder can need a rebore and then the Pistons are out

Thank you! I am gonna update when I get more time for measurements. Definitely gonna get it cleaned up and attempt to reuse everything I can.

 

[MedicWild]

To remove the carbon buildup and any old stuck on gaskets, you can use paint stripper. Soaking for 10 to 15 minutes will soften the carbon and old gaskets up so that minimal scraping will be required. It usually takes a couple applications to get it all off.

Haven’t seen the paint stripper trick yet. Thanks for this. There is a shit ton of stuck gasket so this will be great.

 

[gggGary]

To my mind the cam lobes will tell you much more about the motor's wear, health than about anything else.
Can we see em?

 

[5twins]

I don't see the oil baffle for the breather in your head. Did you remove it?

 

[MedicWild]

I don't see the oil baffle for the breather in your head. Did you remove it?

View attachment 260663

Yep I removed it. I will post more pics tomorrow. Thanks for the inquiry

 

[MedicWild]

To my mind the cam lobes will tell you much more about the motor's wear, health than about anything else.
Can we see em?

Yep. I will post more pics tomorrow. Thanks for the suggestion and help.

 

[mike in idaho]

I like to use walnut shell, and a siphon blaster to clean carbon off aluminum parts, gets the carbon off without roughing up the surface or marking up the surface. Valves, I take over to the wire wheel on My bench grinder, removes the carbon and doesn't harm the valve.

 

[toglhot]

I like to use walnut shell, and a siphon blaster to clean carbon off aluminum parts, gets the carbon off without roughing up the surface or marking up the surface. Valves, I take over to the wire wheel on My bench grinder, removes the carbon and doesn't harm the valve.

lucky devil - walnut shell. About all I can get here is soda. For a while I could only get very large glass beads which were terrible, I managed to find some fine glass beads a few months ago, so, I bought a couple of buckets..

 

[5twins]

You don't want to glass bead blast any internal engine parts or surfaces, especially alloy. The glass beads embed themselves into the surface and don't just wash off. What does release them is engine heat once you start running the motor. Then they are released into your oil and wreak havoc on the bearings.

 

[toglhot]

Glass beads don't really imbed themselves in steel, but can in aluminium if you aren't careful. That said, I've been bead blasting aluminium for 20+ years, never had any problems or excess wear. I always blast several times with a high pressure cleaner afterwards though.

Soda is worse. Soda is single use and turns to a very fine powder getting caught in small crevices, galleries, bolt holes, etc. Get it wet and it's impossible to find and remove. Funnily enough, high pressure cleaners always seem to fail in removing the stuff, it has to be dug out or loosened up first. Once it turns to mud?

Soda blasting medium is actually baking soda. It is abrasive, obviously, but having miniscule particles can be worse for imbedding itself in aluminium, and more difficult to remove. I never use it, too troublesome.

I use a hard plastic ruler for removing stuck gasket material, grinding a sharpenedl edge on it first. It doesn't scratch or damage aluminium, but needs to be sharpened frequently in use. It may work for removing carbon, never tried. I generally use a wire wheel in a rotary tool, then polish with a mop and compound.

I have used glass beads on plastic, specifically the rear plastic guard in front of the rear wheel. The plastic was gouged, scratched and in pretty bad shape. Glass beads did a great job giving a nice even, flat finish and masking a lot of the damage.

 

[MedicWild]

I don't see the oil baffle for the breather in your head. Did you remove it?

View attachment 260663

The stripping continues… paint stripper is working slowly

 

[MedicWild]

I have seen w

To my mind the cam lobes will tell you much more about the motor's wear, health than about anything else.
Can we see em?

cam lobes look ok to me. Am I missing anything? What can expert eyes tell me?

 

[Jan_P]

Not an expert I can see wear on them having Satin finish but no pitting . I have seen 3 cams all of them was better looking than this
I would inspect the mating surfaces on the rocker arms and consider take out the cam from the other motor
See how it looks
Is odometer numbers known ?
This is not an exact science I would probably Borderline use it unless some replacement shows up quickly .
Thinking it over Summing up the grand total . I bought a replacement cam for ca $ 100 because pitting
I depends on finances time and what status one wants to get the machine.

A picture of the piston skirts perhaps