Unfortunate results

[Jfl0528]

Lots of ifs and buts but engine comes apart regardless of oil added or borescope or inspection through small holes.

$300 is a good start. Maybe suck it up.

Agreed

 

[Jfl0528]

I would certainly fix it if it were up to me. I have 2 XS 650's, one I did a budget rebuild on for about 800 bucks to get it into rideable shape and the other one is complete for parts but has major issues to get it running again (needs crank rebuilt). I have about 1800 in the rideable one and it is a hoot to ride. It had cam installed incorrectly when purchased, causing bent valve and broken valve guide therefore causing it to be parked in 1984 and never touched til I bought it with title for a whopping 75 bucks. With much elbow grease and a decent chunk of change thrown in, I had a running bike. So if you are mechanically inclined, you should have no problem.

thank you I will rebuild

 

[jetmechmarty]

thank you I will rebuild

Are you capable of starting a project and seeing it to completion? You know yourself better than we do. Do you enjoy this kind of thing? It's not that expensive as hobbies go. How much it's going to cost depends upon you. That thing could end up $2500 or less, or four times that. It's a matter of where you want to take it. Enjoy the journey. Share it with your friends at XS650.com

 

[grouchie83]

100%! But their big argument is that I can buy a running bike for the cost of all the parts

True... but these things are pretty simple really I think. No emissions crap, no fancy computer controlled fuel injection. Carbs and a charging system really. Once you have a handle on those two things most everything else is a cake walk.

Of course, I say that now. Ask me again when it's time for me to get all the electricals done on mine and let me tell you how much I hate life...

 

[gggGary]

Confirm you have correct valve clearance. .003 and .006". If one is too big it might just be carbon on a seat.
Just had one in the shop, a po had set one side too tight. Easy fix!

 

[Jfl0528]

Here we are as of today, it looks pretty bad, I undid the cam chain and didn’t pay attention to any timing marks. Got too excited oops

 

[JOHNDADDY]

Is that a dent in the top of the left exhaust valve?
Any marks on the pistons showing collision?
Can't really tell with my eyes. lol
Timing's easy, no worries.

 

[Jim]

Here we are as of today, it looks pretty bad,

Looking at the pics, I agree with @JOHNDADDY ... looks like that left exhaust valve hit something. Everything else though looks pretty normal for a well used motor. After you get the valves out, we'd like to see closeups of the valve face and it's seat. Hopefully they can be reworked.

 

[Jfl0528]

Is that a dent in the top of the left exhaust valve?
Any marks on the pistons showing collision?
Can't really tell with my eyes. lol
Timing's easy, no worries.

No marks that I can see, I’m getting a quote from a machine shop today to see what he’ll charge for a resurface, on one side I poured water in the combustion chamber with the spark plug in and it leaked everything out immediately, hence the zero compression, the other side leaked while giving it compressed air. Both sides need work

 

[Jim]

on one side I poured water in the combustion chamber with the spark plug in and it leaked everything out immediately,

Where did it leak from?

 

[Jan_P]

Some carbon there but over all OK
I wold have oil on top of the pistons lubricating downwards

Maybe a lapping of valves can be enough

 

[Jfl0528]

Here’s a better pic of the valves. I marked the bad side with chalk, I don’t see any signs of damage

 

[Jfl0528]

Some carbon there but over all OK
I wold have oil on top of the pistons lubricating downwards

Maybe a lapping of valves can be enough

Unfortunately no, wipers weren’t wiping. Rings are frozen to the pistons.

 

[Jfl0528]

Where did it leak from?

Out of the exhaust

 

[JOHNDADDY]

Looks like a tap on that exhaust valve

 

[Jfl0528]

Looks like a tap on that exhaust valve
View attachment 345916

Wow good eye, I have it right in front of me and I didn’t even see that

 

[JOHNDADDY]

Looks like a light hit but enough to lose compression,
piston's probably ok.

 

[Jim]

I marked the bad side with chalk, I don’t see any signs of damage

It's right here.
EDIT: Oops, shoulda kept reading. John beat me to it.

 

[Its been a long time]

It's right here.

View attachment 345920

Yeah, something has passed through there, it seems.

 

[Jan_P]

Thinking out loud This can be a cheap problem to solve
Rather Low mileage .the valve stem, play is tight unless damages
The valve taking a hit .. replacement
With some luck the pistons is OK
And bore also OK ..New rings
I give it a chance that lapping compound can make it tight again with some patience and work

Maybe new valve springs I would replace cam bearings ..because i have seen mine wear out
Inspection will tell