$150 XS score! now unfreeze the engine?

[xscorex]

I was hangin out at the boneyard and bought an almost complete 81 xs650 for $150, the engine is of course locked up as its been sitting in a backyard for 20 years. Usually I would spray pb blaster in the spark plug holes every day and try to kick it until it frees up. But I saw on youtube dudes put a hose in the top breather mount and then run marvel mystery oil and diesel fuel mixture and pump it through the engine. Ive never seen this before , I don't really understand exactly how to pull it off. Has anyone done this? can you give me specifics of where to stick what hose and things I need to plug? looks like it flushes out the whole system and gets any rust out. Any tips or ideas.

 

[DogBunny]

Don't know what he was un-sticking, but on an XS650, 99.999% of the time it is the pistons that are stuck. So, you put penetrating fluid of your choice in the cylinders via the spark plug holes.
A lot has already been written on this, just do a simple Google search using "xs650 stuck motor" or some such terms.

 

[nj1639]

And don't be kicking it to try and free it up. Get an air gun or a breaker bar with a rubber mallet and hit the crank under the left side engine cover.....shock whacks.

Lucky score !

 

[xscorex]

Ive already poured marvel mystery in it, thats the way I've always heard to try it why shouldn't you try to kick? I was just wondering about this way I saw on youtube as it looked pretty good. ill try to post some links. basically looks like they run the diesel through the top then out the oil plug then a pump cycles it back up, I guess running it through the oil pathways.

 

[Downeaster]

By trying to break it loose with the kickstarter, you're stressing the entire drivetrain. It's better to apply the force as close to the problem as possible. In this case, the crankshaft.

There are nuts on both ends of the crankshaft that you can put a socket and breaker bar on. Even here, brute force is NOT the best approach. Patience is the key.

Tapping on things to set up vibrations to encourage the penetrant of your choice (I like PB Blaster for lightly stuck stuff, a 50-50 mix of acetone and ATF for the real boogers) to seep down through any openings is also helpful. Again, brute force is just asking to break something so wailing on the end of the crank with a 5 pound hammer is not the approach to take.

Soak, tap, try, repeat. If it starts to move a little in one direction, rock it back and forth to work the penetrant in.

Patience and Persistence.

 

[DogBunny]

Okay, I'll say it: It's a terrible idea. You don't need to oil the whole engine, you just need to lubricate the cylinders.
Kicking can damage the kick mechanism, trying to rotate the crank puts force where it is needed.
If it is just mildly stuck from sitting, it might free up. If it seized from abuse, you will never free it without disassembling and whacking the pistons. Lots of other methods and ideas if you do the search I suggested.

 

[jd750ace]

I've found that heating the MMO to boiling in a coffee can then funneling it in the top gets heat and deep penetration where it will do it's magic. Unlocked an old Benelli single that hadn't turned in 30 years like that.

 

[5twins]

It's probably not a good idea to run one that's been stuck that long if you do get it free. There's probably a massive ring of rust in there. Rubbing it away via the rings will accelerate their wear, not to mention all the rust particles that will get circulated through your motor, possibly damaging other parts.

I worked on one last summer that appeared to have this done to it. That cylinder was badly worn and had a ring etched into the bore where the rings had sat. The rings were way out of spec and the rod small end was toast. Sure, it ran for a little while after being freed up, but did a lot of damage in the process.

 

[gggGary]

+1 anything beyond a light stick, is going to be a ticking time bomb even if you do get it freed up....

 

[peanut]

easiest way to free up stuck pistons with the maximum force and minimum damage is to ...

Remove sparkplugs
Pour some thin oil in the bores (gunoil,3:1etc )
Stick the bike in 2nd gear
Pull the clutch in
Run like crazy down a slope jump on the bike and drop the clutch when you've got a good speed up.

If that doesn't work ...its time for a lump hammer and a piece of 2"x2" hardwood

 

[gggGary]

Remove sparkplugs
Pour some thin oil in the bores (gunoil,3:1etc )
Stick the bike in 2nd gear
Pull the clutch in
Run like crazy down a slope jump on the bike and drop the clutch when you've got a good speed up.

Done this and it's worked a few times, put several hundred miles on a CB350 after a run and bump break free.

 

[ippytattoo]

The first xs I had I got with a stuck motor. Used the old Marvels Mystery Oil in the cylinders trick. Put some in through the spark plug holes and let it sit for a couple of days, repeated a couple times and then put it in gear and rocked it back and forth a few times and it broke free. I must have put about 1500 miles on it before I moved and had to sell it.

 

[peanut]

Remove sparkplugs
Pour some thin oil in the bores (gunoil,3:1etc )
Stick the bike in 2nd gear
Pull the clutch in
Run like crazy down a slope jump on the bike and drop the clutch when you've got a good speed up.

Done this and it's worked a few times, put several hundred miles on a CB350 after a run and bump break free.

 

[xscorex]

Ive had marvel mystery in it for a few days, I cut the chain off because it was rusted and I couldn't roll it. Its a real POS but for $150 I figured I could part it out or at least get the engine freed up and build a chopper with it.

 

[jamesgs4]

like Downeaster says, 50/50 ATF and acetone.

 

[xscorex]

well, with the breaker bar and marvel mystery its been over a week and no luck, looks like Im gonna have to pull the head off. Ive never done it before. Kinda scary, but I guess I gotta learn sometime and I cant really break it more than it is right?

 

[nj1639]

Marvel has a unique smell to it. Check the oil and see if you smell it down in the case.

Have you checked the intake and exhaust ports for whatever condition you can see? Sometimes critters make homes in there......

 

[DozerDan]

Kroil. Its pricey but by far they pest penetrating oil I have found.

 

[5twins]

If you're going to be dealing with old bikes, especially old junk bikes from junkyards then yes, you're going to have to learn this topend teardown business. These really are quite simple to work on and pretty much every one, even those not seized, can benefit from having the topend gone through. It's that cam chain front guide thing, they're pretty much all going bad now.

 

[xscorex]

I actually have two xs650 manuals. I think I have a Clymer and another one. Ive had about 6 of these bikes over the years but have never had to pull the engines apart. Is there a walkthrough somewhere online I should look at or should everything be in the manual?