Burning oil After Rebuild

[bikerphil]

[Rettic]

Been a bit, and not made any progress. I tried to do a leak down test, but my compressor has crapped out on me and only goes up to 30psi, so doing. a proper leak down is out. Tired to attach the compression tester hose directly to the compressor and felt air coming out of the breather vent and thought, awesome now I know it is the rings. Put it on #4 and got roughly the same amount of air flowing through, so I am still not sure what is going on.
Plan is to pull the head and jugs again to make sure all rings are set right and the gaps are good. Might as well. I am going to check the valve guides again while it is all apart. I hate that I messed up and it has kept me from moving forward. Wold be great to just have it magically work, but I guess I got myself in this mess.
Anyone want to come help run tests on it and get this done and over with?

[tarzan]

You know you can tear it down and put it back together in a weekend. You know it is in the rings from what I have read. I would pull it back down and check the suspect cylinder. Make sure the rings are installed in the right orientation. Also, I can't remember if this applies to the XS's, but sometimes certain rings have to be installed with a beveled edge or stepped edge either towards top or bottom. If you had a ring upside down, it could cause a problem. One other thing I would check is if the cylinder is round or tapered.

[ViperRon]

I am not sure where the problem is but since you can not perform a leak test I would first pull the head and look at the valves and stems for that cylinder. Follow all the previous advice on direction for installing rings and before pulling the seal hand move the valves up and down watching the seal. I have seen seals pushed down to hard cocked and be in a bind to where they leak oil because they are not centered arround stem. More than likely from what you have done testing and how it acts I would look for a broken ring or the gap spacing not being stagered. Even if the rings are burnt up or have too much gap and you are having low compression in the 90's you will not normally foul plugs. For the amount of oil you say you are loosing it normally needs a good gap to excape threw.

Also check the pistons for any cracks that would normally show low compression but check them.

Do it once more check everything and if any questions ask and send pictures there are many here who can help identify what's good or bad.

[trbig]

Did you MIC the cylinders for roundness and wear limits before honing? Over time, the cylinders get egg-shaped front to back.

My best guess on this, even though you say they were installed correctly, is going to be that bottom wavy oil ring. With it's acordian shape, it's very easy to get the ends to push together and jump over the other. (Imagine squeezing a "W" together to get a "V") If this happened, you'll have the oil usage you're seeing. The problem is... it's total disassembly to check this out. Cylinder roundness would be my next check since that's just a head removal. Just my 2 cents.

[Rettic]

Broked

Got the head off and investigated the cylinders. Basically what looked like burn marks on the cylinder wall of #3. Pulled the jugs off and found 2 issues, the bottom oil ring was in 2 pieces and the piston has 2 indentations on the side. Heres what I need to know, can I get it re-honed without worry about needing bigger pistons, and does anyone have an extra piston if I do not need to go up a size?
Measurements from initial honing (they told me there was no roundness issues):
1-2.817
2-2.8175
3-2.8175
4-2.8175
Piston Marks
Busted Ring
Cylinder Wall
No fun, this sucks. My old xj650 is getting alot of love right now.

[petejw]

that sux, but at least u now know whats
wrong with it,

hard to tell by the pics, the 'burn'mark on the bore,
if u can run ur finger nail over it and it feels the same
as the rest of the cylinder u should be ok, but if theres
any scoring ull need to rehone, depending on the depth
of the scratch will depend on whether u need new pistons.

regarding the piston, if ur talking about the small notches on the top
of the piston, i would just smooth it out and not worry about it.

[GLoweVA]

I've got 3 used pistons here that I'd gladly send you. I've also got some used rings too. When I did my #4 piston replacement last year, I redid all 4 sets of rings, so I've got the old ones still. I'll offer them up to you too if you want them.

There's a spec in the manual about how far down you can hone until you've got to go up a size in the piston diameter.

[WSL91]

Got the head off and investigated the cylinders. Basically what looked like burn marks on the cylinder wall of #3. Pulled the jugs off and found 2 issues, the bottom oil ring was in 2 pieces and the piston has 2 indentations on the side. Heres what I need to know, can I get it re-honed without worry about needing bigger pistons, and does anyone have an extra piston if I do not need to go up a size?
Measurements from initial honing (they told me there was no roundness issues):
1-2.817
2-2.8175
3-2.8175
4-2.8175
Piston Marks
Busted Ring
Cylinder Wall
No fun, this sucks. My old xj650 is getting alot of love right now.

I wouldn't sweat the nicks on the top of the piston, take a fine file and knock off the high spots., don't try to file off the low spots. How deep is that big mark in the side of the cylinder? Can't tell from the picture but a big bore kit is 2.5mm larger so unless its just a honing mark deep you are looking at boring that cylinder. While not best case practice you could theoretically find 1 oversize piston/rings and have that 1 cylinder bored. Other option if to find a new set of jugs that are in good shape.

[skipper]

Best guess is that you installed the jugs over the pistons rather that pulling the pan and inserting the pistons one at a time from the top. It's awfully easy to break a ring when you have to install two at a time (I've managed to break a few doing one at a time). I would beg/borrow a bore gauge and check that burn area. Chance there isn't any damage and you can just replace the rings in that hole.

[Rettic]

What do you mean by removing the pan? Do you mean removing the PIN from the piston and then reattaching underneath? I know we tried that the first time and was able to get the pin back through the piston easily. i do feel a small grove near the top of the burn marks, so I am going to run the jugs by a machine shop to see what they say. Will let you know if they need more work or not. Thanks for the pointers guys!

[Rettic]

Just took the jugs to a shop that does honing and they told me since there is an indentation that can be felt, it would have to be bored at least 10 and would need an oversized piston. So, I have a few options I can think of:
Big Bore kit (the one for 150 on ebay)
Find a new set of jugs ( anyone have a good set? )
or find a parts bike (anyone got one laying around?)
Bout tired of broken stuff. Shouldn't have torn the engine down.
Chris

[skids]

I would just find a good running engine with good compression and just swap it out.

[Rettic]

Found a parts bike

Looks like I am picking up a parts bike tomorrow night. Found one complete on craigslist for 300. After talking to my wife, she said sounds good. Gotta love an understanding wife. http://columbia.craigslist.org/mcy/3204949261.html Taking my compression tester with to validate, but the guy SAYS that it ran when he got it earlier this year. He says it had been sitting with the previous owner for 8yrs. The plan will be to swap the engine out and next year some time bore out the messed up jugs and complete the engine build up and get a 2nd bike on the road. Just want to get my current one running for now because of all the work I have put into it.

[tarzan]

I've bought three XS's in the last couple months. I would beat him up on price.
Not running, under $200 would be my goal. Although, you guys on the right coast seem to have to pay a little more than on the west. Remember, even if it ran when he got it, that doesn't necessarily mean the trans is good, among other things. Sometimes you have to remind a seller of these things.