Oh No!! I've got a big problem!

[trbig]

Shawn,

I have an XJ, running an XS motor, with XJ heads (YICS ports plugged) and XS cams. FINALLY got to ride it a few days ago.. after a mess with synching the carbs... runs smooth, and accelerates hard. Yesterday was the first real day of riding. I have stock airbox and exhaust with some holes in the baffles in back. I am going for a hard run up what these Okies call a mountain (hill), and will check my plugs today, but it runs better than it ever has since I have had it. I agree with TC... you could play with your carb floats a couple mm each way and get your mix right (If it's even off) and probably not have to buy new jets, since the Mac exhaust is your only change really from stock. Talk to TC about pre-synching the carbs (No bread ties).... mine ended up being pretty much right on.. only 1/2 pound variance to any of the cylinders.

Tod

[trbig]

Sorry... I am running the XJ carbs on this bike.


Tod

[Shawn27530]

THE VERDICT IS IN!!!

Ok this afternoon, I got the jugs to come up rather easily, but when #2 and #3 got to the last maybe 1/3rd of the cylinder it stopped and would not budge, I had to take a prybar and put it underneath the cylinders and pry up and hit #2 and #3 pistons with the wooden handle end of a 3 pound sledge, after an hour or so I got the cylinders off after the rings on #2 and 3 broke.

Well there is no friggen wonder the thing wouldn't turn over. About the last inch and a half at the bottom of #2 and #3 was badly corroded and pitted, so bad that the shiny part of the sleeves was missing in about a golf ball size section at the bottom. How in the world the bottoms of these cylinders corroded so bad is beyond me. When I got the bike it was all sealed up, Air box, Carbs, Exhaust, etc.

So Boys! There is your answer, The piston rings could not go past the corroded portion of the Sleeves.

[TopCatGr58]

Not being one to GLOAT!!!

12-10-05 post:

With the engine spinning just so far and stopping, it's hitting on something. And since the topend is clear of FOD(foreign object/debris) then must be something in the bottom below the pistons, either a broken piston skirt, or else getting caught on and between the balance sections of the crank and the case?? Will be interesting to find out what it is!!
T.C.

12-13-05 post:

As for the XJ engine, sounds more like there may be a large deposit of RUST inside one of the cylinders? Perhaps one that had the valve(s) open to the atmosphere, either intake or exhaust, and humidity and vapor got in and rusted the cylinder walls pretty thickly?? I know I had a bit-o-trouble getting my cylinders off due to corrosion around the case threaded rods that the head nuts bolt onto, as well as RUST in the cylinders!

[Shawn27530]

You were right!

Well you hit that right on the head didn't you. You Da man T.C. LOL, It still seems to me though that with the valves being open to atmosphere on #2 and 3 that it would rust above the rings, but anyway, its a done deal.. Thank you guys for all the ideas

I hate when people leave a perfectly good motorcycle outside, its sinful I tell ya.

[fxrer]

"How in the world the bottoms of these cylinders corroded so bad"

Shawn,

Thanks for your diligence in determining the "cause".

Now, all you XSer's........... How could that happen?

[prometheus578]

"Hey everyone... come on over and meet my friend Rusty."

Nice work, Shawn!
Now... how did the bottoms rust like that... that's the real mystery.
Wait... I have another theory about THAT!
Suppose that... blah blah blah.......
Real deserved praise to T.C., as usual!
Nice job!

(HiVo chain... what was I thinkin'?) Doh!

[pggg]

Apparently it's not rust but corrosion. battery acid?

[e.z.nightrider]

Could it be from combustion blow by in old oil which can form acids in the oil? A good reason to change oil before the winter lay up and do regular oil changes.

Ed Z.