Screwed up big time...XJ head

[Jerry]

OK, tell me what I did wrong and what it will cost to fix. I wanted to replace the gasket under the XJ's cam chain tensioner. I took off the left cover plate, rotated the crank to the "C" position, removed the cam chain tensioner, replaced the gasket, and reinstalled the tensioner. I had compressed the tensioner spring/shaft in a vise before I put it back in, so did the standard cam chain adjustment procedure once I had it back in place; loosened the adjusting nut and stop nut, hear a noise as the tensioner re-adjusted itself, tightened adjuster bolt and stop nut. "C" mark was still aligned correctly Turned the crank about 1 revolution before I put the cover back on. Went to start, hear a clanking, now no compression.

Have not pulled the head, but probably bent a bunch of valves. Still cannot figure out what I did wrong.

Anyone have a good XJ head, ready to use as-is, or rebuildable? Maybe a complete engine?

I am really bummed about this, as it means no Yosemite rally for me this year unless I can get parts / pieces in the next couple weeks. And it figures...I had just done the first gear fix! The gasket replacement was the last thing on my list before the Yosemite trip.

[xschop]

cam chain adjuster

Shine a flashlight and see if the cam chain guide is still there. This sounds strange and gives me the GB's since I'm about to embark on the head rebuild myself. You shouldn't have to compress the tensioner with a vise before install. What you "heard" maybe was not the plunger releasing and tensioning the chain if it was lodged inside the tensioner housing.....Hope everything is O.K.

[trbig]

Pull your valve cover as it sits and see if there's slack in the chain. THEN pull the adjuster and see what's up with that.

Even if you bent valves, you can use the head you have and get someone to do a valve job for you. They are used, but I have plenty of the larger valves if you need them, Jerry. I hate to see anyone miss a rally.

After a seat/valve grind, (I'd replace the seals while in there. I have a new set of those also you can replace at your convenience if you need them...) the used valves should work just fine.

The first thing though is to tear a few things down to try to find the problem. A new cam chain wouldn't hurt either since that possibly could have been the culprit?? Rubber stopper fell off the end of the adjuster?? Maybe a stupid question, but are you sure the stop bolt didn't get stripped? I don't know, I'm just guessing here, but I wouldn't even consider a motor swap unless something was wrong with the bottom end of the one that's in there.... especially since you've done the gear fix on it already.


Tod

[prometheus578]

I have no idea what went wrong, Jerry.
Let me ask you... why use a vise with the tensioner?
I mean... one should be able to push the plunger back in by hand and then lock it down for installation.
Now... I know that you didn't do this:
Removed the tensioner...
"Gee it won't compress(forgetting that the bolt is locking it in place), I think I'll use the vise to push the plunger back in."
Then you forced the plunger back in... and when reinstalled and adjusted, it failed because of the wear groove that the bolt cut into it because of the vise use.

I know you didn't do this, right Jerry?
Right Jerry?

[HobbyMan]

Also, which way did you turn the crank to line up the C?

[Paintman]

XJ Head

Hey Jerry i cant figure out what went wrong unles liek prom said the nut wasnt loose when you compressed it either way good Luck and i have a good XJ head in shop if ya need it .
John

[Jerry]

Thanks for all the replies so far. To answer Prom, I did have the adjuster bolt and stop nut loose. I had pulled the shaft out of the tensioner housing to check for nicks or wear that would have kept the tensioner shaft from moving properly. (Didn't find any problems, FWIW.)

Just used the vice as it was handy to compress the tensioner spring/shaft assembly while I tightened the adjuster bolt and stop nut. Rubber tip was in place when I installed it

Turning the crank by hand...looking from the left side of the bike, pick-coil side, I turned the crank clockwise. Thats the same direction it goes when cranking/running. And, no, I didn't over-shoot and turn the crank backward (counter-clockwise) but went around again.

No doubt the cam chain is near or at the end of its useful life, replacement was going to be the next major project. I *thought* there was still a bit of adjustment in the tensioner, but maybe not. I didn't measure it to check.

I will pull the valve cover timer and check the chain, maybe pull the tensioner again, will probably end up pulling the entire head. Pulled #1 and #4 plugs, put my thumb over the respective holes. No vacuum or pressure while cranking, something is stuck open. Anyway, seems like the best way to go is pull what I have and see what the damage is, then go from there.

Thanks for the support and offers of parts / pieces; I'll just have to see what I need to do next.

[prometheus578]

"Just one of those things."

Sorry to hear about it, Jerry.

[saddle up]

Maybe pull the valve cover off, put her on the "c" mark and still see if the the cam dots or arrows are still lined up?
Bummer Man...



Moderator note - follow-up note inserted here to avoid any possible confusion from unintended wrong advice. KT

quote:
--------------------------------------------------------------------------------
Originally posted by dbeardslee
Saddleup - stop me if I'm wrong, but don't the cam dots line up on the "T" mark, not the "C" mark.
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Sorry guys, I didn't mean to give out bum scoop. you got me. An honest mistake

[81xsproject]

If you do replace the head out of simplicity, you could probably use an 80's XS head. Should be fairly easy to get your hands on one.

[skids]

Jerry, I screwed up one myself by overtensioning the stopper bolt and weakening the threads. When the motor was running, the tenioner then slipped to loosen the chain, but was held in the loosened position, chain slipped, valves bent.

[gareth]

1980 special head..

If the xs head is a bolt-on substitute for the one on the XJ, there is one listed on eBay right now with a claimed 15k on it. Color on the valves looks nice, complete with cams etc..

G.

[trbig]

An '80 or '81 head will bolt right on. You could trim off the XS head gasket material that covers the YICS area of the head, then plug off the tubes on the cylinders so they don't get moisture in them. Sounds like a good way to get rid of that YICS crap.

Tod

[dbeardslee]

Saddleup - stop me if I'm wrong, but don't the cam dots line up on the "T" mark, not the "C" mark.

[trbig]

I like to set my cams to the crank "C" mark now days... It saves gas when they don't start!

dbeardslee, you are correct. Sometimes you hafta listen to what people mean, not what they say... lol.