Serious problem with Cam Chain adjuster

Hey all!

Got together with SalCycle today to give the XJ some much-needed TLC.

We took the carbs off, cleaned them a bit, but the #3 and #4 drain screws are totally seized. Didn't get the carbs apart as much as we'd have liked, but we decided to sync and colortune just to get me running reasonably until I can get the carbs ripped completely apart for a proper job.

We took the carbs out, drained them as best we could, but were stymied by the stuck screws. Mixture screws turned like they were new, so we had a spot of good luck there. SalCycle bench-synced the carbs, and made sure all the mechanisms worked the way they should. Butterfly seals looked A-OK.

While we were reattaching the carbs (for at least the fourth time, man you get good at that quick!), SalCycle suggested resetting the cam chain tension. As this has been suggested, nay demanded on the boards pretty frequently, I agreed and we got to work.

Here's where things start to get interesting. We reset the tensioner, but forgot to take the ignition cover off and do the two-clockwise-rotations thing. Hooked up a satellite fuel source (long hose to tank), found a fuel leak at the incoming T junction for the fuel line due to mashed O-rings. We replaced the O-rings without incident, and the fuel leak stopped dead, yay.

After we got the carbs put back on, reconnected fine, we fired the bike up. We were then greeted by a very uncomfortable rattling noise from the top of the engine. We immediately shut the bike down, suspecting that the tensioner had malfunctioned. Pulled the tensioner out, set it back to the mark on the shaft that corresponded to the previously unadjusted position to see if it was just an issue with the way we fiddled with things. No dice. still making the horrible rattling noise.

Even though it was getting pretty dark and late and we were getting tired to the point of making silly mistakes, we decided to take the head off so we could inspect the valves and the timing chain. Lo and behold, there are brand-new shiny scrape marks on the bottom of the head cover where the timing chain has been flying up off of the sprocket to pitter-patter on the underside of the head cover. Problem located. We pulled the ignition cover off, did the two-clockwise-rotation trick and reset the tensioner. No change. Engine rotates as expected, valves operate properly, cam chain is still loose to the point where you can get a good finger's worth of slack out of it.

We're now leaving SalCycle and I's combined comfort zones.

Question out of all this is: What are our options when it comes to either manhandling the tensioner so it actually does its damn job? Does it sound like the timing chain has just become stretched enough that the tensioner can't adjust anymore and the chain now needs to be replaced? Am I going to have to crack the case and get a bunch of very expensive parts?

Help! My poor XJ is sick and we need help putting her back together again!

 

Oh yeah, forgot to mention that I did a 150km round-trip this weekend, and the bike ran like a swiss watch. Finally got a chance to open her up to 7k and felt the four-cylinder ROAR that makes an XJ owner proud.

This cam-chain thing wasn't an issue then, it only started making noise when we tried to let the auto-adjuster do its thing.

 

Lefty:

You have a MANUAL Tensioner on that bike.

The "2-Turn Method" is for AUTOMATIC Tensioners.

You have to follow the "Timing Procedure" ... and then, Rotate the Engine backward to present the Timing Chain Slack between the Crank Sproket and Intake Cam Sproket.

When you have the Slack that in the Chain presented between the Intake Sproket and Crank Sproket ... you release the Tensioner from it being reloaded.

Slack the Rod Holding Bolt.
Release the Tensioner
The Tensioner Rod will push itself OUT to take-up the slack.
Tighten the Rod Holding Bolt so the Chain won't push the Rod Back.

You are one lucky Mugger-Fogger that you didn't "Throw the Chain"

>>>>>>>>

Either:
Reset the Tensioner presenting the slack before-it before the Tensioner is released ...
-or-
Find yourself a decent used Automatic Tensioner and Upgrade to Auto.

Don't run the bike until you get the slack out of there. Be sure to check the marks and do a Test-Lift of the Chain off the Guide Bridge between the two Cams.

If you can easily lift the Chain off that Bridge ... it isn't right!!!

 

Rick, when you turn the motor forward, the slack is on the tensioner side. Does it get caught just below the tensioner sometimes? I don't understand why turning it backwards will help. That will just put the slack between the exaust cam and the crank, not where the tensioner is at all. (When you say backwards, do mean clockwise (looking at the ingnition plate, of course)? )

When we removed the tensioner, I noticed that the mark from the set screw was very close to the end of the shaft.

When we installed the tensioner, I released the tension as per the manual for my bike.

THe timing is good. Nothing slipped.

What led me to release the tensioner was the noise the chain was making, albeit it was a much quieter one than the noise made after I released it.

 

OK ...
When the Engine is rotated Clockwise ... the Crank Pully is Pulling the Chain down from the Intake Sproket.

That's a False Tension. Because the Slack is going UP the Front between the Crank Sproket and the Exhaust Sproket.

The Skack needs to be in front of the Tensioner.

To do that the Crank Sproket needs to feed the Chain UP to the Intake Sproket and get it in front of the Tensioner.

Since I cannot inspect any of the components, and as you say ... your at the end of the Tensioner Rod's travel ... It might be the best course of action to replace the Chain.

Although ... a Chain is supposed to be good for 45,000 Minimum and almost 50,000 Miles before being evaluated for replacement.

Since the Chain is so vital a component and any mistake we make emailing what the situation does NOT allow for a proper diagnosis ... I would be remiss if I didn't suggest you replace the Chain after hearing how slack it is and that the Rod is at the very END of its travel.

For ALL concerned and with the life of your engine at stake:

Have a NEW Cam Chain Installed.
Safety FIRST!

 

Right. There's no need to turn it backward/clockwise.

 

Yeah, not comfortable running the bike under any circumstances with timing chain problems, that's for sure.

SalCycle and I discussed replacing the chain without cracking the case, is that possible?

Also, thanks for the insight, Rick

 

Oh, yes ...

No splitting cases.
Just snaking the new chain around.

The process involves breaking the chain.
Attaching NEW Chain to OLD Chain.
Rotating the Crank to allow the OLD Chain to come-around and bring the NEW Chain UP.
Disconnecting the Old Chain and fastening the New Chain Ends Together with whichever style is used.
Rivet or Master Link.

I don't do them. I outsource that job to someone with PLENTY of experience and the exactly right tools.
Too much at stake for not having done one in 15 years.

 

Had to replace the cam chain on my old '82 Seca 650 (28k miles), the tensioner was at the end of it's travel with a noisy chain. Took the cams out to have room to work, my daughter turned over the crank while I fed the new chain in wired to the old one, keeping tension on the old one coming out. Used a small chisel and with her backing up the master link with a large hammer head, I punched a slot in the link pin ends, just enough to retain the link plate.
Take your time, it's really not that bad.

 

The only problem with replacing the cam chain without digging deeper is the question as to why resetting the tensioner created such a monster. Might there be other problems down below, such as the guides?


Lefty, since you've got that messy head gasket leak......??????

 

Wait a minute!

There's only 14,000 Miles on that bike?

NO WAY you need a Chain!

NO WAY in h***. Something ain't right. But, it sure ain't the Chain!

***Edited by Robert, mind the language please. Thanks.***

 

We'll take another crack at it tonight, there's gotta be a simple answer here. It was absolutely fine before we touched the tensioner.

Wish us luck!

 

I think I'd look to see that the Chain didn't get-off the rear guide.

I like to have a Video of you guys working on the Chain Tensioner.

When I did my shims ... I had the Intake Cam jump out of the Journals and the Tensioner took up the slack in a heartbeat. (Auto)

I had to remove the Tensioner and get the thing Re-loaded and get it back on the bike and then put the two springs back in.
My wife and I managed to do it without taking the Carbs off the bike!

 

Headed over to SalCycle's place to see if we could get the XJ back together and running without timing chain issues.

Long story short, success! We managed to finagle the tensioner into taking up enough slack to make it rideable, but I'll be sourcing a new tensioner off of Fleabay within the week. The chain guides are fine, as when they're pushed gently with a finger, there's no slack at all, and the chain turns perfectly. Whew! I'll be babying it until a shiny new auto-tensioner arrives.

Rick, you were absolutely right, it was a manual tensioner. The rubbery plasticky bit that actually contacts with the chain guide looks like it got overheated or something, got a bit soft, and the chain guide left an impression in the face of it, so even when the rod is at full travel, the acutal stopper bit on the end isn't giving as much tension as it should. We managed to get the rod to release just a hair more to get reasonable tension. I'll take pictures when I get a new tensioner and show you what I mean.

It's safe enough now, it's not flying up off the cam sprockets anymore. However, no 8000rpm traffic weaving for me for the next few days.

Thanks again to SalCycle for the use of his tools, his garage, and his noggin. When he gets his 550 put back together, we'll be doing some serious joyriding. Hooray!

 

Rick, the chain isn't off the tensioner. I was able to push it with my finger and take up the slack.

Yeah....video would be nice.

Here's what we did: We let the rod go beyond it's stop to get more slack out of the chain. It's just a temporary fix, so that Lefty can get his bike home and order a new tensioner. If that doesn't do it, then well...we'll see.

Lefty's tensioner is different than mine, so I"m not sure how it's supposed to look, but it looks as though the plastic end that pushes against the chain guide is worn a little.

I haven't seen enough of these chains to make a good evaluation on the condition of the chain, but it seems pretty good. But...

I know that you're saying that a bike with this many miles shouldn't have much wear, but, from my experience, poor lubrication of some kind or the other on roller chain greatly reduces the life of a chain. I realize that the thing lives in oil, but there is far more surface area of friction on that chain that any of the bearings in the motor, and if that oil is bad it will experience more wear than other components.

That's all for now.

Thanks again for the help.

 

Considering the PO used 10w30 car oil, I'd be surprised if that's the only issue that's come to light in the engine. I'm worried that the clutch/transmission was greatly abused due to the "friction stoppers" that they put in car oil.

Nothing but the finest 20w50 wet clutch oil for the XJ now, though.

 

I'm very happy you guys got that worked out. I'm pretty sure that the only difficulty swapping over to an Automatic Tensioner is going to be locating the Auto-tensioner.

Be prepared for a bit of frustration installing an Auto Tensioner. The slack gets pushed-out by a PAIR of Springs. The smaller diameter Spring is placed within the inside of the larger diameter one.

Getting the End Cap "Close" to buttoning-up the Tensioner is easy enough; but the last 10mm needed to compress the combined force of both Springs is quite a difficult maneuver with the Carbs on.