XJ Inconsistent Idle

[Smash]

I'm absolutely petrified of messing up the cam chain!

But at that cost, either we don't do it or we do it ourselves.

[motoman]

Take CaptionZap up on the offer! Wasting time trying to get sync right if valvetrain is off a bit. Carbs is the last thing to mess with untill your sure primary and secondary igition and valve adjustment are all good. In this case, definitely be worth checking those valve clearances.......then tune and sync the the carbs. Would definitely be worth having some assistance and guidance!.......not worth the valve-train damage if your unsure of your capabilities at this point!

[Smash]

Take CaptionZap up on the offer! Wasting time trying to get sync right if valvetrain is off a bit. Carbs is the last thing to mess with untill your sure primary and secondary igition and valve adjustment are all good. In this case, definitely be worth checking those valve clearances.......then tune and sync the the carbs. Would definitely be worth having some assistance and guidance!.......not worth the valve-train damage if your unsure of your capabilities at this point!

Yeah I agree. While the sync helped it is clearly not the source of the problem.

CZ was such a huge help with what proved to be a simple problem of removing that stuck middle drive fill bolt, I'm hesitant to inconvenience the kind man again!

[3Phase]

While the sync helped it is clearly not the source of the problem.

Smash, this is a real long shot but check the vacuum advance switch to see if it's 'hunting'. If the carburetor synch is off and the #2 throttle plate is open too far it will start to expose the vacuum advance port to high idle vacuum and that could trigger the advance switch.

The XJ's vacuum advance switch is on the frame under the gas tank and it's hooked up to the #2 carburetor with a small vacuum line just like the XS11's mechanical vacuum advance.

To test the switch, pull the vacuum line off the carburetor and cap the nipple.

Connect a vacuum pump to the vacuum advance line then, while the engine is idling, use the pump to trigger the switch and listen for a change in engine RPM.

[CaptonZap]

Yeah you guys are right, I'm just wishing it wasn't so.

Ugh, called the local shop we use occasionally, and even with a reasonable shop rate ($66/hr) we're still looking at $270 or so for the valve check/adjustment depending on # of shims needed.

Smash, once more, if you want to check them, give me a call, I will tell you what to do to get ready. If they need adjustment, it will take longer to get the shims than it will to change them. I have the tool. CZ

[CaptonZap]

I'm absolutely petrified of messing up the cam chain!

But at that cost, either we don't do it or we do it ourselves.

Here is a thought.
If you are worried about the chain tension, the best way to do it is to take the
cover off the left side, set the wheel to "C", take the cam cover off, apply tension to the chain, and remove the tensioner.
Install the new or fixed tensioner, release the chain. If you want to tap the tensioner for the bolt mod, I have the tap. Release the tension, rotate the engine and check the timing marks.
Now, since you're in there, check the valve clearance. You wouldn't want to burn a valve or seat. That makes junk out of engines.
Now, if you are in a rush, and don't want to take the cam cover off, you can do the tensioner without takeing the cover off. Takes 15 min.

Simple. CZ