650 Engine Clicking

So there's this clicking noise that sounds like it's coming from the right side of the engine on the 650.

650 Engine Noise

(I can convert to another format if no one can play 3GPs.)

Anyway, this bike has never quite run correctly, and I recall it having kind of a ticking or knocking when I would ride it before, but only at idle. This year, I've decided to really get into the engine and fix stuff. Here's what has been done so far, in order:

1) Carbs removed and cleaned thoroughly. Enrichment wells blown out. Pilot fuel jets replaced (#40s, if memory serves). Noted that the main fuel jets were #120s. Ordered #114s for mains and #41s for pilots, since the bike has pod air filters and a 4-into-1 exhaust. O-rings in mixture screw replaced. Carbs cleaned and re-installed. Did NOT break apart the carb rack. Mix screws set at 2.75 turns out. Bench synched.

2) Installed carbs and used electronic sync tool to sync all four carbs. (Started and idled better after that! Surprise!)

3) Checked valve clearances. Decided to increase the clearance on six of the eight valves, if memory serves. Forgot to re-measure after installing new shims. :/

4) Found that the flange that holds the header on cyl #4 (starboard side) was rattling around. Quite loose! Tightened header bolts on all four cyilnders to 5.4 ft-lbs.

Bike has little in the way of engine breaking once warm and has this ticking sound. It also doesn't want to idle unless I turn the idle screw up a little too high (1350 or so). Throttle response is pretty good. Has plenty of oil. Haven't re-run a compression check in a while. That should be done with engine warm and TCI disconnected, yes?

Any other suggestions? I seem to recall that these engines have a problem where the main shaft bearings wear out, at which point the engine is pretty much done. Way to detect this? Pretty much anything else I think I can deal with. I've done a piston/ring replacement before and there is a shop in town that could competently replace valves/guides/etc. if a full valve job were necessary. Also, I haven't done anything at all with the timing chain, if that could be a factor.

Suggestions and ideas welcome. I'd like to get the old girl running right for probably the second time in her life (post sales) if possible. But if the engine is done, I'd just as soon put her out to pasture (part it out) than have it seize up on me while I'm cruising along at highway speed.

 

RELATED: I have a ColorTune plug, but no idea how to use it. The instructions that came with it are pretty darned thin...

 

RE: #3: "Decided to?" Either they were in spec or they weren't; now they're either in spec or they're NOT. Regardless, you do the valve adjustment BEFORE you sync the carbs, not after. Changing shims=changed the sync.

Go back and check your valve clearances, and put any that are out of spec IN spec. If you accidentally made one too loose, it could "tick" excessively. Just for gits-n-shiggles, check compression afterwards.

RE: #4: Now go back and torque them to spec: 7.2 ft/lbs. I'd also recommend replacing the pipe-to-head gaskets if you haven't: http://xjbikes.com/Forums/viewtopic/t=29356.html A minor exhaust leak there can manifest itself as a "tick" you'd swear is mechanical.

And use a dab of anti-sieze compound on the studs before you run the nuts back on.

 

Once you learn how to use the colortune properly, and get the fuel mixtures dialed in, It should take care of this problem.

As long as the oil is changed regularly. There should not be a problem with the bearings.

Ghost

 

I know. That's why I mentioned it. But I didn't want to spend a lot of time running the thing and chasing ghosts if the likely cause of the ticking was something more serious, which it doesn't sound like it is, from the replies.

"Decided to" means "because they were too tight." That is, within the range of measurement allowed by the feeler gauges. Anything that measured 0.10 exactly we put the next size smaller shim in, for example. We should have measured them again afterward, but we had measured valve clearances on five bikes at that point - one of which has four valves x four cylinders - and were rather sick of it. At any rate...

Yup. Will do. I'd also like to run a leak-down test, but not sure how. The compression tester "sticks" at its highest reading, of course. Is there a simple way to do this, or are very expensive tools involved?

We did torque them to spec. Looked it up just before we did it. If I put the wrong value above, it's because I was writing from memory 18 hours later.

I have the anti-seize. I'll get the header gaskets, re-check the valve clearances, check compression, sync the carbs, and see where we get.

Thanks for the advice!

 

The only trouble with THAT is that before I got my hands on her, I'm fairly sure that certain kinds of maintenance were not done too regularly. The oil I drained from the forks and from the rear were *green*. The engine oil was pretty dark, too. I've kept it up better than that, but who knows what damage was already done?

At any rate, I'm going to get a set of header gaskets and finish the usual tuning stuff and see if it doesn't settle down. Probably ought to check the cam chain tension while I'm at it...

Too bad, too. I was hoping to get this bike in good riding condition before the end of the season. May not happen at this point. Here's hoping, though...

 

That thread fitz wrote about the header gaskets suggests that they might need to be doubled up. I have a four-into-one exhaust, but it predates me, so I don't know if it's a MAC or not. Is it fairly obvious if it's necessary to double them up? If I get two sets and only need one, I can use the others on the 750, so it's not cost. I just don't want to cram two sets of gaskets in there unnecessarily...