XJ comes to life... A couple questions

Hey guys. Just took my 550 out on the highway. So far so good, except for a cuple of things:

1. Master cylinder: I've rebuilt both the master cylinder and the caliper assembly. It seems like the brakes drag just a bit. One thing I noticed reading the posts is that there's a pressure relief hole in the reservoir (?) does that need to be cleaned out for proper brake return?

2. After the engine got to operating temp, I noticed a very light valve tap. Could the oil be too thin? I changed it a few days ago, but I'll be changing it again today. The bike has only 7800 miles on it (well, 7815 now). Could it be the CCT at such an early age?

3. What, if any, oil additives can be used in this thing, like lucas or anything like that?

Thanks!

-vlad

 

Glad to hear you got riding!

1 - yes - if that hole is blocked with some crud you'll get dragging brakes.
2 - could be, you didn't mention what wieght oil you're running, or what temperatures are like down there right now. I'd say you should be running 20w50. Not likely to be a timing issue, or even shims yet.
3 - my personal belief is none - oil additives in modern oil are asking for trouble, especially in motorcycle engines.

 

Ditto what Altus said.

 

If you have a front caliper that "Travels" with the pressure. Your traveling bushings need cleaning and lubing.

Noises from bikes that sit for awhile:
Exhaust Flanges
Valve train. Particularly if an Exhaust Valve was open for a long time.

You can tape a section of hose to the end of a probe and listen for the exhaust leaks.

You might as well:
Check the Valve Clearances
Check the exhaust system
Check the Cam Chain tension.
Experiment running a tank of High Test to rule-out pinging.

 

As always, all great info..

To follow up:

The temperature here in Oklahoma is fairly hot, I'd say in mid to upper 80F. The oil seems a bit thin, now I'm wondering if I got some gas in it when I had it bottle fed. I'll change that tonight. What weight is best for hot climates? 20w50 still ok or is there something thicker I should try?

It seems that when I'm going down the road, the rattle gets louder when I'm not accelerating and not decelerating, just kind of running it mid-band. When I speed up or slow down, it completely disappears.

I just found out that my drive chain is a little loose. I'll be tightening it ASAP.

There's definitely crud in the little pressure relief hole because the entire front brake system was full of coagulated brake fluid that I painstakingly cleaned out (replaced the master cyl. plunger, replaced caliper seals, buffed the piston, scrub scrub scrub). I didn't even realize there was a hole there. I saw the "incomplete" hole... That's DIY noob for ya

Would it help to run some seafoam through the fuel system to help the valves a bit?

I'll check the cam chain tonight as well. Any special tools required for this?

Thanks!

-vlad

 

20/50 oil should be great unless you've planning an extended say in hell or somewhere warmer....

Cleaning the return hole with a NYLON brush is easy and quick - should solve the dragging problem.

Seafoam NEVER hurts Not really for the valves though - mainly for your carbs.

Pretty sure you've got the manual cam chain adjuster like mine -- you loosen off the lock-nut and bolt, then tighten 'em back up - that's it. IIRC, it's a 10mm wrench for the bolt, and 12mm for the lock-nut.

 

Quick update:

Changed the oil (castrol 20w50), re-tensioned the cam chain (put timing plate thingy on the C mark, backed out the bolt, tightened back up). The rattle is not as pronounced, but it's still there. It appears pretty much when I keep the throttle right at cruise level - I dunno how else to explain it. When I decelerate or accelerate it pretty much disappears.

I filled up with 91 octane, so I'll find out tomorrow if it's detonation. I do think that cam chain tension was off, because I feel a bit more pickup now.

Rick, you mentioned one of the possible noise sources could be valve train... What, in short, would be involved in diagnosing it -- is this something that would be better hired out or is it no big deal?

The front brake us much, much better - I cleaned out the little pressure relief hole - there was no doubt it's clean now -- it shot brake fluid a foot in the air, and no more drag. Sweet.

 

No bid deal ...

Use a long-enough probe to touch the engine where you think its making a strange noise.
Listen to the other end of the probe by ... pushing the probe onto the rngine with your thumb on the end of the probe ... "Listen to your thumb ... pushing the probe stick.

You'll hear the internal noises. Rotational, tapping and ticking. If its a valve, you might have to adjust the shim for a closer tolerance.

In the mean time ... take comfort in knowing that nobody ever burned a valve they could hear closing.
I have stated many times before.

Running RICH (a little rich) is Good. Lean is what does-in an engine.

Some noises a GOOD. Valves rattling and ticking a little bit isn't a bad thing. You know that they are closing good and that the likelihood of needing to replace a burned valve is slim!

 

Cool. I'll do that as soon as I get home. As far as mixture goes, I don't think I'm running lean - if the engine is warm, and I set the choke to anything past half, it just sputters and dies. If I'm riding, even a little choke makes it run like crap. I hardly ever have to use it to start.

 

Don't over tighten the drive chain they need a bit of give.

I set the drive chain a bit slack then check with the rider (and a pillion if that is nornmal riding condition) sitting on the bike. There should be a small amount of give to account for bumps in the road.

A over tight chain will self destruct and maybe damage the countershaft seal and or shaft.

 

Ok.... I've put my home made stethoscope on the engine in various places. The only problem is, I have no idea what to listen for.

The engine sounds great when it's cold, or when it's not under load. I only hear a (what sounds like) valve rattle when I cruise or accelerate slightly, in just about any gear, after the engine has fully warmed up. If I really step on it, the noise seems to go away. Same thing when I let go of the throttle while in gear.

It sounds like valves, but can they make so much nose without affecting performance? The bike runs like a top. No flat spots, no bogging down... It just goes. As a matter of fact, I'm kind of surprised how much a 550 can you set you back in your seat when you twist on the throttle.

Sorry for being so thick, but I'm just trying to understand the problem a little bit before tearing into it. The bike has been sitting for 20 years, but with only 7800 miles on it. I don't understand how the valve clearances could have changed if they hardly had a chance to wear down. I can understand a weak spring or some rust build up on a valve seat or something like that... What happens to valves after 20 years of sitting in a barn?

I'm gonna check the valve clearances this weekend, and post the results.

 

Here's a suggestion.......when I hear that on my bike, I KNOW what it is. It is a loose down pipe. When your engine is COLD, grab a hold of each pipe and give it a good wiggle. Chances are you have a slightly loose exhaust pipe. Retighten the nuts holding the collar and the sound will be gone. I have that happen every couple years or so. The first couple times, I had a good scare when I thought I had just eaten a valve, until I learned to check the pipes. Now, when I hear it happen I just think "uh-oh, sounds like I just ate a valve shim...........wait, maybe I better check the pipes when I stop". Then, it turns out to be a loose pipe.

FWIW,

dave
63 xj650 maxim

 

On the 550 I just replaced with a 700, I had the engine noise you're speaking of. I had 3 different motorcycle mechanics look at it and they all gave me the same answer. "one of the cam chain components is bad". I didn't have the money to replace (And wasn't brave enough to take the engine apart) so I kept riding it till the rattle got REALLY bad and sold it as a project bike on craigslist. At the time, the best price I had to get it fixed was $700 and it could be more pending complications. One solution would be to try and find another engine and just swap it out. I was going to do that, but the salvage I used at the time went under and so I never got the engine.