Oil fouled plug and low compression

Well, it seems I'm a complete shmuck when it comes to top-end work.

I got everything off (freakin' took forever, all just to get to the valve cover) and the next line in the manual was "make sure all the cam holder bolts are tight to 12psi", so I start unscrewing them to re-set them at 12psi (because they get tight after running, you know?). Well, they were tight, and of course, one broke off inside the head.

So wonderful. Now I have to figure that out. Any ideas? This is starting to look like the way I f***ed up my poor 650.

Oh, and now I can't take proper compression because one of the cam holders is loose due to a broken bolt. Ugh...

do a search for alum (i think thats what its called) i read about it on here, its supposed to eat steel and not aluminum i guess, turns the bolt to mush. maybe someone who has used it can clarify.....

Not sure why you wanted to loosen the cam cap bolts. They have nothing to do with compression really. In any case, you will need to repair the problem. Where is it broken off? Can you remove the cam cap and is there some bolt sticking out? If so, vise grips. If not, drill and retap. If you retap, you can use either 7mm or 8mm bolts to replace the snapped off 6mm. I recommend you just go with 8mm but I have used 7mm in the past. If 7mm, use 7mm w/1.0 pitch tap and 8mm, use 1.25 pitch tap. It really isn't that big a deal... just more work. Racers routinely just pull out all the 6mm bolts and pitch them and tap and replace with 8mm. Use the same length as a stock bolt.

You say that the plug is oil fouled and smoke comes out of the exhust when warm.

I would seriously suspect that you have a ring problem and/or a valve seal problem.

A leakdown test will tell if it is rings.

Post edited by: hwms, at: 2006/06/05 14:13

I'll pull the cam cap off and see what I can do about the bolt.

I was unbolting and rebolting them because the manual said to ensure 12psi on all of them. I was just RTFM (as so many on this forum suggest ).

What's a good tap set (if it gets down to it), as I don't own any and I know they can be pricy...

Thanks!

Well, I've learned two things today:

1) If you're going to drill the cam cap bolts, you need to take the head off and disassemble it to keep shavings from getting inside (which I didn't do, and so I now have an ugly amount of shavings in my head).

2) After removing the head, you need to use a drill press to do the drilling on a flat surface (I ended up with some irregular and too-wide drilled holes that will not hold the cam cap properly, and I don't own a drill press).

So now I get to go shopping for a new head (which is a shame, because the head I just ruined was new). All just to try to adjust my cams. I guess next time I'll just take it into a proper mechanic since I can't seem to do much to the engine without braking it.

Oh well. Some people just aren't cut out for this level of repair, eh? I can change tires, sprockets, chains, rebuild & balance my carbs, repair the electrical system, and just about everything else except anything that has to do with the engine and transmission (and to be honest, I'm pretty tired of screwing up my own bikes in the process ).

Thanks for the tips though! Had I done it properly, I'm sure it would have worked out great.

Bummer!!!,you might have tried using the camcap as a guide for your drill bit,if you didn't have a drill press.

True, true...that may have helped...

At least I have a garage to keep it in. I would be even more bummed if I had to cover it in a carport or something.

hey before you go crazy take that head to a machine shop. I learned the hard way; but they can fix ALOT. Its worth the time even if yhey say its shot at least you know for sure before you spend 100 on a new to you head.

They can even clean up the valve seats toss in some new seals and whatnot for you! It would be well worth your time; you may solve more problems this way (if your valve guides are out of spec and part of the problem!)

I'll have to look for a shop and see what they say...

There aren't a lot of machine shops near here...it's not a very industrial area (just really smug-y).

Thanks for the tip. We'll see what they say.

you need to put oil into the cylinders and take a second set of readings for compression. if the pressure is higher in any cylinder it represents piston ring wear. if the pressure is the same you have valve leakage. also if the readings are over 10% off from one cyl to another you have some work that needs done.
example
ie: #1 100
#2 95
#3 97
#4 104
the variance in this example will be 10 or 10.4 if you need to be precise and since the lowest to the highest cylinder difference is only 9psi you are in the good zone.
#4 seems to be the smoker if the side stand is bent and the bike leans heavily to the left. very common for our hallowed KZs'

Just a little follow-up:

I've pulled the head (after spending 15 minutes trying to break the seal between the head and the cylinders) and taken a good look at it.

I filled my bad drill hole with JB weld so I can try again with a drill press. Luckily, I only drilled one hole, so the other broken bolt will be taken out properly with the drill press.

I flipped the head over to see if I couldn't determine exactly what kind of smoke has been coming out my #4 cylinder (since that was the cylinder with the fouled plug) and low and behold, a ton of carbon build-up. Dry as a bone, so I wasn't burning oil, because that would leave a wet or tacky residue, right?

Here're some shots I took before I filled the hole with JB weld:

The hole:


The head:


And the #4 cylinder:


I took pics of the other cylinders and I noticed that #3 and #4 are significantly more fouled than #1 and #2, so I'll check my clearances on all 4 after I get the head back on (luckily, I properly labeled an egg carton and kept my intake and exhaust bucket-shims organized).

Here're the other cylinders (link):
kz1000p5.russbernhardt.com/photos/headrepair/

Kudos to Wired George if the deposits are carbon and not oil. I guess smoke color is subjective...

Any tips on how to properly clean these deposits without having to remove the valves? I don't have a proper valve spring tool, but if that's the only way, then I'll add it to my shopping list (I've learned the hard way that the right tool is usually 90% of the problem solved).

Thanks for the help, I get pretty pissed when I screw something seemingly easy up (but then I go eat some pizza and have a coke and feel better). :woohoo: