jumped timing chain

Bought a 77 KX650. Nice looking, garage kept bike. Rode girlfriend to Chicago from IN. w/o problem. Took to work, about 64 mikle ride. Ran super on the highway, but when I got off in the city, engine lost power, began smoking and I noticed lots of oil had blown out the crank breather. Started right up when it would die, but had a hell of a time getting to the job site another 6 miles away. I suspect timing chain jumped a tooth, 'cause it fires right up, idles smoothly, but barely pulls. Any suggestions before I go crazy on the engine?

A jumped timing chain shouldn't make it smoke and it wouldn't refire easily, do a compression or leak down test. I'm gonna guess scored piston.

You have ring issues most likely. Blow-by is a ring-thing! Do a compression check, as suggested and I am guessing a cylinder is way down on compression.

Did comp test first thing. Had three cyl.'s at 150 and the fourth at 145. Don't think that's too awful. Did pull v-covers and TDC'd the crank. cam arrows were in the right position, but not quite pointing at the head surfaces. . . ex seemed a hair above and the in seemed a hair under surface. Didn't look quite a whole tooth. Doesn't seem to have any slop in the timing chain, too.
Hmmm?

wonder if it has pods on it and a filter on the end of the breather hose, may be plugged up

BSKZ650 wrote:

wonder if it has pods on it and a filter on the end of the breather hose, may be plugged up

now that made a "click" noise in my head, if you have stock airbox, could be something shifted and covered the air intake (like a rain coat :blush: ) idles nice, even runs nice at small throtle openings but falls on it's face if opened up too much. I know this doesn't expain the oil, two problems maybe?

Unfamiliar with the term "pods". Carbs have individual smaller filters on each, and they are clear. Was told last night it was possibly a dead ignition coil. Gonna check that later today. If that proves to be the case, where might I procure these ancient coils? Is there a clearinghouse for older KZ PARTS? Oh, I forgot an important (maybe) item; when I accelerate, sounds like a massive intake leak (sucking air sound) but could find nothing wrong on the intake side.

How do the plugs look and what is the oil level???
I have some parts you can have I'll take inventory and get back with you. I think I have some coils if you need them. I would just get a set of dynas, but if you want stock ones I might still have them.

Oil blowing out of the crank case??

Post edited by: Snakebyte, at: 2007/07/11 08:12

Plug #1 damp, #2 lean, #3 and 4 rich. Guy I bought it from said he installed "larger" jets. Been out of the "wrenching" scene since the early eightys:unsure:
What are Dynas? E-ignition? I sure feel dumb sometimes.
Used to service foreign cars for a living, so I'm no idiot, but reading these forums makes me feel pre-historic. I surely appreciate any help. Yeah, got oil all over my new shoes that day. Before that, I did notice a small amount of oil leaking from the same place. At first I thought it was a head gasket, but the engine was dry everywhere except the crank breather.
The oikl has less than five hundred miles and looks like it just came out of the bottle. 10w40

Your cam arrows position sounds exactly like mine, compression is similar too. Sounds normal to me.

Since you have the valve cover off, check all the valve clearances. If they are small then that explains the lost power off the freeway, small clearances can produce that symptom... The clearance on a cold engine should be from .08mm to .18mm. Here is a link to a valve clearance chart kz650files.kz650.info/adobe/650ValveLash.pdf

The oil blow-by may just have been from overfilling the crankcase, you said the oil was fresh.
Check the oil level in the sight glass when it's on the center stand, it should be in the middle of the sight glass.

Will the bike start up and run now, or is it dead?

Check your intake boots for leaks. Cracks in the sides.
The most over looked leak is were the boot meats the head.

bike starts and runs great until you ask for power, then it's a chore to make it pull. Loud sucking sound too. Opened exhaust in the event it was plugged pipes. . . same thing. Not finding any intake leak.
Sucking sound has me concerned.