top-end troubleshooting redux

Thanks for the responses. A few clarifications:

I have gotten the bike to run, and have done so as recently as last Sunday. A little squirt of starting fluid and it'll chug along for a while, when warm it will even respond to throttle (when cold, throttle does a little, but then bogs down & kills it). Once warm, no starting fluid is needed. I was even able to take it on a two-mile spin the other day, staying close to my house since I've been stranded before and don't have a truck.

It does run on all four. I'm not certain it -starts- on all four, or has great combustion on all four, but when warmed up for a while, all four pipes are sizzling hot when I spit beer on them (as I'm sure you are aware, beer is a required resource for troubleshooting -- not only does it quench thirst, it also provides a fine "emotion damper" if your temperment is otherwise affected by nonfunctional mechanical devices).

I agree that carbs might be the next thing, but first it seems I need to rule out compression. Regarding the carbs, while I haven't thoroughly cleaned them by any means, before I put the bike down for the winter I drained the carbs, removed them from the bike, and stored them indoors. The inside of the bowls don't appear to be very dirty or varnished.

As an aside, I try to stay away from carb work for as long as possible. I know too many people whose problems can be traced back to when they took apart their carbs. But it's still on the list...

Carbs have not been rebalanced. I have the tube & everything to use as a differential manometer. I was planning to balance post coil mod and post compression test / diagnosis.

Points can't be a problem because the iggy is electronic. I suppose the advancer could use some lube, this may partially explain some of the problems when I add throttle. I'm skeptical, but it's easy to get at & lube the advancer.

Plugs are new. I checked, they all spark. Battery is new. Coil mod not done yet, I finally got the relay and the stuff for it. Coils are older but primary & secondary resistance doesn't raise any eyebrows. Igniter checks out.

Now, I just need to get a moment to do the compression test right. Weather forecast isn't helping me, nor is working late, nor is the SO's list of stuff to do when I get home.

Thanks for the comments, keep 'em coming.

Post edited by: nick_borer, at: 2007/07/18 09:08

clean the CARBS its not scarey. It has to be them. Just take them off the bike and take the bowls off and clean the jets, its not hard.

So this time, I did the compression check correctly. Engine warmed up. Plugs out. Throttle wide open. New values are, in order (1-4), psi:

170 155 165 170

Or something like that. I don't have my notes in front of me. I like these values much more.

I don't have a friend with a leakdown tester. Hell, I don't even have a friend with a compressor right now. I clearly need different friends with more tools.

Plugs... #2, #3, and #4 getting shiny black electrodes. #1 doesn't look like it fires much.

Now, pipe #1 seems cooler than the other four. If you recall, this is the one with the intake valve clearance slightly higher than spec (.012", spec is .006-.010).

I'll try the coil power mod next, and clean the carbs thoroughly. My guess is that I'm going to need to get a bunch of stainless allen head screws... the cheapo pot metal screws in the carbs now love to cam out & strip. My guess is that no one has been in the carbs for a long time. I also need to balance the carbs.

Before I turn this over to a carb forum, any thoughts on valve clearances? If my intake is .002" over on #1, what would this likely cause? As I recall, valves are spring loaded closed, so a larger clearance means the valve will be open later (less), correct? Is this enough to need to shim the valves?

Thanks!
Nick

you'll get a tick shouldn't affect performance of that cylinder that much but should be fixed. You say #1 is cool. Is the plug wet? if so you have a igniotion problem. If its not wet its a carb problem!!!!! CLEAN THEM!!!!!

You know, Frank, I'm beginning to think that you are suggesting that I clean the carbs.

Not to worry. I will clean the carbs. I promise. This is an engine forum, I am trying to find out if there is other trouble with the top end I should worry about. I already know that I need to worry about the carbs. I'm not looking forward to cleaning them, but I will clean them.

#1 sparks. Plug is not wet. #1 isn't "cool," it's just "not as hot" as the other pipes. #2-4 sizzle when I spit beer on them. #1 steams but doesn't sizzle with such vigor. It's still "hot" -- if I were to touch it with my hand, I would burn myself.

Should I be concerned that the #1 intake valve is .002" over the spec range?

Should I be concerned over a 15 psi compression difference across cylinders?

so number is colder than the rest do to the fact its not getting enough fuel. Carbs are dirty lol. The shim should be replaced. THe differece in pressure could be simple as carbon build up.

nick_borer wrote:

You know, Frank, I'm beginning to think that you are suggesting that I clean the carbs.

Not to worry. I will clean the carbs. I promise. This is an engine forum, I am trying to find out if there is other trouble with the top end I should worry about. I already know that I need to worry about the carbs. I'm not looking forward to cleaning them, but I will clean them.

#1 sparks. Plug is not wet. #1 isn't "cool," it's just "not as hot" as the other pipes. #2-4 sizzle when I spit beer on them. #1 steams but doesn't sizzle with such vigor. It's still "hot" -- if I were to touch it with my hand, I would burn myself.

Should I be concerned that the #1 intake valve is .002" over the spec range?

Should I be concerned over a 15 psi compression difference across cylinders?

Nick - Did I read that correctly???? You spit beer on your exhaust pipes? That sir is blasphemous!!!! Beer is for drinking and you should never spit on any part of a vintage Kawasaki. If it is another brand of bike then this is an acceptable practice.

In the future, I recommend that you use a spray bottle filled with Holy Water from The Vatican, these bikes deserve only the best, and save the beer for the belly:)

A good soak of the carbs and a thorough cleaning of the pilot circuit sounds like a good place to look next to solve your gremlins.

Don't get frustrated and keep us posted on your progress. You will get it solved eventually.

Cheers-Colin Firth-Ontario Canada

Post edited by: reborn650, at: 2007/07/23 17:54

Thanks for the comments. I figure it's good to spit beer on the pipes, the bike may like it. At least it's good beer (most of the time).

Carbs will happen next. I'm not going to be able to dig into anything for at least a week and a half, but expect to post some carb forum topics as soon as I f*** that up.

Post edited by: nick_borer, at: 2007/07/24 10:05

It sounds like you are well on your way to having things worked out.
May I put in my 2cents worth?

Forget the valve adjustment for now ,
it will run just fine the way they are.

Read AND understand the whole tune up BEFORE you jump back into it.
ALL the little things add up to a good running bike.

When you clean the carbs , try to get all the parts back into the carb they came from .
Don't take the tops off unless you have to for some reason.

If you don't have a compressor ,use a can or 2 of the canned computer cleaning "air" to blow stuff out.

And don't forget the drill bit trick to static sync the carbs before you reinstall them.