I'm at my wit's end with my kz650

Sunday, I pulled the carbs, and cleaned all the main and pilot jets. I physically removed both jets in each carb, and sprayed B-12 carb cleaner in them, and blew them out with air. I could see a good clean hole through all of them before I put them back in.

I got everything back together, and rode for about an hour, and it idled and ran great except it seemed weak at 5,000rpm and up. BUT, all 4 exhaust headers would sizzle water.

Hopped on yesterday afternoon, and had to choke it to get it to start. About a 1/4 mile down the road, it could barely pull itself in 3rd gear, and I barely made it to the shop before it died.

I got it into the shop, and only the #2 exhaust header was hot enough to sizzle water.

I took out the #4 plug, and it was wet and sooty.

I'm at a loss here... The only thing I know to do is to clean the carbs again, but, I don't feel that'll fix it.

Help?!

Post edited by: kc5deb, at: 2007/07/11 11:39

It's getting gas if the plug was wet, it sounds like the spark is going-gone. Pull the plugs, keep them hooked up, lay them on the head and turn on the key. Turn the engine over and see if you get spark on any plugs. It should be fat and blue, not yellow or weak looking. Maybe a wire shook off or broke.

Can you answer a few questions?
Well, just tell us as much about the bike as you can, example; Did you just get the bike, or how long you have owned it?? What is it's general condition?

Are you trying to get an old bike from a barn running? Or is this a good running, daily rider bike with a new problem?

What kind of exhaust; is it stock or 4-1? What kind of air filter; stock, or individual pods?

When you had the jets out did you write down the sizes?

Thanks

The spark is a good blue color, and makes some impressive snapping noises.

As far as the bike goes, I've owned it a little over a year now. It was brought back to life by a motorcycle mechanic in town, and ran beautiful last summer with absolutely no problems last summer at all.

Aesthetically, it could use some work. It's missing the right side cover, and the tank has some dings. I'd give it a 5 out of 10 rating. The drive train is still sound, and I'd give it a 8 out of 10 (when it's running, of course).

This has come about after it started running rough about a month ago, and I discovered it was dumping fuel past the rings and into my oil. I had left it on prime, and didn't know the overflows were plugged on the carbs. I also had a plugged main jet on the #1 carb, and when I pulled the rest, I noticed they were all a little gummed up.

It has the stock exhaust, and I put the pod filters on. I did not rejet, for the mechanic I bought the bike from advised me that I didn't need to unless I did the 4to1 exhaust.

I did not write down the size of the jets when I had them out; I kick myself for not doing so, but, when I get off work this afternoon, my first task will be take the carbs off (again), and I'll take the jets out and write down the numbers.

Last year (when the bike was running great) did you have the pod filters on or did you put them on recently? If it was running great with the stock airbox you may want to put it back on and see if that helps. Ed

Last year I was running the stock airbox, and was running the stock airbox until I got gas in my oil, and this problem started snowballing.

The problem at 5000 rpm may be a lean condition, as the pods flow so much air that the main jet can't supply enough gas at higher rpms.
If you want to keep the pods then you probably have to buy main jets 1-2 sizes larger than what is in there now.
As 650ed said, try the airbox again.

There still may be spark problems, could be anything from bad plugs, bad caps, bad plug wire, and a bad coil, to a loose wire connection.

In your shop manual there are procedures to test the caps, plug wire and coil measurements. Make sure everything tests ok. All you need is a multimeter to test them.

Pull the cap off the wire, (it unscrews) and see if the wire end is corroded. If it is, snip off a 1/4" to get to good wire.
I just checked a friends Honda 700 plug caps and he had a broken spike in the cap, and corroded wires, that's why it was running lousy. Oh , also the two inch long cracks on each coil didn't help either.
:lol:

Post edited by: OKC_Kent, at: 2007/07/11 18:43

kc5deb, Edit your profile and put your bike year/model and your location in your signature. Are you a Texan? If so, where do you live? Someone local may be able to help. This doesn't really sound like a carburetor issue but it is hard to say, due to the lack of info. A bike with pods that has not been rejetted will be a bit hard to start but once started and warmed, will run OK up to a certain point. The point is GENERALLY above 5K rpm... perhaps 6K to 6.5K rpm on a 650 then it will not pull. This is a jetting issue. Your description sounds like cold pipes; that is, cylinders not firing. While the carbs CAN cause this, if all cylinders are firing one day and then not the next, it is more likely ignition.

HISTORY OF BIKE? Did you just get this bike or have you owned it awhile and this problem is just now occuring? If I was at all unsure of the history, I would NOT take anyones word for any work being done to the bike and would perform a FULL tune up... valves, timing, points/condensors, lube timing advance, replace, plugs, wires/caps, etc and sync/tune carbs. You might find that your problems will go away with a full tune up.

Yes sounds like a combo ignition+carb jetting problem to me too. Does your bike have points? Have they recently been replaced & even more recently adjusted? Have you lubed the timing advancer?

Frankly, I think it will be easier to jet for the pods than to put the stock airbox back on, unless you have developed a good way to wrestle that thing back on... But thats a matter of opinion. Get yer ignition squared away first. Don't forget the spark plugs!

How many miles on that bad boy? If its real low <10K I say don't bother with the valve clearances especially if you're new to the game. I've found that valve clearances can be pretty bad without causing the type of problems you are describing.

A proper carb sync will increase the life of your machine and make it much more enjoyable to ride, but again it probably wouldn't cause the type of problems you are describing.

Peter

This sounds like my problem also. I have a 750 h3 (ltd) That is doing the same thing.
Mods are pods, stage 3 jet kit, 4 to 1 pipes, Dynas with 3 ohm coils.

any ideas I am open to thanks

Nubs... If you don't mind, start a new thread... it quickly gets confusing if a couple of folks are being helped in one thread. Thanks and welcome to the site.

Ok, here's how I got my problems fixed.

Took the carbs off again, and discovered a couple of what I take to be air jets (my pilot and main jets were all clean). Some B-12 carb cleaner and compressed air, and the air jets were clear again.

Upon taking the pods off, one fell apart, so, it's back to the factory airbox. Guess I got what I paid for them; nothing.

SIDE NOTE: I don't know who designed the airbox on these bikes, but they well deserve a swift kick in the crotch...

After FINALLY getting the airbox back in, and getting the carbs back on, I discovered that the inlets on the airbox were so hard, I couldn't get them to go completely onto the carbs all the way. So, some electrical tape had to do. It's only temporary until I can get some more inlets or a whole new airbox.

I also noticed I had something else that may have played part in my problems. I had a large fuel filter, and it was so big, that when the fuel tank was pushed down, it seemed to be restricting the fuel. So, I got a smaller fuel filter, and the gas flows MUCH better through it.

So, everything's back together, and I give her a start... batteries has gone damn near dead.. Out comes the charger. After I get enough juice to start it, it idles for a bit, and I finally think I got it running. All 4 exhaust headers are finger burning hot, and it's idling smooth as butter.

I get out on the road and give it a good go. Man, this thing is running right again. I get about a mile down the road and turn around when it starts dying again... So, I'm able to limp back to the shop, and discover I've run out of gas... Luckily I have a gallon or two in a jug, and I put that all in. I get some gas in the tank, prime the bowls, and she starts up and purrs like a kitten again. I run her up and down the road for a while, and it's just running beautiful. No more surging, the power's back, and no hesitation at any RPM's.

So, down the road I head to a gas station to fill up the tank. I get another mile down the road, slow down to turn, AND THE DAMNED CLUTCH CABLE BREAKS!?!? Thank goodness I wasn't stopped, and I was able to limp BACK to the shop to throw one of the biggest snot slinging fits that would make even the saltiest of sailors mutter "wow... that's excessive".

Then it hits me as to what day it is... I laughed, locked the shop up, and came home for a shower. Bedtime will come early tonight...