Bad missfire????? NEED HELP - Kawasaki KLR 650 Forum
1987 to 2007 Wrenching & Mods For maintaining, repair or modifications of Generation 1 KLR's. 2007 and earlier.

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post #1 of 11 Old 07-14-2010, 11:56 AM Thread Starter
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Bad missfire????? NEED HELP

The 1st part of this is from a previous thread I posted.

I just purchased a 88 klr 650 with 7000 miles on it. Been sitting for 15 years. Cleaned the carb, tank and change the oil, filter and antifreeze and it ran great for 25 miles. On my way home it started to idle around 3000. Shut if off with I got home and left it til the morning. The next morning there was gas all over. It was leaking from the air box. Went to start it wouldn't crank. Took out the plug and the cylinder was filled to the top with gas. Cleaned the carb again, dipped it, put it back together and and it was tuff to start and ran with a bad miss. Let it cool started it again and it ran better then ever, until I tried to ride it. Stalled then ran crapy again.

Rebuilt carb,petcock and replaced the plug changed the oil. Same results. Spark plug was carbon covered with a short amount of run time. Light black smoke out the exhaust when reved up. Just can't figure it out.
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post #2 of 11 Old 07-14-2010, 12:31 PM
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Have you cleaned out the tank yet? After sitting for 15 years I'll bet you are sucking down rust and gunk that has formed inside the tank. You may have to clean it out and seal it with a sealer like Kreem or other similar product. I would change the fuel lines as well.

Greg
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post #3 of 11 Old 07-14-2010, 12:32 PM
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Quote:
Originally Posted by dawgslife View Post
The 1st part of this is from a previous thread I posted.

I just purchased a 88 klr 650 with 7000 miles on it. Been sitting for 15 years. Cleaned the carb, tank and change the oil, filter and antifreeze and it ran great for 25 miles. On my way home it started to idle around 3000. Shut if off with I got home and left it til the morning. The next morning there was gas all over. It was leaking from the air box. Went to start it wouldn't crank. Took out the plug and the cylinder was filled to the top with gas. Cleaned the carb again, dipped it, put it back together and and it was tuff to start and ran with a bad miss. Let it cool started it again and it ran better then ever, until I tried to ride it. Stalled then ran crapy again.

Rebuilt carb,petcock and replaced the plug changed the oil. Same results. Spark plug was carbon covered with a short amount of run time. Light black smoke out the exhaust when reved up. Just can't figure it out.

When you worked on the carb did you take out the jets, clean them and the passages? Did you take the petcock off the tank, clean it and flush out the tank?

The flooded engine happened because gas got by the float valve. If the petcock doesn't shut off gas will eventually get by even a good float valve. Don't crank the engine when it's flooded like that, you'll bend a valve stem. It's called hydrolock. You need to change the oil also when that happens, gas leaks by the rings and gets into the oil.

Wierd idle type stuff could be an air leak on the intake side somewhere. Start it and spray carb or brake cleaner around the intake components. If there's a leak the idle will surge up.

Black smoke out the exhaust means it's burning oil either the rings or more likely the valve seals are bad.

Last edited by Spec; 07-14-2010 at 12:36 PM.
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post #4 of 11 Old 07-14-2010, 02:27 PM
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Smoke from too rich of a fuel mixture, or unburned fuel, is black. Smoke from oil getting into the combustion chamber is blue.
All it takes is one pop or backfire to shoot carbon into the carburetor circuits, and all your cleaning may need to be repeated. And if you have that much carbon on the plug, there is plenty floating around elsewhere.

What have you done with the air cleaner since the hydrolock fiasco? Was it cleaned up and lightly re-oiled? If you did nothing with it, and it air dried after being rinsed out with gasoline, you may be getting an unrestricted air flow, creating some imbalance in your settings.

Describe how the engine runs at an idle. Once warm, does it require any help from the enrichener [choke]? Does it stumble when you attempt to apply throttle? Do you get black smoke at an idle or at higher RPM's only? Did you have the diaphragm / needle slide out?
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post #5 of 11 Old 07-14-2010, 04:05 PM Thread Starter
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Cleaned the tank twice. It was certainly full of rust. Didn't seal it though, but I will. Already changed the fuel lines. Tpr. Dave NJSP 3 years to go.

Spec
I did take the jets out and clean them and I took the petcock off the tank and replaced the diaphram. The engine was definately hydrolocked which I found out after I tried to start it. It barely cranked.

Vatrader
The air filter is brand new and clean. When I start it when it is cool. Idles absolutely perfect. Let it get warm still idles perfect. Give it gas, that's when the problems start. Runs like crap. If I let off the throttle at that point, it stalls and is a pita to start if it starts at all. Only get the light black smoke when reving the hell out of it. I did take the diaphram out.

Thanks for all the info. I think I will take the carb off for the 5th time and take it apart and clean it. I don't know what else to do. It only has 7000 miles on it. What the heck could it be? I just replaced the float valve in the carb too. I think I forgot to mention that.
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post #6 of 11 Old 07-14-2010, 04:12 PM
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Originally Posted by dawgslife View Post
Extrooper
Cleaned the tank twice. It was certainly full of rust. Didn't seal it though, but I will. Already changed the fuel lines. Tpr. Dave NJSP 3 years to go.

Spec
I did take the jets out and clean them and I took the petcock off the tank and replaced the diaphram. The engine was definately hydrolocked which I found out after I tried to start it. It barely cranked.

Vatrader
The air filter is brand new and clean. When I start it when it is cool. Idles absolutely perfect. Let it get warm still idles perfect. Give it gas, that's when the problems start. Runs like crap. If I let off the throttle at that point, it stalls and is a pita to start if it starts at all. Only get the light black smoke when reving the hell out of it. I did take the diaphram out.

Thanks for all the info. I think I will take the carb off for the 5th time and take it apart and clean it. I don't know what else to do. It only has 7000 miles on it. What the heck could it be? I just replaced the float valve in the carb too. I think I forgot to mention that.
I would check the diaphragm on the slide for seating, tear, hole. It is a SOB to get back together. But that is exactly how a damaged diaphragm will act....bad, bad stumble off of idle.
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post #7 of 11 Old 07-15-2010, 07:16 AM Thread Starter
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Great advise again. I will do that today!
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post #8 of 11 Old 07-20-2010, 10:29 AM Thread Starter
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Nothing worked. Still runs terrible. Can't even ride it. Had my buddy go over the carb just to see if I was missing anyting. Said the carb looks like new. Can't figure this one out. Getting worse. Now it wont even idle. I'm going to post a video so you guys can see and hear it. Maybe that will help. One step away from selling it like it is. Been going on for a month.
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post #9 of 11 Old 07-20-2010, 12:10 PM
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Quote:
Originally Posted by dawgslife View Post
Nothing worked. Still runs terrible. Can't even ride it. Had my buddy go over the carb just to see if I was missing anyting. Said the carb looks like new. Can't figure this one out. Getting worse. Now it wont even idle. I'm going to post a video so you guys can see and hear it. Maybe that will help. One step away from selling it like it is. Been going on for a month.

Have you checked the valves and the timing? Maybe the doo broke and jammed up something in the cam chain? Any metal debris when you changed the oil after the hydrolock? Got a good spark?

Motors need 3 things to run: fuel, spark and compression. Timing needs to be reasonably close.
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post #10 of 11 Old 08-13-2010, 10:24 AM Thread Starter
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Well, I don't want to admit this but I will. I was looking at a schmatic of the carb and realized the needle jet under the main jet was missing in my carb. When I took the carb off initially I must have blown it out and not realized it. I have taken that carb off at least 20x since the initial problem. Seven weeks of frustration over something stupid. Popping real bad now .22 cent mod next. At least I can ride it. Thanks for the responses!!!!!!!
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