KLF400-B1 won't start please help

[lee4699]

I have a 1993 bayou 400 that started great untill the other day when I was riding it started sputtering like it was running out of gas. It eventually died and wouldn't restart. It had plenty of gas and the carb is working. When I pull the spark plug out I can get it to spark but it does not seem to ignite anything when I put it back in including either. The gas is clean and fresh.
Anybody have any suggestions? I would appreciate them.
Thanks

[99prairie400]

Start at the basics, charge your battery. Even if it seems fine...

Take your carb off, remove all of the rubber pieces, and clean it thoroughly with a good carb cleaner.

Replace the spark plug. There can be a small piece of carbon down beside the electrode that will ground the tip out under compression but not out in the open air.

[lee4699]

Thanks for the good suggestions 99prairie400! I have tried all of the basics though including your suggestions. I charged the battery, cleaned the carb, and bought a new spark plug and installed it.
The engine did have a slight knock to it but I was told that all of the older kawasakis did that and it started and ran great so I did not pay any attention to it.

[99prairie400]

Mine has a slight bit a noise too! Has had it since I've owned it, hasn't gotten any worse, and the oil is clean and changed regularly...nothing to worry about I think.

Has this quad had any bottom end work at any point since you've owned it? If you have spark, fuel, and compression, you should have run... It could be a sheared flywheel keyway. The engine is sparking but not on time to run.

[lee4699]

I don't think it has had any bottom end work done.
Is there any way to check if it is sheared flywheel keyway without tearing completely into it?
Thanks for the help!

[99prairie400]

You have to pull the rocker cover off to check the timing. Unless you've exhausted all other possibilities, I wouldn't tear into the engine.

Do you have/know someone who has a compression tester? A low compression number that doesn't come up with the addition of oil to the cylinder indicates jumped timing or improperly adjusted valves. That could cause it not to start/run properly either.

[lee4699]

I found a busted intake valve. Replaced it tonight and ran like new again. The valve adjustment was way off. It probably never been adjusted since new. I was hoping the slight knocking would quit but it did not. It might be a little less but it is still there. I checked everything in the top end. Everything was more than satisfactory for a sixteen year old except for maybe the cam shaft. It had a very little play from side to side the long way. Could that be the cause? The piston rod had a lot of play back in forth, is that normal?
Thanks for the help!

[99prairie400]

There is a service spec for all of that. End play (or axial) on the camshaft is ok, up and down or side to side (or radial) is not ok. The big end of the rod has a side to side clearance spec. I can check it when I get home but just guessing, it's less than .030" or .75 mm which is basically a good healthy clunk. If you have some clunk, it's not necessarily cause for alarm. The wrist pin and piston skirt are "splash cooled" by oil squirting out of the big end of the rod so you have to have some area to let the oil squirt out.

The real concern is, why did your engine devour an intake valve? Usually burning a valve is the exhaust. Too loose a valve means the engine simply stops running well. Too tight a valve could possibly bend it but it would have to be WAY too tight to hit the piston.

[lee4699]

I appreciate the good input. When I gaped the valves they were all loose I believe. The gap was two to three times larger than the factory specs, especially on the intake side. I don't know why, but the engine ran fine and started great till the day it died. I just figured the valve clearance caused the valve to bend and then break. The valve looked like it got really hot to me. I took the whole top half with the broken valve to a machine shop and they agreed with me and said everything else looked great. I am not a mechanic, I am just really good at taking things apart and putting them back together. I know the basics, but I rely on good people like you that seem to know what they are talking about to help me out. Thanks

[99prairie400]

Very interesting. I'd keep a close eye on the valve lash setting at least a few checks throughout the first 6-7 rides. Make sure that the new valve isn't going the way of the old valve. As long as the lash doesn't change much, ride on!

[lee4699]

Thanks, Ill do that.

[86klf300guy]

i wonder being the machine is older if the valve springs are weak causein the noise your hearin. those i think have the dual springs ,a inner and outer. a waek spring or worn spring can cause vlave lash to change with out notice.and cause more waer on the vlave train and cam. and running issues.

may want to find out what the hieght spec of the valve springs are supposed to be and also the tentsion rate they are supposed to be at.

a quick check i use is to take my two fingers and see if i can push the vavle open if so the spring is weak
just a thought maybe want to look into-corey-

[lee4699]

Thanks for the input 86klf300guy. I pushed on all of the valve springs when I replace the valve and I could barely push them open, but I have big strong working hands. I will check on the height spec though I am not sure the valve lash was ever adjusted in its life. I am not for sure, I have not had the bike for only a couple months. The valve clearance has been off for some time more than likely even though from what I have read the engine will not function properly with a poorly adjusted clearance. That part does not add up because it started awesome and ran great.
I did see significant wear in the rocker arms where the cam lobes push which would explain the large valve gap.
I took it for the a long drive today and seemed to run good. I have not had time to check the valve lash again though.
I appreciate the idea.

[99prairie400]

My Prairie 400 had worn into the exhaust rocker arm. When I replaced the bottom end I ordered a new rocker arm to go with it. The problem is, they are only hardened on the surface. They'll run forever as long as the surface isn't damaged but run it once without oil and the surface is damaged. Once that hard finished layer is gone, it won't stop there. You can probably keep an eye on the lash and keep rocking on for a while but maybe like next season, you should look into a set of rocker arms. They aren't cheap from the dealer. I think about $40 a piece, but they are still available.

[lee4699]

The rocker arms on both sides were wore into pretty bad. I checked the valve lash again today after only driving for a couple hours total since I replaced the valve. The gap was over twice what it should be just on the intake side. It started smoking and stinking kind of bad but it still ran good. It started on the first crank and never died. I might have noticed power difference but I cant completely sure because I haven't had it long.
The ticking noise I am pretty sure got louder too. It is really starting to bother me. It also seems like the engine was running plenty hot for being liquid cooled even though I was working it hard. I am not sure how hot it is actually suppose to run. The temperature light does not work.
I think you are right about the rocker arms. Just looked, 80$ on Kawasakipartsnation.com. They are about 20% cheaper than the dealer on everything else I've priced.

[99prairie400]

You may want to stop riding for a minute and check some stuff. If your rocker arm is continuing to wear it may be running low on oil pressure. Before you totally ****can your motor, you may want to confirm that your bypass valve is functional, check your pump screen, change your filter, and possibly spec out your oil pump.