I bought a 04 KLX 300 nearby for $700 the other day for a spring project and to ride with my kids but it’s been sitting with gas in it for 5+ years in a garage. It needs a few things like a clutch cable and throttle cable(s) and a few very minor cosmetic fixes but is in relatively good condition. I took the carb apart and cleaned the crap out of it as it was loaded with varnish and crud. I took the spark plug off and kicked it over and the smell of old gas came out and stunk up my whole garage. My questions are should I been concerned with anything else, what about the inside of the cylinder, valves, etc. and should there still be a lot of compression when kicking over a bike with the plug out? I never worked on a 4 stroke just 2 strokes.

Thanks, Chris

Good deal on the bike.
Here's what I'd do.
Change the oil and filter.
Put a new plug in.
Clean and oil the air filter.
Clean out the airbox.
Get some new gas in there with a few Ounces of SeaFoam.
Kick it over slowly for awhile to get things moving.
Try to fire it up.
If it fires, you're good.
If not, check for spark, check for gas.

Let us know.

After you get it running, clean and lube the chain and check the sprockets for wear. It'll probably need wheel bearings, fork seals and some other little things.
There won't be much compression with plug out.
good luck and have fun with your kid.


Rob

Thanks for the tips, Im starting to get a little nervous about the fact it feels the same compression wise when cranking the bike over with and without the spark plug installed. I'll look into it when I get home.

Chris

The compression you are feeling is the valve trane. The motor has an automatic compression release so it feels about the same with the plug in. One thing I like to do if a bike sits that long is add just a little light oil to the cylinder, let it set a few minutes, and then slowly turn it over a few dozen times to prevent a dry start which is hard on the rings, etc. Its probably dry and a little rusty after sitting that long.

motorman_55792, on 19 April 2012 - 10:14 AM, said:

Good tip about the oil.
And, yes the 04 model has the updated compression release.

Ok thats makes me feel a little better. Where do I add the oil, right in the top where the plug goes?

thanks, Chris

Yes, right in the plug hole. Best to take the tank off so you can be sure you aren't washing any dirt in when you do that.

You can also use cylinder fogging oil which comes in an aerosol can. If you stick the straw into the plug hole and shoot it in while someone is kicking the engine over you get a pretty good coverage. Regardless of what you use when the engine starts up it will probably rev up. Try to get the idle down to it lowest sustainable point as quick as you can.  

Good luck.

Allright so I got it running thanks to you guys for the tips. I forgot how hard it was to kick over a 4 stroke 40-50 times, my shins really took a beating. Anyway is the header pipe supposed to glow bright red ? Idont remember seeing that on any bike before. I'll need to replace a few things like a throttle cable (why does it have 2?) and the clutch cable. Its hard to make any adjustments without riding it but hopefully next weekend Ill take it out to the trails.
thanks again
Chris

It sounds like its running lean. Did you have the idle real high? You probably need to clean the carb, particularly the pilot jet.

I thought I cleaned it really good but maybe not but I adjusted the idle not very high. Well I guess i'll pull the carb off again for a closer inspection.

Edited by jester125, 22 April 2012 - 12:31 PM.

Congratulations on getting it running. Sounds like you're getting close.
Did it smoke a lot when you got it started? What color was the smoke?
It shouldn't take that many kicks to start. Mine is a 98 without the ACR mod and it fires up on the first or second kick. There is a technique to starting the older models. It involves finding the top of the compression stroke with the kick starter and going a little past, letting the kick starter return to the top, then giving it a swift kick. But, I'm not sure it applies to the 04 with the updated ACR? Maybe somebody will chime in?
Many times hard starting is related to the valves needing adjusted.
If you're pulling the carb off again and the tank it's pretty easy to check the valves.
When you have the carb apart, make note of the jetting. The main jet and the needle jet are the ones usually replaced or adjusted. If the fuel air adjustment screw still has the factory cap over it, the carb most likely still has stock jetting.
Did you replace the spark plug?
What's going on with the throttle and clutch cables? How are they responding?

Good luck
Rob

Edited by System6, 22 April 2012 - 02:00 PM.

The second cable on the throttle to the carb is a manual closing of the carb as the other one is for opening up. Even though the slide is spring loaded to close on it own the second cable is there to pull it shut if it were to stick in the open position.

Thanks, it smoked at first because I put about a tablespoon of engine oil in the cyl just to loosen up the piston/rings from sitting as was suggested but it didnt smoke much at all after about 30 seconds. I didnt mess with any settings on the carb other than th idle, I removed the floats/valve and pilot jet (I think), cleaned everything else in place with carb cleaner. I have a UNI air filter with an inside layer that looks like it would restrict air, I think it was used for riding in water or something, Im wondering if that has something to do with it. I did install a new plug and the throttle tube is all meassed up so I put it and the cables on enough to start it up. I'll be placing a good sized order for parts.
Chris

Edited by jester125, 23 April 2012 - 09:34 AM.

You might want to pull the main jet and the needle tube out and check them as well. The needle tube has little holes cross drilled in it which can become plugged under the right conditions. The main jet sets in the lowest point in the carb so it also is susceptable to plugging from time to time. If you have compressed air it is beneficial to blow out the ports to remove any deposits that may have accumulated over time. Just be sure to remove any loose item before using air pressure.

I fired it up after cleaning the carb 2nd time. It started up on second kick, idle ok but I noticed a loud popping on decel of the throttle.

I have a set of throttle cables, and a carb . if you need parts pm me.

If its popping on decel its lean.