Lots of smoke??

[MinnesotaJim]

Anyone know why my 87 KDX 200 would produce a bunch of smoke only when going down a long straight or up big sandy hills? I assume this is when the motor reaches maximum temperature. Could there be stuff in the pipe burning? The bike is stock (even original chain and sprockets) and I am using Klotz at 32:1.

Thanks

 

[CaptainObvious]

The rings are going. Time to check the top end.

 

[skipro3]

I think you are correct MinnesotaJim. My bike does the same thing after a long hard pull and I have a new wiseco piston and rings. The extra spooge in the pipe is getting cooked. If it bothers you, clean the pipe and repack the spark arrester. Let us know what you find out, O.K.?

 

[MinnesotaJim]

I thought only four strokes would smoke with bad rings. I assume a 2 stroke has the gas/oil mixure everywhere inside the engine (crank case, cylinder walls and combustion chamber) and rings would have very little affect on the smoking. I'll clean the pipe for now and pull the cylinder after the season is over.

 

[wallasaki]

Jetting? Might need to lean your main jet.? Need more description for a better answer. Are you full throttle? Loss of power? ...etc.

 

[wallasaki]

Original chain and sprockets? Mine lasted 3 months - what's your secret.

 

[beefking]

I don't have much experience with the 87-era KDX, but I was having similar problem in my 89 kdx. I was running 32:1 Spectro; now I run 42-48:1 and that cleared it all up! Changing jetting wouldn't help smoking with the 32:1, with an 8 series plug. Now it burns perfect (had to richen jetting a tiny bit on MJ) with no visible smoke once warmed up.

But...what kind of useage does the bike get? If it has stock sprockets and chain I'll assume not very much, but it may be time for new rings. Check ring end gap first, they may just be worn out; gap should be .010-.012" roughly. Good luck. :thumb:

 

[JasonWho]

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[MinnesotaJim]

Thanks for all the input.

I bought my bike last year from a guy that was well into his 70's. He bought it new and appreared by the tires he only rode it down gravel roads. It had the original tires on it when I got it. They were weather crack and the back tire only had the center knobs worn down.

The bike was near perfect with just a couple of paint scrapes on it. The chain and sprockets were fine but I will need ones a couple hundred more miles.

It is a great bike to ride. I ride with buddies that have CR500, XR400, CR125 and YZ250F. The KDX is always the fastest thought the woods but the really big sand hills are a problem and straight gravel roads I get passed.

The spark plug looks fine (maybe just slightly rich) after a WOT run. I'll probably just keep riding it this way until winter and then pull the cylinder and have a look.