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At my wits end


mac250

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I have been putting a lot of work into a 97 dr200se.

Finally obtained the title. And created a mad max street fighter style bike.

But all things redone, now I can't get it running and when it does. It doesn't stay.

So to start,

New oil and filter, new air filter, wiring completely redone, top to bottom.

Carb has been rebuilt, quite a few times now. New spark plug. And I am getting spark!

When I try to start the bike cold with choke fully pulled I can crank it for about 30 seconds with starter spray and throttle fully open, bike will start, but doesn't idle and will die if I don't keep pulling the throttle.

Once it's warmed up, I can only start it by removing the air box cap and pulling out the filter, then with choke on, and full throttle it'll start, but same idle issues.

I have tried all the way up and back on the idle fuel screw and sometimes starting requires less throttle but still no idle.

At all times the idle isn't just fluctuating with throttle constant, but the bike immediately dies without throttle. And throttle has to be to high for the idle adjust screw to compensate.

Spark plug is black from to much fuel, but I just don't know anymore, the obvious doesn't seem to work. I can only imagine I've done something wrong.

Any help and advice?post-17975-0-30002500-1431744296_thumb.j

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Check your carb bowl float height, could put a brick under front then back tires to see if either makes a difference first.

With throttle held spray carb connections, choke boot with water and see if rpm changes for vacuum leak

 

Does the fuel petcock open under vacuum and stop when off? I had a bad diaphram on my 650 with fuel going into the vac line.

 

What's the voltage @ off/ lowest running rpm/higher rpm

 

Also a bit of foam on that seat will make for  easier sitting down after a ride.

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The symptoms you describe are indicative of a clogged idle jet, but you also say the spark plug shows an over-rich condition, which doesn't make sense.  A black plug can also be caused by incomplete combustion--have you checked basics like compression (for a head gasket leak) and valve lash (for overly tight or burnt valves)?  Either condition will make for a poor running motor and cause incomplete combustion and hard starting.  If you've done your basic homework and the bike was running fine before you took it apart, it certainly sounds like you've missed something in the carb rebuild, most likely in the idle jet circuit.  Did you put new jets in?  Or just clean the old ones?  

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I never changed anything as far as the engine goes.

The valves were fine when the bike was running last year, and I can't imagine timing would be an issue.

The compression (although I can't seem to find a general psi for this bike) has remained constant. So I don't believe it to be the motor or gaskets.

I did spray my boots with wd-40, however the Roma fluctuate to fast and sporadically it's impossible to tell whether that's having the slightest effect. But the boots visually look fine.

My idle jet is the reason I tore the carb down this last time. I soaked it a good while in cleaner. Blew it clean. Even ran a guitar string through the holes and ports. I did not reject.

But yes. Because it was running fine until this year down my only thought is I did something wrong.

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Yup. Sounds like two problems, both in the carburetor. Pull carburetor and disassemble, soak in cleaner (even kerosene), shoot cleaner and compressed air through all tiny idle passages. At least twice, once isn't enough. Verify that air is getting through. Check float for leaking, float position, float needle seat and float needle, and try to figure out if that float needle fuel cutoff is leaking fuel into carburetor. Also check slide needle position and install. Sometimes give up and buy new float needle. Basically all aspects of parts that control the fuel level in the float bowl and combustion chamber.

 

Or, pull carburetor and take it to CrazySkullCrusher...

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