MC250 jetting

[FFRDave]

I just bought a 2004 MC 250 and decided to finaly install my LTR jet & needle kit.

That bike had a 178 main and a 40 pilot. The needle was a N1EF ??

Now I have a 185 main (a 180 came with the LTR kit) and 45 pilot (that came with the LTR kit).

I think I will be much safer running in the cold now.

I have one strange bit

When I installed the 185 main on my EC (an hour before I did the MC) I was able to really tighten that main jet down good. When I did the main for the MC, it seemed stripped. I could get it mildly snug (good enough I think (hope )) and then a weensy-bit more and it would turn too easily again. I thought about lok-tite, but decided against it. The treads looked big and all even and perfect. They did not look stripped or deformed at all. I was not using my 1/2" drive impact wrench.

What would happen if that main jet rattled off inside the bowl ? My guess is that the mixture would just suddenly be way to rich for combustion and the RPM might spike and then just stop. It wouold drop into the sediment bowl and I would just have to fix it.

Would I need to buy a whole new carb in order to get threads that would hold ?

Theres never a dull moment in MY garage !!

 

[GMP]

You could send it to Ron (RBD) and have the nozzle replaced, not a bad idea anyway on an older bike. Then you would start out with a known good carb and not have to compensate with jetting.

 

[FFRDave]

Jetting

Thanks GMP.

Im only jetting this way due to the cold weather. My MC ran great, but I dont want to hurt my motor by running too lean.

I am willing to bet that the main jet will stay put and never give me a problem.
As long as that problem is small (like having to stop and put it back in there some time on the trail), I thinkn I can live with it. If that jet falling out of its orfice could damage my motor, I will look into it sooner.

I plan to have Ron reshape my squishband on both bikes soon. I will probably send the carb along too.

 

[gasser]

You could try some teflon plumbing tape on the threads to make it fit tighter. It would also reduce the tendency for the jet to back out due to vibration. Make sure none of the tape covers the end of the jet and trim all excess away after you screw the jet in. Cheap easy fix that may work. - Ken

 

[HydroDog]

I think I would at least put some blue loctite on it.