Being new to 4 wheelers, I have found it rather difficult to tune the carb on my 86 TRX250 because it's sooooo hard to adjust the needle being located under the carb, especially when it's hot. Is there a secret to adjusting this needle to tune the carb? I set the needle according to my Clymer repair manual after rebuilding the carb but I know it's not quite perfect. Any secrets for this dilema?

 

No one out there has a problem tuning the older TRX's? You just about have to be a skilled surgeon to tune the carb!?

 

It must be a little different than my 87 TRX250X. I just use a short small screwdriver and I wear a leather glove. I turn it in until it runs rough, then out until it runs rough, then set it half way between the 2. But I don't know which way makes it richer, in or out, and I want to set it a little richer. I have a post about that but no answer yet.

 

Thanks for the response! Even a little screw driver is very hard to maneuver in that small space...does your bike have that crankcase vent tube under the carb too? I've even tried a screwdriver bit with a small piece of hose on the end...still a pain. I wonder if one of those bendable screwdrivers would work? Probably not!?

 

Sometimes I will use a ratchet with a 1/4" socket and a screwdriver tip in the socket.

 

No, mine doesn't have the vent tube. Have you ever seen how a 300EX's idle screw is set up ? There's a 5" soft flexible tube slipped onto the head of the idle screw. I don't think it's possible to do you jet screw like this because the head is inside. But, what if you carefully drilled and tapped a very small hole in the head of the jet screw, then screwed and glued (epoxy?) a longer screw into it, and attached a flexible tube to it?

 

I screw it in until it runs rough and then slowly turn it out until you get the highest rpm at idle and after that you set the idle to where it needs to be.