The bike: 1987 Honda Fourtrax 250x, bone stock.

The problem: Blubbers at 1/8 throttle, smokes black.

I have removed the carb and cleaned it. The fuel tank has been drained and cleaned with new fuel. Air filter is clean.

Everything seems to be pointing in the direction of the pilot jet. The current setup is: air screw closed off (this makes the machine run best. Opening it will only make the machine blubber more and refuse to idle) #35 pilot, needle clip at center position, 125 main jet.

I have searched everywhere on the net for stock jetting and can find it nowhere! All local Honda dealers has been of no help what-so-ever, which as a why I bought a new Yamaha Grizzly(hope Honda is reading this, your customer support sucks)

Other than the jetting issue, the bike has plenty of power, is very solid and well looked after.

I was hoping someone out there could tell me what the stock jets are, and any other input to help solve this problem.

Thank-you.

 

Check the timing of the carb plates to the slide . My buddy had a similar problem on his 87 and it turned out he bent the linkage inside the carb just a little when he changed the throttle cable . It also had a problem with the choke detent being worn out and flopping open and closed while riding.