[86trx500r]

Got a 1986 trx250r with a 1989 cr500 motor. It has a pj38 carb on it. Jetting is a 168 main and a 55 pilot. My question is why is it so hard to start and why can't I use my choke plunger anymore? My choke plunger is adjusted all the way out (counter clockwise) for it to idle. The air screw is 3/4 turns out (counter clockwise). Runs good high rpm and mid range. Doesn't really hesitate off idle. It seems rich. It smokes heavy and the plugs pretty dark. Does adjusting the choke plunger out add more fuel or more air to the idle circuit? How about the pilot jet? It has a trx11 pipe on it and a k&n pod. Runs on 93 mixed at 32:1. Considering upgrading to a 38 air striker but I wanted to try to get this dialed in better before I spend the money and have to start over completely.

 

[86trx500r]

Also should mention im at 1300ft above sea level and riding is usually 70-80 degrees.

 

[Langbolt]

How's your Compression ? 3/4 turn out on the air screw an it's at it's highest idle ?? That's a rich air screw setting.. (less air mixing with the fuel in the pilot circuit)..meaning you need to increase your pilot to a 60 and then set your Air Screw at 2 turns out.....you want your Air screw between 1-1/2 - 2-1/2 turns out from closed. Adjusting the Choke out adds raw fuel ......so you might wanna adjust it in a bit.....once you increase the pilot jet it should correct this. Try it and report back.

 

[teufelhunden222]

clean your carb. also the 500 is a fuel hungry beast.

 

[FerrinMotorsports]

You should also enlarge that stinger on that TRX11 pipe...Also get a big bore or CR500 silencer...Your choking that motor with that small of a stinger...