bike wont run with 450r carb

[panteramatt]

i just put a 450r carb on my 400ex and it wont run. Ive completely cleaned it and it will start but only for a minute then dies. Will run with choke on but very high idle and as soon as you turn the choke off it dies.

[GPracer2500]

Originally posted by panteramatt
i just put a 450r carb on my 400ex and it wont run. Ive completely cleaned it and it will start but only for a minute then dies. Will run with choke on but very high idle and as soon as you turn the choke off it dies.

Have you rejetted the carb? I'm not sure what jet sizes would be appropriate but I know a stock 04' 450R carb comes with a tiny main jet (118). That shouldn't affect starting but the other jets might not be close to correct for your application either. I'm sure someone around here who is running a 450R carb could give some guidence on that.

[jordan_m6]

I assume you rejetted.

[panteramatt]

I have a 45 pilot and a 168 main in it so the jetting is very close but it wont run at all with the choke off. I dont know of its the tps or something like that.

[Chino886]

Originally posted by panteramatt
I have a 45 pilot and a 168 main in it so the jetting is very close but it wont run at all with the choke off. I dont know of its the tps or something like that.

It sounds like you need a few more sizes on the pilot. I had the same problem with my 39mm FCR. Try that out. Let us know.

[GPracer2500]

Originally posted by panteramatt
I have a 45 pilot and a 168 main in it so the jetting is very close but it wont run at all with the choke off. I dont know of its the tps or something like that.

The TPS shouldn't make any difference. Is the fuel screw turned out X number of turns? If it is turning all the way in then that would cause what your describing.

[panteramatt]

Funny you should talk about th efuel screw cause thats what I was thinking and Im going to check on that. I had a 48 pilot and it did the same thing. By the way, the motor is a fst 500 stroker with cam, ported, and sparks pipe.

[xc416ex]

Run the air screw all the way in and turn it out 3 times. That may be close.

[panteramatt]

fuel screw is fine.Its acting like its starving for fuel. If i jab the throttle a few times it fires but then cuts right out. Think I should try like a 52 pilot?

[premiumtommy]

did you try the idle screw..maybe it all the way down

stupid i know...but simple enought o be a problem

[Chino886]

If you are running a 500cc motor, then I would definitely say go up to a 52, that is what I am running in my 400EX with the FCR....

[Chris S.]

One thing that comes to mind from my expierence with this set up is to check where the hot start cable connects and make sure that spring is holding the plunger tight so it isn't letting in excess air when you don't want it. Also take the carb off and make sure the fuel is shooting out of the carb strong. It should shoot a stream of gas 10 feet or better if it isn't take it apart and clean it out real good. If it running that poorly I would think that it would be something more than just a few jet sizes off. I can change my jet sizes a few increments and it still starts, idles, and revs out fine, just will eventually foul the plug or the motor will run hotter than it should.

[aviator4]

Also, do a quick check for vaccuum leaks and make sure you don't have a vent hose plugged up. Check the airbox-to-carb and the carb-to-engine seal, could be causing the problem.

[panteramatt]

Does the hotstart screw into the top? Cause theres a hole with threads and nothing in it.

[Buffalo400]

you must plug anything in the hot start cable hole (with threads).... yes, the Hot start cable is on the top, plug anything in it......

[panteramatt]

Why? Will a bolt do?

[Buffalo400]

because it's like you run with the hot start on.... Plug it and it will run.....

[panteramatt]

You guys are awesome! It was the hotstart.

[Rico]

I had a problem similiar to this with my 450 carb and it was the idle adjustment was screwed out almost all the way..

Just an FYI

[Chris S.]

Glad to hear your problem is solved. You can't beat this forum when you need help with you quad. I had the same problem with my 450r carb, I could not get it to idle and it would backfire and when I plugged that hole it fixed everything.

[Buffalo400]

Originally posted by Rico
I had a problem similiar to this with my 450 carb and it was the idle adjustment was screwed out almost all the way..

Just an FYI


yes, i'm thinking it's my problem also..... when i screw the idle adjustement screw, my bike run richer (I'M not talking about the air/fuel screw)...... it's crazy.............. i'm going to screw a little the Idle adj. and after, adjust. my mixture fuel screw.........
I wish that he will run great at idle.......

[Rico]

start with the 48 pilot, 2 turns out on mixture screw and loosen the idle screw/adjust knob until there is no more pressure on teh spring on the cable were it meets the carb. Then turn it in 1 full turn and go from there. That's what I did and it worked perfectly.

[Buffalo400]

thanks!

I will do it this week end and I will post the result after.....