jetting help

[450rrider69]

ok i took the air mixture screw out like it said put the clip on the 3rd notch on the needle and i got a 175 mj in. it runs best on a 175 then on a 170 and 180, its shooting flames out the pipe, what can i do to fix that?
im running a slip on, no lid, uni filter. thanks in advance with the help

[Quadster450]

i'm not sure what youre asking. you want to fix what? the flames shooting out? your question seems to say it runs fine with a 175 but shoots flames with a 170 or 180? If it's running fine with 175 then leave it as is!!! when do you see the flames? deceleration? acceleration? low, mid top of throttle?

[450rrider69]

ok if i put a 170 in it it bogs down. if i put a 180 in it it pops alot and also shoots flames, if i put the 175 in it it shoots flames, i just hit the gas in neutral and it shoots flames out, my question is how can i fix the flames, try different settings on the needle? diff pilot? take the air screw in or out? thats my question thanks.

[Quadster450]

if you're saying it bogs down, that's running too rich.. flames are caused by unburnt gas from your carb that is igniting in the exhaust system, so if you've got flames, you are too rich. from idle to 1/4 throttle, try turning your A/F screw out a bit. How many turns out are you now? The needle controls fuel from 1/4 to 3/4 throttle - move the clip up to lean it out, lower the clip to richen. What pilot jet are you running? The pilot also affects mid throttle. I run a 45 which is a little leaner that the 48 stock. If you're bogging down and backfiring at top throttle then that's your main jet. Try a leaner jet there too maybe a 168 or so. Do one jet or adjustment at a time and see how it runs before making another change, it's much easier to dial it in that way. good luck!

[450rrider69]

ok if i just rev it up in neutral its shooting flames out. i got a stock pilot in. the a/f screw is out 2 and a half. the main jet is set at 175 which seems to be running the best at. so if its shooting flames out then i should take the a/f screw out alittle and it should stop shooting flames right. it dont do anything when im going but it just does it when im sitting there. thanks man

[Quadster450]

sorry for any confusion, read this:

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Some people have been just going "3 turns out" or something like that..
You need to bottom the screw (lightly don't crank it down, you'll ruin it) and while the machine is running (it should be warmed up) turn it out from bottomed out to where you get the HIGHEST SMOOTH idle. It will get hi idle then start to get rough..turn it back in until it is smooth. Then set your regular idle to where you like it.

Adjusting the fuel screw will also tell you if you are too rich or lean in the pilot jet. OUT will RICHEN the mixture and IN will LEAN the mixture.

EXAMPLE: If you are at approx. 3.5 turns out from bottomed on the fuel screw this means that the adjustability of the fuel screw is at it's maximum (it will unscrew completely at approx. 5.0 turns out), you will need to go RICHER on the pilot jet.
If you are 1.5 turns out on the fuel screw that means you are at it's minimum (almost bottomed out), this means you are too RICH on the pilot jet and need lean out the pilot jet.

IF you do change the pilot jet to a different size be sure to RE SET the fuel screw to its highest smooth idle then set the regular idle screw to where you like it.
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try that and see how it runs!

[Steve-O]

^^^ nice post!

[450rrider69]

aight thanks man.