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mikuni acclerator pump or a xr400.. does anyone know the pilot screw setting for it and proper jetting as well. it keeps backfiring ,and problems idleing. it brand new . thanks :cry: elevation high desert 2200 to 2500

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Need more info.

Is the bike completely stock?

Have you done any mods?

Do you mean the bike has the Mikuni carb on it now or does it have the stock carb?

Give us more info and we can help.

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hey thanks for the response. I siezed my 2001 xr400 r last spring. i just picked it up from xr's only yesterday. a total rebuild. very costly...

Here are some of the mods and repairs that were done.

piston kit 87.00mm

new valves

cam chain &clutch replaced

gears replaced &,spindle gearshift

And to top it off a 36mm MIKUNI pumper carb.

Carb discription: TM 36 ACCEL PUMP CARB.

AIR BOX ADAPTOR

THROTTLE CABLES ONE PUSH ONE PULL.

# 130 MAIN JET #15.0 PILOT JET.

IT also has a white brothers pipe(silencer) 01 model.

Im experiencing alot of back fireing from the exhaust.and some idle issues.,

I live in ridgecrest elevation 2250 to 2450.Hey thanks again. :cry:

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hey thanks for the response. I siezed my 2001 xr400 r last spring. i just picked it up from xr's only yesterday. a total rebuild. very costly...

Here are some of the mods and repairs that were done.

piston kit 87.00mm

new valves

cam chain &clutch replaced

gears replaced &,spindle gearshift

And to top it off a 36mm MIKUNI pumper carb.

Carb discription: TM 36 ACCEL PUMP CARB.

AIR BOX ADAPTOR

THROTTLE CABLES ONE PUSH ONE PULL.

# 130 MAIN JET #15.0 PILOT JET.

IT also has a white brothers pipe(silencer) 01 model.

Im experiencing alot of back fireing from the exhaust.and some idle issues.,

I live in ridgecrest elevation 2250 to 2450.Hey thanks again. :cry:

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If you got the carb from XR's Only I would start with them for the proper jetting, since it was supposed to COME THAT WAY when reading their web page. Sounds like it might be running lean with the popping your talking about. Even if you didn't, ask them anyway as they should be able to help you.

Get the jetting squared away before you ride it much or all of your money could be wasted. I would hate to see that happen. After you get it jetted I can tell you how to adjust the fuel screw, it is easier if I show you which I would be glad to do.

Shoot me a PM with your number and we can talk off-line.

Jeff

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I have the same Mikuni w/ a 426 bore, FMF PC4 exhaust, snorkel out, header welds ground, Uni and it is jetted 130/15. Like Jeff said, I would call XR's Only. The jetting should be pretty close. It may be something else with all the work you got done.

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Is it backfiring on deceleration? If it is it could be a leaky header pipe. I have'nt experienced it on my XR, but its happened to me on other bikes after a rebuild , because I did'nt replace header gaskets. Also made it idle eratic.

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especially on deceleration, i took off the pipes and did find one loose nut and put some grease on the pipes then put them back on the head it seem to help alittle . if there were gaskets in there i could not get them out.are they a brass gasket> thanks :cry:

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