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need help with jetting DRZ400SM

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alright iv got a 06 drz400sm, it's got the 3x3 mod, pro circuit T4 SLIP ON, and a twin air filter. Around here it's around 900 ft above sea level but i may ride up to around 4000, i have the dyno jet jet kit installed with a 155 main jet factory 22.5 pilot jet @ 3.5 turns out and bad backfires\popping on decel...i bought a 27.5 pilot jet and changed main jet to 150 (because i thought it was maybe too rich?)and in all gears (3rd gear the m0st) around half throttle it has a bad surge, went back to the 155 and it does the same thing...thanks in advance for any advice

i dont know

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Got extended fuel screw or stock screw??..at 3.5 turns you be looking at going to a 25 pilot jet...

The recommended mj size is 160 for open pipe and 3x3....

What needle setting do you have?

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its got the stock air/fuel screw and the clip is on the 2nd grove from the top i done exactly what the dj kit said it just backfired alot on decel and it felt like it didnt pull to the redline like it should thats why i changed to the 150mj when i changed to the 27.5 piolt jet and now it surges at 1/2 throttle with the screw from 2-3 1/2 turns out went back to the 155mj and does the same?

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let me just add also with the bike running i can turn the air/fuel screw all the way in(27.5 jet) and it will kill the motor thought that ment it was not to big?

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22.5 pilot jet with extended screw or 25 pilot jet with stock screw..The 27.5 is too big..

approximately 2.75 turns fuel screw

If you end up at less than 1 turn you need a smaller pilot jet..More than 3 turns you need a bigger pilot jet

Basically,your pilot jet controls your idle circuit, needle for mid range and main jet for wide open throttle..so changing your mj won't have any impact on your 1/2 throttle...

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ok ill try the 25 and im going to go back to the 150mj bc it seemed to run better at w/o with it didnt seem as suggish..

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Ok..The 150mj will work better as the altitude gets closer to the 4000ft mark that you said you ride to ..,but 155/160 should be better at near sea level..and when the weather gets colder..

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ok today i installed the 25 pilot jet at 2 3/4 with the 150mj and i can just hold it at 1/2 throttle in netural and the motor pops just like if i was riding it b4? any thoughts? both lines are on the tank and i dont think i have a air leak at either of the boots.. thinking i may go back to the 22.5 and buy the extended fuel screw bc with it it didnt do anything but pop on decel!!!!!!

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hi i wonder if you can help me i have a pit bike engine in my road bike and its a 125 with a 22 mm carb on and i cant get it running right its got a 110 mean jet in it and the neadle all the way up as far as it will go and when i pull off and try put some revs on its got a flats spot but after you get it reving it fine it will rev ok and when you open it up 3/4 though the range in 4th doing 45mph its holding back but if you back the revs off by half it slowly clims to 50mph and wont rev anymore but theres loads a revs go before. it sound like a limiter and when i come slow down its poping and banging what mean jet do you think i need ovs its running lean but how much would you say wb cheers

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hi i wonder if you can help me i have a pit bike engine in my road bike and its a 125 with a 22 mm carb on and i cant get it running right its got a 110 mean jet in it and the neadle all the way up as far as it will go and when i pull off and try put some revs on its got a flats spot but after you get it reving it fine it will rev ok and when you open it up 3/4 though the range in 4th doing 45mph its holding back but if you back the revs off by half it slowly clims to 50mph and wont rev anymore but theres loads a revs go before. it sound like a limiter and when i come slow down its poping and banging what mean jet do you think i need ovs its running lean but how much would you say wb cheers

You need to START YOUR OWN THREAD to get proper answers...

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ok today i installed the 25 pilot jet at 2 3/4 with the 150mj and i can just hold it at 1/2 throttle in netural and the motor pops just like if i was riding it b4? any thoughts? both lines are on the tank and i dont think i have a air leak at either of the boots.. thinking i may go back to the 22.5 and buy the extended fuel screw bc with it it didnt do anything but pop on decel!!!!!!

How does it run when you ride it?...

At 900ft the 150mj is going to be too lean..

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ok today i went back to the 155mj and the 22.5 pilot at 3 1/2 turns out bc my extendered screw aint came in yet and it still does it...its not even like a surge its like its running out of gas and b4 with this setup it only poped on decel...i put a new cr8eix plug in it today and the factory plug(mileage on bike is only 3100 so it was prob factory idk bc i didnt buy the bike new)and it had a yellow tint to it from what i know that means it was prob to lean yes but im wondering if the carb has trash in it?

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ok so today i finally figured out my problem i cut the air box a bit to much doing the 3x3 i can cover some of the hole and hold it at 1/2 throttle and the pop/backfiring go's away..must have been the big change in weather since it did run fine in the summer...i moved the clip to the 3rd groove and it helped alot but still does it a bit anyone run into this b4? do i need to go down to the 4th groove never heard of anyone going down that far? idle/top end great just this dang mid range surge/popin...

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