Dual VM34 Carbs 1980 XS400 Jetting Help

[jigm400]

Hey guys, so i am looking for a little help on the subject of running Mikuni VM34's on My XS400. I took a guess at the Jetting going off of what the XS650 Guys are running and i think i went way to lean. The bike will start with A (1) choke on then just revs to the moon. i cant get the idle down so i am assuming that i need to richen up. i have not run the bike long enough to give any plug specs and i can not ride it at this point in time as the front wheel is at the machine shop getting worked on.

XS650 specs that i based off.
Main: 185
Pilot: 25
Slide 2.5
Needle Jet P-6
Needle: 6DH4

what i installed:
Main: 150
Pilot: 20
Slide 2.5
Needle Jet: O-8
Needle 6DH3

I have access to tons of Mikuni jets and needles, and needle jets. i am just looking for an educated direction to head in. as 1 i dont want to blow this think up and 2 i want to ride it again. I can assume that dual carb setup will work on this bike as it is only -125cc under the XS650 per cylinder.

 

[arfstrom]

I don't think this is the answer, but the last time I could not get the idle to go down, the vacuum tube to the petcock came off the carb holder. (I failed to notice that prior to failing the Motorcycle drivers test.) Good luck

 

[drewpy]

I'm running a 52.5 pilot on my tracker with pods and free flow exhaust if that helps

 

[jigm400]

52.5 pilot runing 2 vm34s? thats seems really big, however i had tossed around the idea of runing rich on the pilot to compensate for the lower air velocity due to the larger venturi on the VM34.
tomorow i am going to try:
Main 160
Pilot 30
Needle Jet P-4
same needle

the bike has K&N pods and real custom exhaust (not back yard pipes)

 

[drewpy]

well i had 50's on it and it bogged when cold till really warm, then starte to pop and got relly hot.
52.5 's runs really well on cv's

 

[jigm400]

good heads up ill go with it

 

[Mhassic]

Hi!

How did your setup work?
What jetting did you endup with?
Im ordering some jets and stuff for my vm34.ors so i thougt i should have i guidline to follow. =)

 

[XSLeo]

I might try the exact specs for the XS650. Then test and adjust from there.
I might also suggest contacting Micheal Morse at 650central. He has very much experience with VM carbs.
Leo

 

[Scorpio1963]

nevermind