I have a 1978 xs650 special with stock pipes and uni pods. Does anybody have a similar setup around st louis that would be able to tell me what jets they are using? Would like to get a good baseline before i go crazy ordering jets.
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bikefreak69
XS650 Enthusiast
22 pilots
6 F 9 needle
P6 or P6 needle jet
180 main
These should get you running at least.
Straight from carb guide.
Find and download the VM guide in the tech section.
Get a copy of Mikuni Tuning Manual.
6 F 9 needle
P6 or P6 needle jet
180 main
These should get you running at least.
Straight from carb guide.
Find and download the VM guide in the tech section.
Get a copy of Mikuni Tuning Manual.
nichecycle is good.
hot cam 750 is set like this at 950' ASL.
Carb: VM34
MJ: 180
PJ: 25
NJ: 159-P6
JN: 6F9, 3rd slot
Slide: 2.5
Air jet: ?
Float valve 3.3
hot cam 750 is set like this at 950' ASL.
Carb: VM34
MJ: 180
PJ: 25
NJ: 159-P6
JN: 6F9, 3rd slot
Slide: 2.5
Air jet: ?
Float valve 3.3
Check your slides. VM34s leave the factory with #2.5, but some tuners and aftermarket vendors install the richer 2.0. There's an inverse relationship between slide and pilot jet. With the generic 2.5 slide, a 22.5 or 25 PJ is the usual choice. With a 2.0 slide, a leaner pilot jet,17.5 or even 15.0, is called for.
Jet lists are nearly meaningless unless every last piece of brass in the carburetor is accounted for. Guys, let's put more effort into teaching how to tune than telling what to buy!
Jet lists are nearly meaningless unless every last piece of brass in the carburetor is accounted for. Guys, let's put more effort into teaching how to tune than telling what to buy!
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Thank you. Ive got 15 pilots in at the moment and it seems to at least idle alright. Might have to go up once I really try to tune it in
Ive got the 2.0s. So that would explain why the much smaller pilot seems to be working my pin setting is also in the 3rd position. 180 main jet 15 pilot
So, what slide do you have?
Ive got the carbs from tcbros. I believe the needle is a DH9 or something like that. Jet to match
Uh, that's a little vague, Hands ("Jet to match" what, exactly?) You'll get more useful suggestions if you post operating problems that you think need to be addressed, along with a complete jet list.
The needle jet and needle i believe have the same ID number. 15 pilot jet 180 main. Just trying to get some suggestions for proper running and was seeing if anyone had a similar setup to base off of. I realize im gonna need to tweak it a bit but was looking for a place to start. ATM i think im just the tiniest bit lean at idle
Oops! see Griz' post below Air jet is a minor tweak thing located in the intake bell, a size smaller there is kinda like a half step up in the pilot jet. Many tunes just leave it out.
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Mikuni needle and needle jet numbers are not the same or even similar. Gary, that observation re. air jets is true of BS34 carbs which have a removable pilot air jet and a fixed main air jet. The VM34 has a fixed pilot air jet and a removable main air jet. The MAJ has no influence at all on the pilot mixture. It's there to control emulsification in high rpm motors, which ours are not. The VM34 comes from the factory with a #2 MAJ (the largest) in place, which can be useful in some full race applications. Even with hot big bore street motors, it's best to remove it.
