The difference between a right- and left-handed VM is the location of the idle speed screw. The air screw is always on the right side. Look at your right carb. Note the idle speed adjuster screw is on the right side, easy to access. Now look at your left carb. Were it a true left-handed VM, it would have it's idle speed adjusting screw on the left side, the "outside" when it's mounted, so it would also be easy to access. It's on the inside, the right side of the carb, and that makes it a right-handed VM. There's no issue running them, it's just harder to adjust the left one.
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Jetting questions
- Thread starter roach61
- Start date
Alright, let's get down to the nut cuttin' here. First: these carbies with the mixture screw behind the slide tower turn in (right) to lean the mix. That you have them seated all the way tells you that your pilot jets are too small--maybe.
Why "maybe"? Two reasons. First, troubleshooting is a process of elimination, and it's best and easiest to start checking what you can see--valve lash, compression test, ignition (resistance at primaries and secondaries,voltage).
Then to the carbies. Nothing, absolutely nothing can help you until you strip them and list every piece of brass: slide, pilot jet, needle jet (AKA emulsion tube), needle and clip position, and main jet.
There are known and tested baselines for jetting VM34 and36 carbs for the XS650. Do not--repeat, do not--pay any attention at all to any list of multiple users. You don't know who is who or how the bike is used. Race motors take very different jetting from the street, and all a drag builder cares about is getting off the line at WOT and holding there. Jetting for flat track and road race is similarly specialized.
Consider getting rid of that 2-1. IMO those things have no business on street bikes. They present tuning problems and will get you in a whole lot of grief if you're forced to heel deep to the right.
Good luck to you. Consult the Tech section. That's what it's there for.
Why "maybe"? Two reasons. First, troubleshooting is a process of elimination, and it's best and easiest to start checking what you can see--valve lash, compression test, ignition (resistance at primaries and secondaries,voltage).
Then to the carbies. Nothing, absolutely nothing can help you until you strip them and list every piece of brass: slide, pilot jet, needle jet (AKA emulsion tube), needle and clip position, and main jet.
There are known and tested baselines for jetting VM34 and36 carbs for the XS650. Do not--repeat, do not--pay any attention at all to any list of multiple users. You don't know who is who or how the bike is used. Race motors take very different jetting from the street, and all a drag builder cares about is getting off the line at WOT and holding there. Jetting for flat track and road race is similarly specialized.
Consider getting rid of that 2-1. IMO those things have no business on street bikes. They present tuning problems and will get you in a whole lot of grief if you're forced to heel deep to the right.
Good luck to you. Consult the Tech section. That's what it's there for.
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On the VM carbs, the mix screw is actually an air screw, so turning it in reduces the amount of air added and makes things richer. So, if you must run with the screws turned all the way in, that might indicate the pilots are too small.
Indeed, an air screw that controls the pilot mixture. Might as well call the tower front mix screw an air screw too, since turning it out admits more low pressure air to the PJ, thus richening the pilot mixture. Between us we've covered this business how many times? I'm done with this kind of carb thread. No more repitition for those who think it's less effort for others to answer the same old question just for them than it is to use the Tech section and fine search function on the site to do just a little homework. If you catch me doing otherwise, old partner in crime, just post one phrase, please: STF UP, OLD MAN!
Yeah! Screw different people that ask me the same question! What do I look like a teacher?! A parent? Or any other kind of human that interacts in a functioning society? Some guy asks me the time I say get bent buddy I already told my wife what time it was! I see why they call you grumpy old man hahah go watch murder, she wrote
I kid thanks for your input and help. I did try searching the tech section but found it lackluster and some terms flew right over my head. But alas I will continue my studies and learn what I can with what I have and from whom may teach.
This is the ignition I have on here.
Attachments
Thank you have I have been reading through them. A lot of info!
That might even be a "genuine Pamco" ignition.
The ignition pickup unit appears to be an original PAMCO.
Uh, the Grizld1 is the author of the second carb link I posted and likely could have written both of the links provided
Uh, the Grizld1 is the author of the second carb link I posted and likely could have written both of the links provided
Nope, only the second one. JP--that and the 26 page Yamaha 650 Society carburetor manual, which is the property of the Society and available for sale
from the Society. If you want it, contact desmoman900. He leads the club in more ways than one--an exceptional human being.
from the Society. If you want it, contact desmoman900. He leads the club in more ways than one--an exceptional human being.
Right on thank you! I have been swamped at work but hope to get back to her asap. I'll let y'all know what's what when I can. Thanks again!
