Newbie asking newbie carb questions.

Did you happen to mean VM34's from TC Bros? That would make more sense as I don't think they sell BS34's carbs...and if considering it, just note that they will also need to be tuned regardless of what they say has been done to make them XS650 appropriate. But VM's are super simple and tuning them is a breeze. You'll need new intakes. You'll also need a two-into-one throttle cable. Get a few pilot and main jets in various sizes, as no two bikes will be the same with jetting. (There are a few threads on here that provide good info on tuning these and jetting combinations that seem to work well). I personally have VM34's and I like them. I don't know if they are better than really well tuned BS38's, though to be honest. But they are easy and I like the way they look/perform.

Yes that is what I meant. The kit comes with some jets and a dual throttle cable. I just didn't know if there was anything else I needed since it's a custom frame with 20 inch apes.

Benwastyxx said:

Yes that is what I meant. The kit comes with some jets and a dual throttle cable. I just didn't know if there was anything else I needed since it's a custom frame with 20 inch apes.

Click to expand...

I also have the intakes already and unipod foam filters

Update. I noticed one side isn't firing. I switch the wires around, now the other side isn't firing. I think I have lost a coil since it only has one pick up coil. Any suggestions for a great coil? Lord this thing is touchy haha

Adjust the valves
Ignition...
Float level. Gary went through this in addition to "carburetors from the grave" recently. Fuel level is where it starts. Get this wrong and tuning becomes guessing.
Individual filters on BS carb? Heating the #2 phillips screwdriver as I type. Jam the hot screwdriver in your eye. It will hurt less.
Did I mention adjust the valves? (probably)
And that ignition? No comment. Other than what the hell is wrong with points. A fool's errand and a solution in search of a problem.
The grizld1 may be Dick
but,
I am a Dick
etcetra et errata ...
http://www.xs650.com/threads/carburettors-from-the-grave.34737/
http://xs650temp.proboards.com/thread/7899/19-junkyard-electronic-ignition
http://www.xs650.com/threads/dwell-readings-and-timing-question.50137/#post-518385

Alright guys, thanks so much! Update. The battery was full on dead, unit not charging. Charged up the battery, fires up first kick. Just finished installing pma and cap to stop with that nonsense. No patience for the mail so I started experimenting with drilling the jets. Just bought a number drill set and proceeded to test things out. I think I have found the right combination. The pma kit solved a lot of issues. The bs 38 carbs are doing better than ever but still not perfect. Next upgrade will be a clutch and the vm34 carbs. I already have the manifolds and I have to order a custom dual throttle cable so who does everyone recommend on just the carbs without all the extras that come in the tc bros kit? Again thanks for all the input from everyone.

For the VM34's. If you buy genuine carbs (not knock-offs), and you don't go the route of a kit (like from TC Bros or Niche Cycle, etc), then you'll need to set the carb up manually. Essentially, they are set up stock for dirt bikes/two strokes (from what I understand) so you'll need to make sure it has something like the following: (this is my set up)
175 Main Jet
20 Pilot Jet
P6 Needle jet
6F9 Jet Needle
2.0 Throttle Body
2.0 Air Jet (some people remove altogether--but I haven't found the need to)
3.3 Needle valve
1-1.5 turns out (air mix)
2nd from bottom clip on needle

Your results may differ, but this is a good ballpark I would think to start with (I'm pretty close to sea level btw)

Good starting point for VM 34 jetting--if you want to pay over $100 for slides (AKA throttle valves) alone. Most of us leave the generic 2.5 slides in place and use a richer 22.5 or 25 pilot jet, with mains from 180 up, depending on motor setup and altitude. (I don't mean to be pedantic, but a "throttle body" is a fuel injector component). Bear in mind that unless you've made sure that every other system is good, aftermarket carbs may only add to the problems. If you're set on VM34s, IMO the best thing you can do is to buy a kit from a reputable vendor. By reputable vendor I mean someone who knows tuning and provides tech support, not a bling peddler. Two recommendations: Michael Morse at 650 Central and Gary Hoos at hoosracing.com.

Welcome to the site benwasty, as you found out you’ll get all the answers, pros and cons, on what you want to do! Good luck and don’t get frustrated with it ,just have fun experimenting with it, once you get it tuned the way you want it will be worth it! Be careful messing with the electronics, it is easy to fry something, make sure you have good fuses to everything, and plugs grounded when checking them!