Hast PN!
Alex

Brilliant all way round, but following Sepp's jetting advice (#20 pilot and #260-280 mains), I have to say he was jetting very lean or had some other issues with the exhaust not flowing enough. With the stock jetting (#30, #300) it was way rich, but pulls like a raging bull all through the range. But the pilots are definitely too big as the bike starts without choke on a nearly zero degrees day, so I instantly stepped down the pilots to #22.5 (even though I am running with filter and currently running #230 mains, but I seem to have an airleak from the carb joints with the frame (carbs are too big for the stuck joints).

The VM38 come jetted #30 #300, which should be a brilliant starting point, when running velocity stacks. The 6DP10-needle gives a rich midrange and lots of punch. I am really curious to compare it with a Dellorto-powered TR1, when the chance arises, because if that solution is even better, it's got to be a rocket.

So how does it run? Well, you can feel it's gutsier at around 2.5k building up steam to 3.5k and then really pushing forward till 5k, which is where I now start to feel a too small mainjet, which becomes pretty obvious at around 6k.

I'll actually build a Mk.3 version of my exhaust in the next two weeks, because I want to slim it down even further and improve the interference pipe where the front cylinder joins the rear.

So, yes it's a brilliant carb and you can even buy a ready-made 2in1 choke cable for them from various XS650 shops, even though they seem to use different (angled) cable guides on the carbs, which make the cables slightly too long. (I've ordered those now and will post my results on this thread!) Furthermore you have to re-think the choke-actuation - either go for a cable-kit or go for knobs directly on the choke. The levers are very hard to reach  and thus a pain in the a$$ to operate.

Hope this helps
Greg

Jamie, did you check your mixture with a lambda probe sounds like you're rather far off? The VM34s even if just moderately dialed in should make AT LEAST the same amount of power as the stock carbs. Only thing that'll be noticeable is the amount of power beyond 5000rpm, actually down low you should have a lot more grunt than me. That is if you've junked the stock exhaust!

Cheers,
Greg

P.S.: Don't throw out the baby with the bathwater! I'd say there are more things that would recommend themselves to improvement than just the carbs on your bike. Why don't you open a thread? I am pretty sure, if you post some pix and share some specs that some of the elders can give you pointers towards where there's room for improvement.