GS425 vm34 carb conversion

[bhd27!]

Was wondering if anyone has done it and what it required. Put a set on the the bike and have been chasing my tail. Any experienced help would be great appreciated.

[Nessism]

A VM34 (didn't know such a carb exists) is way too big for your engine. The GS1000, which has similar sized cylinders as your 425, uses VM26's.

[Big Rich]

Nessism is correct. Physically, those VM34's will allow too much air into the engine (the cylinders can only hold SO much gas / air).

I have VM34's on my GR650 (the parallel twin, 650cc's) and a lot of people put those carbs on XS650's. Just to give you an idea of what they are suited for.

[83_450E]

Mikuni vm32 are regularly put on Honda cb 350 to cb 450. I doubt you'll need a vm34 but if you have to, go for it and post results

[Big Rich]

To clarify...... people put VM32's on Honda CB350's, but they still won't run properly. Even VM30's are a little on the "big" side for a CB350. I've heard the best carbs for a CB350 (which has around 325cc's btw) are VM28's.

[bhd27!]

Well this is it....got it running pretty well. Pulls hard all the way through the throttle just have a tiny hiccup when you go from closed throttle to nearly wide open but it recovers really fast. Little more fine tuning and should have it pretty close to dialed.

[tkent02]

Is it any more powerful than it was?

[BassCliff]

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[83_450E]

To clarify...... people put VM32's on Honda CB350's, but they still won't run properly. Even VM30's are a little on the "big" side for a CB350. I've heard the best carbs for a CB350 (which has around 325cc's btw) are VM28's.

Exactly. When over carbing a motor you get to pick at what rpm and throttle opening you want it to run at well at and all other inputs just get taken for the ride.

[bhd27!]

Is it any more powerful than it was?

Well the stock carbs were damaged so I never got to run the motor with the stock carbs so I have nothing to compare it to. Bike seems to run really well. Once rolling ill post a quarter mile time and maybe that will give a idea. I've made contact with another guy who was successful at tuning this setup and he said it was a "MONSTER".