xs250 carb conversion

[FLEA]

with this xs250 i bought was wondering about a carb conversion , even though only 32 cv mukuni recommends a vm30 swap instead .. now the question is iv a good spare set of vm34s from the 650 , any way of using these and change the jetting etc

 

[arcticXS]

VM34 does seem a bit too big for a 4 stroke 250 twin, even if it revs a bit higher than the XS650.
I have been messing a bit with a Suzuki 125 single, which has an engine shared between a lot of models, both on and off road (GS, GZ, GN, DR, DRz) this has 12 hp stock, and could be considered as half a 250 twin.
Modifying these is quite popular, as there is various big bore and stroker kits on the market for them. 141, 152, 170 and 187 cc are commonly available options.
Even with a 187 cc big bore kit, most end up with an 28 mm carb.
And for street use, 30 mm DellOrto or Mikuni are recommended options for Honda CB350 twins.
So the 34s are definitely too big for your 250 imho.

 

[FLEA]

VM34 does seem a bit too big for a 4 stroke 250 twin, even if it revs a bit higher than the XS650.
I have been messing a bit with a Suzuki 125 single, which has an engine shared between a lot of models, both on and off road (GS, GZ, GN, DR, DRz) this has 12 hp stock, and could be considered as half a 250 twin.
Modifying these is quite popular, as there is various big bore and stroker kits on the market for them. 141, 152, 170 and 187 cc are commonly available options.
Even with a 187 cc big bore kit, most end up with an 28 mm carb.
And for street use, 30 mm DellOrto or Mikuni are recommended options for Honda CB350 twins.
So the 34s are definitely too big for your 250 imho.

thanks , after a bit of reading have come to the same verdict , damm ..would have been good if it had worked as would have saved a lot of money , after riding it home from the shop will have to do something , way under powered even for what it is , will have to go looking for cause ,definitly plenty of compression even without putting the gauges on it , had trouble getting it up to 100kph (60mph) and dropping down gears at the sight of a hill , the test ride when buying was just up and down the street on flat ground , will have to go looking as motor seems healthy , 400 conversion might be in the future