Mikuni VM/Mikuni TM mpg

[cbipoki]

Hello guys,

I'm totally new on this forum, so let me first introduce myself - my name is Andrey and I'm from Russia, Moscow. Being a happy owner of Kawasaki W650 for 1 year I'm thinking to tune its performance a bit. And the first thing to come in my mind is to switch the stock Keihin CVK to something more agressive like Mikuni VM or Mikuni TM. I have made some research and generally couldn't find any real users information about the application of these carb for W650 - just very basic information.

I think jetting won't be a problem because I have the access to the workshop with the dyno and AFR meter. My general concern is about miles per gallon (km per litres). I apologize if this topic arised previously and had been already discussed but the information varies A LOT across the Internet about fuel consumption... And I'm a bit frustrated because some guys mention that its MPG drops almost 2 times (which is the result of inproper jetting I think), some state that its MPG stays the same or even increases! (which seems to be kind of unrealistic as stock carbs flow undoubtly worse in comparison with slides).

Could you please share your experience or your thoughts about how VM/TM affects MPG?

Thank you!

 

[cxman]

i build a lot of mikuni kits and here is what i can tell you

generally there is a 20 percent drop over a cv carb if jetted properly and it can go down from there

normally people enjoy the better response and up there driving style and that can decrease the mileage even more

if people took it real easy or steady drive on the highway its not that bad my 650 went from 51-52 down to 47 with mikunis at 73mph steady

originally my bike got around 40 mpg with the kehin cvs the bike is a 650 (674) cafe bike

i used to get 34 mpg with vm34 round slides then i installed tm36 i dyno tuned

and now i am happy to report i am getting 27 mpg

so having stated that most of my kits have a gain in horsepower and torque and that takes fuel

i am now starting to play with the new hsr series carbs for economy

by the way you should note tm carbs are worse at cold starting than vms

 

[cbipoki]

i build a lot of mikuni kits and here is what i can tell you

generally there is a 20 percent drop over a cv carb if jetted properly and it can go down from there

normally people enjoy the better response and up there driving style and that can decrease the mileage even more

if people took it real easy or steady drive on the highway its not that bad my 650 went from 51-52 down to 47 with mikunis at 73mph steady

originally my bike got around 40 mpg with the kehin cvs the bike is a 650 (674) cafe bike

i used to get 34 mpg with vm34 round slides then i installed tm36 i dyno tuned

and now i am happy to report i am getting 27 mpg

so having stated that most of my kits have a gain in horsepower and torque and that takes fuel

i am now starting to play with the new hsr series carbs for economy

by the way you should note tm carbs are worse at cold starting than vms

Thank you for such detailed answer! I've read previously that flat slide are much more sensible to weather conditions and altitude in comparison with CV. If the last point is not really a concern in my case, but the weather differs from around +3C to +35C during the season and that's the issue.

Regarding MPG - I'm beginning to doubt if it's really worth switching to VM for everyday usage...

As for HSR - as far as I know there are only 42+ mm Mikuni HSR. If you're going to install it on W650 do you use single carb kit? Because a pair of 42 mm seems to be oversized except you bored the engine up to 800cc... In case of single carb kit - do you expect any power increase while replacing 2xCarb for 1xHSR?

Thanks!

 

[cxman]

i make kits for bigger bikes they can use dual hsr carbs

the 650 that i have is a honda not a kawasaki