how to tell what size carb i have?

[Dubs chops]

how can i tell what size carb is on this boat i just boat, it is a 89 650 sx, how much would it help me to change to dual cars for freestyle? do they help bottom end BRAP.

 

[Matt_E]

Get a Superjet to help with the bottom end. :biggthumpup:

 

[kawirider00]

measure bottom of carb, probly a 28mm, just go to a bigger single like a 38 or 40

 

[KaosFreestyle]

You can go with a 44mm thats what I put in over the winter.

 

[Shonuff]

Twin carbs help fuel delivery for racing but for your freestyle needs, a single 44 would be just the ticket.

 

[SUPERJET-113]

A 42 Keihin works great to replace the puny 28mm and all you have to do is open up the exsisting stock manifold hole. The bolt patterns are the same.
The later years 650SX had a bigger carb, I think a 38mm Keihin...

 

[Josiah]

my 89 has a 38mm keihin, obviously it was replaced by previous owner. How do you "open" up the existing manifold, would I have to polish and port it? Is there a do it yourself @ home way of going about it? I have a dremel with various bits.