Sitdown 62T in Superjet tuning

[Jfara]

Dropped a 62T/62T from a sitdown into a 90’ SN650. Set the carbs up to a stock superjet 62T w 61X cylinder settings: 130main jets 70 low jets 1 1/4 out high screws 1 3/4 low screws. 115 gram spring.

Runs pretty well but feel like it should have more mid to high end punch as it struggles for a second to get to higher rpm especially when coming out of a turn.

Anyone done this swap ? Looking for help with settings to get this dialed with its new 61X exhaust.

 

[fastgtfairlane]

Did you swap the impeller out to one that will handle the additional horsepower and torque from the 701 over the 650?

 

[john zigler]

What impeller do you have? Needle and seat size, and what gram spring?

We have done this swap MANY times. Did you port match the exhaust manifold to the cyl?

 

[800750]

Turn the screws out more to see if it helps

 

[kevbo]

Using a higher port cylinder with the stock superjet pipe doesnt help your situation. You need to get the RPM up for the engine to work well. A freestyle pitched impeller is usually required. try to get 67000-6800 rpm. At that point adding a pipe will get over 7000 RPM.