Tuning question

[cmc600rr]

Hey guys,

93 650sx 150psi both cylinders.
Westcoast full exhaust.
Westcoast waterbox
Sbn44 carb
I believe the inpeller is stock.

Currently the motor has the stock head. But I have a westcoast high compression head with 30cc domes that I haven't put on yet.

I don't feel like the ski gets out of the hole well. It doesn't bog, or load up but it also doesn't really jump out if the hole. Also I dont believe it's reaching it's top end well.

I will hop out of the water it will bounce off the limiter and then bog like it's under powered once the pump fills up again. As far as redline goes I don't feel like it's achieving it.

The carb is jetted with a 110 low and a 150 high.

I run 40:1 mix with 91 octane.

Any ideas on settings or jets? I am going to put the high compression head on next week. Is the Jetting more geared towards the high compression head?

 

[Crab]

Jetting looks ok but you are most likely over propped. I had a few of those 650 motors with that setup. the stock waterbox is really restrictive and that pipe puts a lot of water in the exhaust.

 

[cmc600rr]

"Over propped" meaning I should look into an inpeller better setup for low end?

Jetting looks ok but you are most likely over propped. I had a few of those 650 motors with that setup. the stock waterbox is really restrictive and that pipe puts a lot of water in the exhaust.

 

[Crab]

exactly

 

[cmc600rr]

From a quick search, 8/16 skat, 9/15 9/17 hooker seems to be the choice prop.

Agreed?

 

[Crab]

8/16 probably