358cc Big Bore tuning question

[drdoom1951]

I'm planning to put in Bore-Tech's 358cc big bore kit in my '65 Superhawk. The bike will be strictly a street machine, no racing, as I just want some additional torque and take whatever power increase I get. I want to keep the OEM carburetors, but I figure with the additional 14% displacement, meaning more air, I will need to modify the stock jetting.
Anyone out there have any experience with jetting the Bore-Tech big bore with sock carbs, and provide some advice on what would be the appropriate jet size?

thanks

[LOUD MOUSE]

Sure would be nice if you gave ALL OF US YOUR LOCATION.
No doubt you will may need to increase the size.
What size are the jets now?. ...............lm

I'm planning to put in Bore-Tech's 358cc big bore kit in my '65 Superhawk. The bike will be strictly a street machine, no racing, as I just want some additional torque and take whatever power increase I get. I want to keep the OEM carburetors, but I figure with the additional 14% displacement, meaning more air, I will need to modify the stock jetting.
Anyone out there have any experience with jetting the Bore-Tech big bore with sock carbs, and provide some advice on what would be the appropriate jet size?

thanks

[drdoom1951]

I’m located in the SF-Bay area. I don’t know the actual sizes yet, but they should be the OEM jets that came with the carbs. I haven’t yet disassembled the carbs.

[G-Man]

The carb sets the air-fuel ratio so the jets may not need changing. The standard jets would be a good starting point in any case. You may need to look at the jetting for wide-open throttle as the air flow increases beyond the flow-rate of the original 305 engine.. The carb has no idea what size the bore is, just the rate of air flow. It meters the fuel accordingly....

My 1961 CB72 had a 350 kit and appeared to be running well on 22mm carbs with standard jets.

G

I’m located in the SF-Bay area. I don’t know the actual sizes yet, but they should be the OEM jets that came with the carbs. I haven’t yet disassembled the carbs.

[leonvjames]

I put a Reid Titan 350 kit in my CB77 many years ago. I think it came with 135 main jets which I used. I found I had to alter the cut away on the slides as the motor was surging at cruising revs, about 6000 rpm. I added about 1/8 inch to the cutaway with solder and it is still there and worked real well.