big bore kit..anybody running this with luck?

[teazer]

Yes. CB77, 350, 750 DOHC are all the same pin diameter. 450 is larger though and I think the 360 was also larger.

[cyclon36]

Feedback from Bill at Boretech when asked about the kit and reliability on a regular rider:

The big bore kit for the 305 motor is the most practical and effective modification you can do. The compression ratio is around 9.0 to 1 which will just require pump gas at 87-89 octane. It can be used with no other modification other than carb jetting. Of course, other power increases can be had with cam change, carbs, ignition. It is always necessary to know that power increases do not come without some risk of loosing dependability. The more power, the less reliable. I would say with the big bore kit only, you could expect a 20 - 25 percent increase in horsepower.
Stock carbs with the correct jetting do seem to work well but that is an area that can be changed at any time.

Teazer, do the power gains seem similar to what you experienced with your route? Are you running anything other than a jet kit? to tune it out?

[teazer]

350/305=115%. If the ports stay the same and no other changes were made, I'd be very surprised by the quoted number.

My motors are ported, have bigger carbs, valves pulled back slightly much higher compression and they make a lot more power than stock.

Stock carbs are probably OK to use, though to be honest, we use a pair of CB77 carbs on our 175 Honda vintage race bike..............

Stock ports are a bit of a mess and benefit from clean up. Add in a mild street cam from megacycle and you would have a tidy package.

Back in the day, a stock bike made about 24HP at the rear wheel and adding the Forgetrue 350 kit took that to 31HP with H&C roller cam but stock ports.

For a street bike, the extra cc won't make it fly at the top end as much as giving it more midrange torque and that should make it more fun to ride.