Yes, I should have qualified my statement. You can run boost on a stock engine, the amount of heat that is generated compressing the intake charge at 3lbs isn't that great. I just find for the complexity, weight, and other associated requirements for goin turbo, you can pull more power more reliably if you do the internals as mentioned by the OP. Just my opinion.

I shouldn't say more power, the sky and money is the limit when it comes to that.
I mean to say if you are doing a low boost Stock engine I think not having to deal
with lag, weight, oil temp and other factors makes the other scenario more attactive.

Sorry it's 2am I'm at work, and typing this on my iPhone.
Prolly doesn't make sense!!

Cheers.

 

bore=bigger displacement which = more hp. There is no substitute for displacement. Increasing the bore along with everything else the OP listed will net some nice HP gains. And it will be alot better than doing with a turbo (sorry guys)!!!

 

You don't have turbo lag if you stay high in RPM's. I'm putting a turbo on my 929 and fully expect to have 0 chicken strip.

 

So what do you est a 1-2mm bore will do for actual HP? All I was saying is I dont think it would be too much, no?

 

There is no replacement for displacement, but never at the cost of rpm. You can get more power increasing the red line than you can out of a 1mm overbore.

 

Sorry to say but I expect you in a not so thrilling post after doing such. Like I said there is a reason there are no turbo'd sportbikes in production.



increasing rpms is a result of more balanced n stronger parts.

As far as bore goes, I know for a fact going from a 85.5mm (1600cc) to a 88mm (1641cc) bore in a aircooled vw engine netted a big gain in hp. Add a cw crank, a good cam, heads, n carbs, I went from the stock 60hp to around 110hp. And thats just a mild build. I worked on serveral that just had a 88mm 'big bore' kit in em n the rest still stock n you still noticed a increase of power. So yea, 2 - 3mm can do alot in these 'lil' engines

 

I've run 10.5:1 on a Busa with 13# boost (occasionally bumping up to 15#). Aquamist water injection took care of the heat build up without needing an IC ... but, you had to remember to fill the water reservoir EVERY time you put gas in it.

It carved twisties just fine thank you but was a lot of work because of the inherent weight of a Busa. A lot of suspension work fore and aft plus the chucking of everything that wasn't essential helped a lot. Larger gearing allowed for slightly shorter wheel base and that made turn in very nice.

There was no lag due to the high compression ... anything over 3000 started spooling up pretty quickly so the power was mostly predictable. Occasionally wheel slip would be a problem and once you hooked up the power would hit like a freight train. But that's pretty much the story with any high HP motorcycle.

I guess it all depends on what you want and how much $$ you are willing to spend. I'll tell you that doing most of the fab work and all of the installation saved me big bucks ... plus I knew my system inside and out. Good luck with your engine work. I can certainly see 40-50 HP out of it.

 

There used to be production turbo bikes. They started to not need them. Anyways, to increase RPM the major setback is valve springs. Your valves will start floating at high RPM's with week springs and retainers. I am in agreement, There is no replacement for displacement, but turbos are predictable fun. I've been down before, I expect I'll go down more. It's just part of riding motorcycles.