higher revving kz750B

im aware the 1977 kz750b isnt a muscle bike or super bike.
what are some things i can do to get more power i.e. rev higher. not that it would make more power.

is there a differrent crank i can swap out? cams? aftermarket pistons.
i would really like to have a higher revving motor. as stock. any higher would destroy it if not changed up.

The 750 twin power starts dropping straight off above about 7000 so revving higher does no good. A vertical twin is not well balanced like a four which is why the twin has internal balancers to help reduce vibration. I don't think the engine is going to rev much above the 7500 redline and it would not help at all if you tried to make it do that.

I tried to post the graph of the power curve but photobucket isn't working. It keeps saying the password is incorrect even though I reset it. What a major league pain in the ass that stupid site is. Too bad this site won't let people just post a picture like everybody else does....

Here we go again..... finally. There's 20 minutes of my life I'll never get back.

As you can see, there's nothing above 7k to be had except a blown engine.

^thats what i was saying. the question was. how can i get that power curve to move farther out? i.e. dif crank? is there any stroker cranks for the motor?
or jus rebuild it with more comp and some cams?

It can be done, it ant cheap....and if you cant do most the work yourself, OMG ON COST. I think bike shops are $65 to $85 per hour if you can find a Kaw mech.

some mods to make

punch it out....go big
pistons
new cams
bigger valves
port head
new carbs
pod's
header or freeflow exhaust.

see what Larry has to say...might want to give him a call.

OK, but just remember: it's still a poorly balanced vertical twin. I remember back when mine was new, I would take it up to redline on rare occasions and it shook so bad it would shake the rear view mirrors enough that they would be pointing at the ground afterwards. I think you are trying to turn Rosie O'Donnel into Angelina Jolie. If you want a high revving engine, there are lots to choose from but this ain't one of them.

If you want to rev higher without blowing up, you'd need to get everything balanced a lot better, as Bounty says, 2 cylinders have vibration problems, so imbalances hit them harder than 4 cylinders, or straight 6's (which are ideal). You also need to worry about valvetrain stuff, don't want to float a valve. I couldn't tell you how high you can go before that's an issue in these engines. But that won't get you the power, just let you run there and keep the engine alive.

The cams, porting, and exhaust are what will get you some more power in those higher rpms. But if you want to make some power out of that thing, I'd recommend going for more low end (I use the term with the understanding that low-end on a bike is still fairly high end). You can still get some power with the valves, porting, carbs, exhaust, and larger pistons. And for everyday riding, it's more useable on the lowend anyways, and then you don't have to drop money on all the concerns with trying to get high rpm's out of it.

i see. i was jus entertaining the though.
i have a 2006 R1 motor. but its pretty tall with all its doodads/carbs/airbox.
plz 1000cc 180hp is a bit too much for me.
i would like to have some power but not increase in size. like a quad 750 motor is huge.
i only weigh 140lbs :blush:

In the engineering world, we say anything can be done given enough time and money. Just depends on what you're willing to do. You certainly can get your 2 cyl up to 12k rpms. But it'll cost a fortune, and probably blow up every other week.

If you're dead-set on the high rpm thing, go for it, but just realize it'll be expensive. And you'll be charting some new territory, so it probably won't be easy to find a lot of answers to the questions you'll run into.

Somebody satisfy the curiosity of another 750 twin owner...

How would you go about adding more LOW end power?

Topper wrote: Somebody satisfy the curiosity of another 750 twin owner...

How would you go about adding more LOW end power?

Find an original stock exhaust system with the crossover pipe. They made really good low end pull. Wish I still had mine.

Hi Rab, Instead of wasting your time trying to make that two cylinder run, sell it and get a KZ 650 or KZ 750. They will run the pants off your two cylinder. The 650s and 750s rev much higher and have more horse-power. There are " make-em go fast products for the 650 and 750 KZs, if you want to spend a lot of money. My stock KZ will out run quite a few bikes, 3even though it,s 30 plus years old. Good luck, and don't waste your time with that boat anchor. Bob