What alternative pistons fit in a 750 twin?

Is there a piston that has the right stuff to bolt in- in a bigger bore? I have seen the posts to make the 875cc twin on the lonesome twin site, called and wrote for prices- the liners are not bad at all price wise- but the pistons are outrageous- being that they are custom made and all-

so I have a question- which piston, off any bike or model, piston needs maybe just a bit of tweaking to be made into a 750 twin piston?

I did this years ago when I raced mopars, before they had all the shelf stuff- I used a chevy piston, speced to the bore size I wanted, and used Chevy BB rods on my stroker 400 crank that was mopar- and I want to try it here

So- did kawi change so much in piston design from model to model? Does, say, for instance- does a 900cc or 1000cc piston have the same ring lands, piston pin, maybe bigger diameter or something, than the 750 twin?

KZ750 twin bore diameter is 78 mm, I think you are going to have to look at big singles to find a larger piston. ie KLR650, XL600/650, XT600, etc.

Oh yeah, 19 mm piston pin

Custom pistons are a lot cheaper when you order a bunch at one time (100 or more), so you could put together your own big bore kits and sell them

Post edited by: steell, at: 2006/12/29 22:54

I also want to have more cc's in my twin. I was looking at the 83mm pistons for a kz1000 big bore up to 1480cc's. You will end up at approx 845cc's, but i do not know if the wristpin has the same diameter....
where do you get the liners from???
wiseco has them from LA sleeves and for the 83mm the will fetch about $60 dollars each. If you find a suitable pistons for more cc's let us know!!!

Good hunt for 2007!!
Martijn:evil:

900/1000 has a 17mm pin, 1100 has a 18mm pin.

And as mentioned above, the 750 twin has a 19mm pin.

You also have to check piston compression height.

I am aware of at least two big bore 750 twins, and both used custom pistons.

A quote from a conversation I had:

785cc motor with stock valve buckets( shim over) it put out 78RWHP.The second motor has been taken to 880cc .The pistons in both motors are from Arai specially made.12 or 13:1.The new liners are Nickasil.The valves in the second motor are also oversize but now titanium and the buckets have been replaced with shim under through Fast by Gast(drag racer in N.Y)The shims were being thrown out through the valve cover.The mega cycle .485 lift cams have been replaced with a set that have different profiles the intake is .585(

You could buy a used ZRX1200 for what that motor cost to build

Post edited by: steell, at: 2006/12/30 17:01

Yes- that is kinda my point- sticking point seems to be the 19mm wrist pin- if you can find a rough piston with a tall deck height and 88mm raw forging, you could machine the rest locally to your specs, saving alot of money, I think.

The lonesome twin 875 costs about 6hun IIRC in liners and pistons, ready to roll. That is from UK and Germany BTW

Post edited by: CruisingRam, at: 2006/12/30 18:31

Since it looks like finding bigger pistons will be quite an issue, why not just add more of them? stick another one on the side and make a triple. I know, easier said than done, but there have been sucessful 4 and 5 cylinder bikes made out of the triple 2 strokes. another idea: make a v4 out of 750 twin parts. base it on the v8 and v12 bikes made out of 1000s and 1300s

But about the wrist pin, could you just bore the hole bigger in a different piston to take the larger pin?

Scott

I don't have a problem maching down a piston- I have done raw forgings before- but what you are talking about is light years from what I am wanting LOL