Kz900: Stock Bore - High Compression Pistons

Hi,

Was wondering if anyone knew where I could find a stock bore, high compression piston? Are they available from somewhere? I know I can get an over-bore (1015) with higher compression. Any information for a supplier would be greatly appreciated.

Cory

I think I have a brand new set on the shelf at the other house, I'd have to check this weekend when we go but I'm pretty sure they are 903 (stock bore) 10.5-1 weisco's, still in the box.

Les

Ooohhh. Let me know if you are interested in getting rid of them.

Cory

I will, knowing me I prolly bought them right cause it ain't something I would buy for myself so I'll make you a good deal on them.

Les

A nice set of drop in cams and some 28s would work good to pump that 900 up with those pistons.

Considering it.... I am operating on the premise that the inspection of the bores I have done, show that they are within spec and probable just need a hone. Might as well just keep as much cylinder wall thickness as I can and get some squeeze. I checked Wiseco's site, they don't appear to offer a stock bore piston. Only the 1015 is the smallest bore for the 900. As far as the cams are concerned, I would simply like a set that are very streetable, and don't require grinding & clearancing the head. A couple of additional questions though:

1. Do I need to weld the crank with this combo?
2. Anything that should be done with the connecting rods?
3. When should bearing plate brace be used?
4. Trans gears back cut?
5. How much would the stock 26's be a restriction?

I am also considering getting the head ported by Larry C. I really don't know if I want to tie money up in the motor. I have two modern liter bikes that make crap loads of power. I may just want to leave this one podded, jetted, and exhaust. Was going to throw the high compression pistons to pull a little more out of it. This includes the new Dyna ignition and coils.

Cory

If youre going into the bottem end its never a bad idea to weld crank,new cam chain etc while youre in there.
As far as undercutting trans I wouldnt waste the money unless the dogs look beat up when you inspect them,throw the 26s under the bench and find some of those stock 28s off a 79-80 1000 itll really help for a low buck investment.

Here you go...
If over 1015cc on 900 engine case, upper case cylinder holes need enlarging for larger diameter cylinder sleeves.

Cylinder w/Piston Kits


#118 Grinds Pop & Go Cams

From what I've read, a 1015cc can be done on a stock 900 sleeve/cylinder as it simply an overbore. If you go to the 1075cc, then you either need new sleeves or a later KZ1000 cylinder?

Wireman,

I got your PM, thanks.

Cory

wireman wrote: If youre going into the bottem end its never a bad idea to weld crank,new cam chain etc while youre in there.
As far as undercutting trans I wouldnt waste the money unless the dogs look beat up when you inspect them,throw the 26s under the bench and find some of those stock 28s off a 79-80 1000 itll really help for a low buck investment.

I tried, but got screwed on Ebay! So I am still on the hunt for now. The VM26's I have, are in nice shape and I thought I would run them if it was only going to give up a couple of horses.

Cory

Id say the 28s will give you as much if not more of a bump in power than those high compression pistons will

NakedFun wrote: From what I've read, a 1015cc can be done on a stock 900 sleeve/cylinder as it simply an overbore. If you go to the 1075cc, then you either need new sleeves or a later KZ1000 cylinder?

Wireman,

I got your PM, thanks.

Cory

1015 pistons in stock 900 sleeves will leave you with really thin sleeves making it hard to keep a round bore,especially when the motor heats up.
youll give up a lot of power if the rings cant seat when cylinder distorts