FZRSupport: the FZROnline Archive

Has anyone ever tried to throw some yzf pistons in an fzr with the 3mm overbore? Looks like you could net up to 60ccm of displacement more. Including higher compression ratio.

I'm anxious to hear how it turns out... now, get to it!

Is the sleeve big enough to bore out 3mm? I swear duane and I were just looking at this over the weekend and the sleeves were like, 2.8mm thick or something

zero9243 wrote:Is the sleeve big enough to bore out 3mm? I swear duane and I were just looking at this over the weekend and the sleeves were like, 2.8mm thick or something

He only needs 1.5mm per side, so that leaves him with 1.3mm. The question is, and I am no engineer, but is that enough side wall left?

how is this better than just swapping the top for the yzf is it just cost wise, and would you need bigger carbs for that like the yzf or can the fzr flow enough to work. also is the yzf the same height from the wrist pin to the top of the piston. deffinatly some out of the box thinking that has my attention

ragedigital wrote:

zero9243 wrote:Is the sleeve big enough to bore out 3mm? I swear duane and I were just looking at this over the weekend and the sleeves were like, 2.8mm thick or something

He only needs 1.5mm per side, so that leaves him with 1.3mm. The question is, and I am no engineer, but is that enough side wall left?

Yea Dillon, we did measure it and it came out to 2.9mm. Removing roughly half that doesn't leave much to work with. They looked thin as it is.

I pose another question now. What size are the wrist pins used in an FZR? If they turn out to be the same size then I can just use the yzf piston jug and keep the standard fzr head and con rods. I'm just trying to find a way to not get rid of my new top end.

isnt the fzr a long throw and the yzf a short needing the connection rods too

sweekster wrote:

ragedigital wrote:

zero9243 wrote:Is the sleeve big enough to bore out 3mm? I swear duane and I were just looking at this over the weekend and the sleeves were like, 2.8mm thick or something

He only needs 1.5mm per side, so that leaves him with 1.3mm. The question is, and I am no engineer, but is that enough side wall left?

Yea Dillon, we did measure it and it came out to 2.9mm. Removing roughly half that doesn't leave much to work with. They looked thin as it is.

Ok I will bite how do guys come up with a 660 cc bike then?

I'm guessing, full YZF top end. With the longer throw of the FZR crank, the gudgeon/wrist pins must be closer the the piston crown (otherwise pistons hit valves) = longer stroke?

Again I pose the same question. What size are the wrist pins used in an FZR? If they turn out to be the same size then I can just use the yzf piston jug and keep the standard fzr head and con rods. I'm just trying to find a way to not get rid of my new top end.

Take a look at this http://fzronline.com/wiki/doku.php?id=d ... ment_chart by cad600, he has a 660 I believe.

I've been poking around on the Archives, there's a thread in the FZR Hybrids forum "660 conversion so far"

duno if posting the link is allowed. It's an interesting read.