Anyone here done this? Any gains from it?
Thanks

Brolo said:

Anyone here done this? Any gains from it?
Thanks



I'm assuming you're talking about your '98.
Haven't heard of it but looking through some specs gives the following data.
Main journals are the same at 34mm so theoretically it would drop into the cases. It would depend on bore centres which I'd expect to be the same and anything else that might be driven off the crank. The camchain sprocket is removable but I'd expect that to be the same as the 600 anyway.
600 stroke is 44.5mm
750 stroke is 46.0mm so there'd be a very small capacity increase - 20cc or so I think.
Big ends are 34mm and 32mm and small ends are 16mm and 15mm so the 600 rods won't fit the crank though it _might_ be possible to machine the crank pins down 2mm to take the 600 rods. Or you run the 750 rods and the piston pins will need to be bushed up to fit the small ends or the 600 pistons drilled to take the larger pins.
If you really want to put that much work into it I'd be looking at dropping a complete 750 top end on with a 750 crank - or just get a 750 or 1000 motor :-)
Cool idea though :-)
I had similar ideas about dropping a 1000 crank into my 750 since the extra 13mm (I think) of stroke makes for a huge capacity difference but I'd still have to machine down the mains.
Be safe,
Larry

Awesome response Larry. Just the info I was hoping for and then some. http://www.gixxer.com/forums/images/graemlins/thumb.gif http://www.gixxer.com/forums/images/graemlins/thumb.gif http://www.gixxer.com/forums/images/graemlins/thumb.gif

It was a '97 750 crankshaft on Ebay and a friend said that it would up my displacement a little. But for the price (already at $41US) and the amount of time and effort it would take to install, it doesn't sound like it would be worth it. I mean, going from 600cc to 620cc amounts to a displacement increase of 3.3% http://www.gixxer.com/forums/images/graemlins/rolleyes.gif Hardly noticeable, and I'd probably be better off spending the $40 on a new rear sprocket (up a tooth or two).

Anyone agree/disagree. Or maybe someone's done this, knows that the crank fits and it was all worth it? http://www.gixxer.com/forums/images/graemlins/confused.gif

I'd do the sproket mod too.....

Other thing to keep in mind is that the dynamic balance of the crank won't be the same. If you machine the crank, its balance will be altered. Also the piston+rod weight on the 600 is different, which again will alter the overall balancing of the engine. (I recall studying this in my mechanical engineer course, a few moons ago...). Nah... don't do it.

Cheers.