650/X-2 Need some motor info.......

[leedesigns148]

Im looking to get some parts to build a motor for my x2. Im looking for a 750 small pin crank and cylinders. If I can im gonna use my 650 bottom cases and the head. Will this work and if so how well.... Any thoughts Help......... Thanks

 

[Wilke]

you cant use the 650 head and you're going about it the hard way, just buy the whole 750 or rebuild and port the 650. Trying to buy a 750 in parts is going to cost you more than just finding a nice used complete short block.

 

[WFO Speedracer]

While a 750 small pin crank would physically fit into a set of 650 cases it willl not rotate because the bottom of the cases is not trenched out for the 4mm stroke difference, I agree with Wilke, unless you are wanting to build something totally new, just find a complete 750 engine and install it,I have seen them go for as low as $400.00 here.

 

[leedesigns148]

Thanks for the advice it very well taken im gonna get a whole motor. Now is a small pin better than a big pin? I had a big pin zxi motor in my last x2 but I sold it and the person I sold it to sold it again and that person said the motor was a turd. But I have only owned 650 x2s before that and I thought it had a lot more power with the zxi but after hearing that i am second guessing myself.

 

[Wilke]

They both make roughly the same power. But the powerband in the small pin is lower in the rpms so it will have a little more punch to it in stock form. Once you do a few engine mods I think the difference is negligable. And with the big pin you have the option to bolt on an sxr top end. just buy which ever is available for the best price.

Odds are the guy who said it was a turd let the tune go to , or the motor had low compression and needed a topend rebuild and the guy just wrote it off.

 

[RivMan]

Hey man, I think I've got your old X2.

It was a bit of a turd being bone stock with a blown head gasket. I added a Coffman pipe, westcoast manifold, and a new head gasket. She's running a bit closer to my modded 650, and a high compression head and bigger carb are on the way. A stock 750 will never touch a modded 650, but a modded 750 will have more power then an equally worked 650.

I plan to do with a small pin cylinder to go with the big pin bottom end (Even better porting for the low end) at some point.

-Rob