newbe help polaris 750 upsize motor question

bearmc · 11-26-2009, 03:56 AM

Hi, I have a 1995 polaris 750 and the motor has seized. I am wanting to replace it with a new one or rebuilt. I would like to get some extra power out of it and am wondering about my options eg. larger motor vs tricked out 750. Does any one know if I went with a larger motor what consequences there would be as far as manifolds impeller, shafts etc. there would be? Would I be better off by putting some high performance parts into a rebuilt 750 where the existing components would fit back on? I like the size of the 750 and its meneuverability for jumping waves etc. as opposed to a newer larger machine.
Any advice would be appreciated
Thanks
Doug

delagem · 11-26-2009, 09:46 AM

It is very easy to take a 750 up to a 780, just jugs, pistons and a new exhaust manifold. Same crank and bottom end.

But the gain is fairly small, like 15hp. You can get similar gains from a well set up 750.

Not at all easy to go beyond that size.

Enjoy your 750 for what it is. You'll pour way more money into it trying to make it a 1200 than a 1200 costs...

A lot of Polaris guys hang out on www.greenhulk.net

Michael

xlint89 · 11-27-2009, 07:45 AM

Welcome to the Polaris family.

You'll get many more responses from greenhulk.net than here.

But to answer your Q, he ^^^^^^ is right.

You can actually install the 780 cyls, heads, and exh manifold onto your 750 pretty easily. I hapen to have a complete set for sale by the way. Just need to have the cyls bored for the pistons.

To take full advantage of the 780 set up, you might want to get a 780 CDI or even a PRO 785 CDI. They have a more agressive timing curve than a 750 CDI, but they are not totally necessary. I bet you'd hardly notice the difference to be honest.

You would need to rejet the carbs for the 780. But, you'll need to rejet the carbs for any mods you do to the 750 as well. Usually would want a free breathing Flame Arrestor installed for more power either route you go.

The impeller would prob want to be changed, but again, not totally necessary. You can take advantage of the added HP from the 780 by going to a 15/20 Skat Trak impeller. This will gain you more top speed with a good holeshot. Or you can leave your 750 impeller in there and have a strong holeshot with a little more top end.

If you decide to stay with the 750, I also have high compression heads for sale.

There are other things to suggest, but I got to run to work now. More on this later.

SflSwampRat · 11-27-2009, 09:05 AM

dont forget to address the reason why the engine seized.

you should install a triple outlet fuel pump to feed all three carbs individually and have the crank trued and welded.

xlint89 · 11-27-2009, 08:59 PM

True ^^^^^^^^, need to address the cause of the problem.

Getting back to what I started saying.

Keeping it a 750, you could gain mph and acceleration by changing the stock ride plate, to one like the Ocean Pro "R" for race, or install a SLX 780 plate onto your hull.

You can also instrall the parts to make your jet pump a long pump. That will increase top speed and gain you better turning with no engine mods at all.