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3003 Views 35 Replies 14 Participants Last post by  aaron_j
talked to a few people, engine builders too, so now ill consult the general v force population.

fst820 top end, 12.5:1 pistons, bored cylinders, ported heads aftermarket valves(stock size), stg 3 cams -


amr ported heads with +1.5 valves and xxx cams, add 730 pistons and boring ill spend roughly $225 more.

ive already got lte's and 38's for the bike. want to be able to drag it and ride out on the dunes, eventually add nitrous. i know 800 and up have head gasket issues, so what would potentially be better? i know i wont beat everyone, just like to surprise a few banshees n 450's. so with that in mind will the 730 be my winning ticket?

and if either of the fellas sellin me this stuff read this, i just want to make sure ill be satisfied with what i end up with, ive talked with you both a great deal and will be buying something.
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Just know any time your compression goes over 11:50 to run your going to need some race fuel
I have never had a head gasket issue on my 800 the 2+ years
Just know any time your compression goes over 11:50 to run your going to need some race fuel

12.3:1 is when you need more than a 93 octane (premium). Unless you're running some crazy advanced timing. If you're buying 12.5:1 pistons just run a double base gasket for a .4 -.5 drop in the compression ratio.

An 820 with the mods you listed would be a beast. I haven't had headgasket issues on my 800 at all, and I REUSED the triple layer headgaskets several tims. :lol:
i plan on mixing fuel regardless erbe!
Just know any time your compression goes over 11:50 to run your going to need some race fuel
12:1 and running 91 octane. No need for race gas, unless you like the smell.
come on guys i know more of you can chime in with your opinions
I would go with the 820 myself. If your worried about head gaskets you can go with Brute 750 cylinders. Thats what Im doing
Im not going to argue about use of race fuel on higher compression motors for me, I mix race fuel for all the quads, gas here in So Cals sucks.
I do run VP110 straight in the DS at 14 to 1 Comp and the LT500 runs at 200/lbs comp, I was just taught way back when any thing over 11 :50 to 1 run around 98oct to 100oct due the heat in Glamis ia all, hate pinging!
i was gonna mix it, cant afford $12/gal for race fuel. at least last i heard that was the goin price round here.

dr love, the cylinders are already bored to the pistons, but i may be picking up a fudged bf750 engine, if so ill keep the top end n sell the bottom.
$12/gal for race fuel.

:eek::eek: Good Lord. Im paying $8/gal here and I though that was bad :lol:
VP110 $6.50 gal at the pump
I'd spray a 730. And build the motor so that you can run straight premium. That way when we stay longer then expected you can gas up and ride. Is the 800+ motor going to be able to run hard for a 2 to 3 hour ride that we go on? You know you will not be happy having to sit out on the riding to let it cool at any time.

...AND the places around here that sell race gas; only sell it 5 gallons at a time. So you don't buy 5 gallons at $9.00 a gallon just to dump the other 3 gallons in the truck when you get home. But have the compression to run it when you want.
Small bore with the spray
see i was kinda thinking that in the shower : 730 kit is roughly 800 + 125 machining, boss noss kits thru trugrip are 625. so id be back near the cost of the 820 but still be a lil quicker. i really just wanna be able to spank a friend of dixie n i's yfz450, hes soon putting in a 490 kit.
And the truth comes out :lol:
well not only him, but many others too! not to mention you, gotta make up for the wieght advantage you carry.
:lol: better for the hole shot :lol:
dale i tried callin you earlier, call me later got a few questions for ya
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