Advice on a motor build.

[biggixxerjim]

Lookin for some advice on my build, was hoping some of you with these set ups could chime in.

thinkin either a stock bore or 727, 12.5:1 compression. stage II port and polish and hotcams stage II. I know that I will need to run race fuel, thats not too much of a concern. Im more worried about the valves; I am gonna have to tear the head appart?? I want to try to aviod doing a valve job. And what about some ARp head bolts??

Im trying to get around 65 hp to the rear wheels without making it grenade happy, as I often ride long distances. Getting towed home SUCKS when ur 6 miles out. Also going to run Dasa duals, PCIII, and intake

[preddy08]

Lookin for some advice on my build, was hoping some of you with these set ups could chime in.

thinkin either a stock bore or 727, 12.5:1 compression. stage II port and polish and hotcams stage II. I know that I will need to run race fuel, thats not too much of a concern. Im more worried about the valves; I am gonna have to tear the head appart?? I want to try to aviod doing a valve job. And what about some ARp head bolts??

Im trying to get around 65 hp to the rear wheels without making it grenade happy, as I often ride long distances. Getting towed home SUCKS when ur 6 miles out. Also going to run Dasa duals, PCIII, and intake

With out a doubt go with more compression!! Little trade secret, get the CP 12.1 mill the cylinder to get about 14 and call it good! By milling the cylinder you retard the cams just a bit yielding more top end.

With 727, 14.1, and a x-2 and a P&P can and duals will get about 73ish hp.

if you fun 12.5 you will need to run a bit of race, so you might as well run it stright.  pump gas is about 4 bucks and sunco 110 is 5.59. You cant beat that.

[socalrappy700]

Lookin for some advice on my build, was hoping some of you with these set ups could chime in.

thinkin either a stock bore or 727, 12.5:1 compression. stage II port and polish and hotcams stage II. I know that I will need to run race fuel, thats not too much of a concern. Im more worried about the valves; I am gonna have to tear the head appart?? I want to try to aviod doing a valve job. And what about some ARp head bolts??

Im trying to get around 65 hp to the rear wheels without making it grenade happy, as I often ride long distances. Getting towed home SUCKS when ur 6 miles out. Also going to run Dasa duals, PCIII, and intake

With out a doubt go with more compression!! Little trade secret, get the CP 12.1 mill the cylinder to get about 14 and call it good! By milling the cylinder you retard the cams just a bit yielding more top end.

With 727, 14.1, and a x-2 and a P&P can and duals will get about 73ish hp.

if you fun 12.5 you will need to run a bit of race, so you might as well run it stright.  pump gas is about 4 bucks and sunco 110 is 5.59. You cant beat that.

+1  And make sure to get duals.  Preddy will tell you, its the only way to go.

[Kenny]

Lookin for some advice on my build, was hoping some of you with these set ups could chime in.

thinkin either a stock bore or 727, 12.5:1 compression. stage II port and polish and hotcams stage II. I know that I will need to run race fuel, thats not too much of a concern. Im more worried about the valves; I am gonna have to tear the head appart?? I want to try to aviod doing a valve job. And what about some ARp head bolts??

Im trying to get around 65 hp to the rear wheels without making it grenade happy, as I often ride long distances. Getting towed home SUCKS when ur 6 miles out. Also going to run Dasa duals, PCIII, and intake

  Getting to 65 true hp is a pretty tall order.....The good news is the 700 motor is turning out to be bulletproof! You are probably aware of the 75+ hp stock bore/stroke Racers Edge builds I've been involved with lately. These guys are beating the snot out of their quads and they just keep rockin'. The build you are talking about may happen with the Stage II, but will probably require a X-2 cam minimum, which in turn requires a trimmed exhaust rocker, and a spring kit. Porting is also mandatory. Of course you know I would wanna see the ported TB on there Dyna ignition works very well to optimize the tune. If you use a stock bore, use the factory Yamaha gasket and factory bolts. The big bore may require something different. I have a few tricks to actually help without having the expense of studs. The crankcase Evac valves are working very well too.

  The main thing to keep in mind is to use good engine building techniques, like getting piston to head clearance right, and having good flat gasket mating surfaces on the block and head. Chamfering the head bolt holes will go a long way toward a good head gasket seal.

  I know this sounds overwhelming.....but if you do these things you will easily meet or surpass your build goals. I would say that if you use a ported head and 12.5:1 you should see the 65 hp range. I would also say that with a CNC'd head and a corrected deck height piston that will still be 12.5:1, you should be near the 70 hp range. We are already seeing about 80 real hp on a stock displacement with the X-4, 14:1, and a really good intake 

[socalrappy700]

One more reason Kenny is the MAN!   

[Jamie700R]

Hey Jim, this motor build wouldnt have anything to do with you riding my quad would it?   

[biggixxerjim]

Hey Jim, this motor build wouldnt have anything to do with you riding my quad would it?   

Yeah maybe

i just wanna go a little more extreme so it can keep my fat ass up next to you haha

Kenny: What is the main reason to going to an X-2 cam vs. the hot cam?? If I run stock bore with a 12.5:1, P&P and stage II cam and duals I should get an honest 60 right?? That should be enough to beat jamie.....

[Jamie700R]

Ah yes, the quest for more power.  :grin_nod: One thing to think about when your in Coal Country is you would be the only one that has the gas you need to fill up your quad. They don't even sell it anywhere around there that i know of. Just something to think about. Thats why i bought a quad with the 11:1 piston. I know i can get 93 octane just about anywhere.

[Kamakazi]

hey kenny, what would it cost to have you build something like that for me???  lookin to only run up to 91 octane, for 93 octane i would have to drive an hour away.

[biggixxerjim]

91 vs 93 is all pump gas; go 11:1

whats your elevation??

[biggixxerjim]

And what about a 11:1 build at 727cc?? Will that still run pump gas??

[Kamakazi]

my elevation is 1890 feet, or 576meters above sea level

[Jamie700R]

And what about a 11:1 build at 727cc?? Will that still run pump gas??

11:1 is the most you can have and still run pump gas.

[Kenny]

And what about a 11:1 build at 727cc?? Will that still run pump gas??

11:1 is the most you can have and still run pump gas.

I think so too.....My pistons are an actual 11:1, which is as much as 1 full point higher than some others. I would rather you build to your octane requirements with a good ignition curve and lower compression. I know people that build higher compression motors with less than optimum timing, and power will always be less than a properly built  and tuned engine. Here is an important point for everyone to keep in mind for a build. You will always want to set compression for your octane, or you will set your octane to your compression while maintaining an ignition curve that will maximize power. Higher compression used with a curve that is compromised for the sake of octane requirements will never run as efficiently as it could

[biggixxerjim]

Very nice explination, much thanks kenny