How to make 150hp from a redhead 700

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enticer300longtrack

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Dec 17, 2013
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I want to build the most badass redhead 700 ever on pump gas. I have bought power inc end dump pipes, and have head work done. Squish was then down to 30 thou. and domes machined out to 165psi. I am wondering if porting with this combo will get me to 150hp. That numberis my goal, adding boost bottle, vforce3 reeds, and having carbs bored out. I will be running benders clutch kit. I guess the real question is can this non power valve monster turn out 150+ with out big bore or nitrous on pump gas???? I'm open to any suggestion to add more power thanks.... Soon coming is a build thread, it's a 97 sx 700 that's I'm building from ground up!
 
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O ya you should get to the 150 make if not damn close to it. Once ported. Only change I make is run heel clickers and U will be fine with srx reeds more surface area than sx reeds.
 
The problem though is its a 97 with the weaker crank case and double crank bearing, I would look for a 98 and up case.
 
Sweet thanks guys, I would like to avoid porting if at all possible, I'm on a budget but is there any triple guru's on here that will port cylinders??? I will pay for it if the benefits are worth it. I have had soooo many people tell me these motors can't make over 140hp and I didn't quite know what to say. Any more suggestions to make this thing rip???? I plan on either using heelclicker clutching or bender, and maybe a team secondary. Any more suggestions?
 
A engines just an air pump, porting makes the engine pump the "air" more efficiently, definitely worth it. Reed spacers? What will you be doing for intake? Stock air box? Might want to look at a cold air intake or something like a gutted box, but this can make it finicky.
 
Yes I forgot to mention reed spacers... I plan stock airbox, it will be enough trouble with the stock one, I don't want to do the airbox mod but the hood is gonna have a highly vented hood if that helps. Will a hotter ignition from a 01+ help? Then I could run the dual headlight too
 
300w ignition system has a hotter spark and from what I have herd yields more power. Tbh I own a 00 and 01 sxr and the 300w one runs noticeably smoother. So I would do it
 
The four vents incorporated on the hood, that pull warm air from the engine compartment........block those off with CHAFFE TAPE. Or something thicker than just normal tape. This prevent the airbox from getting any of the warmer engine compartment air and getting only the colder outside air. Have done this to my 97 SX7 & my sons 99 SX6.
 
enticer300longtrack said:
I have had soooo many people tell me these motors can't make over 140hp and I didn't quite know what to say.
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The 97 SX7 was one of Yamahas most detuned engines they have probably ever made. Probably for insurance reasons. Just like the early 70s Dodge Chargers w/ the 440 mags in em. Holy Sh!T. The power they can be made and are able to put out..........in the right hands. Some Beach!!!
 
we have raced 5 sx,s. from ice, to grass to tar. stock, inproved, pro stock. 97-98-99. there are no different,s in the lower ends that i remember. the hot set-up is the sxr stator-harness - lower end in a sx. than you can use a viper cdi for more timing, huge gains on these motors. but watch fuel and jetting. there are two sets of weights that work, both yamaha, 8ca or 8ab. any good triple pipe will add power, head mod, reed spacers, all good. you will get into the 150 range but thats about it. this is the best motor yamaha triple built. what a sleeper. 3:16 (yammie tony)
 
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Tony, would just running a 3 degree key be an easier thing to do that an sxr bottom end and using a viper cdi?
 
the sx motor really responds to port timing, compression, pipes, and ing. timing. open up transfer ports also. don,t get into clylinder lift with red heads, we lost hp. this motor wants to be lowered to case as possible. now anyway you can add timing works good, sure on the key, but we were able to find a sxr lower end and went with viper cdi. 3:16 (yammie tony)
 
These engines can make very good power with a bit of work.
We have had a few come through our garage over the years and I still love to test these little sleds.
My favorite combination to date on the red head is
CPR tripple pipes
Modded SRX reeds with carbon tech petals and spacers.
Cylinder porting and a well designed head
Bored carbs and modded airbox
2 degree timing advance
We liked the heel clicker hammer time weights with this set up.
Wicked little Yammi!!!
 
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