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I am building a 1986 GSXR 750. I am wodering what kind of horsepower is possible out of this thing. I am putting in a 907 piston kit, stainless valves, mild cams, mikuni carbs etc...
I would like to be in the 125-140 horsepwer range. Also I am not buying an 1100 motor instead of building a 750 so if that will be your response save it!!!
 

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Originally posted by AMAX:
I am building a 1986 GSXR 750. I am wodering what kind of horsepower is possible out of this thing. I am putting in a 907 piston kit, stainless valves, mild cams, mikuni carbs etc...
I would like to be in the 125-140 horsepwer range. Also I am not buying an 1100 motor instead of building a 750 so if that will be your response save it!!!
<font size="2" face="Verdana, Arial">I've got a friend thats selling a complete JE 955cc kit for $400.00 if you are interested. It includes the cylinders that have already been bored and honed.

[ 12-23-2002, 11:52 AM: Message edited by: GixxerRacer371 ]
 

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I got 115.3 with the jetting in it now. I put a 907cc set of JE pistons with a '92 head with stock valves. I put the APE Ti valve retainers in along with 38mmCV's, K&N filters and a Hindle system. I had a slight amount of milling done to the head but it runs fine on pump gas (92 octane just for the fun of it) NO PORTING WAS DONE. I did have it jetted on a dyno and the graph looked like this...

 

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A few years ago I turned my 600 Katana into a dragbike using a '86 gsxr 750. With slick and bars it went 10:01 @ 131. It had Wiseco 771 kit,Lazer level 5 cylinder head,Cam Motion drop-ins,Ape lightened crank,Carillo's,& 38 flat slides. It was dynoed with 40mm Lectrons (mistake). I was really disappointed when it only made 115HP at the wheel. I'm not Pops Yoshimura, but I was sure it would make more power than that. Your going to need a wicked cylinder head and cam combination to make 140HP.
 

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Mine runs fine on the street (race fuel only at sea level) but money to horsepower --- get the 1100. If you want to do the 750 so you can have the "best 750", unless you have too much money your not going to get there. Getting 140 hp out of a 750 if Yosh would do it, I don't think they work on 1st gen stuff anymore, would cost about $10,000. A new 1000 has better performance in every way and will cost less with a warranty. My advice is that if you really want to stay with the 750 then build it with the intent of having a fresh reliable bike to ride without doing anything too exotic.
 

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Yeah...I wanted 140 too when I started. For me it was something to test myself with. Could I do the motorwork myself? What would the limits of my mechanical abilities be? How much power could I get? Most importantly...since my wife wouldn't let me buy a new bike...could I make my older bike more modern?

I now have a crumpled testimony to my lack of mental focus...but I think I did everything right. For less than $2000 I bumped my motor from 750 to 907 and got more power than I need...and it isn't ready to grenade while idling.
 

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You want 140 hp from a 1986 GSXR750? That's very unrealistic considering the bike makes about 80 hp in stock form, mebbe 85-90 hp with an exhaust and rejet.

I'd rather have an old bike that's a nice well-rounded package, somewhat updated but still with the retro look and feel. Give it fresh suspension, lightly modded engine that can still deal with normal daily driving with no reliability problems, and call it a day.

There used to be an old joke in Honda Land, there was always somebody asking "what's the best performance mod for my CBR600?"

The answer was "trade it for a CBR900."
 

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Originally posted by coinspinner12:
"what's the best performance mod for my CBR600?"

The answer was "trade it for a CBR900."
<font size="2" face="Verdana, Arial">Duh-ope!! I should've thought of that!!
 

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Well for me I let a friend adjust my valves and he left them loose. Motor died about 2 weeks after he worked on it. Then on Dec 22 1992 ex asked for divorce. On Dec 26 motor was shipped to Yosh. They were the absolute best you could do, so that is what I did. The motor came back on April 1 1993. I have no regrets but it is still true that I could have gotten more for less with the 1100. If you still decide to go with the 750 build I would suggest that you build it as a complete system, not piecework. Find somebody that will give you a hp result before they start. You will probably end up with a more user-friendly package in the end.

The real questions are:

1. Why the need to keep the 750?
2. Why do you need 140 Hp?
3. Are you trying to keep up with bigger bikes?
or want the "750" for INS reasons. Maybe it has sentimental value.
4 Is it worth $10000 to get what you want?
 

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Just to add fuel to the fire... my 1127 with 46,000 miles on it makes 131HP and 84 ft-lbs at the rear wheel... it's bone-stock except for jet-kit, ignition-advance, BMC filters and hindle 4-2-1. It's got great throttle-response, is mild-mannered when I need it to be, and gets about 30-35mpg (40 if I baby it).
 

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I have been both routes.BUY THE 1100 you can't do much more than a pipe, jet kit and cams in your bike that is equal to the cost of an 1100. take it from someone who has put 20,000 into his bike. ouch
 

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Well AMAX made one post back in 2002 about making big HP with an 86 750 and the thread kinda petered out. I wonder if he ever made that engine :scratch

I read an article back in the 90's in Cycle World where someone grabbed an 86 750, put in a Cosworth 888 kit with a 92 head & cams. The carbs were 38mm or 40mm slides and I can't remember the exhaust... Maybe V&H but it made buckets of power.
 

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If you like the 750 body, why not pick up an 1100 engine on eBay for around $1200......Pipe, around $500......Total after Odds & Ends=around $2,000....... and.....Presto!! Your very own 7/11 with all the HP you could want or Need!!!!



"If You're not 1st, You're Last":banana
 
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