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Discussion Starter #1
Hello, I'm new here. Just picked up an '82 KZ750N. Runs great. Drives good, except I think the wheel bearings are going bad.

Question: What performance options are there for this engine? I'm skilled and can do anything necessary, but I still need to do it cheap. What about cams and piston upgrades? Ignition tweaks?

Also, where can i find a chart or formula to figure out my speed for a given RPM?

Thanks,
Jason
 

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Ignition is fine already, Wiseco sells a 810 (actually 807 I think) cc big bore kit, Web Cams and MegaCycle will regrind yours cams, and may sell new ones. 83-85 GPz750 were the hottest factory cams available, and sometimes a set of Andrews cams will show up on eBay.

Cheap??? Nope, $500 for a Wiseco kit, $200 to bore and hone your cylinders, $400 or so for cams, etc.

Want to keep it cheap? Then keep it fairly stock :)
 

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GHOSTRIDER
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I'd do the Wiseco 810. AFTER you install a set of 29 smoothbores and a pipe. Reason being, you don't have $800 worth of bore job in a $200 bike. You'll be able to sell a set of 29 smoothies for what you have in them and they are the most cost effective modification.
He said he wanted to do it cheap. You keep calling for them 29mm smoothies, got any working "cheap ones?"
 

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Eddie Lawson is God!
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NOTHING I have is cheap. Because I had the foresight to collect it when it was. And now everyone and their brother wants to soup up these old crocks.
My only regret is I didn't buy them for a Honda CB1100F, so I get to pay almost market price for them. Oh well. At $750, I'm getting a smash deal from a good friend. And, they are $750 worth of not having to d1ck with those SCRAP CVs. They are $750 worth of improvement.
 

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Hmm, brand new Mikuni RS34 flat slides for $734, or 35 year old 29mm smoothbores for $750? Unless you're restoring a bike to period correct, then I sure wouldn't spend that kind of money for ancient tech. The amount of BS that has grown around the 29mm carbs is astounding.

http://www.sudco.com/CatalogJPG/086.jpg
 

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Eddie Lawson is God!
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Steell my brotha.The BIKE is thirty plus year old technology. New stuff doesn't matter. A 750 hasn't got enough cam, head or motor to run anything bigger. Best to be somewhat carb limited on the motor, otherwise the fuse is the #3 rod. The bike doesn't know if it's 1983 or 2010.

The motorcycle which doesn't play by the rules is 1260ccs and owns a set of 39mm Keihin FCRs.

OP has a bike which is a fairly high performance bike for it's age. (I have the sameish bike) He wants to go less slow. he DOESN'T want to spend the money. Do you suggest he spends the SAME $800 on a bore kit he WON'T recoup the money on on selling the bike or spend $800 on the carbs and a pipe that he can resell after he tires of the exercise in futility. Or be like me (or YOU) and specialize in a bike he LIKES and that speed stuff can eventually pay for itself.

My $750 is a set of 33s and a NEW VHR canister pipe which is $400 in itself. I told you, smash deal. For a bike which no one (HAS) to soup up.
OP can be 99% of the way there with a set of 28s from a 1978 KZ1000, opening and closing throttle cables from a KZ650 with the matching throttle housing. If he gets lucky, maybe he can find an earlier housing which accomodates a headlight switch.

Jason XS1100? Fixed the wires behind the point plate? If two cylinders go away go there FIRST.
 

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Discussion Starter #8
Thanks. I've been taking old '80s import bikes and changing fenders and seats to update them, without over modernizing them though. I'm just looking to beef performance to keep up with the new stuff. I build these because they a reliable and dead cheap to buy. I've actually been toying with the idea of building a manifold to accept a single carb and using propane for motivation. Taking a tank and gutting it to use as a cover. It would hide two to three of the small torch size propane cylinders fitted to a common fuel manifold. I've played with propane conversions on bigger engines, thought itd be a challenge on a bike.

Also, how well does turbo charging work?

Thanks
 

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Discussion Starter #9
Oh, I say cheap, but really I mean resourceful. I don't do it because I don't have money, I just don't want to buy bolt-ons and call it a day.
 

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GHOSTRIDER
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Thanks. I've been taking old '80s import bikes and changing fenders and seats to update them, without over modernizing them though. I'm just looking to beef performance to keep up with the new stuff. I build these because they a reliable and dead cheap to buy. I've actually been toying with the idea of building a manifold to accept a single carb and using propane for motivation. Taking a tank and gutting it to use as a cover. It would hide two to three of the small torch size propane cylinders fitted to a common fuel manifold. I've played with propane conversions on bigger engines, thought itd be a challenge on a bike.

Also, how well does turbo charging work?

Thanks
Interesting! Ive used golf carts powered by LP gas in plant work, never thought about motorcycle applications. I do know the lp powered engines dont run as well as the gasoline engines. And turbos on bikes are crazy fast! And they are the most expensive option to making horsepower! To get the most bang for your buck, rejet the carbs and install a header. Youll never make an older two valve head engine keep up with todays rockets with four valves per cylinder and cnc engines. You will however blow any v-twin away and the 250cc rockets with properly tuned and jetted carbs and a header!:wink:
 

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Eddie Lawson is God!
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I have a friend who runs 10s for $2000. Being able to do something like that is SMART. Then the junkyard 99% solution is the winner. And I listed it for you. Slide needle Mikunis are your thing. They can be found on Suzuki GS's from the same time. GS 1000 units will do ya. This opens up the realm of silly filters (K&N) too and gives you improved packaging potential.
 

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I never suggested an 810 kit, I just said that's an expensive way to go. using stock parts is how you keep it cheap.

Youll never make an older two valve head engine keep up with todays rockets with four valves per cylinder and cnc engines.
And exactly how many of today's rockets will run nines in the quarter and 211 mph in the flying mile, on the same gearing? 2 valve 84 750 Turbo did in 2008 :D

Slightly modified 85 750 Turbo runs 10's for $2500, my 80 750 four should run the 10's, maybe even in the 9's (when I finish the D#@$ thing) for around $1000. Professionally ported head, 810 kit, Andrews cams, and EFI, all for around $1000, including the purchase price of the bike.
 

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KLR`s and BBQ`s
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somebody is selling some new GPz750 rear bearings and seals on KZR for $20 shipped...not sure if they would fit your bike
 

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GHOSTRIDER
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And exactly how many of today's rockets will run nines in the quarter and 211 mph in the flying mile, on the same gearing? 2 valve 84 750 Turbo did in 2008
Apples to oranges aint it? My claim didnt include turbos or solid rocket boosters.:lol: The same set up on a four valve head will smoke the two valve head every time! Apples to apples!
 

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Apples to oranges aint it? My claim didnt include turbos or solid rocket boosters.:lol: The same set up on a four valve head will smoke the two valve head every time! Apples to apples!
Stock production bike to stock production bike.

You can't call 35 year old two valve air cooled bike, against new 4 valve water cooled bike apples to apples! :toetap:

84-85 GPz750 Turbo was a production bike, and not even limited production.

:D :D
 

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Discussion Starter #16
Zoro, LP powered vehicles run better than gasoline. The drawback to LP is the lack of BTU's. Translated means you get less mileage. However the octane rating is significantly higher allowing more timing. My thoughts were to build a single manifold with throttle body, pipe in a small junkyard turbo and have an LP carb draw through. Packaging for all this ought to be interesting though. How much boost would a stock engine take? Anyone know?
 

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On a 750 Turbo anything over 15 psi and you really need to start thinking about O-ringing the head. Limiting factor for max psi on the 750 turbo is detonation, tends to make holes in pistons on pump gas over 15 psi.
 
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