1200cc piston kit for gs1000

[first timer]

hey guys, i pulled this from another forum with the authors permission. some of you may have seen this guys bike before, his name is is craig smithy.

anyways he had some custom 1200 12:1 pistons pistons done for him by wiseco has posted the info on how to go about getting them for your self.

Hi Guys.
I have just read this thread for the first time. I have used standard Wiseco 1100 pistons and tried to get high compression: It was a real pain. I had to skim the head a lot, and also machine the valve pockets in the pistons. A lot of work.

now I have had Wiseco make me 2 sets of Custom Pistons. One was a 1100cc, 73mm and the other one was a 1200cc, 78mm. The drawing no on the 78mm pistons is BTO-1923M07800. They are my custom designs, so I "own" them, but if you want to use them, feel free! They are designed to use a standard head and make 12:1 compression with a 40 thou head gasket. There is 180 thou clearance on the ex valve and 150 thou on the inlet. HUGE!! So easy to set up. (This was in my 11.5:1 set up though). The pistons have to be ordered in min quantities of 8, and off the top of my head they were US$1500 or so for 8. Might have been a bit less. These are beauties, taken off a head mould, so are guaranteed to work. With a decent head...... And those carbs!!! Boogie!! Anyway, if you want to use this custom design, or the 1100 version which is similar, please feel free. You can get them though Buzz (Dynoman.net). Just my 10 cents worth.. Oh, also, regarding the Dyna S units: WE have had a lot of failures too, but we all use Dyna 2000 now, very few failures with these!
Cheers, Smithy.

so there you guys go, if you want to go balls to the wall now you know where to get them. Craig did stress to order them though Buzz at dynoman.net, say Buzz has been a real big help to him.

if you can get 2 people to split the 8 pistons then that would be a huge savings.

-ryan

 

[Guest]

Somewhat confusing post. Is he talking about a GS1000 2 valve? If so, the 1100cc kit is a Wiseco catalog item. A 78 mm would be 1238cc. Wiseco used to make that as a drag race piston. A 77mm would be a 1207.

Jay

 

[BadBillyB]

Like Jay, I was confused by his stated engine sizes...73mm is a 1085 motor and 78mm is a 1238 motor....The compression numbers he was after would require racing gasoline so the average guy is not going to want to run those pistons. 10 to 10.5 CR is the most you will want to run on the street........And Ryan, if you really wanted to go balls to the wall, you would first have to talk me out of the APE Big Block, with full fins, for the GS1000, that I have sitting in the garage. It will accept 80mm pistons and will fit the factory cases (with of course upper case boring) and the factory head w/o mods.....That puts you right at 1300cc.....Apparently Mr Smithy is an avid road racer and has a very bad ass vintage 1000 from what I saw here.....BadBillyB
http://www.proweigh.co.nz/Pro+Weigh+Racing/Bike+Specs.html

 

[first timer]

yes mr smithy is a avid racer, and yes that is all he uses his bike for is road racing. Yes this kit is a custom kit for the 2v gs1000 motor. He had it specficily developed for his needs, but thats not to say Others who want to do the same thing as him now have this option as well.

Basicly what he is saying is if you want a 1200cc 12:1 piston kit for for your gs1000 8v you can get one. you just need to contact this Buzz guy, tell him the drawing number that wiseco has on file that Mr smith had them develope and he can order you one from wiseco in sets of 8 pistons.

Basiclly this is a kit for a more professional person and one who is not scared to dig deep into a engine. some modification maybe needed.

now i have a question for you guy's. you say 12:1 would require race gas, but then how can gsxr's run 12:1 or 13:1 compression on premium gas and are fine? My sv1000 is 11.6:1 and that only needs 87 octane as stated by the manufacture. so why couldn't a gs1000 with a 12:1 run on 93 octane. or what ever is the highest you can get at the pump?

billy, those are craigs old specs he has since redone his engine and it is now a 1200 cc? not sure, motor plus maybe a couple other things to it, the site is offline right now that has some newer info. That big block kit sounds fun, but but i can't wait to install my yoshimura 11.2:1 1085 kit. cycleworld did a write about the kit back in the 80's and recomend this kit for street use so they didn't seem to think that that compression was a problem for the street. I am still learning all this stuff so my ears are open.

 

[49er]

.

now i have a question for you guy's. you say 12:1 would require race gas, but then how can gsxr's run 12:1 or 13:1 compression on premium gas and are fine? My sv1000 is 11.6:1 and that only needs 87 octane as stated by the manufacture. so why couldn't a gs1000 with a 12:1 run on 93 octane. or what ever is the highest you can get at the pump?

The reason the GSXR's can run 12-1 and 12.5-1 ratios on high grade pump gas is because they run superior designed, twin swirl combustion chambers. This 4 valve configuration gives a superior chamber/piston top shape that enhances the burn off rate across crown and along with the liquid cooling provides better heat dissipation, helping to prevent detonation.
Combining this with the more accurate metering of fuel to air ratios by fuel injection makes the package work.
The carburettored, 2 valve, air cooled, GS hemi-spherical chambers wont tolerate 12-1 on pump gas.

 

[BadBillyB]

billy, those are craigs old specs he has since redone his engine and it is now a 1200 cc? not sure, motor plus maybe a couple other things to it, the site is offline right now that has some newer info. That big block kit sounds fun, but but i can't wait to install my yoshimura 11.2:1 1085 kit. cycleworld did a write about the kit back in the 80's and recomend this kit for street use so they didn't seem to think that that compression was a problem for the street. I am still learning all this stuff so my ears are open.

I got my first Yoshi catalog back in 1980 and still have it. It's still in perfect shape. Do you have one?? Its full of neat stuff. I can send you scanned pages if you like....And 49er is right on the money with his explanation. One thing he did not mention is intake air temps. And possibly ignition timing control. Newer bikes have the ability to draw air from in front of the engine, warding off detonation..........This is a quote from the Yosh R&D catalog from 1980
"Our kits can be installed by simply boring and honing the standard cylinder sleeves. Compression ratios are in the area of 10 to 1 through 10.8 to 1, depending on the engine and application"
It also states "Street machines should have no problem using premium pump gas"
They do not mention what octane the premium pump gas was that they were using.......In the mid seventies you could find Sunoco 260 premium gas at the pump that was 100 octane (mon+ron/2).....By 1981-2, when I built my "beast" motor, this fuel was no longer available in Jax Fla, so I was having to run a mix of 25 to 50 percent avgas and premium fuel....I was running 1175cc MTC piston kit advertised at 10.5 to 1 but just by looking at the dome and comparing them to the just retired 1085 wiseco kit, the compression ratio was probably somewhere between 11 or 12 to 1.........Did fine until I got stuck in slow moving bumper to bumper traffic at which time it would get so hot I would either pull off for a cool down or find an alternate route to get some air over the fins......If I had a cooling fan back then, like the modern water cooled bikes today, it probably would have been fine........BadBillyB

 

[Guest]

And Ryan, if you really wanted to go balls to the wall, you would first have to talk me out of the APE Big Block, with full fins, for the GS1000, that I have sitting in the garage. It will accept 80mm pistons and will fit the factory cases (with of course upper case boring) and the factory head w/o mods.....That puts you right at 1300cc

Billy; You have a very rare piece there as I don't think we ever made over 25 of those.

Jay

 

[BadBillyB]

Billy; You have a very rare piece there as I don't think we ever made over 25 of those.

Jay

Actually I thought it was rarer than that.....25 huh....I would have guessed around 10 or so.....BUT...How many are extra tall like mine for use with a 1100 crank and rods.(Longer stroke & longer rods)\\/ . It could be used with any combination you could imagine. Thanks Jay....APE stickers been on my bike for more than 20 years.....They might be rare too.....BadBillyB