GStwin.com GS500 Message Forum

Main Area => Projects / Builds, Racing and Tech => Topic started by: Agno on August 06, 2012, 07:05:43 PM

Title: Just found an old "GS500" trackbike story from Sport Rider
Post by: Agno on August 06, 2012, 07:05:43 PM
http://www.sportrider.com/bikes/146_0110_suzuki_gs500/index.html

Gonna start dumpster diving at Boeing.
Title: Re: Just found an old "GS500" trackbike story from Sport Rider
Post by: GI_JO_NATHAN on August 06, 2012, 07:21:49 PM
Nice.
Title: Re: Just found an old "GS500" trackbike story from Sport Rider
Post by: TonyKZ1 on August 07, 2012, 09:31:24 AM
Wow, that's quite a story.
Title: Re: Just found an old "GS500" trackbike story from Sport Rider
Post by: iclrag on August 14, 2012, 11:02:53 AM
I remember reading this awhile ago, i think there might actually even be a threa don here about it! that definately made me want to try mounting a head like he did, but i cant afford to break stuff like that
Title: Re: Just found an old "GS500" trackbike story from Sport Rider
Post by: knowles on August 24, 2012, 11:06:54 PM
OK how do people figure this stuff out, maybe in about forty years i can think about doing something like this.
Title: Re: Just found an old "GS500" trackbike story from Sport Rider
Post by: The Buddha on August 28, 2012, 08:30:04 AM
What would break is usually what has been pumped to the limit ... a GSXR750 head is fine, I dont think it will hurt the motor at all ... you do need the right pistons for it ... build the head to the 10's, and put in coffee can sized pistons and you're talking about a hand grenade. BTW a GS425 or was it 450 ... could stand the abuse a bit better, if I recall it had a roller bearing crank.
Cool.
Buddha.
Title: Re: Just found an old "GS500" trackbike story from Sport Rider
Post by: burning1 on August 28, 2012, 10:47:18 AM
I'm not so sure about how well the roller bearings handle power. They absolutely handle low-oil conditions better than our plain bearings. They don't handle being abused better - lugging roller bearings is a great way to ruin them.

But we have someone on the forum who has a turbocharged drag build making 100HP plus with plain bearings. The bearings on the GS500 are certainly comparable to those on bigger bikes, although oil to the rods might be a weak point.
Title: Re: Just found an old "GS500" trackbike story from Sport Rider
Post by: SAFE-T on August 28, 2012, 12:21:35 PM
This is the infamous "GS500 crank can't handle big power" story I remember reading years ago.

Interesting how the member building the Salt Flats GS500 figured he could get in excess of 200hp out of it without breaking anything, and I know he was/is doing a fair bit of dyno testing to confirm the performance of it.
Title: Re: Just found an old "GS500" trackbike story from Sport Rider
Post by: yamahonkawazuki on September 25, 2012, 12:56:55 AM
Quote from: Agno on August 06, 2012, 07:05:43 PM
http://www.sportrider.com/bikes/146_0110_suzuki_gs500/index.html

Gonna start dumpster diving at Boeing.
i remember this story posted here when i joined this site in 2003. this one and motocat still recall  nearly verbatim. that bike kicked/kicks ass
Title: Re: Just found an old "GS500" trackbike story from Sport Rider
Post by: crzydood17 on December 06, 2012, 04:16:28 PM
So I have heard 2 things, The crank cant handle much power and the crank can't handle a lot more RPM.
Title: Re: Just found an old "GS500" trackbike story from Sport Rider
Post by: xunedeinx on December 06, 2012, 09:50:49 PM
Whats easier, this, or a kawasaki 650 swap...
Title: Re: Just found an old "GS500" trackbike story from Sport Rider
Post by: burning1 on December 07, 2012, 01:13:31 PM
Gary might disagree on the issue of how much power the GS crank can take.

http://gstwins.com/gsboard/index.php?topic=58391.0
Title: Re: Just found an old "GS500" trackbike story from Sport Rider
Post by: crzydood17 on December 07, 2012, 01:31:29 PM
Aye, I want to rebuild the GS for like 14-15K rpm :) anyone wanna help me steal some rods and pistons and valves from a LS7... TI FTW.
Title: Re: Just found an old "GS500" trackbike story from Sport Rider
Post by: xunedeinx on December 07, 2012, 07:24:59 PM
Quote from: crzydood17 on December 07, 2012, 01:31:29 PM
Aye, I want to rebuild the GS for like 14-15K rpm :) anyone wanna help me steal some rods and pistons and valves from a LS7... TI FTW.

Bore it and destroke it. Keep it 500cc, but make it a 18000rpm monster!!!
Title: Re: Just found an old "GS500" trackbike story from Sport Rider
Post by: burning1 on December 09, 2012, 06:38:55 AM
Not really a trivial mod. Did the math a while ago; even the maximum de-stroke from Ape would only get you a thousand RPM or two. You might be able to do a custom crank. Con-rods would help, custom pistons would help. The engine would make horrible power at those RPMs, so a custom valve-train would be in order. Even then, I suspect breathing would be a major problem for a 2 valve hemi-engine. Modern sport bikes have notoriously poor* Volumetric Efficiency (VE,) even with 4 valve pentroof heads - a twin valve would have even bigger issues.

* Poor VE is why a modern sport bike can run 87 with a 12:1 compression ratio. The mechanical ratio is very high, but the cylinders don't fill completely with air, so peak pressures are relatively low when the engine is running at high RPM.