big-bore kit

[paui]

does anyone know of a big-bore kit for the gs500? if im burning alot of oil, does that mean my piston rings are bad? if i need to get them replaced i might as well put some bigger pistons in there while the engine is opened up.

[JamesG]

You can get +1mm and +2mm piston kits from Suzuki. This along with copper head and base gaskets to increase compression is probably the cheapest, easiest "big bore" upgrade.

[dgyver]

I was quoted $80 for each 75mm piston with rings.

James...Aren't most copper gaskets thicker than stock? So they would actually decrease compression. Or can they be bought in different thicknesses?

[Rich500]

What kind of power gains do you think we are looking at with this mod?
Im curious.

[JamesG]

Rich - Not much by themselves maybe 1~2 HP, but with some porting work and timing you can get 5 or so.


Dygver - Cometic copper gaskets aren't. They are at least a few mil thinner than the OEM steel ones, plus the copper squishes when the head is torqued.

[Rich500]

Get the head Port and polished would not be a cheap excercise I bet.
If I had time, I guess I could do it on my own, but not worth the trouble for the power.
What would everyone say is the best mod for HP to dollar ratio?

[Reknelb]

Get the head Port and polished would not be a cheap excercise I bet.
If I had time, I guess I could do it on my own, but not worth the trouble for the power.
What would everyone say is the best mod for HP to dollar ratio?

I would say head work. But I'm a little biased seeing as how I work part time at a performance shop that my friend owns and operates.   www.npsracing.com

After the standard re-jet and aftermarket pipe, the next cheapest gain would be the gsxr 36mm carbs. You can usually find a bank of 4 for $100 or so. I've found pairs of them set up for the gs for 100-125.

[JamesG]

What would everyone say is the best mod for HP to dollar ratio?

Track time.
Power is useless if you can't use it.  


But

The biggest single jump in power on a GS is probably exhaust, filter, and jetting.
After that you have to start throwing lots of Ben Franklins on the fire.

[yamahonkawazuki]

droppin' a 'nossed up 'busa motor in it    :mrgreen:  :dunno:

[Blueknyt]

still think a ported and polished RZ350 engine would be kick ass in the GSframe.

[GRU]

it would be but only for racing....i don't know what the RZ350 makes (HP) but i think it's somewhere about 60 on the crank....i almost bought a RZ350 because of the looks and power but i don't like the sound of the 2 stroke engine  :x

[Piper5177]

If you do the filter, exhaust, jetting, port, polish, and timing advance.....you'll almost have 60 at the crank.  No to mention it's almost 60 with a four stroke power band and not a 2 stroke on/off switch.

[KevinC]

60 at the crank is pretty optomistic with those changes. I didn't get any big gains past the exhaust system and pods, until I raised the compression ratio and had 555 cc. That was maybe 60 at the crank.

[Argon5W]

Start with the exhaust, filter, and jetting.  If you are going to tear into the engine you may just need to hone the cylinders and install new rings.  Do not try to port and polish yourself.  The company that polished mine ran an abrasive goo in the ports to polish them evenly.  The head can also be milled down to provide significantly more compression without replacing the pistons.  Having the cams degreed will also help.  That is a project you can do yourself.

My bike is not close to 60 horsepower after all of these mods.

[Reknelb]

Stock carbs suck. If you want 60 hp, you must go to bigger carbs. The stockers are called 34mm, but actually only measure 33mm. Sudco calls for 38mm cr specials on the gs if I remember right. The 36mm gsxr carbs ran great on a stock motor (slip-on) I had, and a semi-built motor. I'm not a big fan of the CR specials, If I was spending the money I would get flatslides (FCR's or mikuni's) in 38mm.

[Blueknyt]

i have a set of 36mm gsxr carbs on 500 rack, just got to get jetting right. but that will be for next engine.