RS125 - going from AVGAS to Unleaded

[stevecrossland]

I'm looking at buying a gearbox sprint chassis with a '97 RS125 in it.
What is involved in setting up the engine for unleaded fuel?
Kart at the moment is setup to run Avgas but the guy tells me he's melted a couple of pistons trying to run it on normal pump fuel (unleaded).

Just want to see if I'm gonna be up for a new ignition system etc before I trade with him.

Cheers,
Steve

[Mike Wayne]

Steve, best peron to speak to would be Brian Stockman....but I wouldn't think you will need a new ignition. Something along the lines of reducing the compression, retarding the ignition & doing a dyno run. Which could be done by simply putting a thicker base gasket, rotating the ignition plate...and loosing alot of power. The cost of doing that would far outweigh the costs of AVGAS over pump fuel over a season and yield a big power loss.

Is there any reason you want to run pump fuel over AVGAS?

[stevecrossland]

Thanks Mike,

The main reason for gong to unleaded fuel is to comply with the NZ regulations for running the sprint circuits here.
The 125 National class is limited to pump fuel. If I leave it on Avgas I can run in 'open' class but it will mean competing against pretty much anything including the 250's and twion engine karts so not really a good option.
To be honest I haven't looked into the Long track (or what us aussies would call Superkarts) regulations for the 125's but I imagine they would mirror what happens on sprint track Regs.

Spoke to my Brother Mick who says same thing as you told me, reduce compression, cooler plug.
So it seems that a common theme is presenting itself here - Glad it doesn't including purchasing more bits & pieces.

[stevecrossland]

Made the decision to leave the 125 for now & wait to get a 250 inter machine.

Thanks for the advice though, most appreciated.

[Mike Wayne]

Thats the spirit