CKRC Forums

Good Input Jack. We certainly should not be using any leaded fuels. I only recently learnt that VP's C12 is leaded (I thought all leaded fuels outside of aviation were no more).

I've had 2 failures (sticks) and both have been the ring spinning from a broken pin. I don't see any signs of detonation. I think most of the problems are just poor quality pistons from Vortex (or elsewhere).

The VLR100 was designed to run on (leaded ?) race gas but allowing that is a double edged sword. one is cost and the other is availabiltiy; you can't buy race gas on every corner so you need to plan carefully.

For reference, the manual states:" Vortex engine works with commercial gasoline, leaded or unleaded, as well as racing fuel, with minimum 95 Octane. Mix Oil and fuel at 4% (i.e. 40cc of oil every 1.000cc of fuel). Use high-quality synthetic oil specifically made for kart engines. Vortex suggests Rok Lube, however other brands with the same composition might be suitable"

...so the engine design isn't relying on lead for lubrication.

That leaves the oil. I think everyone is using the Motul Kart 2T or 800 now and while nothing is impossible, I doubt that the Motul product isn't up to the job.

Mark,

Thanks for the input, glad I am not a lone opinion on the lead thing. The ring pin failure is a common Vortex issue that shortens the top end interval. ROK Shifter has the same issue, we have seen it on TM as well but less commonly.

It would be worth testing your shifter fuel in the VLR I think. We are running the MS109 and 91 pump gas combination I had mentioned at 4% (25:1) with motul kart GP or 800 2T. No modern kart engine is really designed for leaded fuel as they aren't common (or even available?) in Europe, it seems to just be US series that love lead for some reason. There are lubricating properties to lead that the CR125's liked, it doesn't seem appropriate for other engines based on my research.

Supply wise we buy our MS109 from Joey, there is also a VP facility in Calgary. Some motorcycle stores will also carry it, usually C12 or U4 which I advise avoiding for various reasons. It isn't cheap, but for tech and carburetion purposes it will be 100% consistent batch to batch so there is also that aspect.