Two Stroke Motocross

Two Stroke Motocross Forum => Technical => Topic started by: Big Boar on August 16, 2012, 10:14:14 PM

Title: 100LL vs 110 unleaded
Post by: Big Boar on August 16, 2012, 10:14:14 PM

I race a 06 YZ250 which i picked up used and recently blew up due to the last owner shaving the head and decking the cylinder my motor guy told me that it needs to be ran on race gas. My question is weather i can run 100ll aviation fuel or if i need to run race gas and how i can determined weather 100ll is ok to run

Title: 100LL vs 110 unleaded
Post by: _X_ on August 17, 2012, 12:28:36 AM

run a leaded fuel if available your motor will love you.

Title: 100LL vs 110 unleaded
Post by: TotalNZ on August 17, 2012, 06:40:02 AM

i'd find out a bit more about the motor specs first, ie squish height and combution chamber cc.

Title: 100LL vs 110 unleaded
Post by: Big Boar on August 17, 2012, 12:50:46 PM

I've heard that the lead in the 100LL gives the gas the characteristic of a higher octane is this true

Title: 100LL vs 110 unleaded
Post by: _X_ on August 21, 2012, 10:50:28 PM

not sure but my bikes crave it.they just run better. just buy a little of each run one one weekend the other the next and determine for your self. I think we call that testing.

Title: 100LL vs 110 unleaded
Post by: maicoman009 on August 25, 2012, 05:34:37 AM

Quote from: racer x on August 17, 2012, 07:28:36 AM

run a leaded fuel if available your motor will love you.

I have to agree with racer x on this...The 100LL is your best bet. Leaded fuel actually helps lubricate the engine & will be especially good on a 2t race engine. 

Title: 100LL vs 110 unleaded
Post by: riffraff on August 25, 2012, 07:02:28 AM

I'm not too sure if the lead helps a 2 stroke with any type of lubricating properties Tetraethylead was originally added to fuel to lubricate and provide a cushioning layer for the valves, an increase in octane was an unexpected side effect of the Tetraethyllead. A 2 stroke only relies on oil for lubrication. The best reasons for running Avgas are the consistency and quality control, no alcohol, availability, and cost.

Title: 100LL vs 110 unleaded
Post by: ebolhuis on October 12, 2012, 08:55:47 PM

Quote from: riffraff on August 25, 2012, 02:02:28 PM

I'm not too sure if the lead helps a 2 stroke with any type of lubricating properties Tetraethylead was originally added to fuel to lubricate and provide a cushioning layer for the valves, an increase in octane was an unexpected side effect of the Tetraethyllead. A 2 stroke only relies on oil for lubrication. The best reasons for running Avgas are the consistency and quality control, no alcohol, availability, and cost.

Riffraff is correct. Light aircraft piston engines need the lead in the valve train to prevent sticking and failures. Might not be a bad idea for that 4 stroke you secretly have hiding in your garage either. As for the lubricating properties in a two stroke, that is debatable. It does not however contain ethanol and undergoes more sampling and testing to ensure its quality. That and it just smells awesome as premix in a 2 stroke. It is usually cheaper than race fuel as well. I pay about +- $5.00 vs +/- $7.00 a gal for race gas.