110 race fuel

3 replies to this topic
  • yz400fsmasher

Posted August 28, 2009 - 01:37 PM


ok heres the deal. i have a 98 400f and i want more out of it. i did the hot cam upgrade and heard that 110 race fuel would give a little more but i can only find it leaded. will a leaded fuel eat my bike up or would i need to do sum internal mods like a piston and valves?

  • grayracer513

Posted August 28, 2009 - 03:19 PM


It might or it might not give you any more power. But you will gain nothing from having an octane number that high. The reason is simply that you don't need it. One of the best available 4-stroke fuels is the U4 series from VP. It will, when you jet it right, produce nearly 2 extra hp, but it's only 94 octane.

The power output you can expect from a fuel is entirely dependent on its chemical makeup, and is not related to or dependent upon the octane number.

Octane number, on the other hand, is a measurement of the fuel's resistance to being ignited by pressure or heat sources other than a spark or flame, which it needs to do to avoid detonation. That is also the only thing the octane number tells you. It has no relation to the combustion temperature, ignitability, vapor rate, or power content.

Lead in the fuel will increase the amount of carbon deposited in the combustion chamber a bit, and since some of the deposits will be metallic lead, it may lead to hot spots and pre-ignition. Some believe that lead will make the exhaust valves last longer, but Yamaha feels that the opposite is true; that lead deposited on the valve seats may become detrimental to the nitride coating on the valve face.

Overall, it's my opinion that using fuel to gain power is an expensive means of going about it, since you have to continue to pay for it as long as you want the effect.

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  • Spud786

Posted August 28, 2009 - 08:52 PM


just a note on this subject

as I have more than more than 110,000 mile with lead use

First I do believe there's little benefit with coated valves and lead. they are simply fragile once coating is gone, and yes the lead may be abrasive to the coating.

My 100,000 mile is on steel valves and the lead does cushion the valves seats. I also see huge decarbonization effect with lead, deep cleaned spark plugs valves,piston crowns , exhaust every thing virtually carbon free, and I only run cup or so per tank, the lead snow flakes actually are great decarbonizing tools, I dont know where the deposit stuff came from(must be old crap pump lead), but vp leaded in small doses has oustanding decarbonization effect throughout the entire system.

I have even ran in catted bikes for thousand of miles, decarbons the cat too and whole system.

why do I run it, its not for power , but valve recession and internal cleanliness.

This is reality for me, and I back the miles of proof

  • grayracer513

Posted August 29, 2009 - 07:19 AM


So, you're discounting the effect of the other components of VP leaded, and only the lead is having any effect on the cleanliness of your combustion chamber? I see.

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