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Discussion Starter · #1 ·
THIS IS THE SPECS ON MY MOTOR:
2001 Yamaha Raptor 660 YFM660RN Motor. This excellent strong running motor has a Cylinder works 102mm 686 Big Bore kit with JE race gas piston, ported head with Kibblewhite valves, dual valve springs, billet retainers, and a Hot cam in it.
I WAS TOLD THE PISTON IS A 12.5:1 COMPRESSION. WHAT WOULD HAPPEN IF I RAN JUST 93 OCTANE IN IT??
THANKS FOR YOUR HELP???
 

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Discussion Starter · #4 ·
Is this 100LL avgas ok to use in my bike?? My brother picked up 5 gallons of it and i want to make sure it will be fine. I see no reason that it wont but wanting to make sure
 

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What cam is in it? stage 1,2 or 3? Find out you psi of the motor by using a compression calculator online and it will tell you. 93 is good for up to 225psi IIRC but I'm no expert by any means just what I have read on here.
 

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do not use avation fuel in your quad. 12.5:1 should be around 93-96 r+m/2. but there are other factors that can change that.
mike
 

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Because u have a raptor not a fighter jet hehe
Bump
 

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What is wrong with airplane fuel 100ll????? Just trying to figure this out.
thanks
The octane rating with av gas does not compare to automotive style fuel...............
 

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Yes, you'll be okay but it's probably overkill... you're right on the edge of 93 being okay all by itself - a 3/4 93, 1/4 110 (equals 97.25)would be a nice safe mix yet still overkill.
 

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You have a similar setup to my bike. When I did my calculations a stage 2 hotcam was right on borderline for 93 and I would def blend. Stage 3 hotcam would give you a little more wiggle room and could probably run 93 but you should run the calculations for your bike yourself. I am running an x4 cam with a 12.5:1 and I think I could run 91-92 octane in a pinch but I run 93.
 

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When I talked with Kenz after I had my raptor head setup to run a X-4 cam he recomended against running a 12.5:1 piston even with an x-4 cam. He said the shape of the raptors combustion chamber can cause detonation when running pump premium fuel.
 

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What is wrong with airplane fuel 100ll????? Just trying to figure this out.
thanks
It is designed to be burned at high altitude in a engine that runs at relitavly low rpm.
 

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When I talked with Kenz after I had my raptor head setup to run a X-4 cam he recomended against running a 12.5:1 piston even with an x-4 cam. He said the shape of the raptors combustion chamber can cause detonation when running pump premium fuel.
Dont I know that about detonation...........:)
 

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Discussion Starter · #17 ·
ok so i am going to use a 3/4 to 1/4 ratio like quad suggested. Thanks for everybody's help on this issue!!!
 

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What is wrong with airplane fuel 100ll????? Just trying to figure this out.
thanks
its a very dry fuel meaning theres no lubercents meaning your burn a hole in your piston
made that mistake with a drag car ;)
 
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