I have recently purchased a 2005 raptor 660r. I did not get any book/manuals with it.

Can I run 87 octane gas or do I need High octane.

 

your fine with 87 you dont have to run any higher unless its a high compression engine.

 

As far asI know the engine is stock. That is the problem though. I dont know how high they have on a 660r stock. I have seen that some stock ATVs need 92.

 

whats the elevation where u ride?

 

I mainly ride around eastern IL and at the Badlands offroad park in Attica In. I dont know the elevation. Not very high I would guess.

 

to be honest i always use 93 or so for the hell of it, specially if two stroke, my warrior requires 93.
id use 93 anyway, but i dont think stock raptor 660s have that high of compression.

 

I know the 450 stock needs high octane. My yfz will make a ting'n sound from the engine if I run anything below 91. I'm not sure with the 660 but, I figured it would require 91. Call a dealer and ask what Yamaha recommends.

 

with lower elevation i would use good gas. its not that much more $

 

Makes sense,since the 450s have the same high compression motors that are in the high strung go or blow motocross bikes.

The 660 on the other hand has a motor derived from Yamaha,s XT660 on/off commuting motorcycle which run regular gas.

 

I did not know that. If that's the case it most likely does fine on 87.

If you want a positive answer, call a dealership and ask. I know sometimes they would put a sticker on the vehicle if it required anything over 87. Our old 2-stroke GP760 waverunner had a badge stating 91 octane. Anyone know if they did this on quads? (I have aftermarket plastics.)

Most large bore quads are lower compression engines. With that it mind combined with what TLC said. I'd say 87 is fine.