my banshee has toomies and an open airbox. i live at 3200 feet and want to run pump gas 91 octane. my crank is not welded. the shop i go to says the 19 will be perfect. what do you guys say?

 

guys i already have the 19 setup but i dont want to install them until i get more input

 

With that high of an altitude I think you would be cutting it close with the 19cc domes if you still want to run pump gas. I'd put them on and do a compression check first. If you have over 150-160 you might need to run race gas.

 

i put the 19cc domes in the bike runs fantastic so far. it has 139 left 137 right for compression. i think this should be fine for pump gas.

 

That's fine with pump gas... I'm sure I have about that much with my stock head... I ride at sea level though.

 

The 19 will be fine. My buddy run a cool head with 19cc domes at 6000-8500 ft. He runs premium and thats it. Good Luck.

RoostKing...

 

Hello,

Don't run 19cc domes without race gas. I learned the hard way. You'll end up melting holes in your pistons. Cylinder pressure is what you are measuring with the guage. Cylinder pressure in no way determines what octane fuel you need. In fact its a pretty useless number. I was melting pistons with 120 pounds.

What you need to consider is the compression ratio. Give Pro Design a call and they'll tell you the same exact thing. You absolutely must run race gas or your machine will die a slow death.

I recommend VP C12 108.

Good luck and trust me... After $1500.00 of repairs I know that 19cc's are not pump gas ready.

 

so guys what do you think? is slickster correct or will my banshee be ok.

 

Peewee,

Why take a chance? If racing fuel is such a problem why not keep your motor stock? Sounds like that if you run anything but 22cc domes the minimum requirement will be a 50/50 mix. So, if you run 100% racing fuel for the added assurance that you are doing the right thing for your motor, you might have to spend an extra $2 - $3 per gallon compared to the cost per gallon of a 50/50 mix. Big deal! What is this compared to a $1,500 engine repair bill and all of the riding time lost! I can't figure people who will spend hundreds of dollars for performance parts and then fret over spending a few dollars for the proper lubricants and fuels to make them work. Bottom line - if you want performance you are going to have to pay for it. Either up front or in repair bills.

 

bansheebill i did want pretty much a stock replacement, i was after better cooling. the shop here in missoula says to run the 19cc domes. apparently it what they run and have no problems. i just dont want to get into the race fuel thing. i told them this many times and they insist the engine will be fine. told them the compresion and they say thats perfect it wont detonate.