I noticed on the cap on my new DS it recomends 91 octane fuel

I live in the UK so i dont have that option i can get reguler 95 octane or 98 octane.
I have been using the 95 with no problems but i am about to fit a mr hp end cap and he suggested a 175 main jet It just occured to me that the octaine differance might mean i have to go with another size

Any ideas

What octane fuel do you guys call race gas?

:confused[img]i/expressions/face-icon-small-confused.gif[/img]

 

Sound like you got better gas at the pump than we due here in Calif. only 91 or 93 octane. Your need the large main jet because with the end cap will let your engine will flow more air. To keep the correct air to fuel ratio you need to ad more fuel to the mix.

Race gas 100+ octane VP Race fuel info

 

Thanks for the reply

I know i need to rejet due to increased air flow, what i am not so sure on is if i use the recomended jet from mr hp will it still be near the mark or will the differance in octane make a differance in the jet size i need.

In the past i have always jeted by trial and error plug couler ect. Mr hp is sending me a new main with my cap as it is a hassel to get hold of them where i live. so i just wanted to make sure it was the right choice.

our fuel does seem to be of a higher qauity than u guys get but we are paying around 78 pence ($1.41) per litre at the moment so
it would dam well need to be[img]i/expressions/face-icon-small-happy.gif[/img]

 

The only time octane comes in it too the mix is if you change your piston to a higher compression. Your 98 octane should be good for 12.5:1 ratio compression pistons. One of the ATV magazine did a test on pump and race gas and on a stock ATV with just a pipe. The race gas made less HP.

 

Thanks a lot man [img]i/expressions/face-icon-small-smile.gif[/img]