ok guys....I got a real mind boggler for ya....I ran 3 tanks of 100 octane in my bike...the other noght while riding, I was doing about 80-85 and my bike quit, would not start or anything, so I had a friend pick me and the bike up, did not touch it until today.....took the tank,and air filter off, checked spark, i have spark, its not missing, put gas in it and it started right up with the choke on...dumped the tank and put some 93 back in it and it stayed running after I turned the choke off....now here is the boggler

when Idiling it idles fine.....when I take off it feels good until I hit about 5000 rpm, then it starts to sputter, like its not getting gas.....but then I can pull the clutch in and hammer the throttle and it will redline with no problem....so I was doing more riding, and I was like well lest see what it will do if I hammer it out of the hole.....so i did, and it comes out like a banshee, but around 5-6000rpm it hesitates and then picks up again til redline, then when I shift to 2nd it drops to about 6grand, and sputters....

is this my fuel pump?
Fuel Regulator?
Relay?
or is this a vacum problem???

this was running good until friday

any help would be appreciated

 

i have no clue on this one.... dont know much about the motor..


but i do know our bikes perform better with regular 87... i tried premium before... not only did it perform slower.. i got worse MPG...

 

I think the higher octane fuels need a hotter spark and slightly different air fuel ratio to perform normally. I'm not 100% sure on this, but it's worth doing a little research. I was also running premium in my bike for a while and experienced low fuel milage and over bad performance. I did a tune up and a few other things and finally tried running a lower octane fuel and it started running a little better. So maybe the fuel was the problem. Can't be sure though...

 

The higher octane gas should be fine. Check all your vacuum lines for a leak. If you have an F4, we dont have a fuel pump. You can try taking the line off the tank and see if the fuel flows freely too. I would suspect a vacuum leak though.

 

F4s have a fuel pump...

 

Octane ratings are designed for detonation control, higher compression ratio, higher octane. We're already 12:1 compression ratio from the factory, IMHO you should be using premium fuel and that's it. But your problem sounds like the carbs aren't staging properly between the idle and high speed jets, try cleaning your carbs or changing your fuel filter.