mikuni with altitude sickness : V-Twin Forum: Harley Davidson Forums

chainftw · 04-17-2009, 01:48 AM

i have a 97 fxstc 80", 30 over .535 cam screaming eagle highflow heads 9.5 comp, kb pistons,1 3/4 drags with t cones ,"i know but i aint changing the pipes" .ran like a mother when i lived in pa now in new mexico altitude of 7500 and it cant out run a minivan. have a stock set up 42 mikuni,, pilot 25,main 160 ,jet needle 97 middle clip,anyone know how to set it up for this altitude? it don,t pop spit or backfire at all, it just doesn't have any power. plugs look like its rich as heck and have some gas in k&n filter when i check it .any help would be great,
thanks chain
i tried a 155 main ,22.5 pilot and moved i notch up on needle, that seemed to slightly ,slightly help when im doing 95 to 100 and then open the throttle.

THANKS TO ALL, I ENDED UP WITH A 162.5 MAIN, A 22.5 PILOT,ONE SIZE DOWN FOR THE PUMP, AND THE STOCK NEEDEL AT THE 1ST NOTCH ,ITS WORKIN GREAT. I WAS WAY TO LEAN FROM 3/4 TO FULL, AND TO RICH FROM 1/8 TO 1/2 .STILL A LITTLE TWEEKIN TO DO BUT MUCH BETTER.
THANKS CHAIN

farfromiowa · 04-17-2009, 09:16 AM

Mikunis run "off the needle" I run a 17.5 intermediate (pilot) with the lean needle set one notch down from the center. 160 main. I am at sea level, but it also ran fine above 5k.

chainftw · 04-19-2009, 11:18 PM

Quote:

Originally Posted by farfromiowa

Mikunis run "off the needle" I run a 17.5 intermediate (pilot) with the lean needle set one notch down from the center. 160 main. I am at sea level, but it also ran fine above 5k.

THANKS FOR THE REPLY .I NEED A LITTLE MORE INFO .DONT WANT TO RUN IT TO LEAN BUT IT JUST HAS NO POWER ESPECIALLY IN THE LOW END.I HAVE FUEL IN MY FILTER HOUSING EVEN AFTER LEANING IT OUT LIKE I DID. THIS ALTITUDE IS KILLING THE PERFORMANCE .

nmaineron · 04-20-2009, 08:54 AM

There is no air up there.You are too rich.I have mine setup with a "mileage" setup which is quite lean.A smaller pump nozzle and the pump set at instant on, a 20 low speed and 160 main and the needle set one notch down.I am at about 500' above sea level.

You should change out the 25 for sure and maybe lean out the needle some.You aren't going to hurt your machine with any of these changes,they are base line and your machine will tell you if it likes it or not.

TheNowhereman · 04-20-2009, 08:59 AM

Quote:

Originally Posted by chainftw

THANKS FOR THE REPLY .I NEED A LITTLE MORE INFO .DONT WANT TO RUN IT TO LEAN BUT IT JUST HAS NO POWER ESPECIALLY IN THE LOW END.I HAVE FUEL IN MY FILTER HOUSING EVEN AFTER LEANING IT OUT LIKE I DID. THIS ALTITUDE IS KILLING THE PERFORMANCE .

Give me the specifics of your engine and riding style / altitude.
I will jet it for you from that.

chainftw · 04-20-2009, 05:52 PM

thanks man ill keep tryin, i was thinkin the pump nozzel was 2 rich and was going to try that next,
chain

chainftw · 04-20-2009, 06:05 PM

thanks nowhereman,
the bike is a stock 80 with the mods i mentioned ,heads,cam,bore.
i ride hard .the speed limit is 75 out here so 90 is cruzing speed and over 100 threw the desert is normal.
im at 7500 to 8000 feet normally.
my bike would normaly eat a twin cam even with mods, it was just one of those fast ass eveo's even before i did the work to it ,and out here its like a moped.
thanks for any help u can offer,
chain