Converting Over To E85 NEED HELP

[alan]

I am aware that this site seems to be intended for autos but information on e85 and motorcycles is scarce. I have an old school kz900 with much performance upgrades. These old air cooled bikes once bored and such hate the heat. So my brother and me have decided to convert to E85. This bike has a new set of mikuni carbs. I am have a lot of trouble tuning the pilot/idle system . I have no where to turn for help and advice. Im having a hard time trying to find out exactly how the extra 30% in fuel flow is applied. I have read +1 jet size per 10% of alcohol . My motorcycle has 130 main jets in it for the gasoline. If I take and add 30% to 130 , if this is how to compute , leaves me putting a 170 main jet . I have run this 170 main jet . WAAAAAYYY rich . When WOT is applied bike completely dies till I let out of it . On the pilot jet for idle I also increased the size ( but didn't increase the size of the pilot air bleed/jet) . So to obtain a smooth idle my Pilot/Air screws are set at 1/2 turn out . But when I ride the bike it struggles and surges and pops between 2500-5000 and stops as soon as the choke is applied  . But turning the pilot screws out to 3-3.5 turns makes the ide choppy but it helps with the throttle response and almost eliminates the issues I was having at 2500-5000 but still sputters at cruising speeds, but much better. I am sooooooo needing some major help . Any advice at all is GREATLY appreciated.

[butterbean]

I think you are to fat (rich) on your tune, its not set in stone 30% that is a starting point, my tune wound up being aqbout 25% more fuel so maybe you could lean it out a little and see what happens, and you will always need to check the %age of the fuel because they change the fuel in the northern states due to the weather its 85% in the summer and 70% in the winter, I live in south Florida so I don't have that problem LOL!!! you will have to change the jetting when the fuel changes or you can just buy it by the drum and don't worry about at all, anyway good luck tuning and let us know how it goes.

[alan]

Thanks butterbean. How did you determine you were 25% ? Do I just take my main jet size 130 and add 25-30% . 130 + 25% =162.5 ? Or is each jet size a certain % increase? I think each jet size in a Holley is around 4.5% increase. Of course I have mikuni carbs on this bike.

[butterbean]

you need to know how much does jet size = % of increase fuel, i took a guess and came up with 151 not 170 but I don't really know

[alan]

How did you compute the 151? Thanks again butterbean

[butterbean]

can you find out what % of fuel 1 jet size = in % age of fuel? does that make sense?

[butterbean]

also when you here it poping and farting with gas it means its too lean but with E-85 it means its too fat so if its doing what you say it is then you need to lean it out a little and see what happens, good luck

[alan]

The jets in my carbs are all measured by flow. All sized in 2.5 increments. So the size 120 flows 20% more than the 100 . And the 200 flows 33% more than the 150. The pilot jet is measured the same way by flow. The carbs have 17.5 pilots , and 130 main jets. Thanks for your patience butterbean

[alan]

Ok I'm gonna try to lean the idle system out some.

[butterbean]

well did you try and lean it out? and did it help?

[alan]

Yes and it does the same thing but worse. With the large idle jet I was able to richen it up with the air screw where it was ridable with a sputter around cruising speed. I think it's getting enough fuel at idle to 1/2 throttle. But needs a smaller pilot air jet to richer the idle.