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Main Area => General GS500 Discussion => Topic started by: Chuck on June 07, 2008, 06:19:24 PM

Title: E85 rejet attempt
Post by: Chuck on June 07, 2008, 06:19:24 PM
Today I tried to rejet my GS for E85.  It did not work.

My current gasoline setup is 2001 carb, 20/65/140, lunchbox, stock exhaust.  It works great.

As a starting point, I decided to add 30% to all jets: 27.5/87.5/190, in a spare 2006 carb.  Using the idle screw I can encourage it to idle well without backfiring.  Then, applying ANY amount of throttle kills it dead.  It does this with any idle setting and any float height.  It will increase RPM if I apply choke, but using the throttle kills it even then.

I'm having a damn hard time with the float level.  It seems to be high no matter what I do.  (I expected it to be lower, since ethanol is denser than gasoline it should push the float up harder, but that doesn't seem to be the case for me.  I got it to 2-3mm higher than stock, and I thought that would be good enough for rough testing.)

I felt stupid trying to rejet a carb that I've never used before (who knows if the carb has issues to begin with), so I put all my jets into the carb I'm using now.  That didn't work either.  Same symptoms.  So I put my gas jets back in my gas carb and parked it.  (It works fine on gas again, but that's where I started this morning...)

I know precious little about carb tuning becuase I got my jet numbers from Alpha and they worked out of the box, so aside from some float height hassles, I've never really successfully diagnosed anything.  So I'm sure I'm making a big fat rookie mistake.  Someone please help me out.
Title: Re: E85 rejet attempt
Post by: Jay_wolf on June 07, 2008, 06:22:09 PM
Theres A Post going around for a dude that rejetted his bike for E85, ill have a looke
Title: Re: E85 rejet attempt
Post by: Jay_wolf on June 07, 2008, 06:24:11 PM
http://gstwins.com/gsboard/index.php?topic=7945.0

http://gstwins.com/gsboard/index.php?topic=30724.0



Heres The Two Threads... Enjoy
Title: Re: E85 rejet attempt
Post by: ohgood on June 07, 2008, 06:48:37 PM
Quote from: Jay_wolf on June 07, 2008, 06:24:11 PM
http://gstwins.com/gsboard/index.php?topic=7945.0

http://gstwins.com/gsboard/index.php?topic=30724.0



Heres The Two Threads... Enjoy


You know there is a running joke on another of my favorite forums... When people can't find stuff, they press the easy button, which happens to have someone's nickname attached. Either you or gsJack would be it here, me thinks.

My search foo is so weak I CAN'T EVEN FIND MY KEYS !!!
Title: Re: E85 rejet attempt
Post by: Chuck on June 07, 2008, 06:53:03 PM
Thanks.  I've been in those threads, and ate them up before I started my project.  That's where I got my jet sizes, and the idea that it would work.

I think I have a straight-up carb tuning problem.  Something is rich or lean, but I don't know what thing or which way.  It seems to be too rich (very wet and backfiring), but if I restrict the intake, it works a bit better.  But it also works better with choke.  So I don't know what's going on.  If I could get it to take throttle without crapping out, I could probably get the rest of the way.  (I have to get it running on the main jet and work my way down.  That's not going to happen if I can't get it out of idle.)

Thing is, this seems exactly like the problem I had with my rebuild carb.  I'd give it throttle and it would die.  When I sorted out the floats it worked fine.  (Actually, the float seemed fine, but the needle didn't seem to seal.  I put some oil on it thinking it would soften up the rubber, and it seemed to work.  It's been working for the past year.)

The main thing I need to know is if the float has to go up or down for E85.  I think if I could get that right, the rest would be a whole lot easier.  I sent a note to Rema100, maybe he'll find me.
Title: Re: E85 rejet attempt
Post by: cd on June 07, 2008, 06:53:49 PM
search foo, hahahahah
Title: Re: E85 rejet attempt
Post by: Jay_wolf on June 07, 2008, 06:53:50 PM
It does Surpise me sometimes... I mean , Search is so simple . its Rare that i would ask a question with out trying to search...

I asked about the Gasket For the petcock , because i wasnt so sure it was going to be that easy , and it was , and it turned out to be a showcase of the Uk Street Racing Machine :thumb:
Title: Re: E85 rejet attempt
Post by: Chuck on June 07, 2008, 06:57:57 PM
I suppose while you're both acting superior you didn't notice that I found that other thread, and posted in it, weeks ago, and it has nothing to do with my current problem?  (I found the Egaeus lousy math thread, but I didn't post there because, well, the lousy math.)

So thanks for trying to help (except for the ridicule), but I really need some more specific information in this case.
Title: Re: E85 rejet attempt
Post by: Jay_wolf on June 07, 2008, 07:14:08 PM
I was simply saying , that search is easy to use.. Chill? Its Now My 21st Bday , i wanna enjoy it  :cheers:
Title: Re: E85 rejet attempt
Post by: spc on June 07, 2008, 07:19:50 PM
21 ehh???  go get f%$king blazed!!!  Drink until the ugliest chick in the bar looks like a super-model, just make sure you have a friend there to make sure you don't actually do anything :thumb:

Happy B'day Cap'n
Title: Re: E85 rejet attempt
Post by: Jay_wolf on June 07, 2008, 08:15:31 PM
Cheers Buddy! , well it was like 1 am here , so it was my bday . but the party starts 2day ain the afternoon  :cheers:
Title: Re: E85 rejet attempt
Post by: mach1 on June 07, 2008, 08:22:16 PM
I think your on the right track just start going down on the main jet and work from their since no one has really done this with clear results your going to have alot of trial and error on your hands. my carbs a rich for some odd reason and if the bikes not fully warm and I give it gas with the throttle than it dies but the choke works great, durings warm up with the choke it backfires from the carbs.
Title: Re: E85 rejet attempt
Post by: yamahonkawazuki on June 07, 2008, 09:38:51 PM
think thats fun, try jetting for avgas :laugh: :laugh: