• Required reading for all forum users!!!

    Welcome!
    Register to access the full functionality of the GSResources forum. Until you register and activate your account you will not have full forum access, nor will you be able to post or reply to messages.

    A note to new registrants...
    All new forum registrations must be activated via email before you have full access to the forum.

    A Special Note about Email accounts!
    DO NOT SIGN UP USING hotmail, outlook, gmx, sbcglobal, att, bellsouth or email.com. They delete our forum signup emails.

    A note to old forum members...
    I receive numerous requests from people who can no longer log in because their accounts were deleted. As mentioned in the forum FAQ, user accounts are deleted if you haven't logged in for the past 6 months. If you can't log in, then create a new forum account. If you don't get an error message, then check your email account for an activation message. If you get a message stating that the email address is already in use, then your account still exists so follow the instructions in the forum FAQ for resetting your password.

    Have you forgotten your password or have a new email address? Then read the forum FAQ for details on how to reset it.

    Any email requests for "can't log in anymore" problems or "lost my password" problems will be deleted. Read the forum FAQ and follow the instructions there - that's what we have one for...

  • Returning Visitors

    If you are a returning visitor who never received your confirmation email, then odds are your email provider is blockinig emails from our server. The only thing that can be done to get around this is you will have to try creating another forum account using an email address from another domain.

    If you are a returning visitor to the forum and can't log in using your old forum name and password but used to be able to then chances are your account is deleted. Purges of the databases are done regularly. You will have to create a new forum account and you should be all set.

'78 GS1000 jetting for pods and header only

  • Thread starter Thread starter slaveforthewave
  • Start date Start date
S

slaveforthewave

Guest
I had my bike running pretty well for a while. Fuel screw 7/8th from seated and the air screw 1 1/2 from seated. Seemed to really fall on it's face at higher rpm. I have no tach so it is hard to say at what rpm, but anyways. Currently I have the needle set to the 4th clip from the top with the big plastic spacer on top and the little plastic spacer on bottom of the clip, 15 pilots, and 135 mains. All jets and needles are Mikuni branded. I am running slightly restricted emgo pod filters and a 4-1 header only with no muffler or pipe back from the foot pegs.

I ran across a few posts by Keith Krause saying essentially run Mikuni 130 mains, with 15 (possibly 17.5) pilots, with an extra .022" spacer on top of the needle spacer to put it somewhere at 4.5 clips down.

Before I buy smaller mains and larger pilots to dial this thing in, does anyone have any real world tips to these VM26 carbs with similar set up?
 
Do you have a Dynojet needle in it? I think you'll struggle without the slimmer taper...
 
i do not. it is a stock needle. is there any way to acquire the dj needle without buying an absurdly expensive kid that includes a few jets, a screw, and a needle?

or possibly use this chart to buy a slimmer needle?
http://www.jetsrus.com/a_jets_by_carburetor_type/needle_mikuni.html

also my pilot fuel screws were snapped off and i had to sand them back into a point after i got the tips out of the carb bodies. could this be my issue? i cannot find new fuel screws ANYWHERE!
 
Forget about RPM. What throttle position does the bike flatten out at?
 
You're a bit all over the shop really and the best I can advise is you read all the threads that you can find on here on how to tune in carbs for pods and a pipe.

Basics is that ignore the engine revs as a guide to jetting - it's all about throttle position. Having the wrong pilot jets or the fuel screw in the wrong place won't change a thing when you're on full bore. Similarly, on tickover you don't even need main jets fitted. You have to tune each part of the circuit in, one at a time.

Having said that I would have thought you are pretty close and you don't need Dynojet needles with VMs - the existing needles tune in fine.
 
i have read many posts on this. even read through the mikuni tuning guide. i know this is kind of a subject that is beaten to death, and people probably get really sick of answering time and time again.

like i said i read that the dj 138 is made for pods and a pipe which is about a 130 mikuni jet size. at about 3/4 throttle that's when i get spitting and the bike just stops pulling hard. guessing i might be up a jet size. at idle bike has pretty well colored plugs so i'm thinking that the pilot system is doing okay.

i just didn't know is the header only with no pipe or baffle would cause me to need to go up on the mains or no. or if it would cause a back pressure issue.

this site is a wealth of information, so i thought i'd run it by everyone before going out and spending 75 dollars on jets, shims, needles, etc.
 
At 3/4 throttle you are running on the needle (probably still take the mains out and it would run the same). You should really mark up your twistgrip with the opening fractions and do plug chops at 3/4 throttle but my guess is that you need to drop the needle clips in to the lowest slots.
 
You must log in or register to reply here.
Back
Top