• 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.

jetting question

  • Thread starter Thread starter NetBSD
  • Start date Start date
N

NetBSD

Guest
im getting confused here about jetting and stuff, i have this carbs101.pdf and its showing this...

carb1.jpg


now when im crusing at 65mph in 6th gear about 5,000RPM it acts like its starving for fuel, this is around 1.4 throttle, if i go full throttle it is fine or if i back it down to 1.8 throttle (like 3,000RPM). so what do i change? do i raise the needle? the way it looks i can only do the needle or the valve cutaway. lets hear what you guys have

btw this is on a 1980 gs450l with pods, PO put the pods on and the jetting is damn close. i did plug chops and its always gray, even when just crusing around id check them and they are gray.

btw heres the pdf http://imnotmark.zapto.org:3030/gs450/carbs101.pdf


EDIT: i have the air/fuel mixture screws out 3 1/2turns, trying to figure this out and it still acts up.
 
Try raising the needles, if you don't like it put them back.
Much harder to undo a slide cutout change.
 
the next larger pilot jet and /or needle adjustment
maybe both do 1 thing at a time and you'll get there. you are on the right track,and almost there.


Gray is cool but chocolate brown is better (plug color)
 
ill give it a shot next nice day. been raining the past 3 days :(


thanks for the help
 
Raise the needle. You'll probably need to shim it using small washers. Don't turn the air/fuel mixture screws out any more. If it's idling ok and running good around town on the 1/8 - 1/4 throttle, they're fine.
 
don_gibb6512 said:
Raise the needle. You'll probably need to shim it using small washers. Don't turn the air/fuel mixture screws out any more. If it's idling ok and running good around town on the 1/8 - 1/4 throttle, they're fine.
Click to expand...


yeah ive been told anything past 2 1/2 turns you need to change stuff but i was trying to temp fix this till the winter but its really ****ing me off.

ive never had this style carb apart before, im used to working on offroad carbs that have the cable down thru the top of the carb and into the slide, and those have notches in the needles for this sort of thing. how far would you guys say i should shim the needles? i know im gunna have to play a bit but whats a good starting point
 
SMALL increments. I think about 1 mm. You can buy needles with notches but do your research first. The taper of the needle also has a big input on how the bike responds. The guys at www.carbparts.com are good as are www.sudco.com

Normally, if you're turning out past 2.5 turns on the air/fuel mixture screws you should consider increasing the pilot jet size one step but I've learned that that may not be the case on all sets of carbs. My experience has only been with the Mikuni BS34SS and 34mm RS Flatslides.

I do think that raising the needle will fix your problem. No matter what changes you make to the carbs, stick with the rule of "make only ONE change at a time". It can be real nightmare but with some persistence, you can make it work. The GSR is a great resource.
 
Last edited:
well i got it fixed, raised the needle with a few washer/shims i got from a hardware store and backed up the mixture screw to 2 turns out, idles great, all positions of the throttle is perfect and multiple plug chops show a nice gray/brownish burn on the plugs.

also when ripping into the bike i noticed the one filter (these are foam uni filters) was ripped so it was getting alot of air flow on the right cyl. orderd up some universal 48mm pods to toss on it and then gunna play with the jetting if it isnt right. thanks for the help guys
 
Excellent !! Thanks for letting us know how it worked out.

Don
 
You must log in or register to reply here.
Back
Top