• 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.

CV Carb leak

salty_monk

salty_monk

Forum Guru
Past Site Supporter
TGSR Superstar
If the carb is leaking (constant since it started) and coming out into the airbox (primarily on the right or Number 4 side) with some down the airbox drain & some in the breather tubes that come off the rail I assume that means that the Petcock has started letting gas by & that at least one of the float valves is leaking..... Sound about right? :)

Doesn't seem to be any gas in the oil. I've got the Fuel hose pinched off with some Mole grips now.

Think I'm going to bite the bullet & buy some new float valves and change them out. I'm pretty sure that the petcock was replaced a couple of years back so I'll try giving that a clean first. I've had it before where some c*ap makes it's way past the petcock filter & into the body when a bike has restarted after a long layup....

About 150 miles (ish) on her now...

Nessism kindly sent me a link to what I assume are the right valves... https://www.amazon.com/Mikuni-Needl...-2.0&qid=1586210471&s=automotive&sr=1-1-fkmr0
 
Those <look> like the right valves. :-k

If they are, that's one heck of a good price, too.
The place I get them, they are $10 each.
I might have to switch. :encouragement:

Your guessing makes sense to me.

Just make sure you don't leave the petcock in PRIme, you shouldn't have much of a problem unless you are riding.
But again, riding might jostle the needle a bit and re-seat it so it works just fine.
dunno.gif


.
 
The needle spring gets weak after four decades so replacing those valves is money in the bank for a bike that's going to be a keeper. For some reason this seems to be more of a problem with the BS carbs compared to VM's. Typically a VM needle, even an old one, will hold up the full weight of the float assembly. On BS carbs the spring typically compresses significantly with the carbs up side down. Not sure what the difference is exactly but it is something to be watched. Oh, and K&L float needle valves have weak azz springs in them so don't even think of going that route.
 
Ed - Yeah, planning on getting a full set of those ones on Amazon unless you have some new ones you need to get rid of... In which case I'll buy them from you. Didn't quite get your email :)

Steve - That price is each not a set of 4. Where do you get them for 10 bucks (Pm me if you want to protect your source :) )? Maybe I'll get them there instead!

Hoping I don't also have to replace the petcock. Worst thing now is that I have a brimmed tank less 30 miles so I need to drain some gas out of it...
 
That came up in a search for me earlier. Went through the process $7.99 so works out approx the same (plus only 3 in stock).
 
Okay, measured a couple of old valves and they measure like those new Mikuni parts listed.

Oh, and I've got two brand new ones Dan if that would be any help.
 
Last edited:
Assume they are a "replace as a full set type item".. If you particularly want to sell them Ed I'll buy them off you, if not I'll just order some... Thanks for all the help as ever! :)
 
Yep, the Orings are good in these. The carbs were rebuilt fully not so long ago and the bike is running fine. :)
 
So I replaced the valves in full. The new ones sealed right away.

I guess the springs were weak, the floats varied over this first 150 miles getting richer until it started to overflow (pretty sure at least one wasn't sealing, luckily the petcock was fine).

They were towards the rich end of spec when I set them & when I measured again they'd moved by about 2-3mm. Certainly the one that felt worse by hand was the main culprit for leaking (number 4). Amazing how it richened up the whole bank of carbs across the range. I need to make some carb adjustments now... (I will also sync again - bike is due for head re-torque in about 300+ miles)
 
You must log in or register to reply here.

Similar threads

K
Hanging idle troubleshoot help
Replies
18
Views
408
Naulty
N
L
82 750 leaking gas from airbox hose
Replies
17
Views
315
longranger44
L
I
Gs550 cv carb help please
Replies
5
Views
130
dgates1
dgates1
R
1980 GS1000 no-start
Replies
6
Views
124
oldGSfan
oldGSfan
Robyle3
83 GS550L rejet
Replies
4
Views
160
Cipher
C
Back
Top