• 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.

GS850 Carb fluttering and bogging down at 60mph

  • Thread starter Thread starter Welshbird
  • Start date Start date
W

Welshbird

Guest
Hi all, looking for some help please!!!
I bought some vaccum carbs from a GS850 to put on my bike, They have been cleaned and rebuilt and are now on my bike however when i started my bike it runs ok on the choke and it good on the bottom end but when i get it any gas it just bogs down after 60 mph... The slides are not going up very well and are really fluttering... What have i missed out on when doing the carbs or is there something else i am not doing right???
The only thing that i have done do my bike apart from the carbs is new piston rings and a decoke..

Desperate to get it sorted

Cheers All

Sam
 
Sam, Welcome to TheGSR.


Welshbird said:
.................
............................. to put on my bike, .............
Click to expand...

And which model is that...? (maybe add that info in your signature line, then it shows up in every post).

Can you go higher rpm in lower gear?

Describe about your airbox (or lack thereof).
 
Thanks Redman,

It is a GS850G

i can only go very slightly high rpm in lower gear.

Airbox, is a custom one that i have had on my bike for a while.
 
Did it ever work well with your custom airbox? :-k

These carbs are rather sensitive to turbulent air coming into the carbs, so smooth airflow is critical. A stock airbox has individual runners that resemble velocity stacks. Even most (decent) pod filters have a tapered runner that helps smoothe the flow a bit. With a "custom" airbox, there is no way to know.

Just so you know, the slides in the carbs do not control airflow, they respond to it. If you can see the slides fluttering, it seems obvious that you don't have the airbox on, and it will NOT run smoothly.

.
 
One thing I've seen cause this sort of thing on a stock GS850 is the ends of the vent tubes are hanging out in the airstream. They're supposed to be tucked behind the airbox in the little clip provided. If the ends are in the airflow, you'll get all sorts of odd stuff.

But with all the other unknown factors here, uh... I dunno. As Steve mentioned, turbulence in general causes all sorts of odd issues for CV carbs.

In a stock GS850, the airbox MUST be sealed for proper airflow. That means air only gets in the airbox and past the filter where it's supposed to get in. And it also means the snorkel on the back of the airbox MUST be in place and intact.

With your mystery setup... impossible to tell what's happening.
 
Last edited:
I have the same problem but with a stock airbox on an 85 GS850G with CV carbs
 
Just re-checked the registration papers and yep its built in 85 and registered on the road here in 86
Here being Germany not that that matters much really
 
Well, yes, it does. German air behaves considerably different than American air.
dunno.gif


I still have a question, though: How can you tell the slides are fluttering? The only way to see that is to remove the airbox. If you remove the airbox, the slides WILL do strange things, but the bike will be rather unrideable in that condition.

OK, German air might not be all that different, but if you were to ask about where to order something, we would not have the slightest clue that what we were recommending would be on the other side of the globe.

It would be handy for those who respond to your queries to know where you are and what bike you are talking about. Don't need an address, but editing your profile to show a town or region would help. Also handy is creating a signature that mentions your bike. Does not have to be anything fancy, just a simply "Current bike: '85 GS850G" would be good. :encouragement:

.
 
Last edited:
bwringer said:
One thing I've seen cause this sort of thing on a stock GS850 is the ends of the vent tubes are hanging out in the airstream. They're supposed to be tucked behind the airbox in the little clip provided. If the ends are in the airflow, you'll get all sorts of odd stuff.

But with all the other unknown factors here, uh... I dunno. As Steve mentioned, turbulence in general causes all sorts of odd issues for CV carbs.

In a stock GS850, the airbox MUST be sealed for proper airflow. That means air only gets in the airbox and past the filter where it's supposed to get in. And it also means the snorkel on the back of the airbox MUST be in place and intact.

With your mystery setup... impossible to tell what's happening.
Click to expand...


The Snorkel? My airbox has an opening in the back...but it's just bare metal... Am I missing a part?
 
Well, that's not good. Any ideas on what, where and how I can find a replacement? I'm already done an Ebay and Amazon search.... Will check the boneyard this week.
 
Can't order that part, the only thing I can think of is to watch eBay or check the boneyards.

Most of the larger (850+) shafties have that snorkel, so that might expand your search a bit.

.
 
Steve said:
Can't order that part, the only thing I can think of is to watch eBay or check the boneyards.

Most of the larger (850+) shafties have that snorkel, so that might expand your search a bit.

.
Click to expand...
Are the 80, 81, 82 airboxes interchangeable? From what I've read the GS750s have many of the same parts.. And I also guess the "L"s have a different box than the Gs.... ?
 
The '80 850L shares a box with the '80/'81 850G. The '82/'83 850G shares a box with the '81-'83 850L.

The 1000G and GL and the 1100G and GL from the same years will look the same, but have larger airboots that mate up with the larger carbs.

.
 
Next question: How much difference does the snorkel make? Would this be yet another reason why I'm only getting 30 mpg in addition to misaligned floats, different sized pilot jets in all 4 carbs.. 2 carbs running rich and 1 running lean and one running great... In addition to the compression being only just above service limits... and the valves not being adjusted correctly for 8 years..... Other than that my bike is in GREAT shape....


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