• 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.

Pilot jets

R

Retrosteve

Forum Apprentice
Just thought i would mention that although i have stripped the carbs cleaned and rebuilt them with new seals its been a learning curve and something that i did not know or overlooked in the tutorials on here .
Cleaning every orifice is obviously key which i thought id done . However after looking at a number of ytube videos i did not realise that the pilot jets have a pin hole in the bottom that is notorious for getting blocked . This has been the problem with my GS850G from the start . After soaking the jets in carb cleaner for days and using a single wire from a wire brush i cleared the fine hole in the bottom of all the jets . They were totally blocked solid in the bottom fine holes but clear in the side holes .
Was there ever an upgrade on these jets to stop the blockages or is it just normal for them to become clogged after so many miles ?
 
There is no upgrade.
Providing the bike is run regularly and the tank and fuel lines are free from debris etc they rarely give any trouble.
Occasionally one may get a partial blockage which usually clears on the run but for all four to become blocked is nearly always the result of the carbs being laid up for a long period of time.
 
When i got the bike the carbs were not on the bike so assuming these were off a long time or even off another bike that had stood for years . Lesson learnt for the future but at least im up to scratch on total carb rebuilds :) .
Thanks to all ;)
 
Syd said:
Was there any noticeable change in performance after cleaning those jets?
Click to expand...

Im going to put the bike together later in the week so will update you ;) Since owning this bike ive had to re wire everything from scratch then rebuild the carbs fully a few times without success .
Clearing these blocked pilot jets will be the last job hopefully and get the bike running .
 
Im really struggling with these carbs . Every orifice was cleaned and blown out with air , new seals throughout and still it will only run on choke . All i can think of is those tiny holes in the end of the pilot jets have blocked again ? Any other ideas greatly received ?
 
Well, logic leads one to the fact that the carbs are not clean, otherwise your bike would be idling and running.

Did you follow the carb cleaning tutorial?
 
Big T said:
Well, logic leads one to the fact that the carbs are not clean, otherwise your bike would be idling and running.

Did you follow the carb cleaning tutorial?
Click to expand...

Oh yes followed the tutorial exactly . All 4 carbs were separated and new seals on everything . Ive got them off again and checked it all and nothing is blocked or wrong . The only thing that was a bit suspect to me was that when putting the float bowls back on there was some resistance , maybe hanging up on the pilot jet bungs and could be dislodging them leaving them open but will check those today .
 
this may be a suggestion easy to dismiss ... but have seen a number of float bowl gaskets recently that are too large on the float sides.
Rubbing the floats, preventing movement.
So one carb would starve, while the next carb would be stuck in float needle open position.
Are you sure the floats are moving freely ?

side note chuck hahn could this be a cause for your plugs fouling ?
 
Last edited:
Rijko said:
this may be a suggestion easy to dismiss ... but have seen a number of float bowl gaskets recently that are too large on the float sides.
Rubbing the floats, preventing movement.
So one carb would starve, while the next carb would be stuck in float needle open position.
Are you sure the floats are moving freely ?

side note chuck hahn could this be a cause for your plugs fouling ?
Click to expand...

Hi your theory about the gaskets was correct . 2 of the 4 were rubbing . Will test to see if this helps .
One thing i notice was that the rubber bungs over the pilot jets where different hights than the other 2 . Maybe not sealing correctly once the bowls are put back on ?
Have ordered some new bungs .
 
Well once i put the carbs back on , all 4 started to flood , the float hights were spot on . The passageways were all clear , the floats moved up and down freely . New seals on everything so im taking them off again .I dont get defeated easily but patience is running thin on this one . No fuel was getting to number 1 and 2 even though the float chambers were flooded . Amazingly the bike tried to run on number 3 and 4 . But why no fuel is getting to 1 and 2 has me stumped :confused:
 
Plugged main jets? I think the pilot circuit pulls fuel up through the main jet to the bottom side of the pilot plug. Do they fire with the choke on? Or your needle valves are sticking just a little and don't allow the bowls to fill back up when running? I had to take my carbs back off to clean the needle valves again when I was getting cold cylinders.
 
i'd focus on the flooding first.

Only 1 cause for that : the float needles do not shut off for whatever reason.
Floats not moving, float needles stuck, floats at wrong height, something like that.

You have replaced the o-rings between inlet rubbers and head ?
 
dgates1 said:
Plugged main jets? I think the pilot circuit pulls fuel up through the main jet to the bottom side of the pilot plug. Do they fire with the choke on? Or your needle valves are sticking just a little and don't allow the bowls to fill back up when running? I had to take my carbs back off to clean the needle valves again when I was getting cold cylinders.
Click to expand...

Ok the needle jets and seats are brand new but ive checked them again today .. only thing im wondering is where the float tab touches the pin on the jet is that the actual needle jet looks too far down the seat . The tabs on the floats look too far bent down when inverted and probably not closing far enough . The rebuild kit i got with the bike may not be suitable :rolleyes:
 
Rijko said:
i'd focus on the flooding first.

Only 1 cause for that : the float needles do not shut off for whatever reason.
Floats not moving, float needles stuck, floats at wrong height, something like that.

You have replaced the o-rings between inlet rubbers and head ?
Click to expand...

Hello yes the o rings have been replaced , Everything i took apart today to bare bones was very clean . Ive not replaced the inlet rubbers but they are on order . Starting or trying to run on choke makes no difference . maybe i need to inspect the height of the needle jets and seats then go from there . Compare them to the used worn jets .
 
sounds like a plan, maybe even stick the old float seats and needles back in to see if that changes things.

it's a bit messy but if you place the carb rack (without the bowls mounted) on a stand above a tray and feed it gas, you can manually check each carb simply by lifting its float and see if the fuel stops flowing.

Just remembered .. i have seen new o-rings on the float needle seat that were too small and would not seal, and leak.
Something else to check.

So here i go swallowing my "Only 1 cause for that" ;)
 
Last edited:
Rijko said:
sounds like a plan, maybe even stick the old float seats and needles back in to see if that changes things.

it's a bit messy but if you place the carb rack (without the bowls mounted) on a stand above a tray and feed it gas, you can manually check each carb simply by lifting its float and see if the fuel stops flowing.

Just remembered .. i have seen new o-rings on the float seat that were too small and would not seal, and leak.
Something else to check.

So here i go swallowing my "Only 1 cause for that" ;)
Click to expand...

I did blow through the fuel inlet with the float bowls off to see if the air stopped when lifting up each float , and it did stop the flow but im sure the float was too high . I will try the fuel method today to double check . The seals on the seats were new but the seats came out too easily so will replace those together with the intake o rings and go from there and report back soon :pray:
 
Ive found a tare in one of the throat slide diaphragm rubber boots and possibly another next to it on 1 and 2 cylinders which would cause trouble i guess . How do you remove the rubber diaphragm or can it be repaired ?
 
You must log in or register to reply here.
Back
Top