This is why No3 cylinder wasnt firing....

[mighty13d]

A good epoxy would be good in a pinch until you can get your hands on a new set of boots, but i wouldn't suggest trying to use them permanently.

[snowbeard]

I've seen a lot of gummy, gooey intake boots on bikes in the junkyard. I would only assume that it was a big part of the issue.

do they still sell these? I think I need them as well...

[XTlegend]

I've seen a lot of gummy, gooey intake boots on bikes in the junkyard. I would only assume that it was a big part of the issue.

do they still sell these? I think I need them as well...

They do - but in my case 4 new ones would almost cost what I paid for the whole bike!!

Update - this is really why No 3 cylinder wasnt firing, I give you the needle jet! ;-)

[mighty13d]

looks like a sea cucumber! YAY for finding the reason!

[mike-s]

EWWWWWW!!

kind of looks like the emulsion tube i had on my gsx250 before i stripped all the brass parts out and soaked them for 24+ hours.

[XTlegend]

Oh well, weeks have passed by and No3 cylinder still isn't running correctly. I invested in new inlet rubbers bye the way.

Anyway I'm getting ready to run this bike off a cliff top.

I have meticulously followed the excellent guides on dismantling and cleaning the BS32's and I can guarantee that none of the passageways are blocked. To refresh, No3 exhaust pipe gets hot when the choke is on but cools off (you can touch the pipe with bare hand) when off. I have studied and understand how the start, slow and main sections of the carb work and all passage ways are clear. And yet there is clearly no fuel getting through at idle or open throttle - the spark plug still looks like new and is dry Grrrrrrrrrrrrrrrrrrrrrrr !!!!!!!!!!!!!!

[reddirtrider]

Oh well, weeks have passed by and No3 cylinder still isn't running correctly. I invested in new inlet rubbers bye the way.

Anyway I'm getting ready to run this bike off a cliff top.

I have meticulously followed the excellent guides on dismantling and cleaning the BS32's and I can guarantee that none of the passageways are blocked. To refresh, No3 exhaust pipe gets hot when the choke is on but cools off (you can touch the pipe with bare hand) when off. I have studied and understand how the start, slow and main sections of the carb work and all passage ways are clear. And yet there is clearly no fuel getting through at idle or open throttle - the spark plug still looks like new and is dry Grrrrrrrrrrrrrrrrrrrrrrr !!!!!!!!!!!!!!

Sounds like you need to balance the carbs.

[XTlegend]

Sounds like you need to balance the carbs.

Errrrrrrrrrrr what exactly has balancing the carbs got to do with the slow and main circuits inside each carb? There is no fuel getting into the cylinder at any throttle opening. The only part of No3 carb that seems to be working is the choke. With that on the cylinder fires.

[hampshirehog]

At the risk of me sounding stupid.....
1. Are all the linkages connected up?
2. If they are, when you open the butterflies do all the slides lift equally? ('Perfectly' equally when balanced, though 'equal to the eye' will get you a runner).
3. Have you got decent compression on No 3?

If the answer to all 3 is 'yes' the only thing left is a blockage somewhere. If this looks likely, don't beat up on it - you have to be really, really careful all the way on the fuel system on these bikes - a tiny bit of sh*t somewhere (left in the pipe etc) will block things up.

If you can get it to run reasonably well enough to ride and can get it down to my place I can help you out with a carb synch / mixture setting.

[XTlegend]

At the risk of me sounding stupid.....
1. Are all the linkages connected up?
2. If they are, when you open the butterflies do all the slides lift equally? ('Perfectly' equally when balanced, though 'equal to the eye' will get you a runner).
3. Have you got decent compression on No 3?

If the answer to all 3 is 'yes' the only thing left is a blockage somewhere. If this looks likely, don't beat up on it - you have to be really, really careful all the way on the fuel system on these bikes - a tiny bit of sh*t somewhere (left in the pipe etc) will block things up.

If you can get it to run reasonably well enough to ride and can get it down to my place I can help you out with a carb synch / mixture setting.

I might take you up on that - took it for a 4 mile ride yesterday in the hope that things would clear up. Visually they look in sync - but what has this got to do with running on idle?? All pipes should get hot on idle with the throttle closed right? No 3 is cold initally then gets warm due to conduction from the head I guess. However if I start the bike from cold with choke ON then No 3 pipe gets hot otherwise cold. This implies compression is OK no?

[XTlegend]

Well, this moring I took the carbs off my other GS and put them on the problem one. Much grazed fingers later and it runs like a swiss watch. I cannot believe that I have missed anything on the problem carb but there you go. Talk about frustration! All good fun though (or am I kidding myself). Now more determined than ever to find out whats wrong. Thanks for all your suggestions.

[Steve]

... but in my case 4 new ones would almost cost what I paid for the whole bike!!.

I just LOVE this reasoning. I was given a bike a few weeks ago, for FREE. Does this mean that I should not have to pay anything for parts?

Visually they look in sync - but what has this got to do with running on idle?? All pipes should get hot on idle with the throttle closed right? No 3 is cold initally then gets warm due to conduction from the head I guess. However if I start the bike from cold with choke ON then No 3 pipe gets hot otherwise cold. This implies compression is OK no?

"Sync" has everything to do with how it runs at idle.

What you are synchronizing is the opening of the throttle blades. You are trying to align them just fractions of a degree, but their effect is most pronounced as they just barely open. Looking at those fractions of a degree; #1 might be open 2%, #2 might be open 3%, #3 might be open 0%, #4 might be open 2%. If you open up the throttle just a little more, those numbers would be 9, 10, 7, 9. It's getting harder to see the difference. At wide open throttle, those numbers would be 99,100, 97, 99. Can you see why it's much more noticeable at idle?

My opinion is that you still have something blocking the pilot circuit in your #3 carb. First thing to check is for a broken tip on the idle mixture adjustment screw. You should be able to see a hole all the way into the throat of the carb when you remove the screw. There are more small holes in the top of the carb throat, right where the closed butterfly sits. These are what feed some of the mixture for the bike to run at low throttle openings. Their positions are staggered so they add fuel at different times. The adjustment screw only adds to what these holes can provide. It's not as easy to see if these holes are open, but you might be able to poke through them with a bent pin. Also make sure the holes in the pilot fuel jet are open. Finally spray some carb cleaner through the passages, followed by compressed air. I think you will finally clear it up.

It's nice to see that another set of carbs cleared the problem. At least now you know that it's not an electrical issue or something else and can concentrate your efforts on the carbs.

.