(BS series) Throttle Seals: Who's done 'em, who needs to?

[lafayette]

So drive out the left shaft to the left and right one ( with the angle arm ) to the right? And the angle arm will pop off while driving the right one out?

 

[gggGary]

NO! they both go left in your picture. The angle arm is staked on and does not come off. That's why you HAVE to separate the carbs, it's all part of the fun of doing throttle shaft seals.

 

[Sandy]

You will have to remove the choke shaft also(see pic)

Those two claws(with the screws that you loosened) that lift the choke plungers will come off the carbs once you remove the shaft. remember which way they go on the shaft so you dont put them on upside down. they dont work upside down so you would know quickly if you flipped them.

 

[lafayette]

Thanks for helping me not destroy this thing. I've got the new seals in and butterflies in place. Should there be a bit of freeplay in the shaft once it's back together? ( see pic ) When i push on it from the bolted end it shifts a bit. The bolt seems to be torqued down already and all the washers are in. And spring is loaded.

 

[5twins]

Yes, there may be a bit of play. Did you center the butterfly plates before fully tightening their mounting screws? If not, you may experience binding and throttle hanging problems.

 

[lafayette]

Seated the butterflies with several turns of throttle shaft and then I torqued down the screw with loctite blue.

On thing I noticed while doing all this was choke plunger on left carb seams to bubble up and glisten small amounts of gasoline when moving the choke. ( see pic ) Would this be enough to cause idle to hang up?

Both slides still come down real slow when holding the back side port closed with my thumb.

 

[Sandy]

I'd wait to hear from the other guys first, but i'm pretty sure that a leaky choke plunger could allow extra gas into the airstream so i'm sure it would affect your idle.

 

[junkshow]

Replaced my seals tonight, took about a half hour, but...

I slapped the carbs back on the bike and hooked up the fuel line, opened the petcocks and gas poured out of the right side carb, but I only had the left side fuel line hooked up. WTF?

Could this be something as simple as a stuck float?

Sorry to thread jack.

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[Sandy]

there is a fuel line that runs between the carbs so i dont think it matters which fuel line you have hooked up.

i know this is probably a silly question but you said that you only connected one fuel line but turned both petcocks on. where was the gas coming out exactly?

 

[junkshow]

It was a typo, I only opened the petcock I hooked up. That being the left side and gas was coming out of every opening on the right carb, but not the left.

Gonna open the bowls this morning and verify the floats didn't shift.

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[junkshow]

Just removed right side bowl, turned on gas, raised float and gas continued to flow. Something is clogged, but what? Any ideas on where to start?

This is confusing because the only thing I changed was the throttle shaft seals

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[gggGary]

Did you block the fuel port on the RH carb? If you have the fuel port blocked then if you manually raise the float and fuel still runs it has to be the float valve. Or no float valve LOL.

 

[junkshow]

Float valve? It that the little spring loaded piece that the float closes when the fuel level raises?

Why would that act up all of a sudded?

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[gggGary]

You take a look and tell us.

My first guess is a chunk of the inside of the fuel line has wedged between the seat and the plunger. You would not believe how many guys think oh that 40 YEAR OLD rubber fuel line that was not designed for ethanol LOOKS just fine ON THE OUTSIDE I'll reuse it! They then spend the next three weeks of summer fighting carb problems instead of riding but hey they saved a dollar! I see this all the time. Not aimed at you junkshow but it is a common problem. OK rant off.

 

[junkshow]

That's fair but, Ive installed new fuel lines. I know even with inline filters something could have passed from the tank tho.

But it didn't really answer my question, I will check everything, but I was hoping for a starting point when I asked "if the spring loaded part the float pushed on" was what you were talking about.

I understand, you have buttloads of knowledge on these machines, and people ask questions of you all the time. It must be a PITA to answer the same question over and over.

Thanks for the time and input.

You take a look and tell us.

My first guess is a chunk of the inside of the fuel line has wedged between the seat and the plunger. You would not believe how many guys think oh that 40 YEAR OLD rubber fuel line that was not designed for ethanol LOOKS just fine ON THE OUTSIDE I'll reuse it! They then spend the next three weeks of summer fighting carb problems instead of riding but hey they saved a dollar! I see this all the time. Not aimed at you junkshow but it is a common problem. OK rant off.

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[gggGary]

I think that junk in the float valve is the likely answer though, Remove the float and look at the plunger and the seat are they both smooth? Is there any crap in there? The float valve body is threaded into the carb body on BS38's. Remove it, see if there is any crap behind it.

 

[5twins]

Many, many years ago, my buddy's practically new bike started puking gas all over the place from one of the carbs. We took a look at the float needle and seat assembly and found a grain of sand between the needle and seat, that's right, one grain of sand. That's all it took.

 

[gggGary]

As to why did it start acting up, to put in the throttle shaft seals those carbs get turned 7 ways from Sunday. Any little piece O crap has lots of chances to end up where it doesn't belong. Straight up, I can't imagine doing the shaft seals without going through everything else again. Maybe it's just me but if the carb is on the bench about an extra 20-30 minutes has me KNOWING that every port and jet is clean and assembled correctly.

 

[junkshow]

Good points 5twins and gggGary.

I'll be pulling my carbs again tonight and giving them some thorough lovin'.

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[junkshow]

Damn you guys are good. Wouldnt you know it? I took the carbs apart and found a chunk of plastic (or hardened rubber) in the float valve. Nice.

I checked the other side as well but found nothing. Put it all back together, turned in the fuel, fuel pissed out the left carb this time. Aaargghhh!!!!

Guess I'll pull them off tonight and look again.

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