BS36 carb - float is "stiff"

[cjard]

One of the carbs on my FJ has a "stiff" float, coincidentally the one at the lowest level when the bike is on its side stand. Everything in that carb looks a bit more dirty/corroded than the others (the main jet is a dark brown for example, the others at least have a bit of gold pallour to them)

Having disconnected the little spring clip that ties the float needle valve to the float tang I can see for sure that the float itself is stiff; it behaves like it has an oil damper whereas all the others bounce up and down at the slightest touch

I suspect some small amount of corrosion between the pin and the metal collar that wraps around it, forming the hinge for the float, but I'm not sure how to get the pin out; the carb overhaul guide said to tap it out with a punch but mine looks like it's peened over at both ends (one blatantly more than the other)

What's the technique for this pin, please?


Also does anyone know (or have a link to where I can find) th part number for the cast aluminium T piece that goes between carbs 2 and 3, where the fuel pipe attaches? I was most surprised to be pulling my fuel pipe off only to have that metal T piece snap in the middle, part of it remaining in the end of the pipe, part of it still forming the fuel rail between carbs 2 and 3.. :/
Note: my fj 1200 has a single fuel pipe from pump to carb bank, and it connects between 2 and 3. I'm dimly aware there are other carb banks where there are two fuel pipes that connect to T pieces between 1,2 and 3,4 and the two pairs of carbs are not linked, but mine's one of the "all carbs are linked and the fuel delivery point is in the centre"

THanks guys

[Mark Olson]

Um.... the link is the RPM banner ... click it and go to FJ specific parts.  all kinds of carb stuff there.

[X-Ray]

I have my carbs in pieces at the moment giving them a good clean out (clogged jets make the FJ unhappy). With the float pins they definatley should not be peened over both ends, only one end should have a "nail head" end, otherwise they would never come out. I use a spring loaded punch to lightly push on the  end of the pin, and the punch "clicks" and drives the pin about halfway out. Grab some fine pliers and carefully twist/pull it out. Watch those aluminium float towers, hammer or push too hard and they will snap right off, new carb body time if that happens.

With the pins I always give them a shine with some emery paper with a bit of wd40 as lube, and push them back in carefully. Good luck, carbs are actually fun to tear apart etc.
Here's something I found out, Yamaha Carb Cleaner is great for soaking all the brass jets, emulsion tubes etc in. They come out clean and shiny, same for the float arms after only 2 hours soak. Still have to do the carb bodies yet.

[racerrad8]

Is the float stiff on the pivot pin or is the damper plunger of the needle stuck?

Take a photo, you are describing both gravity and fuel version inlet carbs. The gravity feed carbs require dual inlets as the center carbs are not machined to flow fuel between them.

Randy - RPM

[X-Ray]

I'm reading it as pivot pin drag Randy.

[racerrad8]

That's why I want to confirm. The bounce comes from the spring loaded needle damper.

Randy - RPM

[balky1]

That's why I want to confirm. The bounce comes from the spring loaded needle damper.

Randy - RPM

And that's why I think it's the needle he's talking about. 

[Tor-King]

As others have mentioned, take special precaution when removing the float pins.  Be sure to support the aluminum posts when tapping out the pin.  Place a socket on the opposite side to support.  The pin can then be tapped through the socket.

Dean

[cjard]

Having let the carb sit open for a couple of days, the float is now really stiff. I did a video here:

https://vimeo.com/217882460
Password to watch: fjowners

It's now so stiff it will hold itself up and needs pushing wih a finger. Perhaps whatever petrol was providing a bit of lube has evaporated.. There is no spring clip on the tang for this carb (removed by me, to check whether it was the float hinge pin or needle valve that was stiff)

Re getting the pin out, there's one end that is an obvious nail head, the other end on this particular pin looks a bit mashed, you can see that the pin end is short of egg shaped in the circular recess of the aluminium post. I suspect someone has had a go at getting this pin out before and mangled the end.

I think for his pin I'll need to carefully drill a little way down the pin to remove that knackered end. This should then allow me to use a screw as a punch. As well as supporting the lower alu post with a socket, I think I should cut a bit of bar that fits exactly between the posts; don't want to bend the upper one as I drive it down, and I also don't want to rely on the float metal to support the alu post as it needs to fit well without binding on the posts, so I need a support that is a fraction longer than the float hinge


Looking at the broken T piece fuel adaptor I can see now it has actually had quite a clever repair; someone has clearly broken it before, than tapped it out with what looks like an M6x1.25 tap, died the broken stem and screwed them back together wih PTFE tape. It's the new thinner wall of the died section that has broken off as I pulled the fuel pipe off. At a guess, someone has had these carbs in bits before, possibly unsuccessfully releasing the float pin of this carb

[racerrad8]

Ok, so from looking at the video the end of the float pin that you will be removing (The side you will be using the punch on) is not too damaged. We have removed much, much worse very easily. As far as being mushroomed over and damaged it is not bad at all. Use a self centering punch and knock them out. Also, the pin is not held in on that side. The opposite side with the larger head is actually a bit larger where it sits in the casting of the post.(Approximately 2.55mm compared to the 2.45mm of the rest of the pin.) If you do not have a self centering punch you will need to be very careful using a punch and hammer as those posts are very easy to break.

Robert - RPM

[FJ_Hooligan]

I think you need to measure the float level.  The float tangs I've seen usually have more angle to them.

Also, if you push down on the float is it in contact with the carb body?  When you tweaked the other 3, it looked like they banged hard against the carb body and stayed there.  Again, in my experience this is an indication that the floats are too high.  Or, the needle springs are weak.  Even upside down like you were videoing, the needle spring should not collapse under the weight of the float.  It's been a while so hopefully I'm remembering this correctly.

I'm sure someone will chime in if I'm off track.

On a note more related to your topic, whenever I remove a float pivot pin, I hit it with 600 grit to clean it up.  Also, on reassembly I don't seat the pin all the way flush with the post on the nail head side.  I leave a small gap that I can get a knife edge behind to pry the pin out next time.  This is way more gentle than using a punch.  In 32 years I've never had a pin back out.  If you notice the shape of the float bowl, it kind of wraps around the pin and won't let the pin back all the way out.

Good luck.