Any Tips on How to Remove the Float Bowl Top?

phutton · April 10, 2017, 08:45:08 PM

POR-15 - that's the one I was trying to remember! - You can get it from Frosts.

p.

Tiddler · April 10, 2017, 06:38:53 PM

Yesterday, I spoke with the person who has used molasses to clean the inside of his petrol tank. He confirmed that it worked really well and stripped the inside of his tank back to bare metal with no problems using it at all. He also said that the mollasses and water mixture does not damage the paint finish on the outside of the tank. He left it in the tank to soak in for around 3 weeks then emptied the tank out and then dried it out before lining it. It cost around £10.00 for a gallon of mollasses and is available from agricultural suppliers - I think the farmers put it in cattle feed etc as a supplement. I intend to do my tank sometime and then seal it with POR-15 which seems to get good reviews from those who have used it.
Paul

phutton · April 10, 2017, 05:53:03 PM

I used Frost's tank liner stripper. It works very well, but it will also remove your paint finish! Their tank lining is generally thought to be the best and simplest to use. Some of the others are just about impossible.

P.

Tiddler · April 05, 2017, 06:46:41 PM

Quote from: iansoady on April 05, 2017, 11:02:24 AM
It's quite likely that someone has put sealer in the tank and that's now breaking up. It's a real pain to remove by all accounts.

I hope you're wrong Ian as, if it is the case, the sealant will have been put in the tank over 30 years ago! I looked inside the tank through the filler neck and it doesn't look black in there, more a rusty brown! I have been told today that agricultural molasses diluted 1:10 with water will clean everything out very well and then a modern sealant can be used. Apparently the molasses has the same active ingredient as Coca Cola.

iansoady · April 05, 2017, 11:02:24 AM

It's quite likely that someone has put sealer in the tank and that's now breaking up. It's a real pain to remove by all accounts.

Tiddler · April 04, 2017, 07:25:13 PM

Well. I tried to start the bike the other day - no go! There was no fuel coming through when I operated the "tickler" so I disconnected the pipes between the petrol taps and the float bowl only to find that NO FUEL was coming out of the taps. Further investigation revealed that the fuel filters on the petrol tank end of the taps were blocked by that horrible bitumen type sludge which had been at the bottom of the float bowl. (photo attached) This sludge had also gone all the way through the taps too.
After I cleaned both filters and the inside of the tank I reconnected everything, put 5 litres of fresh 97 octane petrol in the tank and two kicks later the bike roared into life and idled very nicely with no overflowing of the petrol as before. YIPPEE! (I've also attached a photo of the bike)
Sorry the photos are a bit big, I don't know how to make them smaller?

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Tiddler · March 27, 2017, 08:28:42 PM

I have refitted the carb but not started the engine yet. I hope to do that tomorrow so fingers and everything else are crossed that all will be well.
Cheers,
Paul

phutton · March 27, 2017, 08:17:38 PM

Top-feed float? I've never looked in one of those, hence my puzzlement. Glad to know you got it sorted!

P.

Tiddler · March 22, 2017, 05:08:17 PM

Quote from: singleminded on March 22, 2017, 10:47:55 AM
Aha you obviously have a top feed float bowl, I was expecting a bottom feed one..
Shake the float, if you hear rattling it make be leaking..john

No rattle and floated on water overnight without problem.
Cheers,
Paul

iansoady · March 22, 2017, 10:58:56 AM

The needle isn't actually attached to the float on the top-feed float chamber but the clip just sits on top of it so it's pushed up to seal. These carbs are easier to lap the seating in than the bottom feed ones.

singleminded · March 22, 2017, 10:47:55 AM

Aha you obviously have a top feed float bowl, I was expecting a bottom feed one..
Shake the float, if you hear rattling it make be leaking..john

Tiddler · March 22, 2017, 10:13:41 AM

Hello Paul,
The float was stuck to the needle with the float also stuck to the goo on the bottom of the float chamber meaning that the assembly could not move and thus control the flow of petrol into the float bowl. This was the cause of the petrol overflowing. The float needle locates in the hole in the bottom of the float bowl to align it with the centre of the float bowl top assembly. The clip ensures that when the float rises with the level of petrol in the float bowl there is a pre-determined distance between the top of the float and the top of the float bowl (on other carburettors the float height is adjustable). The pointed end of the float needle, under upward pressure provided by the float, controls the flow of petrol into the float bowl and maintains a relatively constant level of fuel by blocking or unblocking the fuel input from the petrol tank. In my carburettor, the needle clip fits in a groove around the shaft of the needle and sits on top of the float, this is the method of pre-determining the float height. If the clip were missing, I would just need to fit a new clip - and search for the remnants of the old one!LOL

I have attached a couple of photos to show my, now nice and shiny, float, needle and clip assembly.
Regards to all and thanks for all the advice and input,
Paul

phutton · March 21, 2017, 02:52:24 PM

You say that the float is stuck to the needle? The float should be located on the needle by a clip at the top of the float. The needle does not act as a guide, but closes off the petrol flow when the float rises. If your float doesn't have a clip, you need a new float!

I hope I'm not teaching grandmother here...

Regards

Paul

VicYouel · March 21, 2017, 09:43:38 AM

I have had a couple of bikes that resulted in that nasty black stuff. Both had been petsealed years ago and that substance seems to be carried in suspension by the ethanol effect on petseal. On my triumph twin it even got carried into the engine and caused valves to seize.

Tiddler · March 20, 2017, 08:44:05 PM

Thanks for all the good advice folks. I managed to get the top of the float bowl off this afternoon and found that the float was well and truly stuck to the spindle which is supposed to guide it. Also, the bottom of the float bowl was thickly coated with what I can only describe as a bitumen type substance. So far I have removed as much as I can with one of those coffee stirrers which you can pick up at McDonalds when you eventually succumb to the entreaties of your grandchildren - there has to be a reason to go, doesn't there? Those of you of a gentle disposition should NOT look at the photo of what came out as, doubtless, the innards of your carb will look the same if it has lain undisturbed for a number of years.

Sorry for the poor quality of the image but I guess you will get the gist.
Regards to all,
Paul

iansoady · March 18, 2017, 10:30:07 AM

That little screw you mention actually distorts the thread slightly in order to prevent the top unscrewing accidentally (a bit like a very crude nyloc nut). It's possible it's been distorted too much.

I would try screwing it back in, although leaving it a turn or so back from fully tightened, and tapping it gently which may just restore the thread enough to unscrew it. Failing that, a soak in plus-gas (not wd40) and as singleminded says gentle heat should help. You often find that the central hexagon has been chewed up by overenthusiastic previous owners.....

The 75 series carb is one of the first to use mazac alloy which is pretty rubbish stuff and easily damaged.

singleminded · March 18, 2017, 08:20:47 AM

Usually there is a raised hexagon in the middle oF the lid to get a spanner on.
If that is not there then the only other way i can see is to grip it in a vice or with a large pair of grips,but be careful they are not made out of top grade alloy.
I would heat the main body of the float chamber using rag soaked in boiling water, a flame could be disastrous as it has had fresh petrol in it recently.
If the lid starts to move I would then just gently rock it back and forth slowly increasing the amount of movement.

Tiddler · March 17, 2017, 10:17:10 PM

I have removed the Amal 75 carb from my 250 to see if the float is sticking but I can't get the float bowl top to move at all. I have removed the little screw which goes through the top into the body of the float bowl but nothing moves the top. I assume that since it has a machined rim that the top screws off, is this correct? Is it likely to be just age and dirt which is preventing it from moving or is there something else which I need to take off? I have removed the petrol pipes and the connection to the petrol tank taps and the top of the float bowl. Any help/advice appreciated - or its time for the stillsons!
Regards,
Paul