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#869274 01/16/22 8:34 pm
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Hi guys. I am working on my new (to me,lol) 1969 T120R. While cleaning the carbs and looking at a lot of on-line suppliers, I noticed that many Amals have a float bowl drain plug. This seems like a great idea, but mine of course do not have any. Has anybody ever tried to add one by drilling and tapping a hole in the bottom of the bowl? I've searched but found nothing. Thanks!


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DOPE
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you can buy em on ebay for not much money. look for junk AMAL parts

https://www.ebay.com/itm/153713637350?hash=item23ca0bf7e6:g:YTIAAOSw8Mtdwvq6

https://www.ebay.com/itm/224328269473?hash=item343b01bea1:g:5YAAAOSwvtNgDxPD

then just flatten the flange with emery paper on a piece of glass

Last edited by kevin; 01/16/22 10:43 pm.

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Why bother? Just one more place for a fuel seep from. I have bikes with both the earlier (no drain) and later (drain) and prefer the earlier type. (I live in a dry place, so seldom have any need to need to drain the float bowl.) The drain does allow you to change main jets without removing the float bowl, assuming the jet unscrews before the jet holder does, but once you get it right you probably won't be changing the main jet very often unless you intended to go touring and will be riding at much different altitudes. Just my opinion...


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Hi Sandy, If you have original ticklers, they can take in water mostly parked in rain. Rain water runs down throttle cable too.

I find the plugs are handy in that case.

Drilling bowls for screws I don’t know how thick that are for threads & the flat spot for seal.

Should you purchase used bowls with drains, the float level can be different for different years measuring from bowl gasket surface. Yet liquid level will be the same for all years.

However I would carefully evaluate carbs before putting much money into old carbs. If slide bores are worn I advise new AMAL premier carbs. They work very well & last very, very long.

Another however if you still have original floats & needles, they tend to deteriorate with modern fuel leading to flooding & overflowing fuel, which can lead to bike fire. I had that happen to me.
Don


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yes. ebay carbs are trash.

i need to clarify that i was talking about float bowls only

Last edited by kevin; 01/17/22 3:08 am.

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Hi, I forgot to mention use AMAL stay up floats & viton tip aluminum needles. Both lasts for years. Simply bend float arms to set float level. AMAL recommends that. I’ve done it many times. Of course new Premier comes with all this.
Don


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Originally Posted by kevin
yes. Amal carbs are trash.

i need to clarify that i was talking about float bowls only
There, I fixed it for you, lol


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Thanks for the ideas, guys. The reason that I was contemplating a drain screw is that I live where I can't ride for several months each year due to winter weather. On my other carbureted bike I drain the gas when putting it up, and it would be much simpler to remove a screw than the float bowl on the AMAL. However, it isn't an major problem, just something that I thought others might have done for similar reasons.

Anyway, if these old carbs give me too much trouble, they WILL get replaced!

Thanks again.


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Hi Sandy, I find even thin zinc does well with a smaller fine thread. 3-48 comes to mind. Then thread 3/32 fiber washer on it. I’d start by seeing what sealing washers are available.

Drains would sure be handy for your needs.

There are lots of used bowls around with drains.

You can always set float level by heating bowl & knocking brass needle seat.

I remember well the non drain bowls. By time you deal with banjos & all on Bonnie removing bowls becomes a bit more time consuming. If gasket splits, they are not cheap.

I think adding drains is good idea.


What if you drilled & tapped them. If it doesn’t work, then get used ones.

Here’s a reliable way to test slide/bore wear. Summer weather more accurate, but bad wear will show at 40f.

Do a perfect tune up on bike. Valve adjustment, service points if used. Set timing. Set idle speed & mixture. You have too fast of idle like 1200+ this test is not reliable.

Road test bike until heat soaked. About 30+ miles.

Again idle rpm matters. 950-1000 is good.


Motor is heat soaked. Ride bike 1/2 mile or so on easy riding road 25-40 mph.

Pull ta stop. Put in neutral. Bike is idling. Now very, very slowly give throttle. As slow as you can turn it.

If… you have undo wear motor will reliable falter & die, or try to die. This will be just off idle. If you twist throttle fairly quickly you can reliable pass the dead spot.

Practice this, finding dead spot with slow turning. Then passing it up with quicker turning. Do this on a few road tests. We don’t want false fail!

Now you can feel the dead spot while riding now that you know. But momentum of bike keeps motor running until you pass dead spot.

Also teasing clutch moving up a few feet at stop light motor will tend to stall. You end up giving motor gas than needed to prevent stalling. You don’t even realize this until you pay close attention. Getting new carb is a revelation on this.

A not worn out carb no matter how slow you turn throttle the motor never falters or looses any rpm at all. The rpm just increases no matter how slow you turn. You cannot find a dead spot.

Partly worn carb, rpm falters or dips, but you can’t make motor die no matter how slow you turn.

If motor almost dies, or it falters enough to scare or worry me I replace carb(s). If it just dips a little I reuse carb. I may even consider replacing slide.

On a carb that falters enough to scare me, but owner doesn’t want new carb yet, I’ll not do slide, but will definitely install stay up float kit.

Maybe when the snow clears enough you can give this a try.
Don


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Don, thanks for the thoughtful input. It's 5 deg. F outside just now, so it will be a while before I can do that off-idle test. I have never heard of this way to determine if the slides have too much clearance, although I was aware of the issue. My bike shows 9800 miles on it, but who knows if that is accurate. I did reset the float height (what a pain) and clean them already, and both the slides and the body show a little wear, but I thought that they were usable. We'll see in the spring.

I guess I will wait on the float drains until I find out about the slides. On the drains, I was considering building a raised fitting on the bowls with JB Weld, so that there could be a flat surface to drill and tap. If I decide to try that, I will post my results.

Sandy


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Sandy---might be worth posting on the triples board as a "wanted--float bowls with drain" item.
Reason is that when putting a Madigan electric starter on a T150 there is no room for the drain so people putting an electric starter on have to replace their float bowls with drains with float bowls without drains.
So may well be some bowls with drains knocking around.
HTH

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Originally Posted by Tridentman
Sandy---might be worth posting on the triples board as a "wanted--float bowls with drain" item.
Reason is that when putting a Madigan electric starter on a T150 there is no room for the drain so people putting an electric starter on have to replace their float bowls with drains with float bowls without drains.
So may well be some bowls with drains knocking around.
HTH

Also worth starting a WANTED thread in the Garage Sale Forum....

Cheers,

Steve


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Thanks, kevin. AMAL is certainly proud of their bowls, no? I'd get a set of new ones before I spend that much, lol.

Tridentman, that looks like a possibility. I'll keep that in mind as a source.

Sandy


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Hi Sandy, If Carbs have only 10k miles they’re probably good enough for now. Wait for spring, evaluate then decide.

I don’t know I’d use epoxy to glue on the drain bushing. Very hard to weld zinc. The AMAL drain plugs are costly also.

I know one thing for certain. New Premier cards work well & very durable. Actually worth $200 each.

But I’d run the old ones until they are no longer serviceable.

New slides in worn carb is crap shoot as to effect. Depends on how worn bore is. Twice now I’ve seen new slides want to stick occasionally in worn bore. Snapping throttle frees it.

New slide will wear very quickly in old bore.
Don


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Really, look at the bottom of an old float bowl. With that curved surface, do you really think that you can drill and tap a hole into that and not have it leak?


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Does anyone still bore and sleeve worn out Amals? I used to send out brand new carbs to be bored and sleeved before I put them on. I figured I was going to do it sooner or later so I just got it over with. Have never worn out a sleeved carb and I've got four of them.


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Hi DavidP, Maybe... Depends on how thick the metal is. The key would be to file a flat parallel with bowl gasket surface, slightly smaller than screw head. Then use very small screw. Like a 3-48. Or maybe even a 2-56. Water/gas will run right out a small hole like this. I don't have any old version bowls to test with. My first choice would be 3-48 if possible.

Here's a question. Can you Muggy weld zinc? With zinc rod I mean. If made.

One day at work a tech broke zinc heater lever off heater box on very old Merecedes. Zinc was not deteriorated. Shop foreman was smartest guy I've ever worked with. He took a piece of old lever from a different heater control & used it for filler. He welded the lever back together. He used argon gas from the wire feed welder as a shield. Did it by feel as in Muggy welding as there is not really a visible puddle like in gas welding & not red hot. Never seen anything like it!

So, could you build up metal, drill & tap for a real plug?
Don


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I think the advent of anodised slides has done away to a large extent the re-sleeving guys.
There used to be a guy in Melbourne who used to do them in stainless, i had a set on my
t120 for 20 years and they were great, sill on it when i sold the old thing.

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Hi All, I examined the bore & anodized slide on my premier carb recently. About 10k miles. No visible wear on either bore or slide at 10k miles. Needle as starting to get flat spot. I replaced needle & needle jet. I'd expect well over 40k miles from the slide, bore.

I'm using stock air filter elements & air box. '73 Tiger.
Don


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