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Discussion Starter · #1 · (Edited)
Hi guys,

Got an issue here after refitting my carbs back on. Put fuel into the Aux tank (kept main tank off as I want to resync) and pump got fuel into carb.

So pressing Starter resulted (after a number of presses to get fuel through pipes) in some coughing. I heard a trickle and looked down and saw fuel coming out of the air joint pipe outflow tube onto floor, this cannot be good!

Looking for causes and solutions please. I'm confused as I am sure I put everything back together perfectly, but something's amiss.

Could it be:

I hadn't opened the throttle to allow fuel through into engine causing a backup of fuel to go out of the pipe?

Could it be I haven't oriented the sliders within the chamber correctly? (but I did allign the rubber gasket correctly and didn't dismantle the needle at all, it stayed attached to the slider unit, only the spring was loose).

Could it be fuel bowls over filling?




Any suggestions would be greatly appreciated!

Oh yeh, I ran out of battery juice so charging overnight.

Also, could it be I just didn't try long enough and eventually it would have worked?
 

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Discussion Starter · #3 ·
My guess is inlet valve is stuck open (commonly refered to as Floats")

Did you adjust the float level according to specs?
Wow super fast reply Cap'n :)

This might be it and would make sense. I wanted (in my amateur mind) to make the bike a tad richer so slightly bent the tang up on the floats, does this sound likely to cause my prob? I thought I'd stayed within specs yeh, guess not.
 

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It is possibly the fact, that you caused this, with "adjusting" / "bent the tang"

In maintenance I had to log my work for the day, I refrained from using the word bent==> I adjusted... :D
 

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Discussion Starter · #6 ·
It is possibly the fact, that you caused this, with "adjusting" / "bent the tang"

In maintenance I had to log my work for the day, I refrained from using the word bent==> I adjusted... :D

There's a word we use over here which probably means nothing much to most of you guys and that word is...bollocks! lol (aimed at myself for being too clever :( )

Ok, I'll dismantle the bowls tomorrow and adjust (I am learning techno lingo too :D) the tang back to its original state...I hope.

So basically then, the valve thingy (not quite a pro ) just isn't shutting off you think and causing a backup of fuel?
 

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Like Capt said, Sounds like float needle is not closing due to being out of adjustment. That isn't how you richen your mix. Set your float height per the manual and adjust your mix with the a/f screws. If any further adjustment is needed, you'd have to rejet. If it's not liquid tight, it's not air tight. Also, check your oil for a gasoline smell. Depending on how long you messed with it, you may have put fuel into the crankcase.
 

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Discussion Starter · #8 · (Edited)
Like Capt said, Sounds like float needle is not closing due to being out of adjustment. That isn't how you richen your mix. Set your float height per the manual and adjust your mix with the a/f screws. If any further adjustment is needed, you'd have to rejet. Also get your clamps tight on the rubber. If it's not liquid tight, it's not air tight. Also, check your oil for a gasoline smell. Depending on how long you messed with it, you may have put fuel into the crankcase.

Oh no, it gets worse lol.

Bah!

It's dark now here in the land of the idiots and what with my battery needing a charge I won't really be able to try again until tomorrow. First thing I'll do is sort that tang out!

I'm think, since I left the main tank off, I just might be able to take the cover off the bowl and adjust with carbs still on the bike. Would rather not take it off again and unattach the lines etc, if only for speed reasons. I think I can reach the floats ok.

Yes...I've had a think and I'm now sure it is the tangs.
 

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Don`t beat yourself up, we ALL make blunders...
Yeah, retighten the clamps on those "boots" too..
Insulators is what the book calls those rubber hose like connectors from carb to engine... I call them boots ;)

It`s still raining!
 

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Discussion Starter · #10 ·
Don`t beat yourself up, we ALL make blunders...
Yeah, retighten the clamps on those "boots" too..
Insulators is what the book calls those rubber hose like connectors from carb to engine... I call them boots ;)

It`s still raining!
Boots is good, I've started to call'em boots too. I honestly thought people meant for your feet a few years ago when reading stuff.

Just had a quick looks at the carbs, they'll have to come off unfortunately as I cannot reach the screws while they're on but hey, as you say, it's all learning. As for my evening I've gone and bought some cider, but you can bet it hasn't seen an apple in its life hehe.

An interesting tale I have for you from my cider buyings. I bought my cider and passed by a fellow tucking into the pick and mix sweets/candys, munch munch! He hardly spoke english but I tried to point out they weren't for free and he just mumbled back with a mouthful "Oh, no free!?". So I told an employee who just stood there and didn't do anything, I now wish I'd gone back to this guy chewing away and helped myself too lol :)
 

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Amal carburetors are installed on most British bikes from the factory. Been that way for decades. Just recently the floats have been made of molded plastic instead of the usual soldered brass. I guess I got hold of an early post-revision one on my BSA because for whatever reason it leaked. They are not adjustable either. Best I can tell is that the hinge pin hole is too tight and it doesn't float, but remains down with the valve open, flooding. I installed a new one which works but kept the bad one to run a slightly larger drill through if I have to reuse it some time.
 

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Discussion Starter · #12 · (Edited)
Added a vid
Amal carburetors are installed on most British bikes from the factory. Been that way for decades. Just recently the floats have been made of molded plastic instead of the usual soldered brass. I guess I got hold of an early post-revision one on my BSA because for whatever reason it leaked. They are not adjustable either. Best I can tell is that the hinge pin hole is too tight and it doesn't float, but remains down with the valve open, flooding. I installed a new one which works but kept the bad one to run a slightly larger drill through if I have to reuse it some time.
Now this is a coincidence, I just saw a You Tube vid earlier about a fella from North America talking about how to solve certain carb float stuff with Brit carbs and pieces. I'll see if I can track it down again and post here for interests.

Edit:

Dunno if this'll help :-

https://www.youtube.com/watch?v=Z6Le_HkrkKQ
 

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Discussion Starter · #13 ·
Problem solved...yay :)

I bit the bullet and got stuck in this morning, bent the tang back and everything was groovy!

I took the bike out for a test ride and it started up great from cold, but I'm sure it's still running lean even after tweaking the A/F screws. Going for a "burst" it really wants to cough and splutter, but applying choke makes it much better which would mean it's running lean wouldn't it?

I have a K&N filter in and have read that people often need to increase main jet afterwards, anyone think this may help?
 

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If all you did was add the K&N filter, rejetting isn't necessary. Keep tweeking your a/f screws until you get it right. If all is stock, it should run good as is.
 

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Discussion Starter · #15 ·
If all you did was add the K&N filter, rejetting isn't necessary. Keep tweeking your a/f screws until you get it right. If all is stock, it should run good as is.

Well thing is, I keep reading 3 full turns out is a lot if not too much, when I get to 4 or 5 turns things do improve so when measured against what I've read about 3 being a lot, 4 or 5 seems massive and kinda as though there's a prob somewhere.
 

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I dunno, Jack. Usually beyond 3 1/2 turns or so, there isn't much thread in the carb and little spring pressure. With the age of your bike and all, hard telling what's been done by POs. If the bike is running well where you have it and you still have spring pressure on the screws, put a little blob of silicone on the head of the a/f screws to keep them from vibrating out and run the old girl. After you ride it a bit, pull and check your spark plugs. If things look good, don't look a gift horse in the mouth and ride, baby, ride! Also, if you haven't been already, run some fuel treated with seafoam through it.
 

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Discussion Starter · #17 ·
I dunno, Jack. Usually beyond 3 1/2 turns or so, there isn't much thread in the carb and little spring pressure. With the age of your bike and all, hard telling what's been done by POs. If the bike is running well where you have it and you still have spring pressure on the screws, put a little blob of silicone on the head of the a/f screws to keep them from vibrating out and run the old girl. After you ride it a bit, pull and check your spark plugs. If things look good, don't look a gift horse in the mouth and ride, baby, ride! Also, if you haven't been already, run some fuel treated with seafoam through it.

I like the silicone idea, may give it a shot!

I'm gonna buy a vernier gauge to measure the float height, since I kinda know what I'm doing with taking it all apart I'll double check everything in a week or two.

Think it's time I bought a whole host of gear actually, I'm forever needing a tool of some sort.
 

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I like the silicone idea, may give it a shot!

I'm gonna buy a vernier gauge to measure the float height, since I kinda know what I'm doing with taking it all apart I'll double check everything in a week or two.

Think it's time I bought a whole host of gear actually, I'm forever needing a tool of some sort.
Just buy them as you need them. No point in going for broke right out of the gate. The float height really should be set to factory specs as per your manual. In the meantime, keep an eye on your oil, so you don't wash your cylinders because of float needle not closing.
 

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Discussion Starter · #19 ·
Just buy them as you need them. No point in going for broke right out of the gate. The float height really should be set to factory specs as per your manual. In the meantime, keep an eye on your oil, so you don't wash your cylinders because of float needle not closing.
Good point about the oil, hadn't realised that so thanks for the heads up!

I've had an idea for the awkward throttle stop screw under the tank. I've thought about trying a small "cog" of some sort on top of the screw, using Locktite or something to fix it in place, then using another cog rotated against the one on the screw, it should turn and you should be able to attack it from the side easier rather than a higher angle. I've been having a heck of a time reaching it, even with the tank off and using the spanner for it. If ever I do it I'll report my progress hehe :)
 

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Discussion Starter · #20 ·
Just got another quick question.

Had I fully turned each A/F screw fully in on each carb when the overflow had started, would that have controlled the excessive fuel and maybe stopped the overflow?
 
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