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Hi all,

Have an issue with my slides sticking after a highway run. They were scored inside the slide bores but have since lightly wet and dried them smooth, like wise with the slide itself. They worked fine when re assembled. After a good run on the road, they near enough seize I their bore. These are rubber mounted to the head. Have no clue why this is happening. Anyone with similar problems and can offer some advice?

Cheers,
 

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Mine stick up if I am riding in the rain, all I do is blip the throttle to 'crack' the stick and then they are OK. They only do it in the rain and if I have been sitting on one throttle position for a while. If I am riding in town where you are moving up and down the throttle range they don't do it.
 

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Hi all,

Have an issue with my slides sticking after a highway run. They were scored inside the slide bores but have since lightly wet and dried them smooth, like wise with the slide itself. They worked fine when re assembled. After a good run on the road, they near enough seize I their bore. These are rubber mounted to the head. Have no clue why this is happening. Anyone with similar problems and can offer some advice?

Cheers,
Sad news is, Amal carbs are cast with pot metal. And the slides do actually wear out. Once they have scored inside bore, a lot of times the tolerances come out of spec. Thus, the slide will will get cocked at an angle, causing it to stick. If you wet sanded it, it will be be even more out of spec now. Hate to say it, but it's time to replace the carb.

Keep, in mind, there is another cause to a sticking slide on Amals, as well. If you over-torque the mounting flange, that will pull the bore out of round, also causing a slide to stick. Either of these cases will need the carb replaced. There is no refurbishing for such failures.
 

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Thanks gents, I feared as much.

Might be opening a can of worms here but what carb options do you have for the t140? Surely a decent Jap brand would work from a retro bike or similar?
 

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Thanks gents, I feared as much.

Might be opening a can of worms here but what carb options do you have for the t140? Surely a decent Jap brand would work from a retro bike or similar?
Lots of people will convert to a Mikuni TM flat slide carb for better performance. But, Amal carbs are still available as well for about $200.
 

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there were a few shops doing rebores on Amal- Lund i believe was one , the'd turn down the slide and resleeve it along with clean up the bore in the carb. had a set of 932's done with pretty amazing results -there is a trick invloving an anvil and a large hammer to 'straighten' the carb but i think new carbs would be a better option though -
 

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New carbs are quite cheap, considering.
If the bodies are ok then new slides is an option. Mine are brass
 

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Sad news is, Amal carbs are cast with pot metal. And the slides do actually wear out. Once they have scored inside bore, a lot of times the tolerances come out of spec. Thus, the slide will will get cocked at an angle, causing it to stick. If you wet sanded it, it will be be even more out of spec now. Hate to say it, but it's time to replace the carb.

Keep, in mind, there is another cause to a sticking slide on Amals, as well. If you over-torque the mounting flange, that will pull the bore out of round, also causing a slide to stick. Either of these cases will need the carb replaced. There is no refurbishing for such failures.
Hi
The mk1 Amal Concentric carb was cast in poor metal, but these are the Mk2 Amal Concentric and cast in much better material, these are reasonably long lasting.
There is no flange mount to overtighten and distort the carb as they are rubber mounted. Generally they do not suffer from sticking, but the should not be scored, are your air filters/airbox sealing properly?
If the slides do not stick when cold but are very tight when hot, I would have thought there was a heat expansion problem.
Can you think back to when this started happening, to see if anything was done to the bike just prior to this problem starting.
I think I might be inclined to try swapping the slides left to right, just in case they were mixed up at sometime.
You could try coating the slides with engineers blue or felt tip, then lifting and dropping the slides several times with the fuel off so the marker is not washed off.
Then try again with the engine hot but not running.
Perhaps this will highlight any high/rubbing spots.

FWIW, The Mikuni carb was built under license from the Amal design.
The Mikuni carb works well once set up properly but it can be a little awkward to get right,a couple of land speed racers on the forum have had good results with them.
The new premier mk1 carb is made from good metal, so should be A long lasting carburettor now.
 

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Lots of people will convert to a Mikuni TM flat slide carb for better performance. But, Amal carbs are still available as well for about $200.
I would not say alot but some...More use the VM roundslide..I converted my T140 to 32mm Mikuni TM flat slides...They do fit and and are more compact the MK2's.. However,as they come from the box they need jetting changes to the pilot, needle jet and needle and the main jet...If you don't have the patience or skill you may want to stay away...Once jetted properly,the Mikuni TM performs better than any Amal...If interested,I can give you the jetting sizes that should work...TM flat slides are about $135-$150 each on ebay..And expect to spend $60 more on jetting
 

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As RPW said, the carbies are rubber mounted plus the metal used for the carb body is heaps better and lastly the slides are usually black anodised as well. So no real reason for distortion or excessive wear [unless they are very high mileage, abused, or run on dusty roads with no air cleaner etc].
BTW, I am not the only person who has sticking slides in the rain, other owners I have met also have had this issue - but not every owner.
As I said, the best way to fix it is to get into the habit of blipping the throttle to 'crack the seal' and then your carbies work fine.
This may not work on all Mk II Amals……...but it works on mine.
 

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And over tightening the nuts can cause the bind / sticking issues...over tightening distorts the flange on the carb....lucky me i have never had mine stick in the rain..i've owned the 63 Bonnie since late 63.
 
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