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Triumph 3sw Amal Jet


jenkinov

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my triumph 3sw is fitted with a Amal 75-145 carburettor and a 1AK float chamber , the needle jet is an Amal 150 but has fractured ..I have looked at the Amal website and the 75 carburettor is a discontinued model . Needle jets are listed but these are a different shape and don't go up to 150 .

 

So the Question is does anyone have a 75 150 needle jet The Amal is needle is 4.9cm long has a small hexagonal base 6mm long and 6mm wide a large hexagonal base for 2.4 cm long 8cm wide (3cm total to this point)and then a circular shaft 1.9cm long and 4.5mm wide .total 4.9cm..brass finish Amal 150 ..

 

help greatly appreciated .

 

Jenkinov

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Jenk I don't know what you have fitted. But My 3SW/5SW spec quotes a 107 needle jet with a 120 main jet. But I'm sure Martyn Bratby will be able to help you with new parts. Phone him on 01543 572583 and mention my name (Ron Pier). If he doesn't answer, keep trying as he might be on his lathe/mill etc.

 

It's also possible that you could fit a bigger main jet as they seemed to straggle these bikes in the name of fuel economy, but again ask Martyn. Ron

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Thanks Ron ...I will give him a ring and hopefully get sorted ..

 

The jet is a 150 amal but when it was fitted is any ones guess ..but it may as you suggest have been fitted to get some more fuel in the system ..

Jenkinov

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Jenkinov, Amal needle jets of this period are always around the 105 - 109 area (although many state simply 'standard', whatever that was...)

 

However, based on your dimensions, I'm pretty sure that you haven't yet unscrewed the small main jet from the bottom of the needle jet. Your main may well be a 150 but the needle jet is likely to have a light size marking too. On some, these were engraved as it was only after flow testing that they were sized.

 

This picture shows a late-war stainless steel needle jet and what is probably a post-war part (I'm not sure if it's 'pattern' or if Amal simply reduced their machining operations at some point).

 

P5151186_zpsrjslr6na.jpg

 

You can see how the main jet unscrews and as well as the '170' marking on that part, you can just see an upside down '107' on the needle jet portion of the brass jet.

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Hi Guy good site mate, I've been looking for a float tickler for the 16H with no luck but looks like they might have it once I've check the model number of my carb.

 

Ian , if you don't find the bit for you 16H I have a box of carb spares ;-)

 

Guy

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79x100 thanks for the photos my jet is the brass unit at the bottom of the photo..the diagram showed a 2 part jet but the jets so mucky that we could not see a separation and I assumed it was some wartime one piece jet..

 

I have found the 150 stamp on the main jet but no visible stamping on the needle jet yet...but I will clean it more and see what I find.

 

I am contacting Ron's contact to try and secure the correct jets..

 

Jenkinov

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Caught up with Martyn Bratby who clearly has a wealth of knowledge on carbs, his literature suggests the 3sw should have a 120 main jet and a 106 needle Jet ..He also identified my 1AK float chamber may not be the correct match and i need to test if it is vertical when fitted ..

 

 

Ron , Can i ask what chamber is on your 3sw

 

mine does tend to flood and clearly needs checking...

 

Update to follow

 

Jenkinov

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Jenk unfortunately I can't see the number on my float chamber without removing it. But it really makes no difference as long as it's a vertical float bowl. There are all sorts of angled bowls for OHV bikes, but in your case it should be without any angle on the banjo fitting.

My workshop manual quotes a 107 needle jet with a 120 main jet fitted to it. Unfortunately my 3SW parts list only quotes Triumph number.....Which mean nothing to me!! Ron

3SW 052.jpg

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