Forum

[Mark M]

I'm not suggesting that a 107 will definitely work but for the small sum involved it's worth a go. I've got a spare you can have if you want!

REgards, Mark

[Bullet Whisperer]

Pilot jet - don't forget the pilot jet! If it is a 20, try a 25 and if it is a 25, try a 30.

[Dennis C]

Checking wear is quite easy, if you can move the slide back and forth with your finger the carb is worn just lift it off the stop when you test it, pull the slide right up and try again if the movement is less then the body is worn, there are a few people who can rebore the body and sleeve the slide which is cheaper than a new carb.

[Adrian]

...or forget about the Amal completely and go for a nice compact JRC flat slide Amal replacement.



http://brillbikeparts.co.uk/index.html



A.

[Bullet Whisperer]

For those who slate Amals, here are two of them working perfectly on a BSA A65 ... https://www.youtube.com/watch?v=Oe6ymdn3q-w

[Rattlebattle]

Hmmm. Back in the day I owned an A65L (a bike that many people used to slate though I never touched the bottom end, just changed the oil regularly). All I can say is that the concentrics on that were easily tuned and lasted over 20,000 miles, after which I sold the bike. Same applied to a T140V I owned for 13 years. I used two lengths of brazing rod to get perfect synchronisation of the slides, as verifed when I bought a mercury Carbtune to service a Moto Guzzi I got later on. I don't claim that Amals are the best carbs ever, but I do feel that in part their reputation arises from inexpert fiddling with worn out ones (and I accept that they don't last long unless you get a better slide). Both the new concentric on my C5 and the new (when fitted) monobloc on my Tiger 100 work faultlessly, without any hint of a flat spot. Would that some of the EFI bikes I've owned did the same as delivered from the factory. The only one that did so that I've owned was a Honda Deauville NTV700, which fuelled perfectly.

[Scalyback]

It will be 5 days until I can check that out, (go back to France 18th.) So I should check for slide wear when not resting on throttle stop, and try 107 needle and the next size pilot jet up, and see what works best. If the amal is worn, then I will have to check for repairs (being in France).



I guess the pilot jet and needle are as per book, the main jet was and that caused problems until swapped from a 250 to a 230, which cured the full throttle problems.

[simon]

I have no problem with Amal carbs although they did start to make them rather flimsy in the later years and people would over tighten them and put them out of shape. I faffed around for ages getting the 1 1/8" 389 to work on my 350 Bullet but in the end with the right pilot jet it works a treat. Having more of an issue with a 930 concentric on my B44 but that too will I'm sure finally succumb to endless fiddling and copious profanity.

[Rattlebattle]

Yes, over-tightening is a definite no-no. It can cause the slide to stick open......IIRC the original Amal company stopped making carbs several years ago. The drawings etc were bought by Burlen who introduced long obsolete carbs like the 276/289 series for those of us who own classic bikes and want the correct period carb(s). There is also the Wassell concentric; without checking I'm not sure which concentric this is based on (mk 1 or "1.5", the latter with no tickler). FWIW I went to the Brackley Festival of Motorcycling yesterday. A brilliant day out at which the roads are closed and classic machinery is paraded (read raced) unsilenced around the track. Plenty of Amals working nicely there, oh, and some superb Honda 4s and MV 3s and 4s as well as Norton rotaries and some more modern stuff. Scramblers too. Well worth going to.