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By laganbailey

I have a question about my 376 Amal carb. currently residing in my 1955 Velocette MAC 350.

I have two carbs both 376/48. The newer carb was bought new from Amal and ran fine until the pilot jet became gummed up and I had to drill it out and re-tap (2BA) to accept a new jet. Unfortunately, it never idled properly afterwards as the drilled hole was off centre and allows unmetered air in. This carb still runs fine off idle (1/4-full throttle).
In an attempt to fix this I bought a used body and transferred over everything including jet block and slide. This carb idles nicely but will not run. It's very lumpy and will not rev cleanly.
I bought one of Amal's recon kits in desperation, but that made no difference - good idle but poor running performance.
Reinstalling the original carb and everything was back as before - poor idle and good running performance.

What's going on? Any ideas?
By RoSy
The carb is an instrument and a very clever instrument that is designed to do a specific job, it's also very adjustable to suit certain conditions so drilling and tapping the pilot jet is questionable. Did you think that was really a good idea? if you needed to clean the jets there are cleaning needles for this purpose.

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