376 Setup

[Mosin]

Hi,

Well my 1960 A7SS is now back up and running after a year off the road due to serious "enjine issues". I have treated it to a brand new Amal 376 carb which was set up at the factory as per the recommended settings for my bike (jet size etc etc). I have fitted it on the bike and it is running, but tick-over is way too fast (adjuster screw doesn't seem to slow it down much) and it is also running a bit rich (plugs sooting up).

The "How to tune up" instructions which came from Amal with the carb are so badly written that they are pretty much illegible. I can only assume that they were written by someone who didn't speak English and didn't know what a carb actually was or did, but was possessed of a sadistic streak and took great and perverse pleasure in confusing classic bike lovers!

In the light of this, I was wondering if anyone had ever come across, or written, a basic step by step guide to tuning up a carb from scratch? 

I am also very mindful that the engine has just been rebuilt and has not been run in yet, so I am not wanting to do anything which is going to send the revs sky-high and potentially cause any damage.

Thanks in anticipation.

Simon

[Triton Thrasher]

Google Bushman Amal.

[morris]

Hi Simon,

I recently installed a new 389 which also came with the "correct" jetting set up.
After installing it the bike was very reluctant to fire, and just when I was about to give up, it finally fired, but was running very irregular, and I couldn't get a decent idle
I went out and got myself 2 pilot jets, one a size bigger and one a size smaller, and after some experimenting, the smaller size went best, and is still in doing a perfect job.
I also needed to experiment a bit with the needle height, because at 1/2 to full throttle it was running to lean. I ended up with the needle in 5th from top. I didn't like it to much that way, so I was about to change main jet to a bigger one, but I found that gradually things where improving, as last time when I inspected the plugs, they where a bit sooty so I dropped the needle a notch. Took it for a long drive this afternoon, and it's behaving perfectly now.
It seems that a new carb needs some "running in". Mine certainly does, because it gets better with every mile I'm doing!