Hitchcocks Forum

Once again this is about my 1953 Model G, a 350 single. Previous owner fitted a Concentric 626/300 for some reason, and I have never had the original 276 carburettor. The concentric isn't and never will be or look original. However, with a home made spacer (to make the wires clear the tank) and a pancake filter it looks ok, and has served me well for many years. .-.-.-.-.-.-.-.- A while ago I bought from Hitchcocks an original 276 body in good shape, with the extra long neck needed on my engine. I also have the original air filter. It is mainly a matter of getting the small parts inside the carb to make it complete, and they are all available. .-.-.-.-.-.-.-.- Question is: Is it worth the money and effort to rebuild this 276 carb to fully serviceable condition and put it back with the big box air filter instead of the concentric with the pancake filter? .-.-.-.-.-.-.-.- Will this affect performance, petrol consumption, idle or starting in any way? And if so, to the better or to the worse? .-.-.-.-.-.-.-.- The bike is really running well now, and in the end that is more important to me than the original appearance. I will not do it if starting, performance or anything may suffer. .-.-.-.-.-.-.-.- Thankful for any shared experience or qualified thoughts on this one! .-.-.-.-.-.-.-.- Regards, Anders F. R.

I set up a long throated 276 for my old 51 Bullet. It had a 376 but it looked wrong so I assemble the 276 with some difficulty. The carb ended up working beautifully but there was a bit of shagging around. The big problem with the old 276's particularly the ones that have been assembled out of bits is that the jet block appears to fit in the body tightly but there isn't an airtight joint between the the drillings between the body and the block. Generally what seems to happen is that the bottom nut is over tightened and it crimps the bottom edge giving the appearance of a good fit. The effect of this is that the carb will run very rich and the air screw will have almost no effect. The cure involves restoring the body bore to parallel by scraping it out at the bottom and fitting the jet block with engineers blue . It can be shimmed over with paper so that the airways are a tight fit and this makes it all work nicely. There is a chance that your body will be fine but testing it before you start could save you a lot of grief.

Yesterday I had to get an AJS started for a bloke who had recently bought it and couldn't get it started. He had bought it from somebody who had picked it up from a deceased estate so nobody had any idea as to when it was last started. I got it started but as I told him when I first looked at it that the 276 would most likely be the cause of problems if there was going to be any. For starters it doesn't leak, bonus, but I have to keep blipping the throttle to keep it running. I have the carb sitting here at the moment contemplating what I should do with it to see if I can get it to work properly. Any tips apart from fitting a Monoblock because every ones keeps telling me to mount it on a stand and sit it on a shelf so I can admire it?lol

Read my post Norm, This issue was discovered by a mate of mine who has 29's and 289's and 276's all working perfectly. Wipe a bit of engineer's blue onto the jet block and see where it touches the inside of the body. The big bottom nut when over tightened over years has the effect of belling the body. If the air screw has no effect then that is job number one. The next thing to do if you are deadly serious is to resleeve the carb in brass. It's actually easier than it looks but is a time heavy activity no doubt.