Hitchcocks Forum

This may be of use to the odd Model G (CO?) owner? Firstly let me say that my model G is my fun bike; it gets me out & about, shopping or down the allotment where it can be seen propped up against the shed - a lot of the parts on it have come from various triumphs I've owned over the years, I 'd like to think that in my eyes its unique, not another one like it! When I got the bike (restoration project) it still had the Amal 276 fitted which sort of still worked. Living with the 276 drove me nuts - so I decided to fit an Amal Concentric. The "inlet manifold" is made from 2 tufnol spacers (from our hosts) and is 1 3/4" long - just long enough for the fuel bowl of the carb to clear the top of the magdyno. 5/16" bscy studs and reduced 5/16" nuts (from a triumph) take care of bolting the carb to the engine. Now for the nitty gritty: I spoke to Amal re my intention of using a concentric and they kindly gave me some baseline settings which I tried using an old 24mm Mk1 from my T90 as a testbed. Happy with the results & after a bit of tweaking I ordered a brand new Mk1 premiere from our hosts (err it was cheaper at the time than directly from Amal!). The finishing touch was fitting a proper air filter (ah that Triumph parts bin of mine) which squeezed in with a few mm to spare & works much better than the 276 tea leaf strainer. For the curious amongst you the carb settings are: 24mm carb, no. 4 slide, 106 needle jet, 130 main jet, needle clip position 2. Best regards, Mark

Hi Marko--- that's looking PDG !!( Pretty Dammed Good ).....What primary jet do you have ??.....I realise this might be awkward to answer as some of the Mk 1 carbs have a pressed-in jet which in normal use you can't get at to see.....Triumph parts indeed !!--I've got two of those "Made in England" stickers on my Bonny !!...

Hi Alan, when I did my experimenting I used an old concentric which had a bush as you mentioned. When I swapped over to the Premier it came fitted with a no 17 pilot as std which is the same size as a 107 pilot bush in the earlier concentrics. Works well. I fear things are not going to remain quiet as I have an itch to give my "G" a little more "oomph" this summer so that might mean playing around with the carb again anyway, for what its worth the carb settings are spot on for a G/CO in standard engine trim (ok its got a triumph silencer as well.. & few other odds & sods...

The "Triumph" parts on my "G" are: rear numberplate & light (T110), front mudguard (T140), air filter (T120), front number plate (T20), driveside crank/engine sprocket oil seal in inner primary chaincase (Redditch didn't fit one!)is a fork oil seal from mid 1960s T90/T100/T120... I think that's it??? pretty sure.. :)oh the "metal" for the home made seat pan came from a T90 base!