Hitchcocks Forum

Hi all

After recieving a lot of good advice on how to remove the barrel of my Bullet, the rebuild (new high compression piston 8:1) came out fine. The bike started at first kick, and then (the short version) everything turned bad...loss of compression when I started to ride the bike and a much too rich fuel/air mix. Dismantling and reassembling top end is now performed. Only a very silent hissing sound when I stand on the kick starter. It can't stand my weight anymore, but this might be a natural thing with new piston rings. The worst is a horrifying (?) find in the carb body; Amal MK2 30 mm. A small crack at the end of the tube that the jet holder is screwed into. Do I need a new carb body or can I repair it? Can this be soldered? Is there a sealant strong enough to be submerged in fuel? Or does a small crack influence on the mixture at all?...all advice is most welcome...regards Jacob

jacob ,get a new carb body ,the hiss may be the decopressor valve leaking ,try checking the cable routing
atb paul.

typo forgot the m in decompressor!!oops

Hi JTL you could try this to effect a repair.

http://www.lasertools.co.uk/item.aspx?item=4197

Expensive but expect you could find it useful for all sorts of jobs once you have it in the shed.

gwilly.

Gwilly, it might come in handy with this little alu repair kit, but this sort of repair I would prefer to bring to a skilled person knowing about alu-welding. If anything goes wrong it's a new carb body. Just as Grunda suggested. Welding and I have a history, so I just stay clear of that. Fortunately I know people who are good welders, but alu is a speciallity even to them. Blue Hylomar is stating to be fuel resistant. I'm reluctant to try it, but maybe I should... Grunda, I have removed the cable to the decompressor, so no more routing problems. The hissing sort of comes from the internals of the engine. This is why I was guessing on the piston rings. I will check on the decompressor again. If I end up having to buy a new carb body, I might as well go for a 32 mm Mikuni flat slide. They are recommended over the round slide. Any thoughts? all the best Jacob

hi jacob my recomedation of a new body was serious ,they are available and welding or sealing is in my view dodgy especially if the weld /sealer doesn,t seal.atb paul.

Another problem is that (unless later carb bodies are different) they are made of mazac and not aluminium and even most expert welders can't weld it successfully.

I think you mean Zamak Dennis.
Anyway, it's a zinc alloy with aluminium, magnesium and copper added.
Just the job for die-casting but a bugger to weld. You might just solder it with the right filler and flux, but I think replacement is the way to go.

Just thought - "JB weld" is supposed to be petrol proof.

Pete it looks like we are both correct just looked it up, now known as Zamak formerly known as Mazak.