Forum

[JTL]

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

[grunda 12]

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

[grunda 12]

typo forgot the m in decompressor!!oops

[Gwilly]

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.

[JTL]

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

[grunda 12]

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.

[Dennis C]

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.

[PeteF]

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.

[PeteF]

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

[Dennis C]

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