Author Topic: amal 274 carburettor internals  (Read 2942 times)

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Offline grav220

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amal 274 carburettor internals
« on: 04 Apr 2014 at 20:03 »
Hi all
I have just stripped my carbs, right hand side gave up without much struggle but LHS needed 24 hours soaking, a home made puller, heat from an electric paint stripper and finally a sharp blow with a hammer and wooden drift (plus nervous tension as more and more force was slowly applied) to remove the jet block.
I notice that there is a drilling right through the block about 9 mm above the base. In the LH carb it is open to the atmosphere via the locating slot in the bottom of the body. In the RH carb it is open via a small hole drilled in the carb body. Am I right in thinking that they form some sort of overflow so that the level of fuel in the carb cannot get any higher, eg when over enthusiastic "tickling" or slight leak through float needle valve?
Presumably the fuel level normally only just covers the bottom of the float block, and so will not come out of these holes.?
Graham

Offline eddie

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Re: amal 274 carburettor internals
« Reply #1 on: 04 Apr 2014 at 20:18 »
Hi Graham,
                  Yes, these holes seem to just provide an overflow in cases of high fuel level. When I was building my Comp (trials bike), I wanted to waterproof the carbs, so blocked these holes to prevent the intake of water when crossing streams/fords, etc. Blocking the holes only richened up the idling mixture very slightly, and could easily be compensated for on the mixture screws.
   On the subject of applying heat to the jet blocks to free them from the bodies, be careful, the jet blocks are made in 2 pieces and are only soft soldered together.

  Regards,
                Eddie.

Offline grav220

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Re: amal 274 carburettor internals
« Reply #2 on: 05 Apr 2014 at 08:19 »
Hi Eddie
Thanks for advice.I was very cautious about extracting the jet blocks, they seemed, and are, fragile.
Graham

 

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