Why Can't I.....?

dr nosh

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Get my beautiful Ariel Red Hunter to run properly??:nenau:confused::mad:

Its been unused for a year, but preserved perfectly inside a vaccu-bag and 2 carrier bags full of dessicant.

I built this back in 1981, and I have just looked after it since. Managed 2 rallies into France on it, 'Balade de Clous Vieux'. (Walk of the Old Nails).

Its never been fantastic at ticking over, alway requiring a little blip of the throttle from time to time, but always ran very nicely.

So, looking at the short video by Pro Plumb of his for sale Matchless, I was inspired to make the effort to sort out.

I have now stripped the carb (monoboc 376) twice, the first time seeing jets with Ethanol fuel deposits. Soaked in thinners, blown through with the airline, and examined with an eye glass. Satisfied I re-assembled and refitted the carb.

Gallon of fresh petrol fed to the tank.

It ticks over a little better, but still not good enough. It runs smoothly to start with, and then races a little, before settling back down and then gradually petering out, requiring that little blip of the throttle to keep going.

But the thing that has now got me after a spin round the block, it will just not 'pick up and feels 'strangled'.

Whats happening?

The only thing that I can see with the carb is that the very, very fine thread at the top of the body is badly worn, and in order to screw the knurled brass ring down to hold the carb top in place, 2 winds of ptfe tape is necessary. Could air be getting in here and going down the centre of the slide.

Oh, by the way, the body has previously been turned true (round) and a brass sleeve fitted to the slide. So no air getting in around the slide.

Could the timing be out enough for this to occur?

Did check the timing (magneto) and looked spot on.

This is driving me mad, and I'm nearly at the point to order a Minkuni carb. Checked dimensions and looks to be a pretty close fit with the Amal.

Am I throwing money at a problem that is just sitting just staring me right in the face but yet I cannot see it?
 

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Wish I could help but you lost me at Ethernal.

What a thing of beauty wish I had the skill set to do that, feck If it ran I would be chuffed. Credit were its due sir, hope you find someone to assist, that’s the sort of kit you want to see running around
 
It could be the screw to bleeding air , or the float level in the chamber adjust that and put a new needle valve in that could be sticking.
I would try that before a new carburettor
 
Have the carb ultrasonically cleaned then start looking again.
 
Which piston are you running ?? If you're on a 9:1 it will be lumpy.

What about the cams - are they standard or has someone put a 'HS' set in ??

I have a '58 'VH' very much like yours (but not a shiny), it has a 7:1 piston and standard cams but still needs the ignition lever to be backed-off to tick over. A performance single is unlikely to tick over smoothly unless its got a low compression and a heavy flywheel (one day I'll get my '31 Panther on the road and will see how that ticks over ;).

The Amal Monoblock is considered to be a bit inferior to the Concentric (I am using a 28mm Concentric) so a carb change may sort your problem. A smaller carb will help the tick-over by increasing the speed of the air and thus better fuel spray mixing, but will restrict the top end (I'm going to try my 32mm Concentric to see if the top end cruising is better).

Good luck with it, its a lovely bike.

Are you in the Ariel Owners' Club (I am) ?? lots of advice there from people better qualified to comment than I am.

Bob.
 
Do you have any mates with a classic bike who would let you borrow a carb,even if you have to buy a couple of jets ,if the symptoms improve greatly then there’s your answer.
 
This sounds like it could be an air leak on the carb top. I would agree with the previous suggestion, borrow a carb rather than buying one and try it. Think if it was me, and it's not I would stick with an original carb. It should run well with a good well set up mono bloc. Great looking bike by the way. Let us know how you get on.
 


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