Tick over

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Tick over

Postby leobailey » Sun May 20, 2018 4:31 pm

A small but irritating problem regarding tick over speeds.

After starting my G3, for some 15 seconds or so it absolutely hates choke, but release the twist grip and it will sputter to a stop. Hold the throttle a tad open for 2 or so minutes and a now warmed up engine ticks over steadily.

When I ran on a monobloc carb my solution was to tweak the throttle stop screw by hand a 1/4 turn in, I could then walk away until the engine had warmed up. However I now have a AMAl concentric Mk2 fitted and there is no exposed throttle stop screw ( it's a recessed screw ).

Overall the bike runs quite a bit better on the concentric Mk2 , but does anyone have a suggestion to any method of holding the tick over speed up during warm up. ( except standing there holding the throttle, I can do that anyway :rofl: )


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Re: Tick over

Postby SPRIDDLER » Sun May 20, 2018 5:05 pm

leobailey wrote:I now have a AMAL concentric Mk2 fitted and there is no exposed throttle stop screw ( it's a recessed screw )

Replace the recessed screw with a longer one that you can finger-twiddle?
I poke badgers with spoons.

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Re: Tick over

Postby Mick D » Sun May 20, 2018 5:06 pm


There are handlebar throttles which have an adjustable stop - does yours? if not you could fit one of this type.

Fit a throttle cable with an accessible adjuster, either mid cable or at the handlebar and tweak that during warm up.

Regards Mick

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Re: Tick over

Postby 56G80S » Sun May 20, 2018 6:13 pm

Ironically I replaced the worn out concentric which wouldn't idle for a new monobloc which does.

Ho HUm

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Re: Tick over

Postby g5wqian » Mon May 21, 2018 6:17 am

i did see someone with extended adjustment screw kits for the concentric carb , so you can adjust them by hand , but i think they are made in the usa .

my mate works at amal carb uk and gave me some longer hexagon head adjuster screws but i am not sure which carb he gave me them for and whether they were mixture screws or not .
i told him i had monobloc and concentric carbs and he gave me a bag of parts for both .

i prefer the monobloc for my AJS and when its cold i adjust the idle adjuster up by one turn when starting it so it idles when cold and then when engine is running i back it off bit by bit until its warm and i can reduce the idle speed to normal running .

i have an ariel with a concentric on and it is difficult to make idle speed adjustment as the carb is not that acessable , i did make a small adjuster screwdriver from to steel rod and a bit of alloy bar but it is still fidly and not recommended to keep doing adjustments with it all the time .

perhaps you could try a new monobloc carb it will function as you want it to .

amal uk will build you a carb with your choice of jets in if you ask them to .

my ajs only needs the air valve [choke] closing for actual cold starting and then you immediately need to put the lever half way once its started and then after a minute or two it needs to be fully open .

what the monobloc doesnt like is not being vertical , ie if you have bike on side stand it wont idle well unless the idle speed is up high , but usually mine will splutter and conk out if i try leaving it idling whilst on the side stand , it is fine on the centre stand though .


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Re: Tick over

Postby Rob Harknett » Mon May 21, 2018 9:44 am

A small but irritating problem regarding tick over speeds.
Looking at some of the replies, I would think to myself, why am I getting irritated over such a small problem which is quite common with old bikes. I have never felt the need to have to leave a bike running on its own to warm up. In fact I would not dream of leaving the bike running unattended. It could spit back and catch fire. That will certainly warm it up. It could fall over and also catch fire. When you are warming up the bike, is a time when you may notice something loose, by sight or sound. Also you can check oil return and fuel level. Charging, lights, stop light etc.

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Re: Tick over

Postby Groily » Mon May 21, 2018 10:27 am

I rather agree with you Rob. I haven't ever expected any of mine to tick over from stone cold, and sure enough, they won't.
I don't leave them ticking over to warm up either. I ride off, gently for the first couple of miles, after checking the oil return. And I'd never leave a running machine unattended either, for the reasons you give. Plus, with coil ignition, if it stalls and the points are shut, you drain the battery, heat up the coil and associated wiring, and anything could happen. None of it good!
(Sitting at cold tickover with a rich mixture, air slide down, is also a recipe for a fluffy plug I reckon.)

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Re: Tick over

Postby leobailey » Sun May 27, 2018 4:27 pm

Thanks to all for your responses, but I was rather hoping for solution to my tick over question, rather than ticking-off (pun intended). :(

Thanks to SPRIDDLER, Mick D and g5wqian with helpful possible suggestions, I’ll apply my planet sized brain to the problem and get back to you when I reach a solution.

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Re: Tick over

Postby cbranni » Sun May 27, 2018 5:02 pm

I have one bike with twin concentric and that loves choke to start but like yours takes two minutes to warm up before it will idle, engines are tuned when hot to idle at the right speed, there's nothing worse than an engine cutting out when you come to a stop in traffic.

Cast your mind back a good few years SU carbs had a cam that when the choke was pulled the throttle was lifted a smidge to increase the revs when cold maybe this is the road you need to go down.

Myself I just turn the idle screw in half a turn if it's a mono or wait few minutes if it's a concentric.

only dead fish go with the flow

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Re: Tick over

Postby hunter » Sun May 27, 2018 9:46 pm

If needs must try a bit of innertube,cut to suit, over
the front brake lever and throttle, crude but works

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