Author Topic: A10 Noisy and running rough  (Read 1424 times)

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johnjag

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Re: A10 Noisy and running rough
« Reply #15 on: 10 July, 2019, 17:34:34 »
Hi - sounds to me like a weak mixture, something like the pilot screw adjustment or a blocked pilot jet. What carb are you running? If it is a Concentric the pilot jet is actually a bush which is difficult to unblock. You have to drill through the other side and unblock with a piece of wire (crude I know) and then tap the drilled hole and screw in another shortened pilot screw to block the hole.
John.

Marka10

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Re: A10 Noisy and running rough
« Reply #16 on: 10 July, 2019, 19:43:01 »
Hi John

Thanks for your input,

I now think the original Problem is the petrol mixture. To satisfy myself and increase my knowledge I am going to set valve timing, valve gaps and ignition timing.

I will than know all this is correct and try running again.

I was thinking the mixture is to rich and not all the petrol is burnt on ignition stroke and because electronic ignition fires on exhaust stroke, on each piston (sacrificial spark)  I am getting firing on the exhaust stroke.

Cheers

Mark


Mike Farmer

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Re: A10 Noisy and running rough
« Reply #17 on: 11 July, 2019, 10:38:09 »
 :) :)

Maybe something as simple as loose manifold nut/s

Mike 8) 8) 8)

chaz

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Re: A10 Noisy and running rough
« Reply #18 on: 11 July, 2019, 16:02:50 »
seems to me there is a lot of people suffering fuel problems, common fault misfiring and poor running. we straightaway assume the bike has a problem despite our regular tinkering,makes me wonder if its down to the fuel. As ethanol has been widely discussed over the last few years its dropped back off the radar recently.
a couple of my Brits have problems, the Jap stuff gets used more often and fuel turned over but I see many carbs that have corroded brass parts while overwintering.
as some have problems with fuel evaporating (tufnol spacer discussion) , modern fuel is upto 15% ethanol which absorbs water, this could be vapourising. also I go back to the days of open fuel storage tanks, working in a garage and common to find pinking as droplets of water banging around in the combustion chamber not being burnt off.

would be interesting to use a octane booster additive or maybe try a tankful of Avgas same as we used to use on racetracks until the ACU deemed racers had to use pump fuel.

Mike Farmer

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Re: A10 Noisy and running rough
« Reply #19 on: 11 July, 2019, 16:58:09 »
 :) :)

Back in the day I used a lot of 100/115 AVGAS (occasionally 115/130). On the road A65. But Avgas now is straight 100LL  IE 100 octane low lead--no Heptane content. So I doubt that the new stuff would be much of an improvement. I have no idea what the "funny" content is.

Mike 8) 8) 8)

Marka10

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Re: A10 Noisy and running rough
« Reply #20 on: 11 July, 2019, 17:04:00 »
Hi
Thank you for your inputs, can anyone recommend a additive to try.

Thank you

Mark

chaz

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Re: A10 Noisy and running rough
« Reply #21 on: 11 July, 2019, 17:26:45 »
I have Silkolene ProBoost in the unit, bought for a friend who drives rally cars but outlawed before he bought it...
https://www.silkolene.com/motorcycle/fuel-additives/pro-boost/

TTJOHN

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Re: A10 Noisy and running rough
« Reply #22 on: 13 July, 2019, 21:07:25 »
Sounds like air leak to me, if it's popping and banging, this did happen to me once , bike running fine then started playing up when I checked I could get a feeler gauge between the manifold.

Marka10

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Re: A10 Noisy and running rough
« Reply #23 on: 12 August, 2019, 13:20:47 »
hi John
just picked up your response, being busy and on holiday.

Still not sorted the A10 problem

where was your Air leak

What were the symptoms

My problem seems to be too much petrol. One plug is getting sooty and one pug is wet with petrol and not firing, this is just after a few minutes.

The Carb is 2 year old all seems ok checked jet sizes etc with Amal, I adjust pilot air, makes a small difference but still runs rough and rich.

Cheers

Mark

Marka10

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Re: A10 Noisy and running rough
« Reply #24 on: 12 August, 2019, 21:48:25 »
Checking valve timing with timing disc
inlet valve starts to open at 60 deg before TDC book says  42 deg before TDC

Anyone had experience of check valve timing
The bike is a A10 1961

Marka10

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Re: A10 Noisy and running rough
« Reply #25 on: 13 August, 2019, 07:47:47 »
Valve timing settings

bikerbob

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Re: A10 Noisy and running rough
« Reply #26 on: 13 August, 2019, 09:05:10 »
To set the valve timing correctly you will have to remove both the outer and inner timng cases then pull out the center idling pinion which will have 2 timing marks on it then turn the cam shaft  and also the crankshaft until you can replace the idler pinion with all the marks correctly aligned.

JulianS

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Re: A10 Noisy and running rough
« Reply #27 on: 13 August, 2019, 10:05:28 »
The valve clearances for checking timing will be different to the running valve clearances.

Not seen a figure given for the A10 but the A65 figure is 15 thou for checking timing.

If you are checking running clearances suggest reset and check with a 15 thou clearance and see what result you get. It can be difficult to establish the exact opening and closing point.
« Last Edit: 13 August, 2019, 10:13:57 by JulianS »

Splodger

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Re: A10 Noisy and running rough
« Reply #28 on: 14 August, 2019, 14:40:12 »
Hi Marka10,

Long shot - are your exhaust valve clearances too tight?
Is the camshaft the original for the year?

Figures according to Mr Bacon:
1950 only: 015/.015 (67-334)
1951-54: .010/.010 (67-334)
1955-59: .010/.016 (67-334)
1960-62: .008/.010 (67-356)
A10 Super Flash
1953-54: .008/.008 (67-356)
A10 Road Rocket
1955-57: .008/.008 (67-356)
A10 Super Rocket
1958-59: .008/.008 (67-356)
1960-63: .008/.010 (67-357 probably export only in 60-61, 67-356 for home, used for all from 62)
A10 Rocket Gold Star
1962-63: .008/.010 (67-357)

Marka10

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Re: A10 Noisy and running rough
« Reply #29 on: 18 August, 2019, 19:53:55 »
hi Splodger

I am thinking that when the person who restored the bike fitted the wrong Cam shaft.

I have measured the timing of the valves opening using a dial gauge on the valve stem and deg disc the valves do not correspond with the drawing in B.S.A.Twins W.C.Haywood

The valves seem to be open longer.
The inlet
opening at 60 deg before TDC should be 30 deg
Close at right time 70 Deg after BDC

Could it be wrong Cam shaft?

Can you remove the cam shaft without fully stripping the engine ?

Mark