Author Topic: A10 Valve clearances  (Read 3444 times)

Offline A10Boy

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A10 Valve clearances
« on: 24.08. 2009 14:06 »
In the Haynes Bible its got A10 Ex valve clearances at 16 thou for 1950 - 59 models and 10 thou for 1960 onwards.

I was wondering does anyone know the criteria for the change? I mean was it becuase of different valves, pushrods or what ?

My engine numbers are 1962, but its an early 60 bike, so it could be a 62 engine, or merely replacement cases with happen to be 1962 with the original pre 60 internals. It would be good to set the right clearances.

Ive got a 356 cam, alloy pushrods, cast head
Regards

Andy

1958 Super Rocket
Plus
1974 Kawasaki Z1a
Yam XJR 1300

Offline MikeN

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Re: A10 Valve clearances
« Reply #1 on: 24.08. 2009 15:18 »

Ive got a 356 cam, alloy pushrods, cast head

Cast iron or cast alloy ?

Mike

Offline A10Boy

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Re: A10 Valve clearances
« Reply #2 on: 24.08. 2009 16:45 »
Iron
Regards

Andy

1958 Super Rocket
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1974 Kawasaki Z1a
Yam XJR 1300

Offline beezalex

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Re: A10 Valve clearances
« Reply #3 on: 24.08. 2009 16:57 »
According to S.S. 701, all A10's except Road Rockets and Super Rockets used .010" and .016".  This would indicate that all iron head A10's should be set to these values.
Alex

Too many BSA's


G/F DAVE

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Re: A10 Valve clearances
« Reply #4 on: 24.08. 2009 17:29 »
Just done tappets on my 1952 goldflash,service sheet 203 states A10 & A7 engines after engine number AA7-101   inlet .010in / exhaust .016in. A10 superflash   .008in inlet / exhaust .008in. A10 road rocket 008in inlet / exhaust .008in .A10 & A10sr frame prefixed GA .008in inlet /  010in exhaust. There is also
a note for quite running clearances which are .008in lnlet & .010in exhaust which replaces .010in inlet & .016in exhaust which are full power clearances. I set my 52 flash to .008 in inlet & exhaust. I wouldnt take a lot of notice of haynes manuals but ok! for basic info. Dave...

Online bsa-bill

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Re: A10 Valve clearances
« Reply #5 on: 24.08. 2009 17:50 »
Agree with G/F DAVE, the owners book that came with my flash (in 61) specified two sets of clearances one for quiet running and the other for max power ( as G/F DAVE states)
Don't need to say what set of clearances I choose as a nineteenyear old, the local bobby had already had his steel rule out to test baffles so a bit of rocker clatter wasn't going to get noticed.


All the best - Bill
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Online trevinoz

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Re: A10 Valve clearances
« Reply #6 on: 24.08. 2009 22:06 »
The valve clearances are determined by the camshaft used.
67-334   .010/.016
67-356   .008/.008  Later changed to .008/.010
67-357   .008/.010,  Max power - .010/.012
Trev.

Offline A10Boy

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Re: A10 Valve clearances
« Reply #7 on: 25.08. 2009 19:47 »
Thanks Guys.

I don't take a lot of notice of what the Haynes Manual states - at least I always double check it.

So if I'm reading this right, 59/60 Iron Flash with 356 cam should be set at .008/.010 which is what I have set them at - now I can sleep easy..

Cheers
Regards

Andy

1958 Super Rocket
Plus
1974 Kawasaki Z1a
Yam XJR 1300

Online Joolstacho

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Re: A10 Valve clearances
« Reply #8 on: 03.02. 2010 01:46 »
Cold clearances with alloy pushrods.
I know these should be set hot, but the first start is always cold, so what's about the right settings for the first cold start?
(Alloy head)

-Jools

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Re: A10 Valve clearances
« Reply #9 on: 03.02. 2010 06:43 »
G'day all,
            I can't get my head around the different settings. Less gap = quiet running OK but larger gap + more power if valves open later and close earlier = less duration and lift. What am I missing ?
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
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Offline mike667

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Re: A10 Valve clearances
« Reply #10 on: 03.02. 2010 11:15 »

67-357   .008/.010,  Max power - .010/.012


haha i love it - max power.....thats funny

Offline beezalex

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Re: A10 Valve clearances
« Reply #11 on: 03.02. 2010 18:00 »
Well, here's what I think as regards the larger clearances and power:  Yes, smaller clearances give quieter running and (marginally) more power.... up to a point.  My Flash has S-R pistons in it and I used to set it at .008 and .010.  Unfortunately, when pushed hard (full throttle up a long hill, trying to hang with a T160 and an 850 Commando or extended runs at the Ton), the exhaust clearances closed up.  Now, while it's entertaining to your mates to see 3 ft. flames shoot out yer tailpipe (picture the aftermath of of two Chuychangas with extra green chile sauce from Chuys, Mike) it doesn't do much for the go and I imagine the long-term consequences are also undesirable.  Now, I haven't pushed her quite that hard since I opened up the exhaust clearance, but I'm guessing this is what they're referring to.
Alex

Too many BSA's


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Re: A10 Valve clearances
« Reply #12 on: 03.02. 2010 18:57 »
Thanks Alex. That explains the run up Kangaroo Valley the other week. Pushing hard to keep up with a new Bonnie (only 5 seconds behind at the top) she seemed a little tired. I reset to .010 + .012 and had no problems.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline mike667

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Re: A10 Valve clearances
« Reply #13 on: 03.02. 2010 19:03 »
picture the aftermath of of two Chuychangas with extra green chile sauce from Chuys, Mike

ouch - good one Alex, my roids grimaced in anger at the thought ! Thats why having good clearances in those critical areas will undoubtedly save you many embarrassing moments.....

Offline Josh Cox

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Re: A10 Valve clearances
« Reply #14 on: 04.02. 2010 22:23 »
Please correct me if I am wrong, but, less clearance would equal longer open times and greater volume exchange, i.e more power, cooling and less noise ?.
Black 1953 Golden Flash Plunger