Author Topic: A10 Max Revs  (Read 1486 times)

Offline yar

  • Moving Up
  • **
  • Join Date: Nov 2012
  • Posts: 10
  • Karma: 0
  • coming soon
A10 Max Revs
« on: 16.11. 2012 07:08 »
 HI all you experts out there !!!! As I am waiting for my 1957 A10 Road rocket and am searching for information on the bike.  I have read that they were supposed to get max power Ie 40 bHP at around 6000 revs !! Obviously in good condition, But don't seem to find on any sites I have been to what the max revs  was recommended  by BSA when manufactured,was a safe maximum advised in the original handbook ?  As yet I haven't got a workshop manual for the bike can anybody advise on max revs or? if it  is perhaps is in a particular book

 thanks for any info Ray
Bike Tragic

Offline A10Boy

  • Wise & Enlightened
  • *
  • Join Date: Jun 2008
  • Posts: 1075
  • Karma: 11
  • Solihull, Near Birmingham England.
Re: A10 Max Revs
« Reply #1 on: 16.11. 2012 10:01 »
BSA were not known to shout too much about this type of thing, and you probably know you will get a lot of differing opinion on this, but this is my view.

Your 40bhp @ 6000 seems about right for an ally head bike, Flashes started out at around 35bhp but that increased as they were developed, particularly with the DA10 engine which had the same bottom end and 356 camshaft as the Rockets. The 357 cam engines probably made a few more than 40bhp in the higher rev ranges.

The question is, would you push an un-known engine to 6000+ rpm, personnally I wouldn't, but a properly built engine should be ok in short bursts. It's a question of performance over longevity. There are some great modifications to help with this, SRM make a great oil pump and those MAP conrods are a good mod for sustained high speed running.

The thing to remember is that these engines were designed in the days before motorways / freeways so engines wont tollerate 6000 rpm all day long, but they will be happy cruising at legal speeds.

Enjoy.

Regards

Andy

1960 A10 - Black Golden Flash
Plus
1974 Kawasaki Z1a
Yam XJR 1300

Online Rocket Racer

  • Wise & Enlightened
  • *
  • Join Date: Jun 2009
  • Posts: 1377
  • Karma: 16
  • A kiwi with a racing A10 rig
    • NZ Classic Sidecar Racing
Re: A10 Max Revs
« Reply #2 on: 02.12. 2012 00:44 »
HI all you experts out there !!!! As I am waiting for my 1957 A10 Road rocket and am searching for information on the bike.  I have read that they were supposed to get max power Ie 40 bHP at around 6000 revs !! Obviously in good condition, But don't seem to find on any sites I have been to what the max revs  was recommended  by BSA when manufactured,was a safe maximum advised in the original handbook ?  As yet I haven't got a workshop manual for the bike can anybody advise on max revs or? if it  is perhaps is in a particular book

 thanks for any info Ray

Eddie Dows "twin tips" mentions peak power at 6800, with safe peak rpm of 7000 for sustained running, with 7200-7400 through the middle gears.
I do not exceed those revs, but concur they suit my 55 road rocket motor nicely (on the track)

Depending on the cam, if you are hard on throttle, does pay to watch the tach as they will spin past that quite easily. They do pull nicely through 5-7k but can get into the high 7's far too quickly...

If you are expecting those revs, you should be shot peening and crack testing rods given these engines are all 60 years old.  
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
New Zealand

Offline yar

  • Moving Up
  • **
  • Join Date: Nov 2012
  • Posts: 10
  • Karma: 0
  • coming soon
Re: A10 Max Revs
« Reply #3 on: 02.12. 2012 07:48 »
 Hi Rocket Racer
 thanks for your the info and Eddie Dow articals, very interesting!!  its unlikely that I will be running at the high revs mentioned for this engine but was curious what the engine was built to do and at what revs
so thanks once again for your input

 Ray
Bike Tragic

Online BSA_54A10

  • Wise & Enlightened
  • *
  • Join Date: May 2008
  • Posts: 1866
  • Karma: 31
    • BSA National
Re: A10 Max Revs
« Reply #4 on: 03.12. 2012 07:15 »
Back in my youth I knew every time I went over 7200 rpm. ( 115 mph )
The bike stopped dead & I spent hours trying to put the push rods back under their rockers
Bike Beesa
Trevor

Offline iansoady

  • Valued Contributor
  • ****
  • Join Date: Jul 2010
  • Posts: 471
  • Karma: 9
Re: A10 Max Revs
« Reply #5 on: 03.12. 2012 12:07 »
.... And I thought rev limiters were a new invention.....
Ian.
1962 Golden Flash (arrived)
1955 Velo Viper/Venom (departed)
2004 Triumph Tiger 955i (staying)

Online Rocket Racer

  • Wise & Enlightened
  • *
  • Join Date: Jun 2009
  • Posts: 1377
  • Karma: 16
  • A kiwi with a racing A10 rig
    • NZ Classic Sidecar Racing
Re: A10 Max Revs
« Reply #6 on: 03.12. 2012 23:14 »
This provides another perspective
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
New Zealand

Offline yar

  • Moving Up
  • **
  • Join Date: Nov 2012
  • Posts: 10
  • Karma: 0
  • coming soon
Re: A10 Max Revs
« Reply #7 on: 04.12. 2012 04:05 »
 looks like 6500 revs it is then  Thanks for that rocket racer  I would says that's confirmed for a standard engine
  thanks Ray
Bike Tragic