The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: chamber66 on 29.10. 2013 08:29

Title: Racing an A10
Post by: chamber66 on 29.10. 2013 08:29
Hi, just come on here  mainly for my dad (he's a tecnophobe)
Is it possible to make an A10 engine competative in scrambles. I have seen heaps of other engines grafted in to BSA frames, TRIBSA, MABSA etc. But I have never seen an A10/7 compete?

I was going to build a TRIBSA myself, for classic racing, but I'm quite fancying an A10 for something different.
So just wondering why you never see them, and, can they be made competative to run against the Triumphs?

Oh! and what would I need to do to it
Thanks
Title: Re: Racing an A10
Post by: muskrat on 29.10. 2013 09:16
G'day again.
Look here http://www.a7a10.net/forum/index.php?topic=6024.0  9 pages of reading for you.
I road raced a "57 A7SS, there were more 650 Trihards and sNortons behind than in front.
Cheers
Title: Re: Racing an A10
Post by: fido on 29.10. 2013 09:34
I suppose weight is the main challenge. Triumph had the lighter 350 and 500 engine but BSA used a very similar engine for the 500 and 650. Things like alloy barrels and lightened crank might help.
Title: Re: Racing an A10
Post by: chamber66 on 29.10. 2013 12:05
I suppose weight is the main challenge. Triumph had the lighter 350 and 500 engine but BSA used a very similar engine for the 500 and 650. Things like alloy barrels and lightened crank might help.
I have seen that thread already. Kind of what stared me thinking about using. An a10. Unfortunately I don,t have a cnc machine or his budget or skill, come to think of it lol.. Where can I get alloy barrels from, and who does crank work?
Title: Re: Racing an A10
Post by: muskrat on 29.10. 2013 19:09
It really depends on how fast do you want to spend? A big valve Super Rocket motor would be a good start, then the SRM roller conversion and oil pump. Then electric ignition, running total loss so you don't need the dynamo.
Then the frame, wheels, brakes and suspension.
Or find an old shed sitter, clean it, get it going and have some fun.
Cheers
Title: Re: Racing an A10
Post by: Bsa Nut on 29.10. 2013 20:30
"""It really depends on how fast do you want to spend?"""

I love that line. ;)
Great advice.

I have an A65...with the billet conrods from Thunder, SRM oil pump, mild head work, Boyer Ignition...etc.etc.
She runs FINE! ;0

Speed is expensive, how fast can you afford to go?
-Luke
Title: Re: Racing an A10
Post by: muskrat on 30.10. 2013 07:00
I recently went on a dirt ride with my club (Shoalhaven Classic Motorcycle Club) of about 70 miles of fire trails (4WD only). All others on old XR250's TT600's a few tidlers and a newish Kwaka 650 trailie, all with knobies. I was on my '64 A65 with road tyres and high bars. I was first at every turn, had a ball. At the next meeting i was awarded a Superman suit ;D.
So really you can do almost anything on anything and have fun, and don't need to spend a cent.
Cheers
Title: Re: Racing an A10
Post by: chamber66 on 30.10. 2013 07:25
Ummm good advice, i'm still a bit torn on this one as to which way to go. I'm not to worried about being competetive, but i don't want to come last either. So does anyone make alloy barrels for the A10?
Title: Re: Racing an A10
Post by: Rocket Racer on 30.10. 2013 08:27
you aren't going to find alloy barrell's unless you::
a.  have more money than sense or
b. are a very clever engineer and can make some

however I've recently shortened my A10 race motor by half an inch (std cast iron barrel) and very pleased with it.

An A7 or A10 can certainly punch above its weight, however the throttle does need to be twisted  ;)
Over the weekend on a track with damp corners I was driving round the outside of a unit triumph 750 and a pre unit triumph 780, sadly could quite stay ahead but they couldn't shake me off and I only run 650cc

Nothing wrong with the humble beesa twins
Title: Re: Racing an A10
Post by: WozzA on 30.10. 2013 08:41
It would'nt be too hard or expensive to fabricate some home made mods like these for racing..
Title: Re: Racing an A10
Post by: muskrat on 30.10. 2013 11:15
Even a mildly tuned Road Rocket or Super Rocket will perform well. Large journal crank and thick flange barrels are a must, roller timing side would be good. A scr gearbox would be a good choice. Dow type double damper rods for the forks and better rear shocks should keep the frame off the ground.
A cricket box for yourself will keep the wife happy. *eek*
Cheers
Title: Re: Racing an A10
Post by: tombeau on 30.10. 2013 12:34
I'll probably be drummed off the site for saying this...
But me and a mate swapped bikes for an afternoon run. His was a Preunit Thunderbird.
We both came to the conclusion that a Tribsa was a good idea.
...well, over a Triumph anyway  *smile*
Title: Re: Racing an A10
Post by: Topdad on 30.10. 2013 12:51
Think you're bang on the money, in our crowd many moons ago one mate had a pre-unit Thunderbird and not for nothing were they called " the one with the wobbily frame " we regularly used to take the p*** out of it by getting  around it and inspected it for a hinge in the middle and I don't mean  s/w arm  ,no exageration when I was behind him and he opened her up the frame shortened on the drive side and lengthened when he closed down again very scary . That being said I've seen some very quick tribsa, BobH.
Title: Re: Racing an A10
Post by: tombeau on 30.10. 2013 14:26
It went lovely though!
Like the look of this:


http://www.ebay.co.uk/itm/BSA-Classic-Bike-Tribsa-BSA-triumph-triumph-/151087202543?pt=UK_Motorcycles&hash=item232d7fc0ef
Title: Re: Racing an A10
Post by: chamber66 on 30.10. 2013 15:43
Not my cup of tea. I really like this though *smile*

http://upload.wikimedia.org/wikipedia/commons/5/53/TriBSA_466.jpg

adm edit: see http://www.a7a10.net/forum/index.php?topic=2545.0
Title: Re: Racing an A10
Post by: chamber66 on 30.10. 2013 15:44
Large journal. Which ones are these?
Title: Re: Racing an A10
Post by: muskrat on 30.10. 2013 19:01
LJ cranks were std in A10's from '58, the big end journals are bigger (1.461" = SL, 1.687" = LJ) and the flywheel is bolted by 3 radially.
Cheers
Title: Re: Racing an A10
Post by: bikerboy on 04.11. 2013 03:00
tombeau

I actually have a tribsa I dumped a T140E engine in a bsa frame some 20 years ago and its ok, I have also put a Trident T150V engine in an A10 frame and that really was quick. I have to be honest tho I actually prefer riding my Super Rocket.
Title: Re: Racing an A10
Post by: Rocket Racer on 04.11. 2013 03:28
I would certainly say that an A7 or A10 is at no disadvantage to its subsidiary companies twin cam products on the racetrack.
I'm no trail rider but would suspect lightening the rolling chassis would be the main emphasis.
Depending on the nature of the tracks you race on the ultimate lightweight would be to race a rigid frame, no good if you run on bumpy circuits, but good enough for the Daytona BSA twins to clean up all opposition in '54.
Title: Re: Racing an A10
Post by: chaterlea25 on 05.11. 2013 22:55
Hi All
This might help ????????????

http://www.ebay.co.uk/itm/BSA-A10-TWIN-CARB-ALLOY-HEAD-/321239918506?pt=UK_Motorcycle_Parts_13&hash=item4acb6427aa

Regards
John
Title: Re: Racing an A10
Post by: muskrat on 06.11. 2013 09:55
Or even better, a proper one. http://www.ebay.co.uk/itm/360782840837?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
Sorry if a member already bid on it.
Cheers
Title: Re: Racing an A10
Post by: JulianM on 06.11. 2013 14:41
Hi,

I have an interesting A10 Ally Barreled 780cc Twin carb Scrambler I may just part with if the right offer was made   *smile* *smile*


Julian  ;)
Title: Re: Racing an A10
Post by: chaterlea25 on 06.11. 2013 19:16
Hi Musky,
Yes I saw that after posting my reply, probably will make a lot more than the modded head ??
For a racer the modded head would seem better value?? carbs and all

Julian,
Are you tired of the "Beast" already ??? or are you onto the next project ?


Regards
John
Title: Re: Racing an A10
Post by: morris on 06.11. 2013 19:45
I have an interesting A10 Ally Barreled 780cc Twin carb Scrambler I may just part with if the right offer was made   *smile* *smile*

Sorry Julian, firstly because my wallet isn't big enough, and secondly I don't think you're serious ;)

I don't want to take the p**s out of anyone (well actually I do *smile*), but I have seen it in the flesh, and I can testify that it looks a mean little bastard.
When standing next to it something tells you not to come any closer cos' it'll eat you alive.....remember Christine? Well, me damn sure I vaguely heard Buddy Holly's "Not Fade Away" while looking at it....
Pure Rock and Roll *wink2*
Title: Re: Racing an A10
Post by: Rocket Racer on 06.11. 2013 20:04
Hi,

I have an interesting A10 Ally Barreled 780cc Twin carb Scrambler I may just part with if the right offer was made   *smile* *smile*


Julian  ;)

I think that motor would be far more suitable for a sidecar outfit  ;)
Title: Re: Racing an A10
Post by: JulianM on 06.11. 2013 20:44
Not totally serious  *smiley4*
But ................

Naa, not fed up with it but I Always find building them more fun than anything else!

Got two Laverda SFs on the go, one std and one rather modified, so not short of things to do  *smiley4* *smiley4* *smiley4*

Regards,
Julian

Was good to see you Morris,
Title: Re: Racing an A10
Post by: chamber66 on 24.11. 2013 08:21
Hi,

I have an interesting A10 Ally Barreled 780cc Twin carb Scrambler I may just part with if the right offer was made   *smile* *smile*


Julian  ;)

I've read your thread Julian, which is what got me thinking about using a BSA twin. I also, now i'm older enjoy the building more.Not that I have your skills or facilities, which I have to say are very impressive .
Anyway, no doubt i'm going to burn in hell for this, but I picked up a B44 instead of a twin. Seemed the sensible option considering that this is my first British bike build. And i've never done a 4 stroke before. I mean there's just so many parts in that engine, whatever do they do  *smile*
Title: Re: Racing an A10
Post by: tombeau on 24.11. 2013 08:40
B44 probably a very sensible option. Big fan of BSA unit singles here.
Title: Re: Racing an A10
Post by: JulianM on 10.12. 2013 09:23
do agree!

A B44 shows a lot of promise!  especially if you look at the last CCM versions of what was basically once a B44.

good luck and ask if you need to know where all those bits go, I have no idea but am sure we can guess   *smile* *smile*

Julian