BSA gearbox for MX3

[Wilks]

Hi all
Does anybody out there have any experience of BSA gearbox conversions for a 24MX 3 Challenger ? Is the end result worth the effort ? Is the BSA clutch any good ? My kidney 'box works OK but the lever throw is a real pain, if not a BSA 'box does any body have any suggestions to give me the gearbox the bike deserves ?
Cheers Allan

[riflegreen]

The Dutch Greeves rider , Frits Selling , fitted BSA boxes to his scramblers .

You need the plunger frame twin gearbox , it bolts on in a similar way to the Albion box .

You can use a Norton clutch , the end spline on the plunger mainshaft is almost identical to the Norton clutch spline .

A common change round was fitting the plunger mainshaft in a Goldstar gearbox to get a decent Norton clutch .

Won't say it is easy to do but you get a decent gearbox & clutch .

Chris

[druid]

BSA Gearbox for MX3

If you do fit a plunger gearbox to your MX3 there's a fair bit of work, engine plates, primary cover etc. Additionally the old plunger gearboxes have risen in price over the last 5 years or so.

If you do fit the BSA box then a plunger mainshaft should take the Norton clutch without mods, my Goldie has one fitted. Alternatively you could fit the S/A mainshaft with the adaptors available to take a Triumph 6 spring clutch, anything is better than the original BSA clutch with the 6 studs in a pressed steel basket.

The standard BSA box (around £100-150) has ratios that are not really suited to MX. The Goldie engine with bags of torque can get away with road ratios, I don't think an MX3 would be quite as accomodating. Expect to pay around £500 plus for a genuine BSA scrambles gearbox.

I personally think the best answer is to graft a Griffon box and clutch onto your engine - less work and all Greeves.

Druid

[Wilks]

Cheers guys
Dont know why I have never considered using a Griffon gearbox before. I am partway there already as I fitted a Griffon clutch about five years ago after fiddling with the Albion job for years.
Many thanks for the advice, now all I have to do is find a good gearbox!!
Thanks Allan

[Kim275]

Griffon Box would have the additional advantage that you can change gear reliably ........they are very slick boxes,

I assume no issue with bike eligibility for pre65 races if you have a Griffon box - but you might want to check that out (Andy #190 might know) or Adrian D.
Good Luck
Cheers Kim

[Andy Z]

Griffon Box would have the additional advantage that you can change gear reliably ........they are very slick boxes,

I assume no issue with bike eligibility for pre65 races if you have a Griffon box - but you might want to check that out (Andy #190 might know) or Adrian D.
Good Luck
Cheers Kim

I can't see anything obvious in the rulebook which bans a Griffon gearbox on a Challenger, and I know of at least one which has been raced with this setup - its something I have considered myself.
However, trying to find a decent Griffon gearbox isn't an easy task - there a lot more BSA gearboxes about, and the internals can all be bought new.

As for the Greeves championship, it would be wise to talk to Dave Harper before ditching the old Albion 'box. Mind you, even if it cost a couple of points it would still be worth it. Every time I lose a gear on my 360 it costs me 2 or 3 places - very frustrating!

Anyone know of any Griffon 'boxes for sale?

Cheers,
Andrew
#190

[dave higgins]

Its cheating...

[druid]

BSA Gearbox

I agree that the gearbox isn't pre 65, but the gears can be. The first Griffons used the Albion cluster.
Likewise the quick unit BSAs often use NEB 3 speed internals in pre 65.
When I first suggested using a Griffon box I was thinking more of the Greeves championship rather than pre 65 rules. I know Dave Harper will allow this, I've got an MX4 with a Griffon box which Dave was happy with.

Druid

[dave higgins]

I just believe that we ought to keep pre 65, as it should be, i understand people wanting to use modern parts for reliabilaty etc, but i think any advantage other than that should be banned, otherwise there`s not a lot of point doing it! is there? dave.

[Kim275]

I just believe that we ought to keep pre 65, as it should be, i understand people wanting to use modern parts for reliabilaty etc, but i think any advantage other than that should be banned, otherwise there`s not a lot of point doing it! is there? dave.

hi Dave - understand your sentiments - on keeping pre65 original - but it is always difficult where to draw the line in terms of perceived fairness...........

my personal view is if a bike is mainly pre65 - and has mods like elec ignition - and an early griffon gearbox - i think it is still in the spirit of the class. .....but this is just my sentiment and yours is different and i respect that.

what counts however is what the AMCA classic rules allow in pre 65 ......so to be sure if it was me I would ask the club AMCA Rep to confirm eligibility - as the worst thing would be to find out you get a problem at race meet having already invested time and money on a solution.
Cheers Kim

[challenger]

Must agree with Dave Higgins,it might be easier all round to buy a Griffon !!!!!,no issues with it being within rules .

[Andy Z]

BSA gearbox

Just a further thought.....

At least if a plunger BSA gearbox is used there cannot be any argument as to pre-65 eligibilty - they started making them in 1949!!

The BSA gearbox has a slick gearchange, and never misses gears. Why Albion couldn't manage it 15 years later is beyond me...

Cheers,
Andrew
#190

[stormer254]

Just a further thought.....

At least if a plunger BSA gearbox is used there cannot be any argument as to pre-65 eligibilty - they started making them in 1949!!

The BSA gearbox has a slick gearchange, and never misses gears. Why Albion couldn't manage it 15 years later is beyond me...

Cheers,
Andrew
#190

They are only any good with Gold Star close ratio gears and you try finding those.

[Andy Z]

They are only any good with Gold Star close ratio gears and you try finding those.

They're easier to find than gears for Albion boxes, plus the gears and shafts are available new!
Bit on the pricey side, admittedly!

Cheers,

Andrew
#190

[dave higgins]

Hi druid/ kim, & all, i did not realise about the g/box cluster being used in a previous form in a challenger, but i am not a greeves specialist like yourself druid.
If that is the case, then it is only a continuation of current design & may be eligable, the g/box casing itself is only cosmetic & is not performance enhancing, so i guess thats not a problem either.
But it is bending the rules & that was the point i was trying to make!, if you keep adding griffon bits to a challenger, when does it stop becoming one & start becoming another?
We have disscused this subject a few times before & i think it is up to the riders themselves to be honest in what goes into their bikes, as any regulation at meetings, seems to have dissapeared, with no scrutineering etc, any more.
Sorry for changing the thread a bit. dave.