The Foster "Otters..."

 The start of the journey.

Page from 2010...




Built By Harry Foster...




This Foster BSA "Otter" now lives in Spain...

I would like to here about the history of this Foster Otter bike.



This is the man that started the story that is now History of the Now Famous,

Foster BSA "OTTER"...


Harry Foster. Riding his International Trial Triumph Metisse...



This smart "Foster Otter" lives in Austria or Germany, I am trying to get the story! 2020 update : (It now has its own page.)







This is Mark Griffiths "Foster Otter".







Mark Griffiths, has sent me more details about this Foster Otter bike...

This is what he said.

We keep finding the "Foster" bikes don't we.


Hello Charlie.

The frame is an original complete with 'Otter Product' sticker on the headstock.

Engine is WD GB alloy barrel, trials gearing etc.

I bought the bike locally from a friend of a friend, was in a bad state, bent valve/broken guide; wrong length primary chain; dodgy fixings everywhere; leaking fuel tank etc etc.

I've rebuilt the top end, fitted new tank, new fork yokes, bearings and seals everywhere!

New sump guard, footrests, bars, alloy clutch, exhaust...too much to remember!

Runs well now, I've ridden it in the last couple of Bonanza trials with no trouble whatsoever.

Regards Mark.



From 2010, start of the BSA Otter web site


Now that the story about how the "Otter" was born, and the interest that seems to be growing every day, about these bikes on this site, I thought Harry better have a page for his bikes, has I now keep finding out more and more about the guy.



This is the frame kit that Harry started the Foster "Otter" breed with.



This is Rick's well worn Foster "Otter", that he bought in Oxfordshire, with probably a GB BSA B40 engine supplied by "Johnson's  Cables" from Banbury.

They seemed to supply most of the engines for the "Otter" projects at the time.

It was during the period of the Foster "Otters", that the WD were selling of the surplus spares for the BSA B40's. The last of the British built bikes supplied to them.


We would love to hear from anyone still owning a Harry Foster built "Otter" in any condition...


Here Is another that Lives in Belgium, and was ridden in the 2016 TALMAG trial by

J Castiaux.



Photo Courtesy Ian Ballard.



I am personally looking for a frame to rebuild for my youngest grandson Edward Prescott for his first birthday.

If you remember his brother owns the John Draper BSA B40.


Although Harry had borrowed BOK228C from Colin Dommett to build the jig from, he took the decision to make his frame better, has you would do, upgrading any design.


So for a start the swinging arm box was made slightly wider, for better tyre clearance, and a new swinging arm was also fabricated to take advantage of the extra width now available.


Later frames had the swinging arm box dropped slightly, to give more ground clearance etc...


It was Harry's philosophy, that if he was going to fabricate this new frame kit, he would build onto it every bracket and fixing for the engine to be fitted.

So that the new owner of the kit, would be able to build up his new machine using this kit, within twenty four hours of receiving it if they wished.


Well we know it does not work like that? But It Could be done.


But the philosophy was right, the frame was designed so this could be achieved! That is how the man worked practical to the last detail.


When I have sifted through what I have, I will place the stories onto this page.


Now If you have a "Foster" Otter, please let me know, about your bike and how you came to own it? We would love to put the story onto Harry's page too.


And don't forget I am now looking for a "Foster" frame, if you have one you don't want.

The above from year 2010




Carol and Harry Foster also enjoyed years competing with their superb Triumph trials outfit, before Harry concentrated on doing what he loved best constructing engineering master pieces. This trials outfit was one of the items that quickly gave Harry the tag of being a suburb engineer.

 The frame for the plot started life has a Rickman Petite Metisse scrambles, Harry then attached his integral sidecar to this. Front forks were Bultaco. The engine unit was a really special affair. The Unit engine was fitted with a BT-H magneto running directly from the inlet camshaft; it was that good a job it could have been done by the Triumph factory.

Harry and Carol had numerous victories on this outfit, but the best result was becoming runner up in the 1975 British Experts Trial.

 After years competing on this super outfit, it was eventually sold on to. Anthony and Marcia Beeching to compete on...



 Carol and Harry riding in the 1975 British experts trial, finishing second sidecar, on the day.


Photo Courtesy Deryk Wylde ORR.


 This Below is I believe one of the missing "Triumph Foster Otter" frames, being put to good use at the 2010 Classic Trials Show.



Anthony and Marcia Beeching, competing on Harry and Carol's old Triumph Metisse outfit.


                                           Photo. (Offroad Archives) Deryk Wylde.


Harry also built over "eighty" trials sidecars for other people including the ones for the Fantic team. 

Here is Will Hawkes and Howard Crafter with a "Works" Fantic fitted with a Harry Foster "Otter Products" sidecar...


Photo Courtesy Will Hawkes and Deryk Wylde.


Will replied to me on Trials Central,


Posted 05 May 2016 - 07:01 PM

Charlie don't forget that Harry made many a fine sidecar as well as the solos.

I can remember stopping at his house for tea in the days when we rode the West of England trial on the Saturday,and the Otter Vale on the Sunday,when Harry would come out and ride one of his outfits and beat most of us, great days, Will...



So I replied to Will.


Posted 05 May 2016 - 11:37 PM

Hi Guy's.


 Hi Will,


Harry Foster, was one of those guy's that left this planet to early.


He would not describe himself as anything, but was meticulous at anything he did.


I am only glad that I have been able to bring a bit of recognition to the work he carried out, putting his interpretation into the forward thinking and simple design for a trials frame to achieve a 

winning formula, started by Scott Ellis and his father, then aptly improved and adapted by Harry Foster, and also given a name that has stood the test of time, that is the Foster"Otter"...


The Otter frame, and Harry Foster, in my mind are "Legends"...


Regards Charlie.




 Below are some New pictures sent to me by Ian Ballard of his "Foster Otter" Triumph frame.



This is a New Foster Triumph "Otter"frame that Ian Ballard bought from Harry many years ago.

 And he has pledged to finish building the bike we will follow the build.

Now being built and has its own page. 2021...



We could only hope for detail about the Foster Otter frame like this to emerge a few years ago.



This shows that Faber made a good job of copying Harry's frame!

I do like the swagging of the seat tube to give more chain clearance.

One thing not copied by Faber.

I must say that people that have ridden both the Foster Otter's and the Faber,

have always said that the Foster bikes always handle a lot better...

I don't know until I try a Harry Foster Otter...




Good luck with the build Ian, and if you need any help we are here.

And thank you as always for backing me from day one with this website, and helping make it what it has become today. OK.


The last Harry Foster built "Otter" frame from the Foster Jig.

Photo Courtesy Jean Pierre. and Rockshocks.


This is Dick Ramplee competing in France, on his BSA engined

Foster Otter.

The last frame Harry built to come out of the Foster frame jig before I  took on the challenge to use it...

The frame Harry built to take a Triumph motor, and for himself to ride. But it was not to be... So Dick decided to fit a BSA unit into the frame. Probably with some input from George Greenland?


Photo Courtesy Jean Pierre and Rockshocks.

One last action photo of Dick riding the bike again in France, for now, but I hope to get the story behind the build of this machine later.




More updates Later. And don't forget Breaking News Shortly. OK.  October 2016.



So We now have a "Foster Otter", as you will know.


And a New frame for me to build into a bike should be off of Harry's old jig next week. 09/ well.



It is amazing how old news, if you read above gets changed with NEW knowledge about the item or machine come to that.

I could update one of the other Foster Otter Pages, with the information I now have, but it seems more appropriate putting it onto this page.

Don't forget I have several Faber frames, so can check these for the difference, between their version of the "Otter" frame and the original, the Foster.

One thing I soon realized when stripping the newly acquired Foster Otter last year for rebuild, (and that is in the process of rebuild now),

was that every part of the Foster frame was built down to a minimum, with no excess metal where it was not needed, this makes the frame lighter, and just seemed to me neater.

But you can see that Harry spent hours hand crafting every part.

Laser cut parts were just not done then in the eighties.

Surprising was the width of the swinging-arm, an inch narrower than the Faber copy, this would account for the swagging of the left hand seat tube on the Foster frame, but the Foster arm is also slightly longer than the Faber.

So you are thinking there could be clogging issues with the Foster? Well Harry used  1,1/8" tube for his swinging arm, the Faber is 1,1/4".

So does that extra inch of width with the Faber make their version balance differently?



The steering head angle is slightly longer on the Foster than the later Faber Otters, but the Mk 1 was said to be the same, and I have had comments about the Mk 1 Faber handling better the the later ones. 

Steering head angles are a compromise to what suits you, and not what you are told steeper is better, because it is not, in most cases,  unless you are into trick bike riding.

Harry's bearing retainers for the 2" taper roller steering head bearings  were just two simple collars over the tubing, where as the Faber's are machined cups that sit inside the tube. 

So the Foster method again saves a bit of weight but are just has strong?

It is little bits like this, that you can see that Harry put thought into every part of the frame, and tried not to over build it...

The subframe on the Foster, is more like the original Scott Ellis bike Triumph Cub, and about the same shape, where-as the Faber loop is wider more like a BSA C15, again I have comments about the Faber loop, being too wide. But I must say I have no problem with that, but other people seem too.

The loop is easier to bend like the Faber loop, so that is probably the reason for using it.

The cylinder head steady is another little item that has taken a lot of thought, Harry obviously thought this was more important as a "Third" engine mounting, and spent  a lot of time making this item fit for the job, and a bit over engineered, but does this make the difference in the handling of the two breeds, this is the question...

I will continue with this when I start to build up the New frame into a bike, and use the photos of this build so that you can see the differences.


I am not knocking the Faber frames, and I love mine, but just showing the difference between two frame builders interpretation of the same design, and one did use the others product to copy.

My interpretation the "Otter On The Cheap" is different again.


More Later...