BSA Bantam Race Preparation Manual

2015 BSA Bantam Race Preparation Manual

Derek has asked me to post this piece on his behalf on the forum, as he is still not allowed to do so?

It is to be hoped that newcomers and current racers alike will find a new, modernized hand book enjoyable, informative and factually instructive.

The old, existing manual should be left as is and nothing taken forward to be included in the new, second edition. That stuff is, in the main, outmoded and obsolescent and firmly rooted in the 60s/ 70s. Technology has moved on significantly since then. Anecdotal nostalgia is always to be enjoyed, but we are in the 21stC and such stuff as that, in the main, is not! One might suggest that: the moving hand having writ, moved on!

The growth class, based on do-ability and cost is the 175/186; and should be prioritized. Only the odd one or two people could attempt and finish a new 125 because of the extensive re-engineering involved and cost, hence all of the re-use of existing engines that takes place. But there should be adequate space for these more sophisticated engines to be described and analyzed, be they air or water-cooled. It is around these engines that the majority of technological progress in Bantam racing has been made!
Not everyone feels comfortable in writing for public viewing so perhaps a ghost writing, or editing collaboration could be set up to guide, help and assist?

Number one essential is to ask the current 175 champion, Michael, and also Robbie if they would be willing to contribute a construction and preparation article on his engine. Every big Bantam user is also invited to add to the bulk of 175/186 information to be made available.
There is nothing more persuasive than reading an “I did it this way and won, so can you!” article and then the reader being inspired to do like-wise!

Rex should also be asked if he would offer an article relating his motivation, experiences and details of those spares and services he offers. Brian White, very importantly offers his source of heads, barrels, bits and services and is also a must for asking for an article should he be willing.

Impartiality must be seen to be applied in all instances.

Common to all engines is the gearbox, the current debate has produced a lot of advice in solving problems and offering improvements and is a must for inclusion. There are no more new sets available so gears and shafts will always be a crucial factor. All of the BSA drawings and data sheets could also be included. Tom Miller`s various conversions and services should also be detailed, and of course Brian White also does a lot of gearbox stuff, the photo montage of his workshop and engine stuff from the Bantam site would look impressive!

Something else essential to all engines is the exhaust system and also the methodology of arriving at realistic dimensions. Again, not every would be racer is comfortable doing the maths involved, so a step by step example to walk people through would be of great assistance. Also important are the reasons why a pipe functions as it does and the effect it can have on the power output.
I`m happy to do this, but if anyone else prefers to, I don`t mind one bit!

Other inclusions can be combustion, chamber profiles, squish action, compression ratios, ignition systems, carburation and a whole raft of other things.

Careful pre-race engine assembly is critical to success, if there is a volunteer to write down his sequence, methods and advice for doing that then a lot of mystery can be removed for the newcomer?

The old manual has never included the frame and cycle parts and a race setup, the new one should. Nothing too sophisticated but based on the twin shock D7 frame. Mick Potter is the obvious choice, and it did occur to me that if he got a standard frame and did a step by step photo shoot of progress then that would be a real innovation, including suggestions for front fork and brake options.
The more help and instruction potential Bantam racers have the easier it seems the task is to achieve, and the new manual should be seen to offer as complete race conversion package for the newcomer, as is sensibly achievable.

I have missed out loads of other detail but equally important stuff but that can all be included if the venture ever gets going.
All is open to debate and restructure.

Derek has very generously suggested that he would be willing to underwrite publication costs. This is very much his idea, but is totally accessible to everyone, and I for one think it a worthy and long overdue innovation, and it does oblige us all to thank Derek.
However, the contents will be what other Bantam enthusiasts want and contribute. It all depends on you guys to, firstly, indicate that the enterprise is worthwhile, and secondly the offering of articles to be included!
Given the correct amount of input it can be a very fine, impressive document, that will promote the cause of Bantam Racing in a serious and authoritative and yet inviting way!

What do you think, it`s all up to you?

Trevor

Great Trevor!

Brilliant idea...

But what was the `Old manual?´ -- I only ever knew of Roy Bacon´s "Racing on The Cheap" and I´d say Roy´s
bike prep had some very good suggestions as to how one should go about the job, bike and engine. There were a lot of good suggestions posted in the Bantam Racing magazine to which a great number of the Old Boys contributed -- are those notes to be ignored as being the Old Manual? What of Alan Brown´s copious notes on here? Maybe they were not publicised enough.

From what was said & shown  of Champ Michael Brown the pics of him have ever been with his total engine in bits and I wonder if Michael changes things like rings and seals between the weekend´s race days (or should I say night) in similar fashion to Maurice Quincy changing the piston ring between practice and race because of thin ring wearing so rapidly with the Walsh Bantam !****
Michael must be commended on the work he puts in as well as the racing bit....


Of course, the New manual must be up-to-date but some of the good OLD ideas oughtn´t to be thrown out the window as outmoded. Certainly we didn´t go to Mick Potter set-up of suspension because such was in early development in those 60 - 70 days and I think care should be taken about what is thrown out ....

I go quiet now -- I´ve said too much already, perhaps -- and my ideas are definitely Old hat!

Good luck with your endeavours.

Go well and stay well,

JayBee.    

**** Is that ever OLD -- the Walsh Bantam used a megaphone exhaust -- funny thing was it won a great number of 250 Class races....

Evening Trevor, Derek,
    sounds like  a great idea. Obviously their maybe some who feel they need to protect there modifications/ race set up, which is understandable when they have perhaps spent many years,man hours and money to arrive at that "EUREKA" moment when it all fell into place. Rexs posts, which have detailed his progression with his 175/186 engine, have been very informative and i feel  has been very generous in giving that to us.Also the information posted by Robbie , with the regard to his and Michaels  175 engine, again very generous, Mick Scutt a while ago detailing Tom Snows engine. Bringing this and other engine preparation into a formatted ,detailed  and  updated version of the " Bantam Tuning Manual", can only be a good thing.
 

Thanks to both of you, just the kind of enthusiasm and positivity we were hoping for.
We can pull all of the articles mentioned into the new manual, I`m equally sure that the respective authors can add to them in light of more experience and improvements.

Spread the word, much more, encouraging response is needed, just a simple, "Go for it" would be helpful!

If any one has a particular subject they would like to see included, write a post and tell us, or a PM, this is a manual for racers by racers.

Trevor

This sort of thing only help, a worth while project, a few are getting race bikes to shows and a booklet manual on hand along side would I'm sure be useful .

What a brilliant idea.
If you put into a word document to upload on here, then accessible by all who need it and they can print themselves.

Dan, Pete, thanks for the comments.

Being able to view both a machine and a technical handbook that relate directly to each other adds a whole new dimension for interested enthusiasts to form an overview of Bantam racing today. So yes Dan, a great idea !
I can just visualise dads going home with young sons, both eager to delve into the pages of techo stuff and grab a Bantam!

On-line viewing of the manual is very possible Pete, would need some co-operation from Alan but it has to be a positive move, in keeping with our modern digital age, I my self always prefer hard copy.
Is this a possibility Alan, some input from you will be appreciated by all interested parties as to the feasibility of Pete`s suggestion ?

There is some momentum behind Derek`s proposition, but it won`t go any where unless the majority want it to, but then, what`s not to like, every one gains ?

Looking forward to hearing from you all!

Trevor

Trevor!

I was not trying to be awkward -- there are some worthwhile old ideas that cannot be dropped ....

A few  years back Derek thought the idea (I´d suggested)  of a "Downhill Cruising" test -- bike and rider,  dead engine -- or some dead-engine/gearbox components being driven -- was a worthwhile exercise. He told me he thought it a good idea and was going to try it.

The idea is that if some component is producing  dragging loss then it will show up in the time taken to go from the top to bottom of the hill having (sine theta) gravity doing the driving.  The effects of `Reduction of the flab´  can be seen  if the hill is steep and long enough.
Length is more important than steepness (I wonder if that raises eyebrows?)  

Difficulty is finding a hill where one can spend a few hours testing with no outside interferencve . Also when testing of things like gearbox drag with different oils really good time-keeping is essential.    

I know the difference of "Low" tyre pressures and rubbing brakes does show with trucks...

So Trevor, please! since I cannot speak to Derek you might ask if he did try the "Cruise Down Test" and pass on my regards....
Thanks.
Cheers!

John.

Yes of course I will pass on your request John.
It sounds an intriguing and fun exercise, I`m sure you will have a reply in due course

Derek is able to read all that is posted here but is prevented from replying in person. Daft thing is his words can be posted by someone else??



Perhaps the example of Irish Republicans and the British Monarchy shaking hands in reconciliation can be considered by the Forum controllers.

Trevor

Thanks Trevor,

I probably needed a phychiatrist re Race Preparation for Snetterton -- it being my jinx circuit -- in the days of the Long,  Old Norwich straight compared with Llandow being like a tarmacked  grass track without any left hand kinks...

A lot of us would  walk around a circuit -- first time there. Sort of calmed the pre-practice/race feelings of unease. Feeling too confident was a sure indication I´d fall over  at Snetterton. Come to think on it all my broken bones with BRC racing happened there.

I guess that getting the ratio of GearBox and Rear wheel sprockets combination right for the circuit compatible with the engine performance goes without saying but there was an occasion at Brands when the combination I´d used during a earlier race meeting was not suitable for changes we´d made and a lot of valuable race practice time was lost to trying other G/B to R/W combinations ....

Not much use for a Race Prep Manual but I always had an enjoyable meeting when I went through every bend in my mind the night before and then piut it out of mind and getting a good kip.... A good night´s sleep before race day is essential ....

Cheers!

Ps -- I didn´t always stick to that resolution and regretted it on race day.

I´ll curl up and go to kip now --  hogged too much already.

Soon be 86 and and wondering how that could have been possible ...

What happened at last weekend´s Anglesey Bantam racing?

hi all, i too think that an updated manual would be an asset to new builders, myself included, perhaps it would attract more people to the 175, as proved by rex and nick that an almost standard bantam motor can race, their efforts have inspired me to collect the necessary items to create a similar motor.

Thanks for the positive reply Adam, just think how much further along you could have been with the assistance of a bang up to date, broad ranging manual?
Let us hope that the whole thing materialises, there is plenty of enthusiasm in some quarters but, seemingly, indifference in others, we can but hope the "rolling ball" draws every one to the cause.

Trevor

A Manual would be better than anything posted on this site...

Whatever it be on this section  it´ll get pushed out of the way by sheer quantity of chat,,,, Useful chat mind -- but it gets lodged away somewhere .... ??

Several people have contributed to this same subject -- partly, or in different ways -- on this web-ste. By the number and variety of questions asked on this Chat section those other sections have been ignored.

For instance,  under the heading "BIKES" there is "Tuning Info"; "Build a 175 Racer"  by Alan Brown; and "Bantam Racer"  and under the Heading "RACING - Getting Started" a lot of info about how to go about it.... I wonder how many times those sites have been opened....?

Either the readers have insuffiient time to read those articles (under those headings running along the top) or just plain miss them yet they are there . -- I remember now, reading one by Peter Tibbits  which was also -- like Alan´s very good...

No,  you are right Trevor/Derek a modern manual is needed that newly baptised  Bantam (and would-be) racers can have with them in the garden shed -- or even down the pub.  
Go ahead and good luck to yee...

Cheers!


"

John,
Reacquainting myself with the existing manual, that had its genesis back in 1978, it became very clear that a reappraisal of those articles is necessary. It is quite feasible to update some the near 40 year old stuff but so many of the fundamental recommendations and suggestions are simply remnants of that era, important in their day but not so for 2015 and moving ahead.
I don`t see a fully modernized manual as being just another, “do, a, b and c and you get z!” style of document, but one that delves into the, “why and how” this data is arrived at, the reasons as to its functions. The science and engineering behind all of the engine functions, but presented in an accessible way by deconstructing the mysteries!
As an example of what can be included in the hand book, let`s have a look at the exhaust tail pipe, the last element in the entire gas flow regime through the engine, and is just a simple circular pipe. That gas flow of course starts with the carburetor bell mouth and is finalized at the silencer outlet.
In the existing manual, recommendations are made, that’s fine, they work, but could something else work a lot better for you?
The tail pipe is a restrictor, and the more the restriction, the higher the average pressure in the pipe is, hence a higher temperature and less expansion of the gas, higher resonance rpm and speed of sound.
The required flow restriction is dependent on the amount of gas the engine produces, and that is proportional to the horse-power produced.
But, if you make the restriction too small the exhaust gas will not be fully evacuated in an engine cycle, so when the transfer ports open that gas will flow back into the transfer ducts and both dilute and pre-heat the mixture waiting in the crankcase. The consequences of that happening will eventually be engine failure!
That brief resume` is by no means the full story, for the exhaust system starts at the cylinder port window, but just a flavor of what information can be available to the new generation and oldies alike.
None of the forgoing is in the old manual but can be in the new if it is what members would like? The important how and why`s, of two-stroke engine and in particular, Bantam tuning today.

Trevor

Point made Trevor... but I was not concerning myself with  out-of-date  detail.....
.

Make it a manual, like an old-fashioned book -- that´s what I meant  --  and New Boy has it in his pocket ready to read ....

Cheers!

Go welll and keep well,
John-Boy.

Oh dear John. I wait for your contributions and attempts to keep it simple. No joy friend. This `manual` will be a tome and the poor novice tied up in a load of technical detail without knowing what provides the rpm or the torque required for him to enjoy. The chapter on the head should not only confuse but create enough damage to keep the poor bloke tied up expensively for months. I think what is needed is simplicity and enough pointers to where one can obtain deep technical explanations even though they may not apply to Bantams at all. The enormous value of simplicity is lost in the search for the secrets that govern performance. There are no secrets and to improve the power output they have, at great expence, added some delightful technical do das that have nothing at all to do with Bantams. There is something else, far more important, that worries me. The rules. What is the point if those who want to bend them are congratulated. The rules are for you and me not for the `wise` who, like the bankers and other sharks seek to profit at other`s expense. No. Don`t start with the tail pipe and the frightening results of doing it wrong, start with the blowdown period and its simple but huge effect on the whole performance. I would suggest you take the old manual, modify it to show what equipment is available and imagine you are catering for a Bantam. You may have made a mistake John declaring your age. It gives the impression that you are mired in the sixties. They are still trying to get fresh gas into the head and it hasn`t moved on a lot. Terry Beckett.

My experience is very much out of date, but still (I think) relevant. The matter of modifying/preparing a bike for racing should be treated as a separate subject from that of two-stroke tuning. The former is essentially a practical process, which a beginner needs to sort out in order to have a race-worthy bike.

To overwhelm novices with all the arcane, confusing, and often controversial, stuff that comes under "tuning", is likely to discourage them.

There is already a good bit of helpful advice on getting started on the Bantam Racing website. It just needs to be collated into one article, or booklet, along with a basic set of port shapes/positions, carburettor types, exhaust dimensions; a known set-up that will yield a good, reliable result. Or two set-ups - one for an alloy barrel, one for an iron barrel.

When our brave beginner has got the basics sorted out, and has performed reliably for a couple of meetings, it may be time for them to look for advice on making it go quicker.

If it were possible, could a little thought be given to some youtube content to back up the 'word content'.

Good idea Jimmie,
                         In our digital age almost anything visual and transmitable is possible, what, specifically did you have in mind, racing footage, engine assembly, frame conversion and so on?
Just to reassure you the new manual will not be solely word content, photos and drawings etc, will be plentiful!

Trevor

Simple little but important issues such as handle bar/tank clearance, 'correct' application of gasket goo i.e. hermetite, cable adjustment, etc. I appreciate most can be found on the net already, provided the enthusiast has the background knowledge to look for them. Even links would be better than nothing.

That`s fine Jimmie,
All of those points noted and are in the "to include" folder and the camera man will get it all in due course!

Cheers, Trevor

Here is an offer, why don`t you, John and Terry, collaborate in compiling an article of your own to be included in the new manual, containing only those things you both feel necessary for the beginner to progress with to such a point where an upgrade is necessary or not, as you see fit?
There will be room I feel sure for all aspects of Bantam conversion to be aired, from a heap of bits, to a race winner I would hope!
What do you both think ?

Trevor

Trevor, my previous post in this thread was meant to be a helpful suggestion - nothing more. I'm flattered that you think my fifty year old experience of building a racing Bantam might be worthy of inclusion in a modern "How To" handbook, but I think not.

I speak for myself only. The other Old Codger you included in your offer may speak for himself - or not.

I can think of nothing better than Michael Brown`s series on machine preparation. It was detailed albeit daunting and I wonder what needs to be added after some judicious editing. The other article I read was that by David Hunter on engine preparation. Written by a genuine, thinking expert. The object of Terry Beckett Chat was to simplify the concept of “Tuning” and originally, to examine the future of Bantam racing and the specifications necessary to achieve it. What I found was a plethora of highly technical information that served to confirm, or otherwise, my assumptions and needless to say I read it avidly but I couldn`t apply a lot of it to the Bantam. Perhaps, the most helpful way of helping a would be racer would be to get together the salient points and provide the way to access the most helpful information available. The Forum could be the key to question and answer expertise. I would be glad to participate under the heading of `Tuning`
Terry Beckett