Is it time to ban....

Airboxes?

What do you think? When we came over to BHR our formula was even more open than it is now.... and in 2003ish we tightened it to make it more in keeping with the rest of the stuff out on circuit....

Out went - any back brake - to bantam hub must be kept.
Out went - any front forks- to conventional forks (not USD).
Out went - Carbon disc's and wavy disc's - to normal disc's.
Out went - any wheels - to remain wire spoked.

So what about Airboxes? I think we should ban them - at the mo, nobody has one.....

Mike

always believed these were the rules anyway.

always believed these were the rules anyway.

I think Andy Moulden has an air box on his bike, I don't think its fair to ban his bike especially if he's not racing !

besides he may be considering a return

In my opinion we should leave the formula as it is as there are some bikes with some sort of air box, if only an elaborate stone guard. We must also have some ways to try to improve as this is the essence of Bantam racing. Air boxes are not easy to get working and I feel they do not detract from the appearance of the bikes when viewed from track side. We probable all tried big flour sieve’s at one time to stop stones but not many use them now. I want to try when I return to get an air box working, as there must be an advantage or the rest of the motorcycle world would not use them. So I do have a declared interest.

Like Mr Smith I should declare an interest in air boxes,

Mike,

I would be interested to know what prompted the question, is this a BHR committee topic ?

James

Hi Mike,
If no body is running one seems a bit pointless. has someone got one under wraps ?
My understanding of a good working air box is that it has most of the benefit at high speed so could make things very difficult with carbs that most are using at the moment, i think most systems need lots of electronics to really work well.
As one 125 has a box how about no air boxes for 175s ,also as these bike are ment to be the more basic bike to build.

cheers Nick.

Hi
...the worse senario for a reliable bantam race bike must be a 4sp 175 with an airbox!!!!

Ian had an airbox on the Roger Louis bike for a season and rarely got out of the paddock!

Andy Moulden 58mm stroke bike had an airbox and when Paul bought it I tested it a Mallory
and couldn't get it to run with the airbox on! so i took it off....

So there are no bikes with airboxes on !! We are all the same - bit like a level playing field??
like everyones body weight/bike weight being the same? Nick the time to change things is when
nobody has one and not when somebody- HAS one!

Data logging can't be banned because people now have them - if you want to be the same get
yourself a data logger??

James I was just interested in peoples view point on the subject - I think an airbox is an achilles
heel but I don't mind being proven wrong!

Ref BHR no nothing came from them - just me ... but i'm a luddite at heart lol....

Mike

Hi I beg to differ,

I have a different opinion, I don't agree on the air box being allowed or dis-allowed, the air box rule should be down to the person tuning /riding a 125 or 175 ? no matter, besides all motocross and road bikes have them!.

I'm sure they are a waste of time, without the electronics, to manage stability with the variances of air flow, pressure and fuel. what we should do is ban the electronics that will make them work.

However on Andy M - BOX , I heard a different storey, that it worked fine before it had a lot of holes drilled in it!!!!, that affected it before it was removed, sure AM could put substance to this storey.

But I do agree with Mike on the data logger, they should be banned, just not required.

All this electronic stuff is just to complex! and another thing to go wrong!.

if Ted wishes to try an air box, he should be allowed to, beside it should slow him down, while others catch up. ?

James you don't need an air box either, especially with Al in your pit crew. ! it shouldn't be allowed either.!

As someone bought up the weight topic again, I would like to agree with Mike, and say I would like to see all light riders and the top three in championship the previous year, given time penalties.

so as it's already been discussed and decided policing would not work, I have been reading up on this in other sports, car rallying give time penalties for weight, as Robbie has said, they have scales at mallory, I propose for all bikes and riders to check the combined weight, I will volunteer to work out with my calculator how much time you all need to add to your race times, C'pt james i promise not to make a mistake with yours, but it would be a good idea to be nice to me.! just in case i forget I said this.!

so effectively if you finished in the top three of the championship, or you are over light, you get time penalties, I have worked out in advance of any weights, what these time would be based on with my very accurate calculations on your weight or where you finished in last years championship.

you would need to add these times to each race time, for the following times for riders:

rider name / time to add to race time /reason
Ian +2.min 55.9 seconds championship + weight
Robbie +2.05min weight
michael +2.10 weight
james c +2hr 45 seconds, weight
mike p +3.05 seconds- championship + weight
peter T +2.58 seconds - championship
mike R +2.10 seconds weight
Tom s +2 .30 seconds weight
D.betts -0.30 seconds interlectual capacity.+weight
F frane -0.30 seconds weight
C Bennion -0.20 seconds age+weight
as I have had no response to this, I assume you all agree with it being unfair then. !

serious I feel the current underweight riders have too much of an unfair advantage!.

Rgds Derek

I agree with Derek in disagree-ing with everything his says,thinks and posts..

underweight people .. time penalties....

Data loggers are here and been in use for 15? years You can't move the goal posts...

I wish an airbox upon you .....

Mike

steady Tiger

Mike How do you know what I'm thinking" - So how can you possibly disagree ? of course I did not expect you to agree with it all, just something to consider, actually I was agreeing with you, on one point, but not on the other ! and making a suggestion on other possibilities on how to make this weight subject fair.

I understand its important for us all to have our say, I was half expecting a coloured nose comment, but surprised Igot this lf Ihave offended anyone I will appologise, but I will re read my post. and respond.

now can I remind you "it was not me" who bought up weight again - Robbie did (it was his fault) but then you commenetd on it so i believed it was an open topic again

"I'm thinking again" are you agreeing or disagreeing with me this time. !

I think looking at the post there is actually an interesting pattern and a light hearted comment about the mathematician !.

This forum could be dangerious, ??

kind regards

Derek

I had not heard of AirBoxes on a Bantam before...

... and have to ask why it is assumed that they don´t work -- also that some say they should be banned??
Resonant exhaust systems are allowed so why not resonant intake systems? Its all part of the development.
...
Of course, if you look at the Walsh Bantam as test-ridden by Bill Lomas in his report you´d have to ask why bother with a resonant exhaust pipe? The pic I saw of it showed a megaphone exhaust. Part of The Walsh development seemed to be `Reduction of Friction Forces´ of which the piston and piston Ring(s) drag amounts to a considerable amount ... Walsh used a single, 16thou thick ring which required changing between practice and race -- there was no mention of cyl barrel wear.
...
What I understand of AirBoxes are long induction pipes, one per each cylinder (taking up a lot of space) connected to a box without an air filter or any obstruction to air flow....?
...
Maybe you´d fill me in!
JayBee.

PS -- we didn´t even have a bell-mouth (venturi) on Icarus-1´s carb and a proper developed bell-mouth can assist air-flow ... albeit a small amount at one particular speed.

Derek I accept your apologies.....

I wasn't agreeing with you in the first part or the second but maybe the third part ? not sure now?

Whatever your thinking of.... Stop.....

John mentioned - How does an airbox work? (or not work?)

Anyone know?

Derek i don't agree...

Mike

Mike,

Thanks, I did wonder if it was something that came up in a meeting that you were pre empting, my interest in an airbox is all to do with stabilising airflow in the hope of getting more carburettor control. I am not expecting any performance benefit beyond a more manageable torque curve.

Derek

Thats the point in the electronics, to collect data for analytical purposes, maybe even run some CFD.

I am not chasing performance I am chasing a reliabilty but don't have 30 years of knowledge so need to accumulate it quickly.

James

Hi Mike
- your welcome "no problems" I have said before, no need to apologise to me. We can discuss this during our next review along with drops / rider -bike combined weight / air boxes / gear boxes / data lodgers.


Hi James, thanks for that, i will respond when I get a moment.

Derek

Derek,

Could you also include the prices at the bar, the weather and Al Browns aftershave all very important topics that need resolving

James

We called the development work, "Induction Pipe Length Effects" whilst we were developing an air-cooled diesel engine in Canada.
Obviously the pressure pulses -- running back and forth in the pipe -- work the same as a resonant exhaust pipe does. With the diesel 4-stroke, in tune with the inlet valve opening & shutting of course. It is the same effect as "Water-Hammer" you get when rapidly shutting off the flow by a valve in a longish length of metal water pipe, it `Hammers´ loudly. Pressure waves caused by the rapid valve shutting -- rush along the pipe at the speed of sound...
---
To get a showing of torque-curve improvement -- which was the objective of the exercise -- we needed long pipes (as many as were cylinders) which had to be serpentined to fit into the space we had for the engine. THIS SPACE CRAMMING & ADDITIONAL COST was the reason for dropping the idea.
Porche use long intake pipes on some of their high-performance petrol engines and on one model the intake pipes go horizontally outward, both ways, to the full extent of the car´s underbonnet width.
...
What I could not visualise was this being done on a Bantam?
Is the "Airbox" actually a long induction pipe serpentined inside a BOX?
---
I just cannot visualise it....
Cheers!
JayBee.

Since I knew nothing about the subject of Airboxes and there was NO reply on here to my query I did a bit of research and what I came up with was not tuned intake-air pipes -- serpentining all over the place -- as I had thought the "Airbox" to be but a very similar set up to what the resonant exhaust system is & does -- only more simple to make than a resonant exhaust pipe...
Yet it still seems a very clumsy `lump´ to incorporate on a Bantam and taking up a lot of space...
---
The one I found has a bell-mouth intake venturi attached to the carb -- such as you´d see on many carburetors. There´s free air-space to a straight pipe in which there is is a `Flowed Deflector´ which I think must act in a similar way to the Diffuser in the resonant exhaust pipe. Surrounding these two -- and obviously fixed to both is a circular box. The carb end of this box is fixed to the bell-mouth´s parellel portion (ie closer to the carb) and the other end a considerable distance along the straight pipe which means this surrounding cannister could be bigger than the Bantam cylinder barrel: Hence my remark about its size.
...
Now, as I see it, the engine sucks thro´the bell-mouth venturi at the same time as drawing air from the diffuser and from the surrounding atmospheric air in the airbox. The tricky bit is how much ventilation has there to be in the surrounding casing of the air-box?
What I visualise is that if tuned correctly it would increase the air-charge over a fairly wide band of engine speed hence bumping the BMEP & improving the Torque Back Up*** whilst operating in that speed band -- which I think was the intended ovjective.

***Torque Back Up:- as the engine speed drops the torque increases.

Corrections from members who know more onthis subject would be greatfully received -- at least some sort of response because suddenly this seems to me to be a bit of development lacking in Bantam Racing progress.

Go well and keep well!
Cheers!

As with forks, why did they ban USD's? I've found a few quite adequate USD forks that are a perfect fit for a standard Bantam frame... Aprilia RS50 etc.

T

Right Tim!
Unfortunately many of the old BRC members wanted the Bantam to look like a REAL RACER so the fairings were allowed in -- and even I appreciated the change it made to the appearance -- look at my Avatar and see the Grotty Look of Icarus-1 as cheap as anything on a pair of wheels could look! compared with all the others wearing skirts!! -- that is -- otherwise, I was proud of the machine... made mostly from a load of scrap, yet sporting a cadmium-plated frame (by kind permission of Leyland Motors Ltd -- done bucksheesh by the blue-collars on nightshift there during my visits for Simms, Finchley).
...
The fairing, of course, increased the cost, then the Bantam forks were "not quite the thing..." and we went on changing the Formula -- some really progressive changes, I must add: reed valve for one -- until `Racing On The Cheap´ became, "Just a bit cheaper than racing a Japanese 2nd Hand Racer."
...
With a family -- 2 kids and an observant Officer IC to care about -- and loads of family bills to pay I started building Icarus-1 because I knew it would cost less than a 100 quid (80 something in the end! because we found our 125 engine in a field!) without any intention of racing it -- just keeping my hand in, as it were. And one could not really say "racing" when to be competitive one should compete in every meeting of the season which in my circumstances was not possible.
See what happened when Peter Tibbitts attended every meeting -- he won the championship.
...
So, why should an Old Gitt of a Hasbeen like me bother to write all this crud just lately?
Fact is I was always smarting about the fairings and the fact is we really killed off one of the prime reasons for the Bantam Racing Club existing at all which was what we all knew and ex-BRC Chairman, Roy Bacon called his book, "Racing On The Cheap".
...
Well, I reckon that idea could be resurrected. Have the 175 Formula banning fairings, reed valves, electronic ignition and all those things `foreign´ to the memory of the BSA Bantam -- don´t forget the Walsh Bantam was a 250 Giant killer
and its most expensive bits were in the engine ...

Uh oh! I´ll creep away and hide....

I.B. Hasbinn.

actually I agree with John is saying here! he has got a point, not sure we should ban fairings though, my suggestion is you have to compete in 10 meetings before your allowed to use one.

the other topic - I remeber once you won a novice race you became an inter once you won an intern you became a senior, i think,


"now how about" - " wait for it".

anyone winning any race automatically gets a 30 seconds added to his time in the next race, if it means on time he finish second his point accordingly, only applies to race winners though ? think about it, before you respond - as its not as strange as it may appear. ? overall I'm not sure it would make any difference to the championship but it would mean many other winners and close the field up, especially if we could do this actually.

it would alos put more enfo-sis on reliability.

comments on post cards only please


Derek

Derek if we agree to all your time penalties for winning,being light weight, reliable etc, just one of our races will take a whole day

Hi Ian

! That 's the whole idea,"" we got to slow you and the other two numties down somehow. ? I think this is a very fair way of doing it ?" looking at the amount of PM i have had on this seems all the others agree to. !


besides we managed to lose 4lbs off the bike yesterday.

our target is 90kg for the practice day and 86kg by the end of the year, we believe moving to a disc will allow us to hit this straight away.


kind regards Derek

We had Bantam Novices for those racers who´d never won a Bantam race.
When they did win they could not enter Novice races again. Hence it was wise for those hunting trophies to finish second or third so that at the end of the season the Novice trophy looked better with more results on it.
---
George Harris ran two Novice races at his Llandow meetings and generally we catered for about 20 to 30 Novices at each meeting of the year which meant the Inter ranks were always full. George put on 4 Inter races at Llandow which pleased me no end -- such an easy circuit to ride. That is except when Peter Williams sister came to race a Bantam there and got in my way....
---
Having won an Intermediate race the rider automatically became a Senior and could not ride in Inters again during the season of the win. Hence some of us, without the quick bike or capabilitiy of mixing it with seniors, purposely hung back to get more Inter 2nd & 3rd places during the season. In fact I´d do 3 or 4 Inter races and not bother with the Seniors at a Llandow meeting.
---
I think it was the first 14 Seniors who had priority in all Senior Bantam races and went on into the following season as Seniors.
---
When I got to that stage I had the 250ABS (Andy Boyle´s Alpha engined apecial) to help develope and with Icarus-2´s unreliabilty had much ado about nothing in terms of results but there were enough good places to make it worthwhile.
The 250 was exciting ... As fast as the Greeves Silverstone and getting more reliabile when the Canadian job offer put paid to all that!