Bantam Star at Plum Pudding Mallory!!

King of heavy crankshafts and broken gearboxes - Robbie Brown is
giving his Big Bantam an end of season thrashing during the few hours
of daylight availible on boxing day at Mallory Park...

Go Robbie! ... Go Robbie! ... Its your Party!.... or words to that effect....

Robbie will be availible for chats/info and autographs

Evening Robbie,

Hope you got back down south ok ,Weather has been very mild all be it a bit damp.
Seen the you tube stuff (great) and spoke to Tom last week he let me know testing has been going well.
Good Luck at the plum pudding meeting Mate ,go well & stay safe.

Cheers Nick.

I feel sick ...



... sick with envy...

...sloppy nostalgia strikes again...

I went to Brands on Boxing Day -- `68 or `69 it werrr -- was all alone at 09.00 hours, just the old chap with flatcap and home-made fag hanging from his bottom lip who complimented me on my fortitude -- it was bitterly cold -- and told me that there werrn´t no Blood-Wagon until later so it was forbidden to fall orf.

Well, my fingers were freezing and a couple of times the back wheel locked which sort of had me concentrating again and then at about the tenth lap I looked up in Clearways and there on the top row of a wooden sort of dilapidated grandstand was this georgeous looking woman in a bikini ...!!!!???

Well, of course I left the road and did a bit grasstracking with the motor dead...

I was too cold to restart and freewheeled back to the paddock. Flatcap greeted me with, "Overdiditt dinn ya!" he chortled, "Tode ya not to, dinn I. S´gettin´warmer an´ a few more comin´in -- " I interrupted with, "Who´s the dolly bird wearing a bikini, then? Where´s she gone?"

"Ain´t no wimmin `ere mate. `Ere cumm a bit closer -- let´´s smell yer breff...!?"

So it was that I was banned from practice until 14.00 hours -- when the sun came out anyway.

Merry Xmas all and have a good day Robbie -- and Happy New Year ALLL...!1

Hi all
Yes as mike says I am at mallory on boxing day I have 2 races just a bit of fun should be good
I have just finished the bike has been rebuild with smaller flywheels to try and stop me braking gears they are the same now as mr snows looking forward to trying it out

Robbie:- big flywheels breaking gears?? Is that so???

hmmmm! now that IS something to think about until 3rd Jan 2012 (be back from Süd Eifel then...) --- I must have a quick look at how many Joules of energy a BIG flywheel -- 14inches weren´t it? Giant size!! -- makes? It certainly many times more than the 96mm dia job because the increase is the square of the diameter -- the bigger they are the more they feel --- whoops getting out of hand again...

14 inches I measured ...

...from your pic Robbie...

Q? -- a big question! how many times have you broken gears when using your big flywheels???

I think Mr Carcreek also broke some gears -- at Lydden, was it? Small crank on that one!!

Sounds rather ominous! To start off 2012 with the thought that gears are prone to break ....????

Trevor!! -- are you sleeping there below? -- wake up son!

JB should that be 14cm?
14" won't fit in the cases!! I think std wheels are 5and1/2"?
With Robbie running a Snow rep crank, we will find out wether
it was the big wheels or if Robbie is mechanically brutal to g/boxes.
I think the latter - he needs a small mass crank and a smaller right
foot! oh and to remember to use the clutch!!

Hope all goes well tomorrow Rob

No Mike! Take a look back at some of the old photos under heavier flywheels or whatever the crazy topic it was YOU started with "...what´s wrong with Rossi´s Ducati ...?" or something like that. Take a look back....

Robbie had laid a ruler alongside his wheels and it could not be a centimeter rule -- `cos that would make his flywheels small. 14cm divided by 2.54 = 5.51 inches.
And Robbie said he jhad BIG ones.

I was given 3 samples: (A)96mm, (B)136mm, (C)100mm & (D)200mm to work with and that -- when reviewing as free running flywheels -- AS DISCS -- with (A) at 2.4kg, (B) at 3.8kg, (C) at 4.5kg & (D) also at 4.5kg showed some interesting results in that (B) although being lighter than (C) still stored more energy than (B)...

Obviously the increased diameter has more energy-storing ability!!

Yes! 14 INCHES would not go into a Bantam cases -- so I shall take a look back -- myself -- there is something mighty suspicious about that ruler..:

Be back........?

OOOOOUUUUUCCCCHHHH!! it was a centimeter rule -- of course.

So 14cm is smaller than my largest sample of 200cm(D) so why is Robbie saying things like I got big-uns and getting me all excited thinking I had discovered something useful??

There´s just not enough stress from the stored energy to break gears so we can only come to the conclusion you have voiced Mike -- yon Laddie is a wee bit BRUTAL wi´ his foot.

But we come back to HOW MANY gears has Robbie ruined?

I mean when you think of what happens when a piston locks up the shock-loading must be much more than a mere push with the toe on the short gear lever --

you have, say 340lbs*** suddenly applied at the rear tyre-contact -- at a foot of leverage (rolling radius) -- in say 1/10,000th of a second becomes 3,400,000 ftlbs per second of torque at the gear teeth and I have yet to hear of a piston seizure -- with much heavier bikes plus podgy riders -- of breaking gear teeth or a shaft.

So, I think the jury is out Robbie -- just don´t break any gears tomorrow and have a good day -- I just saw that the Superbikes are there also....

***total weight of rider + bike...

Can´t let it be... Now what if the 140mm -- and above dia... flywheels DO STORE enough energy....??

... enough energy that when that is added to the instantaneous crankshaft output -- it would be enough ...?? Hmmm? I think I shall concentrate on Xmas....

NO! I said the subject was, IS -- IS -- dead. And so be it... the slightly heavier flywheels assist the 175 in overcoming the 18.4% increase in bores-size-Friction-Losses -- attributable to the increase in bore size of the 175 over the 125, of course....!!

AaaaahhhMenn!

"g force" means that when you are accelerating -- out of the saddle -- at 32.2 ft/sec² your weight becomes the force in pounds with which your body strikes the ground.

Oh gee!

Cheers!

Hi John
The gears let go as I do a quick get away off the line it's not my right foot The old flywheels were 140mm and the new ones are 114 mm so we have to see what happens at mallory

Only once!?

As Judge here -- I would say that is Not Proven!

Mr Powell will have to retract the prosecution`s case and pay damages of 25.000Joules -- about 35 New Pence -- to the defendant who was also libellously called "Big Foot" at Lydden in 2011!

It is the dia more than the weight that makes the difference -- 26mm smaller might be enough to show. Try and time how long you are slipping the clutch on getaway, Robbie -- like Brian White said to me, when I asked that same question ...
.
...he said do you think I have a stop-watch up my ausspuff when sprinting??
-- Well words to that effect!!!!--

--- hey! What the heck, as far as I was concerned I declared this subject dead....!

And Cheessuzz Murphy! and it happens to be Xmas day.....

JB Rob hasn't answered your question, he telling you why!
I think it because of premature down changes
I'm guessing 3 gearbox nasties this season so far??

Breaking g/boes is an interesting subject, somthing I'm sure we would all like to avoid, But I can not possibly imagine its due to pulling away or from the torque of the engine, No matter how big the crank is ? the thought would be good !.

I would assume there is more load if 1st gear is thrown up the layshaft into connecting through top output gears (or jumping out of 1st gear)

I have to agree with "the old un" a bantam just does not produce enough torque, well not unless there is some other information we are missing, like injecting exotic mixture in at the start ? the whole thing sound more like fantasy than fiction, but then we can all dream.

the most stressed Gea is the Top output press on Gear "mechnically", I did work out in which gear it was in, when this was so, anyway I did not write it down,so just from memory, I would more assume its to do with Rob not using the clutch properly when changing Gear, as Mike points out ! tut tut.

Derek

off to mallory now will let you all no how things go tonight and will do a bit on gear box problems may be tonight or in the next coulpe of days

Just got a rollicking for being on here!

I was supposed to switch off -- instead of that you are sitting there -- playing wivv ya keyboard again....

Rabbit rabbit rabbit ...

3 times ey -- Mr P... Prosecutor?

Gears or shafts...?

Pity I have to go...

... when you gotta go --

-- you gotta go....

Happy New Year --- aaaaallll!

Ouch!

Im really looking forwards to hearing about Robbie's Gear box Gremlins, and problems he's had to overcome I would imagine this will be a usefull subject for all to discuss


Rob good luck at Mallory tomorrow".

Derek

I can give you all a quick update on Robbie's exploits at the plum pud meeting.

Race 1, decent finish mixing it with a 250 LC on a damp track

Race 2, DNS Didn't make it out of the collecting area as the rear chain broke, must be all that power he has on tap snapping chains instead of breaking gearboxes now

mm_tribsa wrote:

I can give you all a quick update on Robbie's exploits at the plum pud meeting.

Race 1, decent finish mixing it with a 250 LC on a damp track

Race 2, DNS Didn't make it out of the collecting area as the rear chain broke, must be all that power he has on tap snapping chains instead of breaking gearboxes now

A very pleasant day talking bantams, learning the ropes.
The best bit was watching Robbie getting it on with the big boys.
Photos will follow soon.
Motor “great”, Gear box “great”, back chain “?” obviously all that power has gone for the weak link?
Thanks Guys

Hi all just came back down to earth after a great days fun what a buzz. well recommended for the off season
was great to see some B H R members and also Mr Carl coombs EX racer
And newcomer Colin oldham (coneman) and Joe for coming as my spanner man thanks Joe
and not to forget up and coming star reborn Mike mc donald
just to put things right the lc was a 350cc
first im pressions flywheel seem good but needs more carb set up
so another trak day soon
as for the rear chain no not horse power
this the 3RD time I have lost a chain
will be redesigning the shark fin
was looking forward to playing with the big bikes sorry for you that was watchin
and a quick note to derek and mike I do know how to use the clutch properly
check on board footage on utube been riding bikes for a long time now
off to do some house work dont you just love it

Hi Robbie

sounds like you had a great day Robbie and great to hear you know what the left hand lever is for, !! LOL

Please tell us all about the type of Gear box issues you had and what you guys been doing to overcome them.

You seen the new culture in the USA "Mods and Rockers" and the good old "cafe racer" - I jugjing the next biggest thing On TV next to customising bikes, Im not sure this is a magazine or a new cult uprising "but it has incredible finacial support from some very !! big machines and organisations, and directly the opposite to the idiots In the EU, It would be good to find some way of embrasing this cult into our ranks, a joint meeting/gathering at one of the cafe's lots of like minded people who knows where the ACE CAFE LONDON is ?.

regards D.B

ACE CAFE
could be there in a hour
I know were it is they is a day which is twostroke day may be we should all turn up with the bantams
would be a good P R DAY. talking of pr days what about 1000 bikes have my entries here and will be filling them in the next week me and mike had great fun and put on a great display of riding but would be good if we all could get there would look most impressive if all the bantams in a line like we did at brands but more bikes. 2sessions vmcc members £66.00 which gets you 2 tickets for the whole weekend beer tent and live band friday saturday night be warned if your thinking of doing it sessions sell out very quick dates are 7th and 8th july