BSA Bantam Racing

Bantam Racing Club
 
HomeHome  FAQFAQ  SearchSearch  RegisterRegister  MemberlistMemberlist  UsergroupsUsergroups  Log in  

Share | 
 

 what are we doing this year and what are our targets

View previous topic View next topic Go down 
Go to page : Previous  1, 2, 3
AuthorMessage
luke.plane

avatar

Number of posts : 8
Age : 19
Localisation : Fakenham, Norfolk
Registration date : 2013-01-30

PostSubject: What are we doing this year and what are our targets   Mon Aug 05, 2013 2:58 am

Hi John,

Yes, Snetterton is are local circuit being only about 45 minutes away  

Best regards Luke
Back to top Go down
View user profile
Ned

avatar

Number of posts : 260
Localisation : Rayleigh Essex
Registration date : 2007-01-11

PostSubject: Re: what are we doing this year and what are our targets    Mon Aug 05, 2013 5:43 am

Racing has never been cheap! For the vast majority who wanted to race it meant making sacrifices.
Promotion is the way forward, Sinatra and Elvis weren't the best singers around but they had people who new how to promote them. Some of the negative comments on here will do nothing but damage. Demolition is easier than construction.

J.B. One of the reasons for introducing fairings was to promote the class and has done more good than harm. Young men weren't keen to get involved in what looked like an antiquated class. The price of a fairing is outweighed by the cost of damage done when a bike bites tarmac without one.
D.B. Early in this thread you said you didn't know why we were discussing riders weight but your the one that keeps referring to it !
Back to top Go down
View user profile
Derek

avatar

Number of posts : 1065
Age : 56
Localisation : worcestershire
Registration date : 2007-06-15

PostSubject: Re: what are we doing this year and what are our targets    Mon Aug 05, 2013 6:02 pm

Hmm "who does Luke plane belong too, my advice to Luke is to save your pennies, and try and purchase that Ex Martin Nash "d"villia Bike, very fast in the right hands still a match for any bike currently being raced.
------------------------------------------------------------------------

John as always agree spot on mate, especially when you agree with me"
---------------------------------------------------------------------------------

Ned what a great decision that was,!! I,m sure you were not involved in that one such a stupid decision (by people who new nothing of marketing or appeal,) !!!! the one thing that made the Bantam stand out, and you covered it up, trying to make it look like something it was never going to be. "why"

I see the scooter boys are having a very big revival. "why", look there.

The Bantam was cheap (compared to other classes) NOT NOW, I could go racing, am going racing and competing on a budget half of what I spent getting my Bantam competitive, The bantam with No fairings had appeal, they looked cheap/ and it was" and it was easy and cheap to build one, without fairings they all looked same or similar, if you turned up as long as it was clean you never looked out of place, all looking similar, but were obviously very different, bringing in fairings was in my opinion an idiotic decision by amateurs trying to do the right thing, its the same in business, you buy something thinking you can sell it and make 25% when in reality you can some times never get what you paid for it.

-------------------------------------------------------------------------------------------

Mike "NO" I have not given up. I'm still Racing !!!! "my Return to Bantam Rcaing was I feel very succesful" the bike has been on the Dyno more than a few times since I last raced with you boys, and its producing quite a bit more, I consider once I have this new ignition cracked, based on what we currently have, it would be untouchable in the class you race in, "with a 7 stone rider aboard it",!!!!! but as I'm struggling with my weight loss, and crank balance factor, we keep breaking little things at the moment.

To answer your questions!!
If your looking for answers, I was just wondering why the vast majority of my posts were ignored, !!! and you afail to make comments to so many who ask questions, besides you are club champion, or have been more than most, perhaps if more people answered other's questions on this forum, perhaps they would feel more inclined to feel they are welcomed, "to me No answer means" your an idiot or don't ask idiot questions, or they are not talking to some secretive cult of self proclaimed "leaders of the dark arts", but instead a steady flow of open answers means they are talking to a friendly bunch of "like for like enthusiasts" only too happy to help, "only a few of them left "sadly",
"This of course is only a passing opinion besides you asked for it". !!!!!

your third point:- Racing for me has to be enjoyable !! to come to "a paddock" or class floundering to survive, is evident, and there are lot of good/nice/ people in there, and where ever you have nice people you are a few not so, or sensitive just like me, it seems the few at the front are unable to see the light of day!.

for your information, I was placed in a difficult position, in public on the receiving end of a verbal onslaught by persons "un named" 5to10 years earlier and that person would not have walk'd away!!, so why do I wish to put myself in that position. I can always go down the local pub for that, besides ? do I really wish to race against a person of such temperament.
Racing is dangerous enough, how do I know I can trust while racing such an person, "push comes to shove" we all need a bit more room "occasionally", and we all have to work on Monday !".

You want"MY opinion! "are your sure""!!

MY opinions are just that, Opinions-they are not the status quo, but some idiots take them to heart, perhaps if I felt comfortable or received my public apology that I have asked him, or perhaps his no show is guilt" poor show !(it takes a man to apologize). I may feel comfortable to return to a paddock full of otherwise friendly like minded enthusiasts but in the mean time I'm very busy racing in another paddock, and I'm enjoying it.

regards (the man of many opinions) Derek.
Back to top Go down
View user profile
mjpowell

avatar

Number of posts : 1074
Localisation : Lincoln England
Registration date : 2006-12-09

PostSubject: Re: what are we doing this year and what are our targets    Mon Aug 05, 2013 7:24 pm

Hi Derek that's good you are still racing your bantam but elsewhere
Hope we see it out in the BHR paddock one day soon.

I must admit I thought the Lydden entry was a little low at 11 when it
was 17 in 2012, but I now see quite a few people had got there reasons
be it holiday, engine still being rebuilt, financial etc etc

Your advice to Buy the Martin Nash bike is sound is it still available?
Have you not meet Luke he's at most meetings with his dad talking and
gleening bantam info and parts etc, they were at 1000bikes..

I remember the first midland meeting that you invited me to, and brought
my piston ported barrel and other bits too, and you and Nobby had your
Bantams running in the car park and Nobby took his apart and we
were passing round warm cylinder and head etc

Regards Mike
Back to top Go down
View user profile
Tim Cornish

avatar

Number of posts : 310
Age : 21
Localisation : Downton, Salisbury, Wiltshire
Registration date : 2009-04-16

PostSubject: Re: what are we doing this year and what are our targets    Tue Aug 06, 2013 12:27 am

Luke - I only have one question and I don't aim to deter you but to only help clarify your mind and your aims in retrospect to the time it'll take you to build your bike - I know you are only slightly younger than me and I do not however know if you've got upcoming exams, ones which I've finished and soon to go onto A-levels. Mike/Derek/Ned I believe they were called O-levels in your time(?!) I only ask is about your time splitting - once I had started my GCSE courses in my 4th year I had no time for the Bantam and had only recently picked it back up but to pursue other ideas (classic cars/driving/becoming 17 for more important trivial!). I would say the best time to do the Bantam is when you have certifiably free time, for me it was hard to concentrate at all when I knew I could be revising/doing work and alike. I know it sounds dire but I wouldn't want anyone else to make the mild mistake I did of starting to restore/aim to race (which I later now believe to be defunct) just before some important exams. I'd say please remain fully interested and whatnot within the Bantam but do not miss light the things that are bigger and are upcoming a lot faster! I don't think I can see myself coming back to Bantaming possibly, we'll see - 6'8 and going on 17/18 stone my legs are round my ears everytime I sit on my frame, wont happen! Moving onto bigger things.

Derek - I will further your point on the steady flow of free answers/questions that have been asked, I have at some points believed that my unanswered questions have been looked at and gone "I think I must've peed them off" and alike, but interest as a whole is all good. The last meeting I attended to have a chat was 2010/11 I believe, was meant to make it up to Lydden but mum's 50th took over - I can't see myself attending next year, perhaps, maybe, if I get the time.

Mike - I believe the De Villiers bike is still available, on the other hand I was speaking to the man who won that Bantam racer and he said he wanted to return the bike to the track, I don't know when and I don't know where but he said he intended to restore it and possibly do sprinting/hillclimb with it. T'was a steal I will admit!


Sorry to natter on, haven't posted in a while so I thought I would add to this interesting debate!

All the best for now,

Tim


Last edited by Tim Cornish on Tue Aug 06, 2013 4:24 am; edited 1 time in total
Back to top Go down
View user profile
dansofield550

avatar

Number of posts : 362
Localisation : gravesend kent
Registration date : 2011-10-23

PostSubject: Re: what are we doing this year and what are our targets    Tue Aug 06, 2013 12:38 am

think this is the bike you mean tim

Back to top Go down
View user profile
Tim Cornish

avatar

Number of posts : 310
Age : 21
Localisation : Downton, Salisbury, Wiltshire
Registration date : 2009-04-16

PostSubject: Re: what are we doing this year and what are our targets    Tue Aug 06, 2013 3:20 am

Yes, that's the one Dan. if you have the money Luke go for that, haven't seen it in the flesh so can't give you a perspective but judging from Mike/Derek and other racers it might be what you're after - certainly beats spending a few years in my case building or as I call it getting nowhere! Ha.

Tim
Back to top Go down
View user profile
john bass

avatar

Number of posts : 1737
Age : 88
Localisation : Bensberg, Germany
Registration date : 2006-12-06

PostSubject: Answering questions...   Tue Aug 06, 2013 6:11 am

You are right about questions not getting answered Tim.

Partly, I think,  the web-site procedure must be to blame. If a question doesn´t get answered immediately it frequently does not appear again. If  you then go to your Own Postings to find the missing one the one you are looking for is not there (because you had not answered, of course!) but others´ postings do not always appear either. I wonder why this is so? Maybe I am doing something wrong.

An interesting question  -- you generated --  I asked, never got answered:  it was concerning the "demise of contact breaker ignition" on the fast modern 125 Bantams. Transitorised and electronic ignitions systems came in about 1968 -- I think -- or a bit earlier.
   I then  thought, that by 1971 or 2 there´d be NO racing 125 Bantams that used CB ignition.
    That was the question which never got answered:  were all 125 racing Bantams without CB points ignition after  say, 1972...?

I say 125... because it seems possible there are 175 Bantams with CB points ignition.

Anyway, we built our first Bantam in late 1967  which was a 150cc scrap bike at 10 quid, which after a considerable bit of sorting and welding etc²²²  I did practice on and rode in a 250cc event. From this Breakers-Yard  scrap --"Icarus-1" evolved with a 125 engine,  our 3rd -project-worker³³³ found in a field.

I would argue with Ned re -- "...there was never cheap racing"
-- Bantam racing was low-cost racing for sure. Otherwise as married with two kids and lots of financial committments  I would never  have done it.

I do think that nowadays it costs a great deal to race a 125 Bantam competitively.  

²²Derek Neil tuned and looked after the engine....
³³Le White who had a lathe at home did all our turning and other clever bits of machining.

Sorry this is so long as the vicar said to ... Whoops! Wrongweb-site.
Cheers!
JayBee

PS -- I must agree with Ned that Icarus-1 does not look very much like a racing motorcycle.
Back to top Go down
View user profile http://t-online.de
Derek

avatar

Number of posts : 1065
Age : 56
Localisation : worcestershire
Registration date : 2007-06-15

PostSubject: Re: what are we doing this year and what are our targets    Wed Aug 07, 2013 5:24 am

Hi All
1) Mike yes:- I do hope to attend the last BHR meeting at Cadwell, as long as it does not clash with other things in my diary, I had not planned to do any this year, however it will be mainly to see how the improvements to my bike's performances fair against your bike, I'm sure I know where you are roughly with HP, I'm not far away but on certain Ihave more Torque, a lot more, ! it may even surprise you!, you will just have to wait and see, of course I'm still on course, with that all important "weight loss program" should help, as none of my trousers fit me, but I've noticed all my hats still fit.!!

Tim; "as always" mate absolutely spot on, with your details, I wish the front runners would make more comments on peoples posts, perhaps I always find Trevors/ Colin Halls and Johns posts interesting, or anything about the internal stuff.

On that picture of Martin Nash 'd'Villia, dan put up, he built it himself, a super nice guy, his bike is very reliable, and its a very fast Bantam, even now with the right rider "in my opinion" its certainly capable of winning races, no doubt about it, I remember Martin being almost 10 seconds behind Mike Powell at Pembrey, having stalled it on the line or something like that but by the end of the race it was a different story.

John makes some very interesting points, hope some one comments on them! so does DAN! great to see Dan having some good rides, your very welcome to come to the next Midlands meeting Dan", I'm sure it will be before the end of the season, possibly not the same venue thou I'm unsure will text Ed about it soon, don,t have time to read them all of Johns points but will do it later, I hope someone comments. !

I understand Nigel asked a few questions and showed a few things on line but got no answers, this must be frustrating perhaps pictures or requests for responses should be directed at the people you wish would comment on them. 9 that way your not feeling ignored or frustrated each time you post, when you get no replies, (just like I do like me), I know Trevor responds more than most so does John, I feel a good way of creating good responses is to direct them, in such a way as asking a direct question. for instance.

Q- I would like a response on this picture/question. I recently found a huge jump in torque by dropping my barrel, this did not affect power out put even though it was quite a big change, ! I had to lift the transfers to maintain a decent blow down, - it lowered my exhaust port timing to 89.5 degrees or 189 total opening period, this did other things like kill the over rev, but there is no torque in this area, so nothing was lost, whats your exhaust port timings - that question to
"Mike Powell" and Nigel, "others welcome to comment please. ?

Derek
Back to top Go down
View user profile
nigel breeze

avatar

Number of posts : 350
Registration date : 2007-12-23

PostSubject: port timings   Wed Aug 07, 2013 7:09 am

evening derek , well my old port map of my broken barrel showed the exhaust port started to open at around 30mm from the top of the barrel( which caused me to go through the port wall and had to braze back up)  and was therefore 28mm in depth and approx 41 mm wide ( when the port rubbing was opened up and measured, so i think thats cordial).the transfers opened at around 47mm, measured again from the top of the barrel and again measured of the rubbing of the port when opened out was around 30mm wide , but that measurement doesnt extend at this into the transfer port its self. the opening is therefore 11mm in depth. the barrel im playing with at present should give me a very different set up. removing 5mm from the top of the barrel then fitting a 5mm alloy packer underneath to raise  the barrel to get the 58mm required, im hoping to get a bit more scope in the port timings. it will move the power further up the rev range (10500) and although it will mean longer  transfer port opening timing, i cant think of another way of increasing this due to the restrictions of a cast iron barrel.(amount of metal available to remove). as it seems that low but wide transfers are the best and a loads of blowdown is crucial. my inlet timing was left pretty much standard with the piston skirt left untouched on the last piston i fitted as i  had losts of problems with carberation at low revs when id removed piston skirt on the a previous piston. (on refection i believe the 34mm flatslide mikuni i had previously fitted was way to big and so wrongly jetted which didnt help.)when the bike ran its best it felt good pulled well, but needed another couple of gears!!
Back to top Go down
View user profile http://leginezeerb@hotmail.co.uk
dansofield550

avatar

Number of posts : 362
Localisation : gravesend kent
Registration date : 2011-10-23

PostSubject: Re: what are we doing this year and what are our targets    Wed Aug 07, 2013 8:40 am

Nobby, interested in what you say is low rev's, I was making the mistake for a long while messing about trying to get an idle before I realized that 5000 was a minimum rev count, even then I'm having to keep it on the boil with gentle removing between 5&6000 , after that was figured out setting the rest of the rest of the carb was easy
Back to top Go down
View user profile
mjpowell

avatar

Number of posts : 1074
Localisation : Lincoln England
Registration date : 2006-12-09

PostSubject: Re: what are we doing this year and what are our targets    Wed Aug 07, 2013 8:49 am

That's good Derek if you can make Cadwell, I was there last Sunday and got my bike (reed valve) set up real well.
My numbers currently are 001 piston valve 21bhp/14ftlbs 001 reed valve 25/12 and 003 23/11 but my fastest laps set up seems to be the 21/14 set 001 ??

Ref weight I think 12st is ideal as any lighter moving your body position to best adjust 'loading your wheels (front or rear) doesn't really happen, but if you have a bit of weight you can use it to your advantage. but you have to be a fit and agile 12st ;-)

I feel Trevor Colin John may have more time to post as they are not turning out racing bantams - week in -week out!
I like your point of directed questions, but you can not definitely get an answer of them if they are not available or haven't the time or have missed said post.

Martins bike will be a great buy for someone - its really top notch!

I noticed you haven't inviteted me to the next Midland meet??

Your question ? Cannot see a picture? I bit confusing if your ex timing is 89.5 then duration should be x2 so 179 not 189?  unless you have done something a bit weird and to excess - de-saxe lay out -Putting your cylinder in front or behind of the centre line. You say it killed the overrun so that means you are going to gear up (smaller rear sprocket) so you may have lost out? or just revs ? maybe not if you have a 'Torque master'? Is your blowdown in the region on 30/32degree?
My ex timings 100 98 and 94 yours Derek sound low circa 70s long stroke motor? Be interesting to see how it performs compared to mine?

Nigel can you measure your port timing? Look at the Bantam Tuning Manual on main site.

Regards Mike
Back to top Go down
View user profile
nigel breeze

avatar

Number of posts : 350
Registration date : 2007-12-23

PostSubject: low revs   Thu Aug 08, 2013 6:03 am

dan,when i first got the bike to the track, way back, i found that the revs had to be kept high as you say.The carb set up was way out and the bike bogged down very easily  wetting the plug and with no experiance previously in any real time riding the bike i found it really unridable along with my steel clutch plate set up which dragged badly, when i tried to hold the bike at the race start on the front brake to keep it still, i tried to keep the revs up but this made  the clutch biteing worse and it wanted to pull away.Iwas subsequently told that i should have kept the bike out of gear untill the lights went out to start the race.. inexperiance. I have read since that  long inlet port timings can cause poor carberation at lower revs something to do with not enough air flow through the carb which causes a rich mixture and wets plugs. since then, even with the bike packing up after several laps, i can now cope easily with keeping up the revs. i have however been using a very small rd lc 350 carb which ive found makes the bike more rideable for me, i was really guttted after my last outing for the bike to sieze again as it felt great..

mike im unable to give timings in terms of degrees for my old barrel but i have since looked at the tuning on the forum site along side the post of snoweys 175 barrel port map, for ways of getting close as i can with the original bantam cast barrel.
Back to top Go down
View user profile http://leginezeerb@hotmail.co.uk
Derek

avatar

Number of posts : 1065
Age : 56
Localisation : worcestershire
Registration date : 2007-06-15

PostSubject: Re: what are we doing this year and what are our targets    Thu Aug 08, 2013 9:06 am

[quote="mjpowell"]That's good Derek if you can make Cadwell, I was there last Sunday and got my bike (reed valve) set up real well.
My numbers currently are 001 piston valve 21bhp/14ftlbs 001 reed valve 25/12 and 003 23/11 but my fastest laps set up seems to be the 21/14 set 001 ??

I noticed you haven't inviteted me to the next Midland meet??
----------------------------------------------------------------------

Hi Mike thanks for that,
70;s long strokes timings, Hmm! well slight typo error there and greaciusly corrected, well spotted good job your alert, ! does 94.5 sound better, but you never said what your lap times were, best posted at Cadwell ?, and the 14ftlbs of torque that's quite a lot! with 25HP, where is it in the rev range, and what your torque curve like, where does it start and stop, ill put my latest graph up, ! if you do.

the 25" I do not challenge, ! but I would like to see what and where its produced, the Dyno your using,!!! I know mine reads lower than most, and its not far away from what you "say" you have "but my torque is better"!, I could tell this at the last meeting I did "up the hill at Cadwell of the start".  

comparing speeds you don't need to wait till Cadwell perhaps you could meet me at a dyno of your choice (sounds a bit like pistols at dawn)!!! "but as I said "if" it does not clash with other priorities, I'm up for any challenge.

Now for those times you never mentioned (lap times) are I did not ask for all that other info, but thank you for it all the same. Good honest dialog is always a good way.  

Yes you are correct "I never invited you to the next midlands Bantam meeting, "perhaps someone will"

just kidding you, I don't actually know when it will be, or who will organize it, perhaps you would like to do it.!

Thank you for the info Mike:- A most interesting/entertaining response, now where's that old long-stroke motor of mine.


So folks that's where we all need to be 20.8 to 25hp and 12 to 16.3 ftlbs of torque, I suppose the next question is how does one set about getting to that state of tune and reliability, well Ill leave that question or answer to others that know, as its taken me a long time to get close, and I have proven in the past "I only need to get close".!!!

kind regards
Derek
Back to top Go down
View user profile
mjpowell

avatar

Number of posts : 1074
Localisation : Lincoln England
Registration date : 2006-12-09

PostSubject: Re: what are we doing this year and what are our targets    Thu Aug 08, 2013 10:33 am

Hi Nigel how did your engine compare with Snowy's ports then close or
Completely different?

Derek I'll have a look for the dyno print outs, some are a bit old now.
I tend to do my testing/set ups at race meetings not in dyno room.
So rather do 'pistols at dawn' at Cadwell if you can make it..
I was impressed with your bikes performance last year. There are quite
a lot of bantams now with better performance that mine, its not very fast
Accelerating but is quick when up to speed. Its Ian's Nicks Snowys
Robbies Mickys and Andys you should have greater competition with.

Lap time 2.00approx
Back to top Go down
View user profile
Derek

avatar

Number of posts : 1065
Age : 56
Localisation : worcestershire
Registration date : 2007-06-15

PostSubject: Re: what are we doing this year and what are our targets    Thu Aug 08, 2013 4:58 pm

Hi Mike sure:- that sound more like a fun thing to do, con not beat a bit of friendly bante'r

I see the logo;s BSA Bantam have increased in size, so much better, not sure who's idea this was, but TED's needs to go bigger, Micky's are great yours are still not big enough! well it may be the position they are in, like your number at the cadwell Bonanza could nis in a great place on fairing you cannot miss it, yes you seemed to be going well there, but always difficult to assess from watching, but a stop watch is a good thing !! .

on the others speeds increasing great to hear clearly things seem to be happening hope its not too little too late, !,

I can only go off last years, AM bike is quick reportedly 26 to 28hp, but I had no issues with speed against him once I had sorted two little things, and then with my bike at 15.8 HP and 9ftlbs of torque, although I had more, it depends on set up, I prefer to do my work on the Dyno now days, no issues at meetings then, I know exactly what to do jet wise just gearing to sort, I have not seen any of the others bikes this year, but I will drop in after one of my meetings to take a closer look perhaps.

regards Derek
Back to top Go down
View user profile
Trevor Amos



Number of posts : 873
Registration date : 2010-08-13

PostSubject: Re: what are we doing this year and what are our targets    Thu Aug 08, 2013 6:10 pm

Morning Derek,
If you are still running with straight line ignition then you will never make comparable performance numbers ,
the improvement in torque available, from low down up and the over rev potential, make so much difference, why compete will the other guys and labour under a self imposed handicap ?

Trevor
Back to top Go down
View user profile
mjpowell

avatar

Number of posts : 1074
Localisation : Lincoln England
Registration date : 2006-12-09

PostSubject: Re: what are we doing this year and what are our targets    Thu Aug 08, 2013 7:24 pm

Derek the large bsa bantam stickers came about ref a post from
a chap called Howard who commented that various bantams at
1000 bikes 2012 put on a good moving show but people didn't know
because their numbers were small on the events card plus bhr
Race numbers confused it more - hence BSA BANTAM stickers
And large event numbers too. Everyone knew who we were and
what we raced this year..

Regards Mike
Back to top Go down
View user profile
nigel breeze

avatar

Number of posts : 350
Registration date : 2007-12-23

PostSubject: port timings   Sat Aug 10, 2013 4:17 am

evening, ... mike, i had close exhaust timings of that shown in the revelations of snowys barrel but the transfer port timing was not achievable due to not enough metal left to raise the transfers any higher and obviously being only two of them. I have since sawn a 175 barrel to pieces to reveal how much meatal is available at the critical points to not cause a re-occurance of grinding out too much and having to braze up holes and making the walls waifer thin. Having removed a significant amount from the top of a barrel and replacing same amount to the base via a spacer plate i have raised the ports to a point where i feel i can remove less metal to now achieve even the port timings shown in the site tuning section and that of snowys port map.
Back to top Go down
View user profile http://leginezeerb@hotmail.co.uk
Derek

avatar

Number of posts : 1065
Age : 56
Localisation : worcestershire
Registration date : 2007-06-15

PostSubject: Re: what are we doing this year and what are our targets    Wed Sep 11, 2013 8:20 am

Hi Nigel just reading this, as not had time lately to brows around,

so for me and other reading this and just to clarify,

An iron Barrel can be set up (D14/D10/or late type D7's) by lifting the barrel with base packers at the joint between crancase and barrel clamping surface with alloy or steel plate, so that the transfer ports, are timed to the following before detailling the exhaust timing, I guess this will be around 63/64 126/128 then once you have achieved this, you can mark the barrel of the exhaust side to raise the top of the exhaust port to, ideally to achieve about 28/30 deg(175) 32/33 deg(125) and a timing of around 90/180 and 96/192 respectively.

please correct if you see any errors.

p.s the joint face between barrel and crankcase is an area of known leaking especially on the exhaust side to a good steel or alloy packer with good and flat finishes is needed, also make sure you bolt the barrel using all the studs for checking or measuring any port timings.

Derek
Back to top Go down
View user profile
nigel breeze

avatar

Number of posts : 350
Registration date : 2007-12-23

PostSubject: Re: what are we doing this year and what are our targets    Wed Sep 11, 2013 5:35 pm

morning , yes i had 5mm removed from the top of the barrel (lost top fin) and made a spacer/ packer of 4mm to fit between the base of the barrel and the crankcase . 4mm spacer made from aluminium and 4mm not 5mm to allow for gaskets between each which also helped to adjust any deck height. i also checked for air leaks with my home made leak tester to ensure that the crankcase was air tight ( 6psi for 6 minutes).most of the metal removal on the transfers was then down the barrel to get them to open fully from bdc. the exhaust port was slightly different as it needed work all around the port, but it made the work less fraught with danger of breakiing through the walls due a little more metal was now available.
Back to top Go down
View user profile http://leginezeerb@hotmail.co.uk
nigel breeze

avatar

Number of posts : 350
Registration date : 2007-12-23

PostSubject: Re: what are we doing this year and what are our targets    Wed Sep 11, 2013 7:12 pm

a few pictures of a175 barrel i cut up to reveal the amounts of metal available around the various ports. trevor has explained in another post that the exhaust port stub  which runs between the barrel face and outlet where the exhaust attaches should be taperd to give an area at the exhaust outlet 90% of the area of the port at the cylinder face and i think to maintain an oval shape,the cut off stub shows in standard form to be the other way around in size and taper and not oval through out its length, quite a bit to do to correct this.. the transfer port shows that there is alot of metal (8mm)thats left above the top of the transfer port and either side to increase port width.
Back to top Go down
View user profile http://leginezeerb@hotmail.co.uk
Derek

avatar

Number of posts : 1065
Age : 56
Localisation : worcestershire
Registration date : 2007-06-15

PostSubject: Re: what are we doing this year and what are our targets    Thu Sep 12, 2013 6:12 am

Hi
Nigel you have been busy, its clear what you have to tackle when water cooling adding ports to get it to a level it does not distort too much, I never thought of doing it the way Trevor has done it, as after all that welding brazing, you then have to try and deal with the load applied by the studs when bolting it to the cases.

what a brilliant idea that is, but if your embarking on this make sure not to remove too much metal from the barrel bore and leave as much as the fins on as possible it aids strength in an otherwise critical area, we started a new water cooled cylinder and will be using Trevor's Idea of 4mm thick outer sleeve as water jacket, this actually adds a lot of weight, but based on the first barrel we built and the distortion issues, because we do not have the so "critical welding knowledge and or welding/brazing skills" as some put it.

keep going Nigel seems you are increasing your knowledge of the critical areas in the std barrel and where you can or cannot remove metal, you are spot on about lifting the barrel then removing from btw of transfer level at Btm dead centre, seems lots of differing opinion on weather the piston should be lower or level at btw dead centre or is it lower than the exhaust port and level with the transfer? some one is sure to help clarify this.

regds Derek

Back to top Go down
View user profile
Trevor Amos



Number of posts : 873
Registration date : 2010-08-13

PostSubject: Re: what are we doing this year and what are our targets    Fri Sep 13, 2013 3:38 am

Nigel,
Great pictures that perfectly illustrate why I opted for the w/cooled construction method, that I have already described, namely that of fixing all the areas that are wrong, at least for racing purposes, with the standard barrel casting. There is little point to having a perfect port concept if the various ducts , collectively, conspire to frustrate power production . Actually, looking at your various shots and the problems they illustrate it all gets a bit depressing !
The Rotam, or Bantax, certainly looks far more attractive a proposition ?

Cheers, Trevor
Back to top Go down
View user profile
Derek

avatar

Number of posts : 1065
Age : 56
Localisation : worcestershire
Registration date : 2007-06-15

PostSubject: Re: what are we doing this year and what are our targets    Fri Sep 13, 2013 5:40 am

actually Trevor if I was going to produce a formula that allowed water cooling now days, I would allow the use of other Barrels, it would be so easy to graft on a rotax/aprilia/Honda RS Barrel onto a bantam engine, that all would be quite capable of doing, and besides you don't need all that secretive welding/engineering expertise then to manufacture tin/cast/fabricated port ducts, for you to spend the next 2 years trying to resolve distortion issues thats before any tuning development begin's, I am of course talking about Engineers superior knowledge, in this area, or the other thing is the name, rather than formula Bantam Rcaing, its should have been named "Engineers Bantam Racing". (other names ? possibly "Trevors Formula" / "Toms Formula" / "Georges Formula" / Birans Formula / my formula would be all allowed or nothing/back to iron wheels and no fairings) !!

My wish list for 2014, will be coming soon.
Back to top Go down
View user profile
Sponsored content




PostSubject: Re: what are we doing this year and what are our targets    

Back to top Go down
 
what are we doing this year and what are our targets
View previous topic View next topic Back to top 
Page 3 of 3Go to page : Previous  1, 2, 3
 Similar topics
-
» Woodstock 40 Year Anniversary
» World's fastest 14 year old girl - Hannah Cunliffe - 11.71
» Belleville Bulls' Mike Murphy named OHL goaltender of the year
» Buying a 20 year old vehicle
» Colin Greening signed to a 3 year deal! 3 years, 0.866 per year, 2.45 total

Permissions in this forum:You cannot reply to topics in this forum
BSA Bantam Racing :: Your first category :: Bantam Racing Forum-
Jump to: