A A A
Avatar

Please consider registering
Guest

Search

— Forum Scope —






— Match —





— Forum Options —





Minimum search word length is 3 characters - maximum search word length is 84 characters

Register Lost password?
sp_Feed sp_PrintTopic sp_TopicIcon
Stuffer plates on and off.
Avatar
mikef
Chatham Kent
Club Technical Advisor
Committee
Forum Posts: 977
Member Since:
September 30, 2011
sp_UserOfflineSmall Offline
1
May 17, 2020 - 2:51 pm
sp_Permalink sp_Print

Hi All.
     I know one or two people have been interested to know the purpose of the stuffer plates on the crank of the Bantam and if they really made any difference to performance.
I had to remove them on my D14 as they were starting to get loose. I mentioned this in a past thread that I have linked below.
** Please log in to view **
The question was, has it made any difference?
I have just got back from a 60 mile ride and think that the difference is minimal, if any.
Down hill I got a clock reading of 70 MPH and going up the same hill 50 MPH. That is exactly the same as it was before I removed the stuffer plates.
The only small difference that I noticed is that it is slightly more jerky on over run, that may be a bit subjective as I was just looking for problems.
I am happy with the way it runs just now, so those plates won't be going back on.
Mike.

Avatar
bantammad
Top Gear User
Club Member
Forum Posts: 252
Member Since:
December 12, 2018
sp_UserOfflineSmall Offline
2
May 17, 2020 - 4:02 pm
sp_Permalink sp_Print

Hi bantammad ere  well Mike just contemplating your thoughts and findings regarding with or with crankshaft compression plates, l to have found that Not really any notable difference in performance just my opinion also From the shed Les 

Avatar
sunny
Norfolk
Top Gear User
Club Member
Forum Posts: 1601
Member Since:
January 9, 2013
sp_UserOnlineSmall Online
3
May 17, 2020 - 4:13 pm
sp_Permalink sp_Print

aparentliy    ther wer     over  81 , 400   YD1   engiens  alone     made   so thats  about   so thats  about  162, 800  plates  wich  cost  B S A mouny   if  thay  didnot   think  thay  were   werth it   i  dont   think   thay   would  have    

Avatar
SpacedMarine
Up north
Top Gear User
Club Member
Forum Posts: 729
Member Since:
July 1, 2018
sp_UserOfflineSmall Offline
4
May 17, 2020 - 4:28 pm
sp_Permalink sp_Print

sunny said
aparentliy    ther wer     over  81 , 400   YD1   engiens  alone     made   so thats  about   so thats  about  162, 800  plates  wich  cost  B S A mouny   if  thay  didnot   think  thay  were   werth it   i  dont   think   thay   would  have      

True that's a few tons of steel 

What's 7/16 in mm again?

Avatar
cocorico
Central France
Top Gear User
Site Member
Forum Posts: 3593
Member Since:
June 23, 2013
sp_UserOfflineSmall Offline
5
May 17, 2020 - 4:29 pm
sp_Permalink sp_Print

Stuffer plates are attached to the crank case, they are not a factory item and if fitted don't come off accidentally. Flywheel plates are attached to the flywheels in the factory and frequently come detached.

1956 D3 running, lights to sort. 7 other bikes in the Barn. 1950 D1 engine now running.

Avatar
mikef
Chatham Kent
Club Technical Advisor
Committee
Forum Posts: 977
Member Since:
September 30, 2011
sp_UserOfflineSmall Offline
6
May 17, 2020 - 4:46 pm
sp_Permalink sp_Print

Yes that's a good point there Cocorico. I was of course referring to the flywheel plates. Quite a bad choice of words there on my part.
As you say stuffer plates would be fitted in the crankcase.
So in future we should refer to the plates that give us problems when the become detached as flywheel plates nor stuffer plates.
Do we all agree??
Mike.

Avatar
SpacedMarine
Up north
Top Gear User
Club Member
Forum Posts: 729
Member Since:
July 1, 2018
sp_UserOfflineSmall Offline
7
May 17, 2020 - 4:55 pm
sp_Permalink sp_Print

Gonna have to get a dyno test set up to determine once and for all.As said previously though it would have to be the same engine with and without.From my own experience the crank I repaired and had plates on felt a little torquier??? Low down compared to the one in the bike at the moment only thing is the one at the moment has a lighter conrod and piston by about 3 ounces plus the crank itself is considerably lighter.It does like to rev quite a bit more than the other make of that what you will.

What's 7/16 in mm again?

Avatar
sunny
Norfolk
Top Gear User
Club Member
Forum Posts: 1601
Member Since:
January 9, 2013
sp_UserOnlineSmall Online
8
May 17, 2020 - 5:05 pm
sp_Permalink sp_Print

so  iv  just gon   to  the  add/info   &  carnt  find  any  that  give a  good  top speed  refrance   thay  do  miles per  Galen    [mpg ]    &  as  we are  serpos to  keep  within   the   speed  linit     wed    usly    not  be   doing  much   moor  than    45  mph   back  in the  hayday   and  even today  on Derv or Petrol   locomoiton       gasflow  &  mpg   go  hand in hand  

Avatar
Blue Heeler
Top Gear User
Site Member
Forum Posts: 2703
Member Since:
November 16, 2011
sp_UserOfflineSmall Offline
9
May 17, 2020 - 5:44 pm
sp_Permalink sp_Print

Bantams are hardy, adaptable creatures, only c*ckroaches & them will survive after we`ve all been nuked. I`ve been leaving out flywheel cover plates for over four decades on my own Bantams, and then on seeing they came to no harm, very soon thereafter  on the ones built for others, and have never noticed any difference in running/performance....with v without.

Just make sure all rivets are removed/dealt with, if going down the sans cover plates route.

Weirdest Bantam adaptable experience was running a flat-topped three-ring piston in a D14, with not only nothing lost on top-end performance, but considerably cooler and smoother running.....all that considering much lower compression ratio, supposed poorer combustion and more friction!

Avatar
bantammad
Top Gear User
Club Member
Forum Posts: 252
Member Since:
December 12, 2018
sp_UserOfflineSmall Offline
10
May 19, 2020 - 1:50 pm
sp_Permalink sp_Print

Hi bantammad ere Sounds like your with me on this one Blue , remember the Thornecroft  engines now that’s 🔧 work from the shed Les  

Avatar
Sponge
Lancashire (A chip shop somewhere near Preston)
Top Gear User
Club Member
Forum Posts: 272
Member Since:
November 6, 2016
sp_UserOfflineSmall Offline
11
May 19, 2020 - 4:38 pm
sp_Permalink sp_Print

It is my understanding that there comes a point, reasonably high in the rev range when crankcase pressure drops to zero - at this point the power drops away.  The side plates on the crankshaft serve to maintain crankcase pressure a little further up the rev range and thus enable higher revs to be sustained and thus power to be available to pull higher revs.  This was explained to me by a 2T racer (Yamaha) a long time ago. 

I, therefore, think that these side plates do little for performance until you start to crack on the revs - if you like to ride with your hair on fire then you will no doubt appreciate the extra revs giving you about 5 mph more in each gear possibly 6 mph in top.  Obviously this might make all the difference to a racer. 

I have also heard a plausible theory - backed up by BSA literature, that the crank side plates offer less resistance to the airflow ( read fuel and oil mixture/mist flow) through the bottom end of the engine and thus more oil gets to the top end via the transfer ports.   The theory gives us to understand that without the side plates more of the oil is deposited on the crankshaft webs - especially whilst the engine is warming up - and less gets upstairs where it is needed to cool and lubricate the bore.   As evidence for this please note that the D7 had no crank side plates as standard but it did have an extra piston ring to give it 3 rings - one of the jobs of a piston ring is to transfer heat from the piston to the bore.  

I have certainly noticed that my engines that do not enjoy side plates anymore (mainly because they are items unavailablum nowadays - otherwise I would fit them) tend to run a bit hotter than they should and as for the rev range - well I don't ride like a mainiac anymore so I don't rightly know.  Given the choice, and if I could get my hands on some, I would fit them - then there can be no argument can there ? However somebody with access to a laser cutter needs to start manufacturing them - I bet they would fly off the shelves.  I would certainly place an order for some B175 side plates. 

Sponge     

 

If Spacedmarine is going to do a dyno test with his D14/4 it would be very interesting to test the above assertion with some science.  Bring it on because it is a question that has been haunting me for years.     

Avatar
bantammad
Top Gear User
Club Member
Forum Posts: 252
Member Since:
December 12, 2018
sp_UserOfflineSmall Offline
12
May 19, 2020 - 4:52 pm
sp_Permalink sp_Print

Hi bantammad ere just wondering how is it that Villiers engines seam to function happily with out crankshaft plates l have late veteran Villiers there performance Doesn’t seam diminished like l say just wondering from the shed Les 

Avatar
mike p5xbx
E-Sussex
Top Gear User
Site Member
Forum Posts: 1719
Member Since:
June 15, 2012
sp_UserOfflineSmall Offline
13
May 19, 2020 - 4:56 pm
sp_Permalink sp_Print

Sponge said
  Given the choice, and if I could get my hands on some, I would fit them - then there can be no argument can there ? However somebody with access to a laser cutter needs to start manufacturing them - I bet they would fly off the shelves.   
       

Some on Ebay, bit expressive seeing as most people are throwing them away you could try a cheeky offer
** Please log in to view **

the Villiers 9e Kart racing engine had full circle cranks

D? - D10- D14 Bantams 350 AJS -500 Triumph http://bsanotru.....lfire.com/

Avatar
bantammad
Top Gear User
Club Member
Forum Posts: 252
Member Since:
December 12, 2018
sp_UserOfflineSmall Offline
14
May 19, 2020 - 5:04 pm
sp_Permalink sp_Print

Hi bantammad ere Mike you’re right about that but it’s not in the same ball park as road going bantam happy 😃 days

Avatar
SpacedMarine
Up north
Top Gear User
Club Member
Forum Posts: 729
Member Since:
July 1, 2018
sp_UserOfflineSmall Offline
15
May 19, 2020 - 6:25 pm
sp_Permalink sp_Print

Screenshot_20200519-182807_Gallery.jpgScreenshot_20200519-182757_Gallery.jpgYoud only need a couple of holesaws and some sheet steel easy peasy..I've got 4 hanging around 2 aren't so bad 2 are a bit chewed up.looking at them they're slightly different makes me wonder what vintage my crank is?Screenshot_20200519-182344_Gallery.jpg

One set is slightly thicker with a recess.They were the originals,the others off the second hand crank I got

What's 7/16 in mm again?

Avatar
bantammad
Top Gear User
Club Member
Forum Posts: 252
Member Since:
December 12, 2018
sp_UserOfflineSmall Offline
16
May 19, 2020 - 9:57 pm
sp_Permalink sp_Print

Hi bantammad ere just wondering as to what grade sheet steel the crankshaft plates are made off any body know regards Les 

Avatar
SpacedMarine
Up north
Top Gear User
Club Member
Forum Posts: 729
Member Since:
July 1, 2018
sp_UserOfflineSmall Offline
17
May 19, 2020 - 9:59 pm
sp_Permalink sp_Print

I'm guessing just mild steel would do it.They do rust if you leave them long enough.

What's 7/16 in mm again?

Avatar
bantammad
Top Gear User
Club Member
Forum Posts: 252
Member Since:
December 12, 2018
sp_UserOfflineSmall Offline
18
May 19, 2020 - 10:18 pm
sp_Permalink sp_Print

Hi bantammad ere what thickness is the relief diameter and of cause central  diameter . Can someone send me a detailed drawing for me to view lm aware of the difference of the B175 plates they’re rolled into the crankshaft wheels from the shed Les 

Avatar
SpacedMarine
Up north
Top Gear User
Club Member
Forum Posts: 729
Member Since:
July 1, 2018
sp_UserOfflineSmall Offline
19
May 19, 2020 - 11:02 pm
sp_Permalink sp_Print

Can do Les if you can hang on a day or 2 unless someone beats me to it 👍🏼

What's 7/16 in mm again?

Avatar
neddyo
Second Gear User
Site Member
Forum Posts: 11
Member Since:
April 16, 2020
sp_UserOfflineSmall Offline
20
May 20, 2020 - 1:43 am
sp_Permalink sp_Print

Hi All,

As a lad I used to go riding on a 51 D1 with a friend on a Norman with a 9d engine.

The Bantam we all know about, the Norman engine was I think a 125 with a

bob weight crank and a deflector top piston.  On the flat and down hill the bantam

would march away but up hill the Norman would pull ahead. Was it the crank or crank plus piston?

(If you have one of those Normans I want it , OK)

Nick.

1946-norman-small.jpg

It was bigger than that

sp_PlupAttachments Attachments
Forum Timezone: Europe/London

Most Users Ever Online: 223

Currently Online: sunny, robbo, N.D.James, Tamos
13 Guest(s)

Currently Browsing this Page:
1 Guest(s)

Top Posters:

cocorico: 3593

Cornish Rooster: 3310

bart: 3125

Blue Heeler: 2703

Sprung Chicken: 2653

David Dale: 2484

Mags 1: 2335

Piquet: 2315

Munchkin: 2209

nickjaxe: 2091

Newest Members:

_2889

Forum Stats:

Groups: 9

Forums: 48

Topics: 12564

Posts: 108863

 

Member Stats:

Guest Posters: 1477

Members: 2057

Moderators: 0

Admins: 4

Administrators: Bantam-Super, JMD, Springs, Stoo63