What is a Cafe Racer?

Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules



Mike

Like many things vibration is not as simple as you think initially. Almost all British twins had a 360 crank which seems completely out of balance. Part of the vibration is the changing of direction of the pistons which is 2 x engine speed, the explosion in the combustion chamber also produces a vibration which is engine speed, 2 sparks in two revolutions. There is also a vibration from the rotation of the crank/ big ends .

A 180 degree crank appears to be much better and in some ways is but the alternate pistons produce a vibration as it tries to rock from side to side while the big ends produce a vibration as they move front to back relative to the piston. Unfortunately the peak of these forces are at different times in the cycle and you get two different vibrations at 2 x engine speed which all together is a really annoying buzz. My sister had 2 honda twins and a yamaha twin they all buzzed like crazy. Trimphs and Nortons made your eyes shake on a motorway but werent unpleasant at all around town.

A 180 crank means the firing is uneven the 2 cylinders fire for one revolution and then nothing for the next revolution which makes the engine seem a bit "flat" and certainly sound uneven.

Thats my simplified understanding, people write books and devote careers to studying vibration, in an engine anything that oscilates or rotates produces some. Honda 4s were notorious for unbalanced carburettors making the cam chain rattle

Brit 360 twins did not have a centre main bearing but a 180 crank has to. For the original twins this wasnt a problem they were 200/350cc but the later models like the Norton 850 had so much crank flexing and unequal loads you could wear out the main bearings in 2000 miles.

Ive just read about the latest triumph thunderbird twin which has a 170 degree crank in a 1.7 litre engine probably so the pistons dont reach TDC/BDC at the same moment. That has balance shafts and only produces 95 ponies while it weighs 750 pounds, its a car with two wheels missing.
 
Last edited:

Allow me to correct you...it wasn't leaking oil; brit motorcycles don't "leak", they "mark their territory".
 
BikerBabe said:
Allow me to correct you...it wasn't leaking oil; brit motorcycles don't "leak", they "mark their territory".
Click to expand...

Thats a fact, if you see one without a leak it doesnt look right.


in fairness the early ones were good but they kept increasing capacity and performance without increasing much else like cylinder head bolts. Most leaks were caused by them not being put together properly, even on new ones. If you put one together without a torque wrench something always leaks.
 
D****mn! What a beauty! Me want one! Here's another Norvin! Does she look right or does she look riiight
Imagine the sound with those megafones or like in some of the pics I saw, straight pipes, no silencers! 8)
 

Attachments

  • 17_norvin_jpg%20(1000x671).jpg
    132.9 KB · Views: 4,745
BikerBabe, you've been spending too much time around Harleys.
CockyPilot- all true since all parts are produced with various tolerances no two moving anythings will have the same mass. However vibrations can be reduced in a number of ways such as rubber mounts and keeping piston mass down and moving them in opposite direction. My touring motorcycle is a Honda Goldwing. 6 cylinders in a 180 degree opposition like the BMWs. At any RPM you can balance a nickel on the engine and it will not fall or move. The British motorcycle makers of the 50s-60s took a take it or leave it attitude quality suffered. along came the high quality afforadable Japanese bikes. People made the decision: Leave 'em
Lucky, yes it is very nice looking but the riding is another story. short hops, bar to bar, and pose out front excellent. Now take it for a 500km ride. when you can hear and move again we'll talk
 
Last edited:
mikewint said:
" Also who can forget those Lucas "Lord of the Dark" electrics
Click to expand...

ahhh the lucas jokes....remember them well

someone actually came out ( as a joke ) with a can of smoke for recharging lucas electical systems.

i like that old style of bike. just like the one you have mike. the mechanic i took my 79 honda to said that style is making a comeback. its comfortable to ride. honda and the other jap scooters inteh 60s and 70s modeled themselves after the brit bikes....norton, triumphs, bsa, etc. when those bikes quit coming to the us....the japs changed stayed with that style for a time but later fashioned them after harleys.

as i understood caferacing...it was just that. they would race to the next cafe sit and drink a tea or coffee then head to the next town...etc.

now if you REALLY want a bike..a vincent black shadow or lightening....in 1948 one of them did 150mph. the norvins CP refered to were nortons with vincent powerplants.
 
Last edited:
Like everything else in this world it's all a matter of personal taste. I'm a travelin rider. When we ride we average 800 - 1000km per day. I personally want to do that in comfort not on a vibrator that sounds like a 747. For fun I want a powerful quick responsive bike that I can still run 500 - 800km if the mood strikes.
My Goldwing and 750cc Kawi
 

Attachments

  • mikebike1R.jpg
    104 KB · Views: 152
  • bikercampR.jpg
    88.1 KB · Views: 152
  • chrisvulcanR.jpg
    76.7 KB · Views: 151
  • vulcanR.jpg
    85 KB · Views: 159
Vincent Black Shadow.....mmmmm! *droool*

In 2007, The Vincent H.R.D. Owners Club commissioned the VOC Spares Company Limited to build a replica Black Shadow from new parts.[citation needed] Amongst other things, the project was to prove that all the parts were in stock and available from the VOC Spares Company Limited. Having received many glowing reports from the motorcycle press in the UK, the machine was eventually auctioned by Bonhams and now resides with a Member of the Vincent H.R.D. Owners Club in New Zealand.


Btw, didn't they produce only 30 Vincent Black Lightnings during 1949-52.

1950 Vincent Series C Black Shadow
 

Attachments

  • 1950_Vincent_Black_Shadow.jpg
    76.2 KB · Views: 153
BikerBabe said:
I've got nothing to add to this thread as I'm a Beemer addict, but damn, those sure are some nice bikes!
Click to expand...

Beemers are cool too as long as they are boxers. I liked the way they rocked from side to side at the lights and the footpegs wernt in line.
 

Mike if you are doing 100mph then a low riding position is comfortable and you can hardly hear the exhaust Ive done it on a Moto Guzzi Lemans But on that it wasnt the extremes you see on cafe race custom bikes...Thats just for posers who havnt noticed that a racing bike has a racing frame and therefor lower seat........look at the pic of the dunstal norton posted before.
 
Lucky13 said:
Italians? Then I'm partial to the classic Ducati 900SS.....
Although, there are some nice MV Agusta bikes too...
Click to expand...

Hi I dont know if youve ridden a ducati but they are a bit strange, loads of noise and uneven firing but actually as smooth as paint when you get going.
 
Also not a Duck fan, always seemed too fussy and fragile for my type of riding
both my bikes have windshields and backrests. hit 70mph, engage cruise-control, feet on the extended pegs, adjust airflow with vents, nice set of tunes on the stereo and i'm good for 200 miles
 
Last edited:
mikewint said:
Also not a Duck fan, always seemed too fussy and fragile for my type of riding
Click to expand...

hey i liked riding it I didnt say BUY one. They are good bikes now but were worse than triumphs until the 1990s

Does anyone else use desmodromic valves?
 
You must log in or register to reply here.

Users who are viewing this thread

Total: 1 (members: 0, guests: 1)

Similar threads

Where is our Pirate? The master of Plastic
2
Replies
35
Views
826
SaparotRob
What Is The Number of Moveable Parts On A....
Replies
4
Views
865
MiTasol
What is this?
Replies
6
Views
1K
bravenest0
O
Well, is he?
Replies
2
Views
771
rochie
Is this real?
Replies
6
Views
986
DBII
Menu
Log in
Register