silly question....

[Steve Lake]

what size does an engine have to be, to be classed a 'thumper' ?...

will my beezer bantam make the grade (if I ever finish it) ?

[SteveC#222]

Not sure about engine size, but surely the definition of a Thumper has to be a single cylinder four stroke? so the Bantam wouldn't cut it ( though a Tiger Cub might!).

Not being anti two stroke here - My old MZ was probably the best motorcycle I've ever owned.....still miss it!...

[JOOLZ]

Technically a Thumper is any 4 stroke, long stroke, single, size dont really make a difference. So modern singles really are not thumpers as they are short stroke

[Steve Lake]

well, I can go with 2 strokes not being thumpers... but don't think length of stroke should make a difference... if we are to exclude short stroke engines (what indeed constitutes 'short' stroke... anything oversquare?)

we would exclude may famous old bike from being classed as a thumper...   some highly tuned manx's and G50's were oversquare..  and I've seen a couple of Vincent comet's tuned to be oversquare, and I'm sure there were plenty of others

discuss

[Richard]

Exactly my thoughts.

[002]

Yes....Me tooo !

Jethro

[guest564]

Well my XBR is a short stroke motor and on race pipes at tickover it definitely goes 'thump, thump, thump......'

[Furry John]

Technically a Thumper is any 4 stroke, long stroke, single, size dont really make a difference. So modern singles really are not thumpers as they are short stroke

So on this basis a GB400/500 is also not a Thumper, I guess we built a club around a Myth (no, M Y T H Mark)

Furry

[002]

Technically a Thumper is any 4 stroke, long stroke, single, size dont really make a difference. So modern singles really are not thumpers as they are short stroke

So on this basis a GB400/500 is also not a Thumper, I guess we built a club around a Myth (no, M Y T H Mark)

Furry

Nasty speech impediment there John !
And your Thruxton doesnt cut it either ! But Molly's Mac and Viper do !   

Jethro

[Furry John]

Technically a Thumper is any 4 stroke, long stroke, single, size dont really make a difference. So modern singles really are not thumpers as they are short stroke

So on this basis a GB400/500 is also not a Thumper, I guess we built a club around a Myth (no, M Y T H Mark)

Furry

Nasty speech impediment there John !
And your Thruxton doesnt cut it either ! But Molly's Mac and Viper do !   
I
Jethro

Yeh, sorry, it's my teeth. I have got a thumper though, the Evans Manxman, the least practical, usable, sensible bike is long stroke and it must thump but it's too loud to tell, 119db at Brooklands. Though you were camping at Llantony?

Furry

[JOOLZ]

I was only repeating the conclusions that came up in a conversation with a couple of people from the vmcc, I put up a video on youtube entitled thumper sound (one of my XBR videos) and had quite a few messages from people saying that a short stroke motor is not classed as a thumper, this conversation was continued on a few facebook sites, and the consensus was a thumper is a long stroke motor, but the word is now used generically to mean any single cylinder 4 stroke

[Furry John]

Technically a Thumper is any 4 stroke, long stroke, single, size dont really make a difference. So modern singles really are not thumpers as they are short stroke

Technically a Thumper seems to be a 4 stroke single who's bore is less diameter than the length of it's stroke ie undersquare, by your definition. I think the majority of my vmcc and voc colleagues take the term to refer to the ability of an engine to pull at very low revs, my Dr 650 Ses will never be a thumper, it is really lumpy below 2500rpm. Molly's GB400tt will however be rideable smoothly at 1500rpm however to get real thumpability you would need a Panther PM 120 which will pull a sidecar at  750rpm cheerfully. You pays your money and takes your choice. I like to think it is based on exhaust noise, distinguishable bangs makes a Thumper, never mind the technicalities.

My 2p's worth

Furry

[JOOLZ]

Sounds reasonable to me

[002]

Mantra for the club Has Always been....For Those With An Interest In Four Stroke Singles !



Not forgetting Landies,Petrol Stoves,Weather Girls,Side cars and East European 2-Strokes !!
Dont understand any of that myself !!!!!

Jethro

[Mark]

I always thought this forum was based on wife beating.