Thumper or not ?

[Fil]

if you spend any where near as much time riding as I do and have done, then maybe.
And I did not come up with a technical definition, it is the historical reality of the bikes for which the termed was coined long ago and with which none of the modern singles have slightest similarity.

Hey Bill,

None of my comments were aimed personally at you mate. I just found it odd that we are questioning whether we are able to call our beloved machines thumpers or not, and that some people shorten their engine's life by riding it like a 'real' thumper when it isn't.

[Garf]

Well, I didnt think my query would cause so much debate !!

Personally I will still refer to my bike as a Thumper as I believe that the term has evolved by popular (mis?) usage to refer to any large capacity single cylinder motorcycle engine.

I can see that historically, as Bill argues, that the term would have probably have been originally coined to describe the low revving, long stroke low compression motors of yesteryear but is that just because most of the larger 4 strokes around when it was first used happened to have engines configured in that way ?

Had our engines been around when the term was first used then I suspect that they would still have been lumped in the same 'category' simply by virtue of the basic design similarities to all the other bikes ie single cylinder and large capacity 4 stroke.

Anyway guys, great input I have enjoyed reading this thread.

Cheers
Garf

[Bill Jurgenson]

well, no, it is and was because those engines "thumped," really thumped. It didn' thave much to do with displacement and a 350 was a thumper, too. The engines we all use do not thump or do anything even approaching that.
Heavy vibes maybe, but no thumping. That can't even idle at speeds those real thumpers operated at.

[keithcross]

Please guys, dont argue with Bill on this one, he is right. In fact he is always right on everything.

Keith

[Garf]

Well, my biking started around 1980 and has exclusively been on Jap twins and 4's so compared to anything have owned or ridden my MZ certainly feels like it thumps.

I hope that sometime I might get to ride something that Bill would class as a thumper then perhaps I would better understand the distinction he makes.

Up until then I am happy enough to continue rightly or wrongly, to refer to my bike as a thumper.

At the end of the day, although interesting to discuss it isnt really of any importance. Surely the main thing is that we all love riding these great bikes.

Garf

[Bill Jurgenson]

Surely the main thing is that we all love riding these great bikes.

fair enuf! me, too.

compared to a Japanese 180º twin (my second bike was a CB72 back in 1962, a 180º twin) or a four or even a big brutish Laverda 1200 3-cylinder with 180º crank, any single is rough and uncultured.
But the classic 360º British twin, once considered to be the pinnacle of culture, jumps around the shop when running on its center stand like a dervish, in fact a lot worse than any of my counter balancer- less singles. The whole floor vibrates. However, the BSA feels real smooth; the pistons do go up and down together, amounting to even more unbalanced mass than any single, but they fire alternatively.

Snide remarks do not help anything, Keith. I am not arguing, just trying to explain how the term came to be and what it means. I did not coin it; it is not my definition.

[Old Dog]

I thought I might chip in my 2 cents worth and say that I have to agree with Bill on this one. Sometimes one does ride one's bike a certain way because it is suggested. I started riding my Tour as Bill recommended and it completely transformed what was previously a bike that I never totally got along with. Now that I ride it like a my old 2T MZ that is keeping the revs up 4.5 -6.5, I find that all the things I didn't like about it are no longer relevant.

I also ride a 500 bullet which is a thumper and once you have tried the real thing, you quickly realise what Bill is on about. The fact that both are large capacity singles is irrelevant, the Bullet is a thumper, it thumps, revs low and will pull in top from just above idle if neccessary, try that on a Skorpion or an XT and you'll be lucky if it doesn't put you on your arse. That said if you ride the bullet like Bill recommends you ride a 660 you will not find a rewarding experience, it gets up there in its own time by building up, building up. You can feel the flywheel momentum.

As to whether you want to call the 660 a thumper well that I guess is purely a matter of preference, people call things all sorts of things but it doesn't make it so...

Cheers

OD

[Fil]

Surely the main thing is that we all love riding these great bikes.
Garf

Aye, that's what matters above anything else. And also to me, that fact that we prefer to go down a road less trodden (ridden?) than the usual UJM inline 4 cyl route by riding big singles.

I'm beginning to think that perhaps the way a person rides a bike has more to do with the sort of machines they grew up with or are used to.

I wouldn't ride my bike like a true thumper because I've never ridden one - I guess that's why I found it odd that anyone would ride a 660 MZ like one. I grew up with single cylinder 2 stroke MX bikes and a brief forray into the world of inline 4 Japanese sports bikes before buying my Mastiff (coming upto 9 years ago now!), so I tend to rev it anyway as that's what I'm used to and that's how it seems to work best.

[Nozz]

Now that we are talking more about suggested rev ranges. I have the Rotax 500 on a Silver Star, and was advised from day one not to ride at too low a rev. The practical range seems to be from over 4000 to 6000-6500, and it feels "bogged down" running much below 4000. Other than just feeling better at the higher rpm, what effect does it have on the engine, etc.?

Secondly, at first glance I thought this was kind of frivolous discussion and was biased towards thinking they are all thumpers. Now I appreciate the difference a little more and we can all discuss it with a bit more authority "out there" among the non-MZ world in which we are so blessedly outnumbered!

Thanks to everyone for sharing your insights and comments.

-Jim in Austin TX

[DAVID THOMPSON]

I have the Rotax 500 on a 95 Saxon tour
i use the spark plug DPR8EA-9 ori was d8ea
runs and idles much better

mine idles at about 1500 rpm and seems to pull good from 3000 up
i seldom run faster than 65 mph on it
town use most of the time 3000 rpm to 4500 rpm
below 2500 it gets to doing the jerk jerk thing on the chain

nice running bike after it got worn in and i changed the plug

20,000km on it now = 12,427 miles
a note for NOZZ the stock sprocket on mine at the engine was 18 tooth
i went to 17 and it does much better in town and on the highway
ar dave

[mr john]

http://en.wikipedia.org/wiki/Thumper_%28Motorcycle%29

[Bill Jurgenson]

being in Wikipedia doe not make it right.
None of those metioned are thumpers and the BMW shown with its paltry 250cc ain't one, either.
Thumper engines are undersquare - way undersquare traditioanlly have heavy flywheels.
A BSA Goldstar is a thumper, but a better examples would be an Ariel Red Hunter, a Matchless G3 or a Notrton Inter. A Guzzi Condor is another. Or the India Enflied - until last year that is, since their new "clean" motor is a relatively modern short stroke unit entirely different from the old one which was in principle the same as Enfield made before the war.
A thumper must be able to idle 500rpm or below and pull away at that engine speed. The xtz engine in stock trim will not run at all at that speed or at 1000rpm either, let alone drive away at that rpm. Like the only correct part of the Wikipedia clipping says: it's called a thumper cause of the thump-thump the engine makes. What we have may be loud but it can hardly said to be going thump-thump.
We been thru this all too often before and repeated misuse doe not make something wrong right.
Go to veteran rallye and listen to a thumper, better yet beg, steal or borrow one to test ride.
You have to go to a veteran rallye cause there are no modern thumpers being made anywhere in the world.

[Bill Jurgenson]

being in Wikipedia does not make it right.
None of those metioned are thumpers and the BMW shown with its paltry 250cc ain't one, either.
Thumper engines are undersquare - way undersquare traditioanlly have heavy flywheels.
A BSA Goldstar is a thumper, but a better examples would be an Ariel Red Hunter, a Matchless G3 or a Notrton Inter. A Guzzi Condor is another. Or the India Enflied - until last year that is, since their new "clean" motor is a relatively modern short stroke unit entirely different from the old one which was in principle the same as Enfield made before the war.
A thumper must be able to idle 500rpm or below and pull away at that engine speed. The xtz engine in stock trim will not run at all at that speed or at 1000rpm either, let alone drive away at that rpm. Like the only correct part of the Wikipedia clipping says: it's called a thumper cause of the thump-thump the engine makes. What we have may be loud but it can hardly said to be going thump-thump.
We been thru this all too often before and repeated misuse doe not make something wrong right.
Go to veteran rallye and listen to a thumper, better yet beg, steal or borrow one to test ride.
You have to go to a veteran rallye cause there are no modern thumpers being made anywhere in the world.

[keithcross]

Bill

Until now I have kept out of any further discussion on this subject as it seems you will only accept your side of the argument. Even when an encyclopedia is quoted it is still they that are wrong and not your error in any way.
I suggest that you accept that not everyone agrees with your point of view and leave it at that.
There is no doubt hat you do have a lot of knowledge on engines, the way they work and on how to repair and tune them, but please try to accept that others in this community will not always agree with you.
As to whether the MZ/Yamaha engine is a thumper or not is up to personal opinion. While I agree that compared to early single cylinder bikes like my recently acquired 1957 Ariel 500 in trails trim, which have a larger percent of there power at the more bottom end than the engines in the 660 Yamaha engine, so the Yamaha 660 engine has more of its power, lower down the rev range compared to a high revving 4 cylinder 4 strike like the GSXR600, this in comparison makes the 660 Yamaha engine a `Thumper'.
Its all a matter of where you set the parameters for your point of view.

Keith