Why are they called "Thumpers"?

Hello All,
I am new to motorcycles, and plan to take my beginner's class next April. I just purchased a 2003 Honda CB250 to learn on, and then I want to purchase a BMW. The local dealer in my area, recommended the G650GS. I am reading all I can about the bike, and would like to know why it is referred to as a "Thumper". Is it due to the sound the engine makes?
Thank you for your replies and any recommendations.

Yes, the term thumper refers to the sound the large bore, single cylinder motor makes. The G650GS is a very good bike for the new and experienced rider alike. It has been the bike of choice for several around the world riders.

Oh, and welcome to the forum.

Thank you for the reply, akbeemer.

Thumpers of yesteryear!

My family's Triumph dealership once took in a BSA 500 Gold Star... Famous bike. That bike and all the big singles of the era literally thumped. When first started and when still cool you could put your hand on the engine head and feel it jump up and down on each revolution and tell exactly when it fired on every other TDC. Many twins had pistons that ran to top dead center (TDC) together but the opposing one fired alternately so they acted a bit different. The name "thumper) has come to be synonymous with singles... even if they really don't "thump" much anymore. Modern large singles have a rotating (counter-rotating) shaft who's purpose is to impart an opposing force to the piston and crank, which makes them smoother. Smoother being a relative term at idle as the every other ignition explosion can still be heard and felt.
Getting old enough to be a historian!
You will love this bike.

The "thumping" also depends largely on the combination of a long stroke and low rpm, which was more common in the 60s and 70s. Today singles have shorter strokes and rev a little higher, thus the "thumping" is less pronounced.

and in the case of this Maico 501...the sound you made when the backlashing kickstarter sent you to the ground

My oldest adrenaline junkie/ Navy pilot brother had one of these in the 70's...recalled it THUMPED quite hard.That is in between the PANG-PANG-PANG two -stroke earsplitting buzz


Our 650 is called the sewing machine compared to our twins. Still a great single.

henzilla said:

and in the case of this Maico 501...the sound you made when the backlashing kickstarter sent you to the ground

My oldest adrenaline junkie/ Navy pilot brother had one of these in the 70's...recalled it THUMPED quite hard.That is in between the PANG-PANG-PANG two -stroke earsplitting buzz
View attachment 42697

Our 650 is called the sewing machine compared to our twins. Still a great single.

Click to expand...

I had a bultaco and BSA single thumper and they had very long strokes, I used to hill climb, power to the ground. But at low RPM you could almost count the strokes of the engine.