I have a 2009 Suzuki Boulevard M90. Been running great, with little to now problems since I bought it new.

The other day as I was riding, a large "clunk" happened. It felt like it was on the left side, down by my feet. Almost felt like my kick stand came out and smacked at my boot. It has been happening more and more and always feels like a hard kick from the bike. Always on the left side. It kind of feels like a gear issue as I am usually sure I know what gear I am in, but have been getting much more confused since this has started (i.e., down shifting taking an extra or less shifts to get to 1).


Bike is shaft driven, and does not have a chain.

I took it for a quick ride this morning to see if I could identify anything more. When I pulled up to a parking space and tried to walk it backwards (in 1st and running), it wouldn't let me. After 2 or 3 times throttling forward and trying to go back again it finally let me.

  • 1
    Are you sure it's not the side stand? Perhaps the spring is loose and it's dropping down while you're riding.
    – jwh20
    Sep 7, 2021 at 18:51
  • 1
    ...or perhaps it does not always retract fully but you don't notice because after it clunks it is positioned correctly. Needs some grease? But if the gear shifting has been getting unreliable too, perhaps take a look at the shift mechanism. Sep 8, 2021 at 8:27
  • when my kickstand comes down, the bike is supposed to shut off automatically
    – D_C
    Sep 8, 2021 at 15:32
  • Use something (bungee?) to tie up the kickstand to eliminate it as a possibility.
    – mike65535
    Sep 9, 2021 at 12:27

2 Answers 2


I suspect a “kink” in the chain. That is to say a portion of the chain with poor lubrication that is wearing unevenly. Another possibility here is "chain stretch" (actually excessive wear), such that the chain causes wear on the sprockets to the point where the tooth doesn't enter the gap in the chain at the correct spacing. This is caused by lots and lots of miles without lubrication.

Those things require cleaning and relube every 500 miles. (Street bike). More frequently for off road bikes.

My guess is if you prop up rear wheel and spin tire in neutral, you will find that issue easily.

The fix? For a simple kink, remove and lubricate chain. For chain wear, you will need a new chain and new front and rear sprockets.

  • my bike doesn't have a chain, it has a drive shaft
    – D_C
    Sep 8, 2021 at 15:30

Oddly enough, a simple WD40 everywhere once I removed the covers seems to have solved it. The clutch must have been sticking.

  • No. A fault in the clutch would be internal to the engine, and would have been unaffected by any external application of WD40. A different cause — whatever it may have been — was responsible. Feb 4 at 5:33

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .