Engine Stop Switch -- 1st Gear Clunk

Constant Mesh · Sep 18, 2017

When you abruptly connect two gears, one motionless and the other turning, you're going to have a clunk or bang.

When you're idling at 1100 rpm the large 1st gear wheel can be turning as fast as 278 rpm or 4 revs per second. When you're sitting still and you shift from neutral to 1st you're trying to grab that gear with one which isn't turning. Going to be some noise and maybe a lurch of the bike unless you have the brakes actuated.

How can you slow down the 4 rev per second gear?

Maybe you don't have a lot of clutch drag and it's turning much slower than 4 revs per second. Maybe you hold in the clutch lever for several seconds hoping that the gear will gradually slow down to minimize the clunk.

How else can you slow down the spinning gear?

Actuate the engine stop switch momentarily for a quick slowdown. Simultaneously execute the shift to 1st. Flip the stop switch back to run and "unstop" the engine.

Engine should still be spinning fast enough to fire back up without using the starter.

Or, you could do what I typically do, shift to 1st before starting the engine.

RossKean · Sep 18, 2017

... or endure the "clunk". Adds character and doesn't seem to hurt anything.

Don't think I like the idea of interrupting the ignition cycle in the middle. Could be quite a jolt to the system if it comes back on at the wrong time. Far more likely to bend or break something than with the "clunk".

Mr_Canoehead · Sep 18, 2017

Every bike with a wet clutch is going to clunk into first for the reasons you have stated. My BMW with a dry clutch actually has the opposite problem - sometimes it hangs up going into first because there is no movement and the dogs don't align properly. The fix is to engage and release the clutch to get everything spinning so that it drops into gear with a satisfying clunk.

If you click the kill switch and drop the engine revs to say 1/2 (550 rpm) and shift to first, the gearset will still be moving at 2 rpm and will still clunk - seems much ado about nothing.

I'd be more worried about the extra drag on the starter if starting cold with the bike in gear and the clutch pulled......and I'm not going to lose any sleep over that, either.