What is this starter sound?

PDC-500B said:

In the past, I took the starter motor out and bench tested it - all it did was just whirr without any screeching sounds at all, even when left running for quite a good many seconds. Admittedly it wasn't under any load at all, but when it is refitted, it doesn't do it every cold and/or wake-up start up after a long idle period. I will replace the starter clutch components when I have the motor out to replace the camchain, when that is required, but whether that will cure it, it will just have to wait until then...

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I had hastily replied last night (terrible habit). I would add that it sounds like an electrical motor whining, not defectively but like the starter clutch parts are slipping and the starter is turning differently.

It was super hard to tell in video if your engine is maintaining the RPMs over the starter noise and the lack of light on the gauge...and then I realized your lights are dimming when it starts making the weird noise. Is there anyway this is a weak battery/bad connection thing? As in the starter is actually not turning fast enough and the starter is making a strained noise or not putting enough torque into the starter clutch?

I can see your oil light went out as the engine turns over and that's normal, but what's the purple-ish light and should it be going out? I have a CX650c so my dash is setup differently but I think that's your hi-beam? Do these bikes cut the head light off on the start cycle? That bottom light goes out the second that weird sound starts, but so does your oil light.



I don't know if you can see on the RPM gauge any change in RPMs as the starter is turning, but a drop in RPMs would definitely indicate slippage. A ninja 250 I just went through and fixed made -almost- a similar sound and the roller bearings on the starter clutch were all sorts of beat up, springs were toast, etc. It would mostly make the 'box of rocks' noise but there was also a slight whir-whine-howl thing as it started to catch and slip.

I've let your video play 100 times on loop and I'm pretty sure it's maintaining the normal starter noise/speed/turn over rate through-out the video and through the weird noise meaning it's not the starter clutch slipping.

I would make a note of what RPMs it turns when it does and does not make that weird noise.

I hopped around different forums trying to find a video of failing starter clutches and it's almost maddening that I couldn't find another audio clip like yours. I did find on the Honda Rebel forums someone claiming the sort of sound you have and it being the starter clutch.

You are right though, just bench testing the starter wouldn't tell you much because it's under no load. I couldn't imagine something slipping internally.

As a weird side note; it'd be great to leave your youtube video up for posterity with a description of a solution if one is found.