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Discussion Starter #1
I was seeing how much force i could apply to rear brakes and when i give it a lot of pressure i feel a clunk underneath the bike. Is this from the rear tire breaking traction? It feels like something is hitting metal on metal.
 

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Super Moderator "Loose Nut"
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Sounds like something is loose, very unsafe! First I would check the tightness of the caliper bolts. Then check that the pad shims which keep the pads in place, number 9 in picture, are there. Then I would check tightness of all swingarm nuts and bolts. Clucking noises on braking is not a good thing, immediate attention for safety concerns. Post back results. Be safe.

 

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I take it you are talking about your Vstar 1300? I know you were working on a 650 for a while, which has drum brakes that could be loose for other reasons.

Have you tried sitting in neutral, putting the rear brake on and rocking the bike to see if any brake parts are moving?

I agree with Les, dont ride the bike till you figure this out.

And if you are testing while riding have to remind everyone: if you lock up the rear brake you have to keep it locked till the bike comes to a complete stop - if you let off while the rear tire has skidded out sideways even a little bit it will snap straight so hard it will throw you off the bike.

its the opposite of the front brake, if you lock the front brake release it instantly or the front will slide out and you go over the handlebars
if you lock the rear brake keep it locked and steer into the skid (hopefully you will not skid into anything) until you stop, or it will throw you off the bike.

one other thought: if you lock up the rear brake with the clutch engaged (not pulled it) it will stall the engine and make horrible sounds
 

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Discussion Starter #4
Its my 1300. Rebuilding carb on 650. Yeah i cant make it happen while rocking bike stationary no matter how hard i try. Could it be an engine mount/bracket loose causing a shift? I havent checked swingarm but brakes/calipers arent loose. It only happens with sudden heavy rear brake with NO front brake (something id never normally do)
 

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when you step on the rear brake it changes the force on the entire rear wheel suspension from the tire pushing the swing arm forward to propel the bike, to pulling the swing arm back

that is quite a bit of force when you really get on the brake, so it could be anything in the rear suspension loose with slack that only clunks from one side to the other under a considerable amount of force

it could also be the wheel on the axle
 

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Super Moderator "Loose Nut"
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Also check shock bushings. A loose shock mounting bolt or bushing could cause a metal to metal clunk.
 

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and make sure your battery is not flopping around...
 
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