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Yesterday I was on a trip about 100 miles from home. It was 95 F out and I was on the freeway. Traffic came to almost a stop then 5 mph. The heat of the day coupled with the heat of the engine started getting to me so I pulled off the freeway to gulp down a Gatorade. I was stopped for less than 10 minutes. When I went to leave the convenience store my bike started making a knocking noise like someone was hitting the frame three or four times with a small ball peen hammer. The knocking was so pronounced I could feel it and people sitting nearby made a comment "that doesn't sound good". My first guess was that a brake caliper bolt, or some wheel bolt had backed out and was hitting on something on the wheel every so often, it was very intermittent. I circled the store parking lot trying to isolate the noise. It would only make the noise below 8 or 9 mph. I tried using only front brake to slow, then rear brake, tight turn left, then right. I could get it to make the intermittent banging in all modes. When the noise would come it would make three or four raps, then silence for 10 seconds then the noise would happen. If I got above 10 mph ,,no noise. I layed beside the bike on the 130F asphalt and inspected the belt, belt pully bolts, front and rear brakes. I saw nothing out of the ordinary. OK I thought, it must be that damn front drive pulley nut again. I pulled the cover off and the nut was tight and staked. Uh oh, I started thinking maybe rear wheel bearings? I did a Google search and lo and behold there was a large Yamaha dealer 2 miles from me and they closed in 30 minutes. I rode to the dealer at about 15 mph so there was no noise what so ever. When I got to the dealer I did several tight circles in the parking lot to make sure the noise was still there. Yep, at 5 mph, bang, bang bang, nothing for 10 seconds , then bang bang. I went in talked to the service writer and dropped the bike off. He came out and rode the bike into the shop. He came back and told me it was smooth as silk and then all of a sudden, bang,,, bang,,,. He said it sounded like a left wheel bearing to him. He said the tech will look at it at 10 am the next day. The next day at 10:30 AM they call and say the tech can't duplicate the noise and he has ridden it for 20 minutes. "What do you want us to do? Do you want to just pick the bike up and see if it does it again" I told them to tear the rear wheel down and inspect. If it was OK at least we could eliminate the bearings.

The dealer replaced all of the rear wheel bearings, seals, cushion bearings and washers. Everything seemed fine when I picked the bike up and test drove it. However when I rode the bike on the freeway for 45 miles the noise was back as soon as I got off the freeway and pulled into a gas station. The noise seems to be related to the speed of the bike as when I slow down with the clutch in the noise slows down with the speed of the bike. Only makes loud banging noise between 4 and 8 mph. Has anyone experienced this type of noise?
 

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So it seems the noise is in relation to the wheel rotation correct? Clutch in or in neutral it will still make the banging noise while coasting?
 

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I can't help ya. I was thinking what Phil said, a rotational thing. Too bad they don't have a dyno type lift where they could run the bike. Couldn't they at least jack it up and spin the wheels by hand to eliminate that possibility. Keep us informed! The only knocking Ive ever heard was a crotch rocket scattering his engine in a parade we were doing after he hit his rev. limiter over and over,lol. I did have a friend of mine have a rock stuck in the center groove in his front tire and it banged off the front fender a bunch of times before he figured it out.
 

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I have a bike at the driving school that does something similar to what you're describing. It turned out to be the clutch that was doing the noise. It doesn't do it at speed but after doing slow maneuvers for a while, the engine is real hot and the clanging begins. From what I can gather, when the mechanic changed the plates out he didn't change out the other worn parts and there's some looseness in the assy. Check your clutch adjustment and notice the temps when the noise occurs. Could be the way you clutch at slow speeds that's causing this. In any case, let us know what you find when you finally resolve the issue.
 

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Yesterday I was on a trip about 100 miles from home. It was 95 F out and I was on the freeway. Traffic came to almost a stop then 5 mph. The heat of the day coupled with the heat of the engine started getting to me so I pulled off the freeway to gulp down a Gatorade. I was stopped for less than 10 minutes. When I went to leave the convenience store my bike started making a knocking noise like someone was hitting the frame three or four times with a small ball peen hammer. The knocking was so pronounced I could feel it and people sitting nearby made a comment "that doesn't sound good". My first guess was that a brake caliper bolt, or some wheel bolt had backed out and was hitting on something on the wheel every so often, it was very intermittent. I circled the store parking lot trying to isolate the noise. It would only make the noise below 8 or 9 mph. I tried using only front brake to slow, then rear brake, tight turn left, then right. I could get it to make the intermittent banging in all modes. When the noise would come it would make three or four raps, then silence for 10 seconds then the noise would happen. If I got above 10 mph ,,no noise. I layed beside the bike on the 130F asphalt and inspected the belt, belt pully bolts, front and rear brakes. I saw nothing out of the ordinary. OK I thought, it must be that damn front drive pulley nut again. I pulled the cover off and the nut was tight and staked. Uh oh, I started thinking maybe rear wheel bearings? I did a Google search and lo and behold there was a large Yamaha dealer 2 miles from me and they closed in 30 minutes. I rode to the dealer at about 15 mph so there was no noise what so ever. When I got to the dealer I did several tight circles in the parking lot to make sure the noise was still there. Yep, at 5 mph, bang, bang bang, nothing for 10 seconds , then bang bang. I went in talked to the service writer and dropped the bike off. He came out and rode the bike into the shop. He came back and told me it was smooth as silk and then all of a sudden, bang,,, bang,,,. He said it sounded like a left wheel bearing to him. He said the tech will look at it at 10 am the next day. The next day at 10:30 AM they call and say the tech can't duplicate the noise and he has ridden it for 20 minutes. "What do you want us to do? Do you want to just pick the bike up and see if it does it again" I told them to tear the rear wheel down and inspect. If it was OK at least we could eliminate the bearings.

The dealer replaced all of the rear wheel bearings, seals, cushion bearings and washers. Everything seemed fine when I picked the bike up and test drove it. However when I rode the bike on the freeway for 45 miles the noise was back as soon as I got off the freeway and pulled into a gas station. The noise seems to be related to the speed of the bike as when I slow down with the clutch in the noise slows down with the speed of the bike. Only makes loud banging noise between 4 and 8 mph. Has anyone experienced this type of noise?
Yesterday I was on a trip about 100 miles from home. It was 95 F out and I was on the freeway. Traffic came to almost a stop then 5 mph. The heat of the day coupled with the heat of the engine started getting to me so I pulled off the freeway to gulp down a Gatorade. I was stopped for less than 10 minutes. When I went to leave the convenience store my bike started making a knocking noise like someone was hitting the frame three or four times with a small ball peen hammer. The knocking was so pronounced I could feel it and people sitting nearby made a comment "that doesn't sound good". My first guess was that a brake caliper bolt, or some wheel bolt had backed out and was hitting on something on the wheel every so often, it was very intermittent. I circled the store parking lot trying to isolate the noise. It would only make the noise below 8 or 9 mph. I tried using only front brake to slow, then rear brake, tight turn left, then right. I could get it to make the intermittent banging in all modes. When the noise would come it would make three or four raps, then silence for 10 seconds then the noise would happen. If I got above 10 mph ,,no noise. I layed beside the bike on the 130F asphalt and inspected the belt, belt pully bolts, front and rear brakes. I saw nothing out of the ordinary. OK I thought, it must be that damn front drive pulley nut again. I pulled the cover off and the nut was tight and staked. Uh oh, I started thinking maybe rear wheel bearings? I did a Google search and lo and behold there was a large Yamaha dealer 2 miles from me and they closed in 30 minutes. I rode to the dealer at about 15 mph so there was no noise what so ever. When I got to the dealer I did several tight circles in the parking lot to make sure the noise was still there. Yep, at 5 mph, bang, bang bang, nothing for 10 seconds , then bang bang. I went in talked to the service writer and dropped the bike off. He came out and rode the bike into the shop. He came back and told me it was smooth as silk and then all of a sudden, bang,,, bang,,,. He said it sounded like a left wheel bearing to him. He said the tech will look at it at 10 am the next day. The next day at 10:30 AM they call and say the tech can't duplicate the noise and he has ridden it for 20 minutes. "What do you want us to do? Do you want to just pick the bike up and see if it does it again" I told them to tear the rear wheel down and inspect. If it was OK at least we could eliminate the bearings.

The dealer replaced all of the rear wheel bearings, seals, cushion bearings and washers. Everything seemed fine when I picked the bike up and test drove it. However when I rode the bike on the freeway for 45 miles the noise was back as soon as I got off the freeway and pulled into a gas station. The noise seems to be related to the speed of the bike as when I slow down with the clutch in the noise slows down with the speed of the bike. Only makes loud banging noise between 4 and 8 mph. Has anyone experienced this type of noise?
Hey mate, just reaching out to see if you solved your problem yet. Started on mine yesterday. Low speed, highish temp, not rhythmic.
 

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Yesterday I was on a trip about 100 miles from home. It was 95 F out and I was on the freeway. Traffic came to almost a stop then 5 mph. The heat of the day coupled with the heat of the engine started getting to me so I pulled off the freeway to gulp down a Gatorade. I was stopped for less than 10 minutes. When I went to leave the convenience store my bike started making a knocking noise like someone was hitting the frame three or four times with a small ball peen hammer. The knocking was so pronounced I could feel it and people sitting nearby made a comment "that doesn't sound good". My first guess was that a brake caliper bolt, or some wheel bolt had backed out and was hitting on something on the wheel every so often, it was very intermittent. I circled the store parking lot trying to isolate the noise. It would only make the noise below 8 or 9 mph. I tried using only front brake to slow, then rear brake, tight turn left, then right. I could get it to make the intermittent banging in all modes. When the noise would come it would make three or four raps, then silence for 10 seconds then the noise would happen. If I got above 10 mph ,,no noise. I layed beside the bike on the 130F asphalt and inspected the belt, belt pully bolts, front and rear brakes. I saw nothing out of the ordinary. OK I thought, it must be that damn front drive pulley nut again. I pulled the cover off and the nut was tight and staked. Uh oh, I started thinking maybe rear wheel bearings? I did a Google search and lo and behold there was a large Yamaha dealer 2 miles from me and they closed in 30 minutes. I rode to the dealer at about 15 mph so there was no noise what so ever. When I got to the dealer I did several tight circles in the parking lot to make sure the noise was still there. Yep, at 5 mph, bang, bang bang, nothing for 10 seconds , then bang bang. I went in talked to the service writer and dropped the bike off. He came out and rode the bike into the shop. He came back and told me it was smooth as silk and then all of a sudden, bang,,, bang,,,. He said it sounded like a left wheel bearing to him. He said the tech will look at it at 10 am the next day. The next day at 10:30 AM they call and say the tech can't duplicate the noise and he has ridden it for 20 minutes. "What do you want us to do? Do you want to just pick the bike up and see if it does it again" I told them to tear the rear wheel down and inspect. If it was OK at least we could eliminate the bearings.

The dealer replaced all of the rear wheel bearings, seals, cushion bearings and washers. Everything seemed fine when I picked the bike up and test drove it. However when I rode the bike on the freeway for 45 miles the noise was back as soon as I got off the freeway and pulled into a gas station. The noise seems to be related to the speed of the bike as when I slow down with the clutch in the noise slows down with the speed of the bike. Only makes loud banging noise between 4 and 8 mph. Has anyone experienced this type of noise?
Just so you know it is a 6 year old thread you may not get a reply but i hope you do. What bike do you have? Some one else may be able to help.
Hey mate, I've got a Vstar 650 custom. Exactly the same symptoms as the thread owner.
 

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the bike in the original post has a belt drive, and there was an early issue with the front pulley for the belt drive coming loose.

your 650 is a shaft drive, there is no commonality with the belt drive configuration

if you have a knock in your engine it could be one of several things:

a bent valve from redlining the engine by downshifting at high RPMs

piston hitting the valves because the timing chain for the valves jumped a few teeth

bad main or rod bearings, usually caused by running the bike with no oil (or oil level low enough for the oil pump to suck air)

Take the crank case access cover off the left side of the engine - its a quarter size cap with a slot that you can unscrew with a quarter held in a pair of vise grips

take the plugs out, and put a wrench on the nut on the crank shaft to turn the engine over by hand. See if you can feel any clunk / slack in the rods on the crank shaft, or if you feel the pistons hitting anything (like a bent valve)

the crankshaft turns clockwise from the left side of the bike (the opposite of the direction the front wheel turns)

if you turn the wrench back and forth about 20 degrees and feel it clunking, like there is freeplay and then something hits, its probably the connecting rod bearings
 

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if you dont feel anything on the crankshaft with the bike in neutral, you can try raising the rear wheel off the ground a bit, and spin it in neutral by hand

see if the shaft drive or universal at the engine output feels sloppy or clunky, again going one way then back the other way
 
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