The mystery thunk continues (solved)...
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Tourer
Joined: Dec 2007
Posts: 437
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The mystery thunk continues (solved)...
So awhile ago I installed Progressive Springs in the Front forks on my 07 Street Bob. Soon after I noticed a thunk in the front end when i held on the front brake and rocked the bike back and forth. I posted a thread to this forum and got some suggestions to try. I cut about a 1/2 inch off the PVC spacer. This softened the front end a little but the thunk is still there. Progressive suggested i take about an ounce of oil out of each leg because the springs displace more oil than the stock springs. Tried it but the thunk is still there.
I performed the Service Bulletin M-1215 fix prior to installing the springs in an effort to fix a different clunk. BTW this didn't fix the original clunk but a HD tech identified that clunk as the front end fall away needed adjusting. This adjustment fixed the original clunk but that clunk was different than the thunk I am now experiencing. Also as an FYI it is not a loose gas tank or jiffy stand.
So here is the strange thing that I have discovered. If I put only the rear brake on and rock back and forth the front suspension compresses the same amount as when I am using the front brake but there is no thunk. If I squeeze the Front and rear brake and rock back and forth....no thunk. When I am riding....no thunk. This thunk only happens when i'm sitting still with the front brake only rocking back and forth.
I took it by the dealer and they felt the thunk also but could not figure out what it was either. They did offer to rebuild my forks for 4 hours of labor (about $320) in case I screwed something up when I replaced the springs. They did feel it was ok to ride and not an unsafe situation.
So i guess I should just ride and forget it but it really bugs me when things aren't right.
I performed the Service Bulletin M-1215 fix prior to installing the springs in an effort to fix a different clunk. BTW this didn't fix the original clunk but a HD tech identified that clunk as the front end fall away needed adjusting. This adjustment fixed the original clunk but that clunk was different than the thunk I am now experiencing. Also as an FYI it is not a loose gas tank or jiffy stand.
So here is the strange thing that I have discovered. If I put only the rear brake on and rock back and forth the front suspension compresses the same amount as when I am using the front brake but there is no thunk. If I squeeze the Front and rear brake and rock back and forth....no thunk. When I am riding....no thunk. This thunk only happens when i'm sitting still with the front brake only rocking back and forth.
I took it by the dealer and they felt the thunk also but could not figure out what it was either. They did offer to rebuild my forks for 4 hours of labor (about $320) in case I screwed something up when I replaced the springs. They did feel it was ok to ride and not an unsafe situation.
So i guess I should just ride and forget it but it really bugs me when things aren't right.
Road Master
Joined: Jan 2006
Posts: 1,154
Likes: 3
From: Colorado Springs
RE: The mystery thunk continues...
It took me and a buddy about an hour to figure this one out.
Believe it or not, itwas the floating rotor. Have someone put there finger in one of the holes in your rotor and then rock the bike back and forth while holding the front brake. They will feel it shift ever so slightly. I am not sure if this is "normal" but it kind of scares me. I might go with a solid rotor when it is time to be changed out.
Let us know if it is the culprit.
Believe it or not, itwas the floating rotor. Have someone put there finger in one of the holes in your rotor and then rock the bike back and forth while holding the front brake. They will feel it shift ever so slightly. I am not sure if this is "normal" but it kind of scares me. I might go with a solid rotor when it is time to be changed out.
Let us know if it is the culprit.
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Tourer
Joined: Dec 2007
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RE: The mystery thunk continues...
ORIGINAL: anubisss
A while back people were finding their front tank bolts a little loose too and that produced the same clunk. Just a thought.
A while back people were finding their front tank bolts a little loose too and that produced the same clunk. Just a thought.
Thread Starter
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Tourer
Joined: Dec 2007
Posts: 437
Likes: 0
RE: The mystery thunk continues...
ORIGINAL: BeavisRules
It took me and a buddy about an hour to figure this one out.
Believe it or not, it was the floating rotor. Have someone put there finger in one of the holes in your rotor and then rock the bike back and forth while holding the front brake. They will feel it shift ever so slightly. I am not sure if this is "normal" but it kind of scares me. I might go with a solid rotor when it is time to be changed out.
Let us know if it is the culprit.
It took me and a buddy about an hour to figure this one out.
Believe it or not, it was the floating rotor. Have someone put there finger in one of the holes in your rotor and then rock the bike back and forth while holding the front brake. They will feel it shift ever so slightly. I am not sure if this is "normal" but it kind of scares me. I might go with a solid rotor when it is time to be changed out.
Let us know if it is the culprit.
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Tourer
Joined: Dec 2006
Posts: 314
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From: North Hills California
RE: The mystery thunk continues...
Had a similar noise in mine, and it would actually chatter a bit just before coming to a stop, turns out it was the steering head bearings. The top nut fas only finger tight.
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Thread Starter
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Tourer
Joined: Dec 2007
Posts: 437
Likes: 0
RE: The mystery thunk continues...
ORIGINAL: SeeNoSun
Now this is something I haven't tried. Thanks for the idea. I'll try it and report back.
ORIGINAL: BeavisRules
It took me and a buddy about an hour to figure this one out.
Believe it or not, it was the floating rotor. Have someone put there finger in one of the holes in your rotor and then rock the bike back and forth while holding the front brake. They will feel it shift ever so slightly. I am not sure if this is "normal" but it kind of scares me. I might go with a solid rotor when it is time to be changed out.
Let us know if it is the culprit.
It took me and a buddy about an hour to figure this one out.
Believe it or not, it was the floating rotor. Have someone put there finger in one of the holes in your rotor and then rock the bike back and forth while holding the front brake. They will feel it shift ever so slightly. I am not sure if this is "normal" but it kind of scares me. I might go with a solid rotor when it is time to be changed out.
Let us know if it is the culprit.
Thread Starter
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Tourer
Joined: Dec 2007
Posts: 437
Likes: 0
RE: The mystery thunk continues...
ORIGINAL: darkdyna06
Had a similar noise in mine, and it would actually chatter a bit just before coming to a stop, turns out it was the steering head bearings. The top nut fas only finger tight.
Had a similar noise in mine, and it would actually chatter a bit just before coming to a stop, turns out it was the steering head bearings. The top nut fas only finger tight.
Thanks for the help.