Clunk noise from front forks
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1st Gear
Joined: Jul 2019
Posts: 5
Likes: 1
From: Wawa ON, CANADA
Clunk noise from front forks
I have a 07 Street Glide with a clunk when I ride over any not so smooth road surface (gravel, breaks in the pavement etc.) The previous owner had lowered springs installed because of a height issue and couldn't reach the ground when on the bike.
I have eliminated all other possibilities such as any loose components, bolts etc. It sounds like there's not enough oil and something is bottoming out.
Any thoughts? Thanks,
I have eliminated all other possibilities such as any loose components, bolts etc. It sounds like there's not enough oil and something is bottoming out.
Any thoughts? Thanks,
Seasoned HDF Member
Joined: Sep 2018
Posts: 6,038
Likes: 1,812
From: Kalifornia
Also might take a look with the front wheel removed and see if the bolts for the damper tubes are still tight. On touring bike I believe you remove front wheel and lower axle cap. If this bolt came loose it would allow the clunk on rebound. This would be, second, after checking steering head bearings.
HDF Community Team
Joined: Jan 2020
Posts: 1,434
Likes: 800
From: Colorado
Don't know the miliage on the bike, but I tend to pull forks apart every 30K to rebuild them. Hence the teflon coated brass seals tend to wear out in that amount of time, and you can get the metal against metal kind of noise with shock movement as well. Plus the added slop, end up with the seals starting to fail as well.
Rebuilt kit cost about $50, new bottom and drain bolts with copper seals run about an extra $10, and two jugs of Maxima fork oil runs about $30. As for the two jugs, I pick up a jug of 15 weight from the forks, and 10w jug to do a 50/50 mix if it and the 15 weight to change the oil out in the air shocks to 12 weight at 11.5 oz per shock on there oil change.
Hence stock, the front air forks have 10 weight, the rear shocks have 7 weight oil at 11oz per shock, and just ends up with too soft/to much pogo'g of a ride. Also, with only 11oz in the rear air shock, and the OEM amount of oil in the air forks, back end does not match the front forks at half to full compression with over pogo'g to what the front is doing.
As for air pressure amount, look at the saddle back sticker for the total weight over 150lbs, and use it for the amount of air to install in the forks and shocks, to set the correct sag for the bike. On mine, it 1lb of air for every 25 lbs over 150lbs, but other bikes use slightly more air for every extra 25 lbs instead.
To sum it up, with the bike used, and knowing that someone did get into the forks to do do the spring kit, you don't have a clue of how much oil they used, nor what weight of oil as well. Also with the noise, really need to get into the forks to find the problem, and with them that far apart, may as well seal/bushing rebuild them as well.
Rebuilt kit cost about $50, new bottom and drain bolts with copper seals run about an extra $10, and two jugs of Maxima fork oil runs about $30. As for the two jugs, I pick up a jug of 15 weight from the forks, and 10w jug to do a 50/50 mix if it and the 15 weight to change the oil out in the air shocks to 12 weight at 11.5 oz per shock on there oil change.
Hence stock, the front air forks have 10 weight, the rear shocks have 7 weight oil at 11oz per shock, and just ends up with too soft/to much pogo'g of a ride. Also, with only 11oz in the rear air shock, and the OEM amount of oil in the air forks, back end does not match the front forks at half to full compression with over pogo'g to what the front is doing.
As for air pressure amount, look at the saddle back sticker for the total weight over 150lbs, and use it for the amount of air to install in the forks and shocks, to set the correct sag for the bike. On mine, it 1lb of air for every 25 lbs over 150lbs, but other bikes use slightly more air for every extra 25 lbs instead.
To sum it up, with the bike used, and knowing that someone did get into the forks to do do the spring kit, you don't have a clue of how much oil they used, nor what weight of oil as well. Also with the noise, really need to get into the forks to find the problem, and with them that far apart, may as well seal/bushing rebuild them as well.
Grand HDF Member
Joined: Jan 2012
Posts: 4,453
Likes: 2,839
From: Oklahoma
If you are not getting a firm or hard shock through the handle bars, you are not bottoming the shock travel and go with the head bearings. If you are getting the hard shock through the handle bars, the forks are bottoming. Heavier shock oil may help, shimming the springs, or replacement with standard springs are about the only options. "Clunk" is normally the steering tube banging around inside the steering head tube caused by bearings being too loose..
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Seasoned HDF Member
Joined: Oct 2019
Posts: 10,759
Likes: 7,385
From: OH
[QUOTE=btsom;19419798], shimming the springs, QUOTE]
I would suspect the P.O. Failed to cut the spring spacers to the proper preload
lots of possibilities though
I would suspect the P.O. Failed to cut the spring spacers to the proper preload
lots of possibilities though
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