Progressive Monotube Update- 3 years later
I have a 2010 Honda GoldWing GL1800 - Audio/Comfort - Base Model. I have 60,500 miles on the bike. I replaced the old factory springs with (I believe the 1st Gen) Mono tubes on 04/02/13 with 37,592 miles on the clock. I have rebuilt the forks once, since the replacement of the mono tubes, only due to my negligence of messing up the left side seal when I installed the mono tubes. I left the messed up seal in the fork tube and the seal lasted for 2 years. The rebuild was at 02/15/15 with 50,720 miles. â€¨Â Â Â Â Â Â Â
My problem is that I have excessive bouncing on any road surface specifically on smooth roads. As far as I can tell, the forks are not compressing when hitting the smaller bumps causing the excessive bounce. Larger bumps, the forks are compressing or absorbing the bump like they are supposed to. This bouncing has started in the last 3 weeks. Prior to this problem, the mono tubes worked perfectly fine.Â â€¨â€¨Speeds when noticeable: 30-45mph, does not matter if I am the only rider or 2 up.
â€¨â€¨What I have done to try to diagnose the problem.â€¨
1. Lower tire pressure to 38 in the front and 42 in the rear.
â€¨2. Loosen up the fork caps to release air in tubes.
â€¨3. Disable Anti Dive Valve.
â€¨4. Adjust rear shock preload from 0-25. I rode the bike on every setting and the bounce is still there.â€¨â€¨ A little more info.â€¨1. My weight is 170 lbs with my riding gear; full face helmet, summer jacket with body armor, gloves and textile riding pants over jeans.â€¨2. I used one shim on each tube, I prefer a stiffer ride.â€¨3. I used Honda Fork Oil SS8 10w and replaced all the bushings seals and dust covers both times. â€¨4. Added the necessary quantity per instructions for each fork leg.â€¨5. Front Tire is 2 years and 2 months old with 14,987 miles, tread depth 3/32â€â€¨6. Rear Tire is 3 years and 5 months old with 28,375 miles, tread depth 3/32â€An update on my 2010 Honda Goldwing GL1800 with Audio and Comfort (Base Model), I finally had time to replace the front and rear tires with Dunlop Elite 3â€™s, the steering head bearings with All Balls, and wheel bearings and seals with Honda OEM. My test ride home was about 36 miles from the shop I had the repair done at. My second test ride was to a work meeting approximately 38 miles. This gave me more time in the saddle to realize that the problem was still there. The bounce can be described as a springy type bouncing.
On 05/20/16, after my meeting and on my way home, I decided to go ahead and disassemble the front forks and inspect the Progressive Mono Tubes (PMT) and rebuild them by replacing the PMTâ€™s, oil, seals, and bushings. Three hours later, I had the all the parts in hand and started disassembling the right fork.
Once the right fork was disassembled, I inspected the PMT and noticed nothing out of the ordinary. I tried compressing the spring by pushing down from above (standing position with the bottom of the tube on the floor and the mono tube and spring closest to my hand) and found it very difficult. I did this with the one shim installed and removed. The Honda SS8 fluid was still red and the bushings looked like they were still new. No metal shavings or plastic chunks when I drained the fluid.
The left PMT, with the anti dive valve, I found the spring to be bulging to one side with or without the shim. I also noticed that at the end of the mono tube (gas side), the plastic spacer was misaligned and it looked like the larger spacer is missing. Again, trying to compress it from above, it was very hard to compress with the shim installed and removed. The Honda SS8 fluid was still red and the bushings looked like they were still new. No metal shavings or plastic chunks when I drained the fluid.
Now comparing my old PMTâ€™s to the new ones, I noticed that the spring thickness was a lot thinner than the older ones and the coil spacing was less from the top and bottom (or tighter wound). When I purchased the PMTâ€™s in early 2013, I believe these were the first generation on PMTâ€™s(??). What generation are the ones I have now? I decided to not put the one shim in per what the instructions said and I finished the job and took the bike bike off the center stand and noticed a dramatic drop in ride height, once all the weight was on 2 wheels. It was dark and late in the evening so I only had a chance to ride it up and down the street twice, I noticed a very dramatic difference when i rode up and down the street. I have 211 miles on the new tires and they are getting better by the mile. Tire pressures are; Front 38.5 and Rear 43.5 Psi +/- 2Psi. Date of Manufacture are; Front 3915 and Rear 0515. I have 112 miles on the new PMTâ€™s with no more spring type bouncing at the speeds I listed in my emails. As a matter of fact, the ride is 110% better with the problem being solved.
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