Messages

Yes,
This bike was originally silver.
Hemi

Yes,
My original '77 back in the day was a D model.
In Canada, the E's arrived the tail end of '77.
Hemi

Spent the winter restoring a 1977 RD400E.
Still some carb work to do, but otherwise ready to roll.
Brings back sweet memories from my late teens when I bought my first new bike, a 1977 RD400D.
Hemi

Jspooner,
You nailed it!
Disassembled the forks today, and found the top out valve had been reassembled incorrectly by the previous owner.
The oil flow ring that contains the spring was upside down, easy to see how that could happen.
No more clunk at extension, hard to believe that little spring and ring make such a big difference.
Many thanks!
Hemi

Jspooner,
Appreciate your advice. Seems you've experienced the very same issue and found a fix.
Fingers crossed that's the issue.
Sounds like it took you a few attempts to get the parts inserted correctly.
Hemi

Thanks Dvsrd,
I've tried more fork oil, thicker oil, less oil.
With more oil, the forks seemed a bit more extended at rest, felt stiffer, less sag, still had the clunk.
I'll check the other things you mentioned.
Hemi

Jspooner,
I've checked several parts diagrams and I don't see the springs you noted at the bottom of the forks?
I can't seem to paste a photo here.
Hemi

Thanks Jspooner!
That gives me something to work with.
Found a couple parts diagrams.
Looks like there are several parts that come together in the  bottom of the forks.
Perhaps the previous owner re-installed incorrectly.
Hemi

STLMike,
That's very interesting.
Let me know how that works out for you when you ride your bike after reassembly.
I've been talking to John at Economy Cycle. He sold me the progressive springs.
He has 2 personal RD400's, one with progressives and the other with stiffer springs for the track.
He hasn't mentioned cutting the springs, and I believe the spacer is supposed to be removed with progressives, leaving about an inch of spring above the tube with forks extended prior to replacing the caps.
Before I switched to progressives, the forks had the spacers and stock springs, and had the same problem, a nasty clunk at full extension.
Hemi

Ok,
Thanks Jspooner,
Looks like it time to disassemble the forks.
Hemi

Also,
The fork tubes were supplied by HVC Cycle- part number 1A0-23124-00-00, 1A1-23124-00-00
Hemi

Thanks Jspooner,
Yes, the previous owner installed the new fork tubes.
Perhaps the damping rod was reassembled incorrectly?
Any other ideas out there would be appreciated.
There are no spacers with the progressive springs.
Either way, with progressives or the stock springs and spacers, there is about a 1" extrusion out the top of the forks before screwing the fork cap back on, which I believe is about the correct amount.
Hemi

I'm looking for assistance with a disturbing clunk at the top of fork travel in my 1977 RD400E, even when going over small bumps at low speed.
The clunk is disturbing to the point of not wanting to ride the bike.
I've been refurbishing the bike, tip to tail, over the winter, added Vape ignition, many parts, paint, top end.
New fork tubes, have now added progressive springs, tried different weights and levels of fork oil.
The clunk is at the top end of travel when forks extended after a bump in the road, nasty clunk felt through the bars.
The steering head seems fine, new bearing, adjusted to specs.
I've owned 20 bikes over the decades, including an RD400 back in the day, and have never experienced anything like this.
Any and all thoughts would be much appreciated.
I'm stumped, as is John at Economy Cycle......
Hemi