Boxerworks.com

A'noon good folks.

Having just started to ride Mrs NHN's R80 Mono roadster again apres foot injury (walking, not bikes!) I find that the rear brake pedal too low, so that when adjusted correctly at the rear wheel I find difficulty in applying enough pressure to actually make much stopping effort. Not that the brake is much use anyway, but it helps.

So I looked to see if I can back off the stop a little to raise it....but where on earth is it? I presume it is something to do with the brake light switch and is behind the plate....that is welded to the frame. How do I access this, and indeed is it adjustable if I get there?

It would appear I need to remove the rear wheel at least, if not the swinging arm to get near it, does anyone have a clue/been there seen it done it?

Thanks in advance,

Neil (noting the glorious weather on the Isle of Man we have had is about to break because TT starts next week. #sigh).

This video is on the earlier twin shock with a disc. Might help, might not?
Either way, it's a pita task.

https://youtu.be/GZUywqL9788?si=mEyqMWfTxfgh8pEU

Thanks Steve - it does give some insight, but the Mono has a drum rear brake. Should have said that, sorry. D'oh.

Fritz definitely was having a laugh when they designed the whole thing though, he's right there!

To clarify... When you say 'Roadster' are you referring to the R80R?

This is important because the rear brake pedal and switch are (uniquely) very different to the parts used on all other road airheads... . In particular, the video shown above relates to a twinshock R100RT, which is very different, in that area, to the R80R.

While the airheads thoughout the production range from 1969 to 1995, are all strongly related, there are literally hundreds of variations to the equipment fitted so it is really important to state the model and year if you want to be sure the information you're getting is relevant...

Rob

New Haven Neil wrote: ↑Fri May 16, 2025 9:46 am Thanks Steve - it does give some insight, but the Mono has a drum rear brake. Should have said that, sorry. D'oh.

I was aware of the differences. I took it for granted you'd know them too "Might help, might not."
The video had a couple of features that would likely apply to most models rear brake system.
1. The rear brake bits and pieces are in a difficult spot. We knew that though.
2. Removal of some of the adjacent bits eg muffler and the wheel, might make access better.

I'd do this job on a lift. Probably an age thing.

Rob Frankham wrote: ↑Sat May 17, 2025 5:41 am To clarify... When you say 'Roadster' are you referring to the R80R?

This is important because the rear brake pedal and switch are (uniquely) very different to the parts used on all other road airheads... . In particular, the video shown above relates to a twinshock R100RT, which is very different, in that area, to the R80R.

While the airheads thoughout the production range from 1969 to 1995, are all strongly related, there are literally hundreds of variations to the equipment fitted so it is really important to state the model and year if you want to be sure the information you're getting is relevant...

Rob

Hi Rob, thanks for the response.

Not, not an R80R, but a plain cooking R80 unfaired single disc mono, 1992.

I have managed some improvement by moving the footpeg around to a lower position, wow that Allen screw was tight! Still far from ideal though, but given the lever is now bearing on the footpeg bracket no further improvement is actually possible. The brake is still poor, it has new shoes so I am now wondering if the shoe/brake cam combination is correct.

I do know that the wheel is not original, when we bought the bike the back brake didn't work at all, this was due to the cast iron liner being cracked (like the old Honda 550/4's used to do) and the dealer supplied a new wheel still in packaging so was genuinely new. I presume they are all the same?? 4 bolt wheel with the correct spoke pattern. I have checked it is not cracked too!

OK,

Adjusting the pedal stop bolt is quite easy but time consuming... but you only have to do it once.

The adjusting bolt is threaded into an eye at the very top of the brake pedal with the head facing rearwards. It is secured with a locking nut. When the brake pedal is released, the head of the bolt comes in contact with a bracket welded to the frame. The rear lamp switch is located to the rear of the bracket with it's plunger protruding through a hole where the bolt on the pedal strikes it (the bracket) so it presses the plunger when the brake is off. (The switch is normally on so pressing the plunger switches it off).

a) Disconnect the brake rod from the rear brake.

b) Undo the nut on the pedal pivot bolt and withdraw the bolt. The pedal will drop down and, by manouvering the brake rod, you can get access to the spring clip/pin that secures it to the pedal. rotate the clip so that the pin can be released freeing the brake pedal. Make a mental note of how the thing goes back together.

c) loosen the stop bolt and rotate it to adjust the pedal rest height, anticlockwise to lower the pedal or clockwise to raise it... and, yes, you may have to do this two or three times to get the pedal exactly where you want it.

d) Once you have the pedal set as you want it, reconnect the brake rod at both ends... the reverse of dismantling.

You might be able to get access by taking the wheel out but it's cramped so it's probably better to do it by removing the pedal.

Wouldn't it be nice if you just had to adjust a screw in situ...

Rob

Thanks for that detailed procedure, Rob.

Having being caught by the brake pedal spring on an old Honda having about ten times the expected resistance and doing the 'perchang' thing and causing much finger damage and producing language I learned at sea, I will dismantle with care!

I hope to get at it some time this week so will report back.

Thank you as usual for sharing your knowledge.