RD Forks

[BrianC]

A couple of questions on the RD forks.
First my owners / workshop manual is clearly for the RC as is hasn’t got the rebound damping mechanism details in the front suspension section. Was there a specific D manual or is there separate documentation available? I appreciate there isn’t a lot to it – parts wise, but you know how you just need the info!!

Second, the fork seal arrangement. The parts manual shows the seal then circlip followed by a “washer, holder” , a “holder, grease” then the dust seal. Now I have a piece missing. The parts manual isn’t really very clear, the owner’s manual is a little different (C model arrangement by the looks) and the description don’t really tell me much. I think the thin nylon type ring that is there may be the “washer, holder” (51439-MB9-781). Question is – what is the holder, grease (51438-MB9-781)? I can’t see what it would do and it hasn’t been there since I’ve had the bike (so therefore it can’t be important!!?) Is it just another seal thing? Can’t say I have ever seen anything on other forks over the years that would fit that description.
Thanks

[Trevor Hughes]

Hi Brian

In answer to your first point and as you have found out, yes the RC and RD manuals are different. The RC 32MA301 the RD 32MA3600 however where things are common you do see the RC pictured in the RD manual. Even some spelling mistakes are common to both manuals.

If you have an RC manual the centre picture on page 93 shows part (6) oil seal, (7) Buck-up ring, ( Gide bushing, (9) Slider bushing, (10) Snap ring, (11) Oil lock valve and (12) Fork piston. This diagram is basically replicated in the RD manual except it is split in 2. Parts 6, 7, 8 and 9 on 1 picture and parts 10, 11 and 12 on the second picture, however the picture far right on page 95 does show a difference. The RC manual shows Dust cover, Snap ring, Oil seal and Back up ring but the RD manual shows Dust seal, Sponge seal, Plastic washer, Snap ring, Oil seal, Back-up ring and Slider bushing. If I remember correctly the Sponge seal is just a fibre washer (what you describe as Holder, Grease 51438-MB9-781) and the plastic washer is just that (what you describe as Holder, Washer 51439-MB9-781).

Its been a long time since I‘ve taken my RD forks apart but I do recall when I first saw the fibre washer I thought it was something that had been added by the previous owner just to mop up any oil leak. I personally don’t think it would cause an issue if it were left out.

[BrianC]

Thanks Trev. As I suspected then. One further quick one–. The rebound damping, is there and information on the assembly? I am assuming setting 1 is the soft, 2 medium ans 3 hard. I am pretty sure the ports in the valving correspond to this , but you never know! Thanks again.

[Trevor Hughes]

Brian

According to the manual:

The rebound Damping Adjuster settings are for riding conditions.

1. Around town
2. Highways or winding roads
3. Rough or uneven

There is little information about assembly, except that when you install the forks you must align the 3 marks on top of the fork tube with the marks in the top yoke. It also states that both forks must be set to the same number.

I’m not sure how long you have been a club member but I do remember in one club magazine a short while ago Andy was looking to swap an original RD owners manual. He was looking for a manual for his RC in exchange. It might be worth dropping him a mail. CB1100rclub@aol.com
Regards

Trev

[Anonymous]

Hi Brian,
Following our recent off forum discussions I thought that I would just update this thread to remind those not aware that a great source of maintenance info for the bikes can be found in one of the Clymer series of manuals that covers the CB900 and CB1100F range from 1980 -1983.
Whilst nothing is R specific the similarities between the R and F bikes are many and the book is a great tool to have in any R owners workshop. Highly recommended.
They are regularly advertised on eBay and may even be obtainable from a local bookshop.
Details are:
Title. Honda CB900 – CB1100 Fours 1980 – 1983
Clymer Manual no M325
ISBN no. 0-89287-352-3

[BrianC]

As a follow / close out on this chaps, I have learned that the oil lock piece should have a small flat on the internal bore into which the damper piston rod locates. My lock pieces have a damaged flat on one side and missing flat on the other. That is why I couldn’t line anything up. With that little bit of info, everything makes sense. Happy about reassembly and setup.
Anybody got a spare Oil Lock Piece they want to sell?? Of course they aren’t available any more.

[Author]

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