RC51 Forums banner
21 - 40 of 42 Posts

·
Registered
Joined
·
352 Posts
Man thank you so much.. awesome info..

Relieved my factory (extra) forks I have are correct before getting them upgraded.


Is there anywhere, or a P/N I'm not seeing for those little o-rings on the bottom compression valve?

Honda parts I'm not seeing those listed anywhere
There probably a break down in a Showa factory manual but Honda doesn’t break it down like that. Too bad the fork uses race technology but doesn’t take advantage. Measure very carefully with a vernier without putting too much pressure on the orings. Do a search using the dimensions and you can probably find matches for them.
 

·
Registered
2002 RC51
Joined
·
156 Posts
Discussion Starter · #24 ·
Thank you guys! Huge help.. I get what you mean by bumps on the SP1. Makes total sense now that I see it..

Will have to look into those little gaskets. I'd like to drain the oil (at least most of it) before shipping, although not a must..

Might be a good question for Mike when I call down to Kyle racing next time. Heck he may have them in stock to replace on rebuilds..

Thanks again fellas 🍻
 

·
Registered
Joined
·
352 Posts
That is one heck of a setup. I love it!!
Thank you. Sometimes I just sit and look at it. Never regretted the time or expense I put into it because just so much fun to ride, the bark of the Satos and the torque trying to straighten your arm when you pin it out of a turn….. well like the ad says- priceless!!😜
 

·
Premium Member
Joined
·
6,499 Posts
Man thank you so much.. awesome info..

Relieved my factory (extra) forks I have are correct before getting them upgraded.


Is there anywhere, or a P/N I'm not seeing for those little o-rings on the bottom compression valve?

Honda parts I'm not seeing those listed anywhere
No part number for the compression adjuster O-rings. Honda assumes you'll never remove the assembly.
You'd have to measure the dimension of the OEM O-Ring to source.
 

·
Premium Member
Joined
·
6,499 Posts
The fork cap / preload adjuster for the SP1 and SP2 differ greatly in disassembly.
The RC51 Service Manual I have (both paper and PDF) ONLY show SP1 fork disassembly, not SP2.
Trying to use SP1 fork cap disassembly procedures on an SP2 fork cap can potentially permanently damage the damper rod.
And no, there's no replacement PN for the damper rod. Only for the entire cartridge assy.
However, the SP2 fork cap / preload adjuster is the same as for the 954 forks, so that can be used as a reference.
 

·
Registered
2002 RC51
Joined
·
156 Posts
Discussion Starter · #29 ·
No part number for the compression adjuster O-rings. Honda assumes you'll never remove the assembly.
You'd have to measure the dimension of the OEM O-Ring to source.


Yea, I get it but that's kinda frustrating on Honda's part.. My 02 is pushing 20 years old new seals would be nice.

I'll see if I can figure out the size, heck maybe I'm better off leaving them sealed up. Who knows
 

·
Registered
Joined
·
352 Posts
Yea, I get it but that's kinda frustrating on Honda's part.. My 02 is pushing 20 years old new seals would be nice.

I'll see if I can figure out the size, heck maybe I'm better off leaving them sealed up. Who knows
The seals and bushings are all available. Do not use all balls seal kits. Honda OEM seals are no more $ than all ball or other aftermarket and are far superior. Unless you are very careful and very lucky the bushings usually suffer some damage on disassembly so recommend having them on hand. The lower bushing tries to slip under the upper one when you slide hammer the upper and lower fork tubes. At the least that will damage the Teflon? surface and sometimes the metal so best to have new bushings available.
 

·
Registered
2002 RC51
Joined
·
156 Posts
Discussion Starter · #32 ·
The seals and bushings are all available. Do not use all balls seal kits. Honda OEM seals are no more $ than all ball or other aftermarket and are far superior. Unless you are very careful and very lucky the bushings usually suffer some damage on disassembly so recommend having them on hand. The lower bushing tries to slip under the upper one when you slide hammer the upper and lower fork tubes. At the least that will damage the Teflon? surface and sometimes the metal so best to have new bushings available.


I'm guessing your referring to the fork oil seals? Yes, all new honda will be used.

I'm striking out so far on the Honda/Showa compression adjuster O-rings..

Since there's no Honda part number anyone have a clue how to find the Showa breakdown for these forks? Maybe a diagram I could find the Showa P/N?

Might just have to try to call them and ask..
 

·
Registered
Joined
·
352 Posts
Tried to measure the o-rings & it’s tricky but seems just about 1.78mm cross section and around 8.5 to 9mm inside diameter. Did a google and got the oringstore.com. I looked up the NBR metric which has numerous sizes in 1.78 cross section. The 1.78 x 7.94 looks like the closest to what your looking for. Minimum quantity of 4 at 32 cents each. You could maybe get one size ID under & one over just to be certain. They have these in many different materials but I chose the NBR which was listed as most common for hydraulic type application. Hope this helps.
 

·
Registered
2002 RC51
Joined
·
156 Posts
Discussion Starter · #34 ·
That does help a ton! Thank you so much for taking the time.. I'll get on that website and poke around.

Makes me wonder, with the very common oil seal service for the forks at Honda dealers I'm curious if they remove the compression adjusters to aid in draining all the old fluid as normal practice. If so, you'd sure think they would ordinarily keep a small supply of these o-rings to replace as needed. Maybe thats not the correct/standard was to drain all the oil?

If nothing else it's been fun to learn more about these RC's the deeper I dig..
 

·
Registered
Joined
·
352 Posts
Well I hate to say it but having worked at 8 dealerships covering all 4 Japanese brands and Norton, Ducati, Moto Guzzi, Harley, Buell, Triumph and some scooter brands a good percentage dump the oil in the pan and if you’re really lucky they may look inside and see if there’s a bunch of crud at the bottom of the fork. As far as the compression valve on the RC it would drain easily if the fork disassembled completely and tilt the fork on its side. I had a friend fabricate me a sheet metal pan with raised cutouts on one side so I can lay the fork parts on the side and get a good drain. I flush the fork tube and wipe the inside of the outer with shop towels until they are clean.
Wood Gas Automotive exterior Auto part Machine
 

·
Registered
2002 RC51
Joined
·
156 Posts
Discussion Starter · #36 ·
Man, unfortunately that's kinda the answer I was afraid to hear..

I've blindly trusted my local dealers years past with my newer 600 and 1000's, funny I get the RC and quickly have learned to know better...
 

·
Registered
Joined
·
352 Posts
S
Man, unfortunately that's kinda the answer I was afraid to hear..

I've blindly trusted my local dealers years past with my newer 600 and 1000's, funny I get the RC and quickly have learned to know better...
To be fair there are some really good techs out there in dealerships as well as independents and they follow the correct service procedures. Unfortunately I saw one guy who was extremely talented tech but he was sometimes dishonest. I caught him once performing a major on a popular Japanese 4 cylinder which required valve adjustment for the service. It was a shim under bucket setup which can be a pita sometimes. I remember him putting it on the bench and then a couple hours later it was done and I know the valve cover never came off. Another dealer charged the full price for Ducati Desmo full service and they didn’t even have the necessary tools. In this case the tech protested but the owner basically said keep yer trap shut kid.😳 on the other hand one of the last shops I worked at made quality of work equal in priority to amount of work turned out. When the techs start out like this the speed will come as they learn the shortcuts that don’t affect quality.
 

·
Registered
Joined
·
9 Posts
There probably a break down in a Showa factory manual but Honda doesn’t break it down like that. Too bad the fork uses race technology but doesn’t take advantage. Measure very carefully with a vernier without putting too much pressure on the orings. Do a search using the dimensions and you can probably find matches for them.
As stated by 10THbikE, you can measure the O-ring and find a match. To add to that statement, because of the aircraft industry O-rings have long since been standardized worldwide for interchangeability purposes. They a cataloged by a single number, based on sizing dimensions, and the material they are made of. Try checking out TheORingStore.com site. On their site you will find an O-ring size chart, which you can use to determine what size you're looking for. Then you can determine what material you need and order the O-ring. TheORingStore.com also has a comprehensive list of the O-ring materials with descriptions of each. You will want a material that is most likely resistant to oil and petroleum products, but determine what the fork oil is chemically so the O-ring material you chose doesn't swell or react to it. Most likely that will be Nitrile. Order enough for spares because they are dirt cheat when you order from a source like this. I used this method to replace the float bowl gaskets on my VF500F's carburetors when I found out they were selling for over $10 each for new old stock with no guarantee they wouldn't be dried out on parts discontinued in the late 1980s. I bought a dozen for less than it cost for the shipping.
 

·
Registered
Joined
·
9 Posts
I have 2004 NH and it's forks are identical to the ones you have not currently mounted on the bike and assumed to be SP2s. I have a set of known SP1 forks I purchased for a project that are identical to the ones currently mounted on your bike. After reading everyone's replies, I believe everyone will agree, the forks not on the bike are SP2s and safe to send. I'm just adding this info as someone who currently has a set of SP1 and SP2 forks and has already made a physical side by side comparison.
 
21 - 40 of 42 Posts
Top