mikstr

My front-end conversion keeps taking detours... and here's the latest:

The forks I picked up on eBay have a 25 mm cartride instead of teh 20 mm one it is "supposed" to have. This means that the cartridge most likely is from a 92-94 model (which used the larger cartridge). Unfortunately, I bought a Gold Valve kit for a 96 (as I was told the forks were from a 96.....) but it is of no use now as it is for a 20 mm cartridge. My buddy, who is doing the work (has a suspension shop), can re-valve the forks but we don't know what needs to be done to make them work better. So, doe anyone have any experience with these older CBR900RR forks and know what needs to be done in tersm of valving to optimize them?

Incidentally, the fork lower is from a 96 as it has the compression adjuster which my buddy says works. We just need to know where to go with the valving.

Any info would be geratly appreciated as I am unable to find anything on the Net despite using every search criteria I can imagine on Google.

thanks

Hawkrider

You're actually better off with the 25mm cartridges. They have less chance over 20mm carts of cavitating if set up correctly. Ohlins and several tuners have developed 25mm replacement kits for modern forks which are significantly better then their 20mm couterparts.

mikstr

Hi Greg,

I noticed that many companies (RT, Ohlins,...) offer 25 mm cartridge upgrade kits. My buddy told me it was a good thing, the issue relates to knowing what has to be done to improve them now that they are apart. I have spent a great deal of time searching on the Net, using every search criteria I can imagine and found two mentions of what sounds like excessive high-speed compression damping (a Honda tradition?).

thanks again

mikstr

I am F***in' pissed!!!!!

I just got a call from my buddy who is working on the forks.... seems one fork has a 25mm cartridge and the other has a 20mm unit!!! That is just the icing on the cake.

The weasel who sold me the forks on eBay:
1) conveniently forgot to send me the axle (so I bought another)
2) sent a lower triple that was bent (so I bought another)
3) sent me two fork tubes with different internals.

I just wrote to the little bastard and told him I want to be reimbursed or I will be reporting him to eBay. Good thing he doesn't live nearby 'cause I'd walk over and have a "friendly chat" with him (get some use out of my four years of karate).....

%&@$!*%#(&

Hawkrider

Hmmm, I really don't know what to say about the two different sizes.

mikstr

Fortunately for me, there was a cartridge out of a 97 fork for sale on eBay so I scooped it up (which means I'll be selling the 25mm one that was in the one fork). Now taht I have the correct cartridges, my buddy will be installing the GV kit and Ohlins springs as per the specs given to me by Roger Ditchfield.

I filed a complaint against the POS seller today (with Paypal as I used it to pay). The chap is lucky I don't live in Florida or he'd be in need of a dentist.....

Hawkrider

Micky,

Don't drill the hole in the cartridge body if that's what Roger D. recommended. Are you revalving the rebound as well?

mikstr

Nope, no drilling.

nothing to be done on the rebound side. I am installing a GV kit with C36 shim stack, 0.90 kg/mm springs (for my weight), and using 5 wt oil with a 120 mm air gap. I am having all teh seals replaced too.

Hawkrider

You're not going to have enough rebound with those springs and that oil. Why 120mm air gap? Is that stock for a 900RR? It's 155mm for VTR forks. Also, RT recommends use of 10wt oil with their valves. The C36 might not be heavy enough depending on their use.

mikstr

Hi Greg,

I just re-checked the notes I got and he made it quite clear that the rebound was not to be touched (referring to the 96 forks). BTW, the Gold Valve kit (FMGV S2040) is for the compression valves, not the rebound. I will start with what he gave me and, should it prove to be out, I can always have my buddy fine-tune the valving for me.

I just want to get the damn things back so I can get them mounted. If it doesn't work out my buddy lives about 90 minutes away and we can do a re-valve in very short order (at least we'd have a starting point; while I am not a suspension expert, testing sleds and bikes over the years has taught me to become somewhat familiar with the effect of each tuning parameter, my buddy is a whiz too so he could surely diagnose it as well).

cheers

superbling

Was it a junkyard dealer in or near miami by the name of dominic profenio (sp?) or something like that?

mikstr

He is indeed in Miami but he sells under the name herel101. He had a good rating (I checked) but now the bastige don't answer e-mails. I will give a couple more days then I will carry forth with a formal complaint and go to arbitration through Paypal (initiated the "conciliation stage" yesterday but the dude has not given any sign of life... big surprise there). I would love to meet him in an alley.....

8541Hawk

So where did you get that spec?? I'm just asking because my service manual calls out a 130mm spec.

mikstr

And the saga continues...

I just found out that Mr. Brain-dead has chosen to move to arbitration with Paypal over the fork sale. In the great scheme of things, he merely beat me to it but I fail to see how he thinks he can gain anything for he already has the money and, given the misrepresentation in his ad, at best he will keep the money (THAT would be total BS) but he is much more likely to be forced to reimburse me some amount for not having delivered the goods as described in his ad.

Hawkrider

You are absolutely correct. I must've had it confused with a different model or something. <brainfart>

8541Hawk

No worries, I just thought I might have missed one of the top secret tips or something......

Hawkrider

Shhhhhh........