RC-51 front end installation

Has anyone done the RC-51 (SP-2) fork, steering stem, brakes, front wheel, rotors, etc. installation? Was it worth it and did it make that much of a difference?

I've got all of the parts and I'm getting ready to dive in. I've already got a set of SP-2 forks with Ohlins valves that were built by Mike Fitzgerald.

 

mmmm ohlins...

 

That's where I've been getting most of my info. Just wanted to see what is being said on the other board(s). I've already got the 954 steering stem so I've already jumped that hurdle.

RDR

 

OK, short course.

RC51 SP-1 forks are a little longer, and for my taste, thats a good thing. You will need RC51 SP 1 lower triple with stem, 954 upper triple, RC51 SP1 lower bearings, VFR upper bearings and will need to shim the lower bearings up about 2 mm. Will need new master cylnder to match new calipers. Be sure to check height after swap to miss radiator at compression, may need to lwoer back a bit if steering is too sharp.

Go to VFRD and look for frankenviffer.

Larry

 

Thanks Larry. Right now I'm trying to get a 929/954 steering stem to work. This is the first time I have heard about checking the radiator. Do you mean the cooling radiators on both sides or the oil cooler? Does the RC-51/929/954 fender sit that much higher that it could hit the oil cooler? Also, I've always been told (and maybe wrongly) that the SP-2 forks are longer than the SP-1 forks.

 

Ask JZH, current caretaker of the frankenviffer DB, or Safe-T. He did a lot of original work on Murphy, his frankenviifer, over at VFRD.

Larry

 

I was looking into a front end swap myself this winter and was tossing around between a f4i setup or the rc51 swap. My parts list I made up for the rc51 swap(mostly from info off of VFRD) included:

SP2 forks
Sp2 wheel, rotors, spacers,axle and fender
SP1 lower triple and lower bearing(2mm shim must be fabricated)
Vfr 800 upper bearing
954 upper tree
929 helibars
954 front calipers
f4i front master cylinder
custom lenth brakelines

Hope this helps

 

Helps a bunch. Right now I'm trying my best to get a 929/954 steering stem to work (that's what came with the front end). The 929/954 steering stem uses the exact same All Balls kit (22-1020 I think) as the VFR. Therefore, I won't have to do any shimming. Wanted to check out both sites (I go by Pete McCrary on VFRD) just to get all the info I can. If you go your route, the 2 mm shim ought to be a piece of cake. Get some 0.080" thick 7076, use a hole saw in a drill press to cut out a disk of the material. Then just find somebody with a Harbor Freight or Grizzly 7" x 12" lathe to whittle it down to the proper ID and OD and you should be in business. I like the idea of 929 HeliBars. I've got some 954 bars now and they don't look all that comfortable.

When you lay the VFR forks next to a fork from an RC-51, the VFR fork looks like a toy fork. The RC-51 forks are heavy duty. Two bolts on each side for the axle, two bolts on each side of the steering stem, etc.

The thing that sold me on it more than anything was when Larry (Busy Little Shop) did the diagram showing the inner tube/outer tube overlap. The RC-51 forks have over twice the amount of inner/outer fork tube overlap.

It's going to be a 2-3 month project. I'm self employed and I buy parts as the extra cash becomes available. Got to pay the light bill and the mortgage first!

 

BTW, for using the RC SP1 steering stem, you don't use the upper VFR bearing. (Not sure if it's actually the same as the RC's upper bearing or not but I don't think the VFR steering stem at the top is the same dia. as the VFR's?) I just bought a full All-Balls RC steering bearing kit, upper and lower.

If you want to go easy, some appropriate sized snap rings work well as the 2-3 mm spacer, no fabbing needed.

A little comparison of the SP1, SP2 and VFR (5G) forks.

 

Hey Capn, it's me, Pete McCrary. I'm just checking out all the sites to get as much info as possible.

Are the two RC-51 forks shown both stock or has the longer one on the left been reworked? I have two sets of SP-2's and the ones that have been reworked by Thermosman are about an inch longer than the stock ones.

Pete (Red Duke Rider)

 

Now I am confused... I thought the sp2 forks were longer than the sp1? Looking at this what you need for the conversion is an Sp1 front end with the 954 upper tripple, is that correct? Also what year RC51s are Sp1s vs Sp2s?

 

The forks that I have look like the ones in the middle. Black preload nut on top and a blue Showa sticker on the legs right above the fork seal/wiper.

2000 & 2001 are SP-1. 2002-2006 are SP-2. Everyone generally agrees that SP-2 forks are superior to the SP-1 forks. However, my forks have been reworked by Mike Fitzgerald (Thermosman) and are longer than stock. Hopefully I'll be able to get the old front end off this weekend and lay them all out side by side like VFRCapn did. Of course he is showing 5G VFR forks. I have a 6G. Be interesting to see what it all looks like laid side by side.

I'll take some pics and post Sunday or Monday.

 

I did the swap last winter and I love it. My avatar shows the results. I used SP2 forks, SP1 lower triple and stem, All Balls roller bearings, and a custom upper triple made by Stuntsteel that allows either conventional or clip on style bars. I went with CBR1000RR Tokiko brakes with custom radial mount adaptors for the RC-51 forks. I've put an Ohlins on the rear, delinked the brakes and did a few other mods as well. It all works very well. I can put up some pics if somebody will tell me how to do that!!

 

Surely if you did all of that mechanical work you should be able to figure out how to post pics.

My suggestion is to get an account (free) at Photobucket.com or some similar place. You upload you photos there, and then each photo is given an html something or other that you just insert into your replies.

 

Did you do any modification to the sp2 forks to make them longer as stated by redduke a few posts ago. I am interested in doing this same mod to my bike this fall and it seems the sp1 fork tubes might be a better option because of their lenth being closer to the stock 5th gen forks. Is your rear set to the stock height or raised? My main concern is that I have tail riser plates(19mm) and worries me that if I bring the front of the bike down too far the bike will become unstable. Is the geometry different in the rc51 triple to acomodate for the shorter fork tube lenth?

 

Hey Pete, I don't know if these RC forks were reworked, this was the way I got them. (Also, not sure if I had the preload nut set the same across all 3 forks in the pic!?!) From reading Sportrider and other reviews the SP2 forks are supposed to work better than the SP1's, so I went with them even though they're shorter. Still, I have them raised about 10mm in the 954 upper clamp currently.

The thing to remember, is the RC fork offset is much less than the VFR's. This results in longer trail of about 10mm and slower steering. The RC bike's steering head angle is about 23.5 deg, the VFR's around 25.5 deg. After putting in the RC triples you can overcome this difference by raising the rear of the VFR. I installed a shorter 4G dogbone link on my 5G, raising the tail about 1" and resetting the steering angle to about 24 deg. My calcs say I have around 97-99mm trail now but my butt handling meter says steering is very nice.

Many others have done the swap without changing the rear end height and are perfectly happy, so YsteeringMV.

capn

 

Capn:

I've already raised the rear end on my VFR 6G. I've got a Penske shock with has a fair amount of length adjustment and of course shimming the top of shock is fairly easy.

I know I'm going to wind up with a lot more trail due to the lesser triple clamp offset (wish I could keep it apples to apples) - but there is more than one way to skin a cat. I just don't want to wind up with a slow turning front end that feels great. I want a quick turning front end that feels great!

If you ever see the internals of a set of RC-51 forks, they have a tremendously long top out spring. Go to the RC-51 forum and a guy named SubSailor (who is the RC-51 guru) took some pics of the RC-51 internals and you can get an idea of what I'm talking about.

SubSailor confirmed that the top caps and the preload adjusters are different from SP-1's to SP-2's.

Also go to RaceTech's site. They make the same mention of installing a different set of top out springs (that they sell of course) and they hint at it changing the length of the forks.

I'm getting ready to take my front RC-51 wheel to the wheel shop (Metro Wheels in Marietta, GA) to have the flat spot fixed Monday. Hope to get the forks off tomorrow and post up some pics.

Pete

 

Cool!! Please post pics and detailed info ant all stages of the install! It woud both be appreciated by me and a usefull tool to anyone that wants to try this mod in the future