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Dilemma: help!!

Old 03-16-2008, 04:50 PM
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Dilemma: help!!

Hi folks,

As some of you may know, I am looking at swapping the front end on my VTR in the coming months and am looking at two possible options:

1) utilize a front end from a 96 CBR900RR

Things to consider:

- direct bolt-on, can keep stock front wheel and rotors (save $$$$)

- this point takes on added significance as I picked up a set of PVM cast magnesium wheels last Fall and was looking at installing them on the bike. By selecting this route, I get to use them, otherwise I would have to sell them (or the front at least)

- I have already purchased all necessary parts to do this conversion



2) utilize a RC51 front end

Things to consider:

- added rigidity, larger brake rotors (better braking), and of course, bling!

- I already have a set of SP-2 forks, axle, and brakes (brakes are already installed on VTR)

- In order to complete this, I need triple clamps, fender, wheel and rotors

- This would mean added $$$$ and not being able to use the PVM front wheel


I use the bike to ride on the street but want to begin doing track days this year. What would you recommend I do? Would the RC front be so greatly superior to justify the added hassle (and expense, I live in Canada and shipping is killing me) in picking up the parts ?

Comments?

thanks in advance
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Old 03-16-2008, 04:58 PM
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How big a man are you Mick? If you're on the lighter side of 200 I would use the 900rr route. Just my .02
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Old 03-16-2008, 05:01 PM
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I weigh 160 lbs
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Old 03-16-2008, 05:02 PM
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All muscle mind you....
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Old 03-16-2008, 05:42 PM
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you already have the 900rr parts all together and its a relatively easy swap so you might as well do it and be back on the road and get to used the lightweight wheels. You can always watch ebay and over time accumulate the missing parts of the RC51 swap and do that later. Its a better fork but not sure how much difference you'll notice. I recall Bob H at BVH saying that with the 900 forks and a fork brace you end up with a very good package.
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Old 03-16-2008, 06:33 PM
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moriwaki and revolution racing also ran that setup on their racebike.
Attached Thumbnails Dilemma: help!!-revolution_vtr.jpg  
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Old 03-17-2008, 08:12 AM
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a proper 900RR fork conversion requires longer stanchions. They were available as an aftermarket part. I don't know if they are still avaliable.

I don't think they ran a fork brace, because the 43 mm stanchions are a lot stiffer than the 41 mm VTR stanchions. I could be wrong. I don't recall Bob's bike having a brace, but he highly recommended it for the stock VTR fork and the improvement was immediately obvious.

The '00 and '01 RC51 fork has the same (or very close) free length as the VTR fork. The '02 up RC51 fork has a top-out spring that affects the last 15mm of travel, so the free length is slightly shorter, if I'm not mistaken.

I almost went the 900RR route, but didn't want to spend a couple hundred $$ on stanchions. Bob didn't thinkg the RC51 forks would work. But it turned out to be a pretty straightforward swap. And I liked the bar position with 929 clip-ons mounted below the top clamp.

Another note: The '02 up RC51 steer tube has a larger diameter. I don't think there is any way to adapt it to the frame. You will need the early triple clamps.



Last edited by RCVTR; 03-17-2008 at 08:23 AM.
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Old 03-17-2008, 08:32 AM
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great pictures rand. and yes, you are correct about the stems, needs to be SP1 triples. I also love the RC51 front end, while it may be overkill it sure works great - less flex, but immeasurably more compliant and adjustable and included brake upgrade. Still in MIKSTR's case with all the parts on hand would be worth trying. I didn't recall the length being an issue - but he can measure and let us know - maybe the clip ons have to move below the triples.
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Old 03-17-2008, 08:37 AM
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Originally Posted by RCVTR View Post
a proper 900RR fork conversion requires longer stanchions. They were available as an aftermarket part. I don't know if they are still avaliable.

Another note: The '02 up RC51 steer tube has a larger diameter. I don't think there is any way to adapt it to the frame. You will need the early triple clamps.
Ditch the 900rr forks for F4i (43mm) and keep the PVM's!!!!! Use VFR, 1100XX or 919 triples to stay closer to the stock geometry. You can bolt on 51, F4i or gixxer1000 brakes. Sell the 51 setup to fund it all.

Well you asked......
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Old 03-17-2008, 08:39 AM
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Originally Posted by RCVTR View Post
a proper 900RR fork conversion requires longer stanchions. They were available as an aftermarket part. I don't know if they are still avaliable.

I don't think they ran a fork brace, because the 43 mm stanchions are a lot stiffer than the 41 mm VTR stanchions. I could be wrong. I don't recall Bob's bike having a brace, but he highly recommended it for the stock VTR fork and the improvement was immediately obvious.

The '00 and '01 RC51 fork has the same (or very close) free length as the VTR fork. The '02 up RC51 fork has a top-out spring that affects the last 15mm of travel, so the free length is slightly shorter, if I'm not mistaken.

I almost went the 900RR route, but didn't want to spend a couple hundred $$ on stanchions. Bob didn't thinkg the RC51 forks would work. But it turned out to be a pretty straightforward swap. And I liked the bar position with 929 clip-ons mounted below the top clamp.

Another note: The '02 up RC51 steer tube has a larger diameter. I don't think there is any way to adapt it to the frame. You will need the early triple clamps.



now i remember why i sold my 900 setup.

worked fine on my hawk gt but to short for superhawk.
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Old 03-17-2008, 08:41 AM
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Good idea, Doug!!
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Old 03-17-2008, 08:58 AM
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Hi gents,

thanks for the input. The 900RR has 45 mm tubes. Here is the basis of the conversion I am/was looking at doing: http://www.vtwo.demon.co.uk/firestorm/bladeforks.htm

In it, he mentions placing the tubes flush in the top triples to compensate for the length. There is a chap called Del on the VTR1000.org sit who mentions that pre-98 900RR forks are a direct bolt-on but that post-98 are 30mm shorter (http://www.vtr1000.org/phpBB2/viewto...ireblade+forks)

BTW, both sets of forks just came in..... oh the horror!!!

cheers

Last edited by mikstr; 03-17-2008 at 09:25 AM.
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Old 03-17-2008, 10:14 AM
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I thought it was 45mm, then 2nd guessed it.

Let us know what you come up with for a length comparison. I think the 900RR forks look great on the VTR and you may not need to trim the fairing as much.

The ability to use your new front wheel makes it an easy decision, if the length will work, IMO
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Old 03-17-2008, 12:27 PM
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Hi again,

I just compared the forks side by side and they are identical in length (or, the 900 tube is maybe 1/16" longer) so if the SP-2 forks are ok then it standes to reason that the 900RR forks will do too.

cheers
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Old 03-17-2008, 03:57 PM
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the SP2 forks have topout springs that affect their static free length and also you set sag differently on them vs. the SP1 or the older style forks. bottom line, not the best comparison for length, not comparing apples to apples. Check it against the VTR fork free length for a more true idea of how muhc length you'll be losing.
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Old 03-17-2008, 04:48 PM
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That is correct. I believe you normally set less static sag on the SP2 fork, so you have the same travel from the sag point to the bottom. The top-out spring prevents the fork from fully extending, however, so you lose the top part of the travel. Not good for a track setup, because the tire loses some ability to track the surface at low suspension loads (hard on the throttle, or unloaded over the crest of a hill).

I agree, you should measure compared to the VTR fork. You may have enough length with clip-ons below the top clamp. You may want some rise to prevent interference with the tank.
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Old 03-17-2008, 05:26 PM
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Hi gents,

the bike is snowed in good right now (two storms in under a week saw to that) so the onloy basis of comparison for now are the SP-2 forks. I will be mounting them flush as the previously article link suggested and likely running clamps and tubular bars (Helibars are too damned expensive unless I stumble across a cheap set).

One last thing, a few guys are running 1000RR forks which are reportedly shorter yet so it may just quicken steering.

cheers
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Old 03-17-2008, 05:38 PM
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Originally Posted by mikstr View Post
One last thing, a few guys are running 1000RR forks which are reportedly shorter yet so it may just quicken steering.

cheers
That's not the entire truth... Yes the forks are shorter... But to be usable requires a gullwing top triple that moves the forks down about an inch, essentially making them an inch longer... And with that they are still somewhat shorter than stock, basicly the same as what I had my stock forks pushed up in the triples...

The 900RR top triple is flat... So you can't compare it to the 1000RR forks... that's apples and oranges for sure...
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