Is the 929 rear shock swap without revalving dangerous!?

[TylerDurdenK]

I got an email from Jamie Daugherty that says 

 

"I'd also look for someone who has experience with revalving because without that upgrade the 929 rear shock is dangerous to ride on the VFR." 

 

Now, I don't wish to question Jamie's knowledge, but reading the thread regarding this swap it seems that lots of people have done the swap but revalving barely gets a mention. 

 

What do you think? Can I do the swap without revalving and still be safe? 

 

[Duc2V4]

Personally I would have it revalved, unless the 929 shock has the proper valving and spring rate for you and for the bike you’re putting it on, what exactly are you gaining? 

[TylerDurdenK]

As I understand it the 929 shock has more adjustment available than the standard vfr800 shock. 

[TylerDurdenK]

Jamie went on to say this after I suggested that it seemed that lots of people had done the swap without any revalving. 

 

"Well, certainly people will do lots of things - but that doesn't mean they are right!  The spring rate and, most importantly the valving/damping, of a stock CBR929 rear shock are significantly different than what the VFR requires.  Those characteristics are what generates not only the handling performance but also the control of the motorcycle.  If the spring rate and damping are not correct then rider control will be compromised, therefore creating the possibility of loss of control and a crash.  This is something that I believe is unacceptable, and I think most riders will agree.  Going 30mph down a straight road will not likely be a problem, but spirited riding or emergency maneuvering is where you would see this come into play.

 

I hope this makes sense! "

 

I was under the impression that the spring rate and other aspects of the 929 shock are virtually identical to that of the VFR800. 

 

[Duc2V4]

Adjustability is one thing but that is really a flow control for the actual valving inside the shock. It’s like a volume control, the content of the music is the same, it’s the loudness and clarity that one adjust. If you’re into rock music and someone gives you a rap record, are you going to blast it as loud as you would the genre you like? Probably play it once to see what it’s like and then trade it in for something you prefer once you listen to it.

 

Again, I feel you’re going to the trouble of changing out the shock, why not get it setup properly first. Especially since it’s not installed yet, a lot easier to have it done now.

[Rice]

It’s only dangerous if you ride it, I guess. 

Will it kill you?  Probably not. 

 

Why not get revalve?

 

if you are looking at a shock swap, you must be riding at the limit of your OEM shock?  The $400 bucks that he charges is the best money you can spend on your bike. Especially when coupled with thr fork upgrade. 

[TylerDurdenK]

I'm swapping the shock as part of a refurbishment. The original one is very badly corroded. 

I'm going to be attempting to find a decent original one to replace it with. 

[SlimWhitey]

I had a discussion with Jamie about my forks. 

 

He asked what my plans were, what options I had. I said I would either be doing his full meal deal upgrades, or, I'd be sourcing an RC51/929/954 front end. 

 

He said that that was indeed a common swap, and relatively easily doable. 

 

He went on to say something to the effect of "but then you're going to have to pay to get THOSE forks set up for you too!"

 

And I sat back and realized.... Dude was right. The VFR has different weight balance, overall weight, gvw, power pulses, and geometry to an extent, than an RC51/929/954. they're vastly different bikes. 

 

So I am in agreement with Jamie. Get it set up for you. For your weight, your riding, your bike. 

[JZH]

Ohlins data:

 

929: 57mm stroke 1093-57 spring (around 825lbs/inch)

FR-FV: 57mm stroke 1092-79 spring (1,085 lbs/inch)

FiW-Fi1: 58mm stroke 1092-59 spring (857 lbs/inch)

VTEC: 53.5mm stroke 1092-69 spring (857 lbs/inch)

 

VFR750F springs are vastly stiffer than 929 springs; what bike is this for?

 

Ciao,