Another Suspension Rebuild 2010 Vfr800 Vtec

Hi

Over the past few months I've been upgrading my suspension to get the VFR to handle more to my liking.

I've ended up with Traxxion AK-20 cartridges and external adjustment caps in the front and an Ohlins HO605 on the rear.

I ride one up and with my gear I'm between 75 and 80kg.

From this, I've installed the following:

Front:

Springs = 9.3Nm/mm (0.95kg/mm)

Oil height = 125mm (Maxima 125/150 Racing Fork Fluid) 7W

Preload = 4 turns in from fully out

Compression = 2.5 turns out from fully in

Rebound = 2.5 turns out from fully in

Fork height = 47mm above top tripple clamp

Rear:

Spring = 160Nm/mm (16.3kg/mm)

Preload = 9 clicks in

Compression = 20 clicks out from fully in

Rebound = 21 clicks out from fully in

Shock length = 1 turn (1mm) out from stock (1mm increase at shock = 4mm at wheel)

When I originally received the Ohlins it was fitted with a 170Nm/mm (17.3kg/mm) spring but with this I could only get about 7mm free sag and 25mm of rider sag.

So, with the above I get the following sag settings and the bike performs really well.

Front:

Free Sag = 25mm

Rider Sag = 34mm

Rear:

Free Sag = 10mm

Rider Sag = 35mm

These sag figures would suggest that I have the correct springs for my weight but lots of other posts suggest that the rear spring should be up around 19kg/mm so I'm a little confused.

By the seat of my pants the bike handles and works well on our crap roads in New Zealand.

Anyone got any thoughts on this?

Cheers

Phil

Question: "external adjustment caps in the front" - how do they look like and from where? I intended to get the internals grom an F4i to achieve rebound adjustment.

Thanks.

Traxxion do a set of caps for their AK-20 cartridges that give you compression on one leg and rebound on the other, as well as spring preload on both.

They work really great.

A bit expensive but just sooo much easier than rebuilding the shim stacks to alter the characteristics that you are after.

Here are a couple of photos.

[image: image-1-1.jpg]

[image: image-1-2.jpg]

Cheers

Phil

Everybody is different even if exact same rider weight, if your happy with the feel from your rear spring & the sag setting is what your after & you still have range to adjust either way then bingo be happy. I'm not sure how the front cartridge internal set up you have perform but if you do want to experiment a little the VFR works a treat with 40mm fork rider sag & 30mm rear rider sag for street use, I use Ohlins forks & have them set to 40mm & find it the best compromise for all conditions. But like I stated we are all different so what I like mightn't be what you like, Either end you can always use compression to gain that firmer feel especially rear when you have luggage or pillion without having to change preload setup form your solo riding set up.

I do feel your rebound & compression settings are a little soft but again I'm not riding your bike but it does play to experiment with such a wide range of adjustment, I chose one setting at a time & add or decrease two clicks or 1/2 turn & ride (it pays to find a stretch of road you like with everything & always use that same road for comparison). I tend to suffer from some shudder at times braking on certain surfaces & it is solely suspension related due to changed trail with inverted fork conversion & extra rebound dials it out but took me a while to find the right compromise.

Great set up you have there enjoy the performance money very well spent.

Yep, uderstand where you are coming from.

I take it you are referring to the comp/rebound on the rear shock.

What I found was that once I put the softer spring on I need to go further out with both to match the softer spring.

I have a favourite bit of road that I use to test setups as you suggest.

It is the only way to do it.  The same as keeping good notes as to what you change and change only one thing at a time.

Do you have any specs/photos of your Ohlins front end?

I'd be realy interested to see how you did it.

Cheers

Phil

I used the normal inverted conversion triple clamps used on the VFR CBR954/929 the top triple I used is same just a billet item, this set up just bolts straight in with the standard steering head bearings.
I used CBR1000RR 08 forks which are more of a pain to use due to different wheel/rotor spacing but if you can find a set of 04-07 zero custom spacers needed for axle.
Due to 08 forks I made custom spacers for axle & the wheel is a RC51 but with 08 rotors because needed there 15mm offset for calliper spacing which is needed for the combo I used.
To use RC51 wheel you have to buy CBR internal bearing spacer & machine it down 2mm (longer than RC51 spacer) & install CBR wheel bearings (CBR axle is larger dia) you also have to machine out wheel internal spacer location ring a little to fit larger dia spacer.
The callipers are standard 108mm spacing so any calliper with that spacing will do CBR/R1 etc, I wanted as much clearance as possible when performing U turns so used a Brembo master as the distance from bar to lever outside is less than standard CBR master so more clearance before hitting instrument panel.
To finish off you need longer brake lines & CBR guard & most importantly Convertibars for there adjustment & mounting under top triple clamp.
The only other mod is you need to move oil cooler forward few mm & trim off some length off the support bkt but nothing major, all the throttle & oil lines have enough length standard.
I used RC51 front wheel due to good match as 3 spoke CBR wheel looks strange, i was going to install oz racing 5 spoke wheel for CBR (must be 04-07 using either 04-07 or 08 CBR forks) so didn't need to do machining to RC51 wheel but picked up the RC51 wheel cheap.
If I didn't already have the Ohlins CBR 08 forks I would have used just standard 04-07 with Ohlins cartridge kits that are more or less same thing & then everything standard parts no need for custom spacers or mix match parts.
[image: Ohlins CBR forks]

Ohlins CBR forks
Ohlins FGRT CBR1000RR 08 forks

[image: MKII vtec top]
MKII vtec top
Billet top triple clamp, convertibars, brembo master
[image: vtecmk11rhs]
vtecmk11rhs

A couple of things to keep in mind:

For your weight 0.90kg/mm fork springs and 1100lb/in (19.8kg/mm) shock spring is recommended.  Don't bother measuring the static/free sag as that will only confuse you.

The AK20's have a large Ø12.5mm damping rod.  That makes them very difficult to tune.  Why Traxxion chose to not use a Ø10mm rod I'll never know.  That means you get excessive compression damping and a lack of rebound damping.  The 7w fluid you are running just makes the compression worse.  Start with switching to Honda Pro Oils 5w (or something with a viscosity in the range of 15-17cSt) and you will already see an inprovement.  To make them work right you'll need to dig in and do some wholesale changes to the shim stacks.  Even with the drawbacks of their design you can get the performance dialed in fairly close with some work.

I hope this helps.  Good luck!

Hi Jamie

Thanks for your input. Greatly valued.

So I take it, reading between the lines, that you feel the balance is not right with the too heavy springs in the front and too soft in the rear?

If I dont take any notice of the sag measurements, what do you feel I should be using as a base line to tune against?

I just would have thought that at 19kg the rear would be like a board. No compliance and pretty skitterish.

Thanks Phil