sv650 fork TLS/R setting

Hi,

I have built an Sv650 (from 2001) track bike. And I have a question for the track riders/racers.
My suspension set up is Ohlins rear shock and TLS/TlR front suspension (came with the bike) with gsxr wheel.
At first tests the front end was very nervous, it felt too hard. This became better after gradually setting the rebound damping fully in (slow out) and compression fully out (softest), (statig sag is good).
But the issue stays more or less the same: In turns with not very good surface, the front tends to 'tuck' away and gives verry little confidence, on good suface and long sweeping turns the feeling is better (but still not how I would like it)

I searched the forum but the only thing I found about the TL forks is that they are not very suited for an sv. Do you guys know why?
Gsxr 750 forks are often used, does anyone know the diffrence between the gsxr and TL forks?
Or maybe a softer spring will help? (the forks are for a much heavier bike, so comp. is fully out and rebound in...)

Any advice would be very welcome.

[yorkie_chris]

TL fork is 25mm internals, GSXR is 20mm. Some say one is better, both can work.

Sounds like your forks are valved way weak in rebound. What springs are in them and what do you weigh? What have you got shock length at?

P.S I have some 750-SRAD showa forks for sale

[jambo]

The first thing to remember about fitting forks from another bike is that they weren't designed and setup for your bike. Ideally you'd be after a fork of the same length, the same travel, same spring rate, and similar damping characteristics to the OE fork.

In practice you'll never quite get this, most GSXR forks are significantly shorter than the SV forks. TL forks are designed for heavier bikes, with different geometry.

Very few people will probably have tried both these, and standard forks to be able to hand good information on. You can get forks re-valved by companies like Maxton and Ktech who would be able to look at these forks on your bike and make changes to suit you. However if the forks are the wrong length for instance, they may not represent a great place to start.

Best of luck, and sorry if the above isn't terribly useful in giving a direct answer.

Jambo

[yorkie_chris]

Originally Posted by jambo

The first thing to remember about fitting forks from another bike is that they weren't designed and setup for your bike. Ideally you'd be after a fork of the same length, the same travel, same spring rate, and similar damping characteristics to the OE fork.

Hang on what? The SV forks weren't designed or setup for the SV

GSXR forks are about an inch shorter than stock and they help matters along nicely. The SV has the geometry of a chopper as stock.

[jambo]

Originally Posted by yorkie_chris

Hang on what? The SV forks weren't designed or setup for the SV

Having ridden plenty of bikes with simple damper rod forks (bandit 600, 1200, SV, VT500, Bros, etc) I would say the SV forks are no worse than any of the others. I'm pretty light, and even I prefer slightly stiffer forks springs in them, and I've generally preferred marginally thicker oil too. But they're genuinely not nearly as bad as some make out.

Jambo

[yorkie_chris]

But in this case you'd be taking supposedly finest steak (the ohlins in back), and then covering it in puke if you used stock forks.

You can't seriously be arguing that the stock door-closers are better suited to the SV than some cartridge forks? He's only having an issue because he's ragging the buggerance out of it on track!

[yorkie_chris]

Anyway off topic. What is your total sag? TLR forks have stiffer springs than TLS. Maybe too hard for you.

[jambo]

I'm seriously suggesting that just because a fork is made of good quality components, doesn't make it suited to every other bike.

I'm not looking to try and be awkward, but I feel people are overly critical of the standard bike, and the complexities of suspension setup can be ignored. The OP has clearly had the confidence to alter settings until he reached they best compromise he could with the setup he has. The obvious solution is to either replace the forks, or have them re-worked by a company that know what they're doing.

Jambo

[fastdruid]

I heard (but don't know how true it is) that the stock TL rebound adjuster has almost no taper so adjustment's are pretty much on or off.

btw wrt spring rates
TL-R are .934 Kg/mm
TL-S are .740 kg/mm
GSXR600K1-3 are .780 kg/mm
GSXR600K4-5 are .850 kg/mm
GSXR600K6-9 are .900 kg/mm
GSXR750Y-K3 are .780 kg/mm
GSXR750K4-5 are .780 kg/mm
GSXR750K6-7 are 1.000 kg/mm
GSXR1300X-K7 are .850 kg/mm
SV650SK1-7 are .706 kg/mm

So it looks like you either have too soft or too hard springs depending on which model you have and how much you weigh.

Currently I have GSXR1300X forks which I'm swapping to GSXR600K8, I probably get .85 springs as that's what is recommended for an SV for racing with my weight (and is what the current forks are).

Druid

[yorkie_chris]

Originally Posted by jambo

I'm seriously suggesting that just because a fork is made of good quality components, doesn't make it suited to every other bike.

True. Ok lets try another angle, everything related to suspension is a compromise. Fitting forks from pretty much anything is less bad than the standard compromises.

Bear in mind if he was trying the same antics on stock forks he would probably spend the entire time rattling his way wide as they'd be on the bump stops the whole way into the corner.

Nothing is right as stock, here is pic of fork piston from GSXR 20mm showa I just pulled out of my bike.
http://img682.imageshack.us/img682/6708/dscf7568u.jpg
See the small notch in the sealing surface? That is just to make sure nobody dies if a retarded owner closes the compression bleed all the way.

Those forks work better as bog stock on SV than they do on SRAD IMO. We see how they do with all new valving and springs