suspension
 

i have a sv650s and have been riding it for about two month now, my previous bike was a nc29 and the suspension was alot better for the type of riding i do, (backroads and around the lakes) i was wondering if there was any recommendations for what type of fork oil i should use, any uprated springs etc? it seems to be mostly the front end but any suggestions on the rear shocker? i've heard that gsxr shockers can fit? weather this is true i don't know. i weigh around about 13.5 stone

Much help would be appreciated.

Re: suspension
 

Hitler question! i.e. search before posting. Tonnes of stuff on here about this. Forks springs are too soft so yes upgrade, best with linear not progressives. GSXR rear shock fits but not that simple, spring is probably too soft, ZX6R is better or just pay for a real replacement from Nitron, Ohlins etc. For the full deal you could go for a GSXR front end, if you have a pointy SV then it's easier than on the curvy.

Re: suspension
 

what do you mean by this? and who makes the different types? this isn't something i've heard about before.

Re: suspension
 

yeah, front springs are 6.3 factory fit, most sites recommend arounf 8.5, check race-tech, k-tech and ohlins. Linear springs have a continuous spring stiffness throughout the range of compression, progressive springs get a bit stiffer the further it's compressed.

Standard oil is Showas SS8, which is a 10w oil. Getting my front sorted tomorrow by Motorcycle Performance, chap there said 15w is too heavy for any bike.

As far as front is concerned, stiffer springs and 10w oil should make a difference.

Re: suspension
 

ok thanks for the replies think my first step is strip the forks down new oil and purchase these spring's glad i asked as i was going to buy the progressive fork springs but now i think i might take the advice and go for the linear's any website's which i can purchase these from recommended? as for the zx6r shocker. what year model will fit? also just one more thing, what are these emulator's and are there worth buying or not?

Much appreciated tom

Re: suspension
 

Emulators - from PDQ, RaceTech is the brand. Yes a big difference over the rubbish stock damper rods (to be fair they're good for damper rods, as in a stone axe is good for killing things). Yep 15W oil generally overdoes the rebound damping. For the ZX6 shock, do a serach on here!

Re: suspension
 

Linears are OK, progressives compromise one end of the travel or another, since the damping cannot change to match the spring rate.

Best results are from either emulators or cartridges.

Most of the gain is in setting it up properly, i.e. the proper weight springs. Go on the racetech website and find out. They have a spring calculator.

There are lots of other bikes shocks which can be fitted which have improved damping as well as a closer spring rate.

Tell him to stop talking balls.
15w and better springs can work very well on the SV.

Re: suspension
 

Got it tweeked yesterday by the Mmotorcycle Performance guys in Glasgow. Instantly better.

After fitting the K-tech fork springs (upto 85 from factory 63) and new 15w oil, the bike felt a bit stiff and skippy at times.

Stewart done a basic sag and preload setup (stage 1 tune) the bike was out a little. slightly too high front and rear. So adjusted and feels much better. Rather than skipping it floats and absorbs more as it's supposed to. It feels more stable in turns too.

Stewart advised that even a 15w oil in the SV, because the internals are so basic, wont make much if any difference.

Definately a worthwhile trip. What i did find in addition is that the steering head bearings, fitted a couple of months past are alittle tight. So looks like some pre-load adjustment on the bearing needed too.

Cheers

Re: suspension
 

So what happened to '15wt is too heavy for any bike'? :rolleyes: The guy must like the sound of his own voice or summat.

Glad you like the change though, it is great when you change something and can feel the difference right away. :D

Re: suspension
 

The 15w comment was made assuming the 650 had more than pre-load adjustment i.e. rebound damping etc.

I think it will make some difference, it's a case of whether it's actually noticeable. Which may or may not be down to the rider.

Anyway, main thing is it's sorted now :)

Re: suspension
 

So he assumed 650 had cartridge forks :rolleyes:

In forks like that oil weight is control over rebound damping, there is little can be done for the compression unless you fit emulators or cartridges. Yes it is noticeable between say 12.5 and 15w.

Re: suspension
 

At the risk of a Hitlerism, be aware that the nominal grading of fork oil is pretty hit and miss. Different makes and "models" of oil have wide ranges of actual real life viscosity even within one grade rating.

Check out the big table of oils here .

My SV was due for a fork oil change, last oil was when I fitted the k-tech 0.85 linear springs and they supplied a Motul Factory line 10W. Following the linked table info, I've just put in some Silkolene Pro RSF 7.5W as a trial (high VI so viscosity doesn't change as much with temperature). Now you may all say 7.5W is far too thin for the SV with those springs, but according to the table it compares to a lot of 10W oils. I've only done a few tens of miles on it but it's an interesting result, maybe slightly more floaty than some might like but it copes with pot-holes and sunken ironworks in a very pleasant manner. I think the RSF 10W would be a bit harsh for me, so might do a mix next time.

Moral - it's not a simple as it looks.

Re: suspension
 

I'm not convinced fork oil gets so hot that VI is a big factor. .85 is pretty high spring rate, I don't think there would be anywhere near enough rebound.

Re: suspension
 

it does get cold.

Re: suspension
 

That was the object of the exercise really, to see what difference I could feel from the oil.

The viscosity at 40C for the 7.5W RSF (37cSt) is higher than the Motul Medium 10W (33.7cSt) it had in before, but significantly it has a very much higher VI (322 vs 115), so by that reckoning they should be similar at normal summer running temps but the Silkolene RSF shouldn't get the sticky/stiff/lumpy feeling when it's cold that I certainly felt with the Motul.

Time will tell, it certainly feels more supple over bumps and holes, more "comfy" really, I'll see how I get on with it. Having said that, new oil always feels better.