FORK OIL CHANGE - ADVICE

[rictus01]

Originally Posted by Sid Squid

Set the oil level, not the volume, the air in the fork is a very effective spring, so they both should be at similar air gaps so that the springing rate is as close as possible.

Ditto.

interestingly, if you get the chance, measure the air gap before you empty the oil, you'll be surprised how different the two sides are from the factory

Cheers Mark.

if anyone fancied having a go at this in west yorks let me know, id like to invalidate my warranty too !!

Originally Posted by Mr Sensible

The Hagon instructions I have don't actualy state an amount of oil to add just an air gap of 140mm (forks depressed without springs).

The amount added will vary depending on the amount drained, I doubt that it's possible to get all the old oil out without fully stripping the leg.

Steve

That is one hell of an air gap compared to standard, which if I recall correctly, is 104mm (or is it 114?). I noticed a marked difference when I enlarged the air gap in mine from standard by 10mm - diving worse on braking but much more 'pliant' ride on the bumpy roads. On the other hand, I've got OE springs still. If you want to experiment, start with a large air gap and add oil equally. In pre-K3 forks, I reckon that a 1mm change in oil height equates to approx 1cc of oil as near as dammit. I don't know the inside diameter of K3 on forks (they may not have changed) but it won't be that much different. I used a small syringe to measure and add the top-up oil.

[Sid Squid]

The later bikes have slightly different forks, hence the difference in levels.

That said I can't remember what the figures for the later bikes are, but they are different, 104mm is the figure for curvies, except if you have an American one, when it's a rather strange 2mm less,

Originally Posted by Sid Squid

The later bikes have slightly different forks, hence the difference in levels.

That said I can't remember what the figures for the later bikes are, but they are different, 104mm is the figure for curvies, except if you have an American one, when it's a rather strange 2mm less,

I guess thats to conform to the American requirement for bouncy suspension

Just been speaking with maxton and they said start with 140mm air gap and see what its like then add or take away 10mm till you get what you want.

Has anyone fitted these springs and what gap did you use and whats it like?, also what difference does it make putting more or less oil in ?

Chris

Job done with no problems!

Original level in both legs was equal @ 130mm, oil was pretty clean with very little sediment.

Thanks again for the advice it saved me from wasting a lot of time messing around.

Now just need some decent weather to try it out!

Steve

Originally Posted by chris SVK3

Has anyone fitted these springs and what gap did you use and whats it like?, also what difference does it make putting more or less oil in ?
Chris

Air is compressible, oil isn't. More air space means when hitting bumps the air will tend to compress rather than push non-compressible oil going through the damper tubes. As the air compresses more, oil starts to move providing compression damping. A shorter air gap compresses sooner (it's 'stiffer') so damping starts sooner. Compression damping stops excessive compression of the springs in the suspension. How this makes the bike feel in bends can vary, particularly what happens if you hit a bump. I think the SV has too much compression damping as standard - drain covers, bumps in the road, etc. cause too much deflection of the front end. Mine's better than it was, but I still sometimes feel the bars are going to get ripped out of my hands on some dodgy surfaces.

[Viney]

Originally Posted by jonboy

So come on you pansy are you selling your bike or not?


.

Mush easier to sell in good condition, with sorted forks