Fork spring upgrade

[Mark_h]

Looking for a cheap way to improve the front end of the bike I came across a pair of progressive springs for £55.

http://www.intobikes.co.uk/products?...f=1&gf=0&rt=60

I recently had the forks re-oiled as the old oil had broken down and they offered no damping at all, but having ridden other bikes with real suspension I now know just how woolly the front end of the SV is.

I do not want to get involved in anything too complex like GSX-R front ends, emulators and other such fancyness, but was wondering if it was a simple job to just swap out the springs.

Is it just a case of taking the weight off the front, taking off the large flange (don't you just love that word) nuts and dragging out the old springs or is there more to it than that? If it involves taking the forks out then I'll probably just not bother at all.

It's a 2001 naked with no adjustment on the front forks at all.

Also does anyone know what the airgap at the top of the oil is supposed to be with the forks unloaded?

Cheers,
Mark

[Sid Squid]

You could take the fork caps out and swap the springs without removing the forks, but the oil levels will likely be a dab off after you do, and resetting them accurately needs the fork to be upright and fully compressed.

It's been discussed before whether the oil could be removed by suction and then the fork refilled with a given volume of oil, but realistically if you're trying for an improvement this isn't an accurate way to go about it.

(2003 reg K1 ) I have just replaced my fork springs etc with hagon progressives and 15w oil - feels well planted now.

Like you I was fishing round for an 'easy' way to do it as I haven't attempted it before. Finally I did take out the fork springs. It was quite easy apart from the fact that the caliper bolts were in solid and I had to make a trip to halfords to get surface gripping sockets (6 flats) to get then out (and similar for the wheelnut too) after I had taken the corners off with an ordinary 18 point socket..

You need something to lift the front end off the ground. After a mishap to do with an idea of suspending the front. I borrowed a headstock lift from a mate. (I know about abba stands thanks)

With the correct spanners/sockets, removing the forks is quite easy. Make sure you loosen the big FLANGE bolt first though. Tip the old oil out into a suitable container and then fish out the spacer, washer and old spring. Try to ensure that the fork tube does fall to its full compressed position or it will tend to stick - you have to get a good grip on it and yank it hard to get it back out.

With hagon prog. springs the air gap is 140mm. For some unknown reason (probably a CRAFT symptom) I left a 150mm air gap, which is approximately 12cc too little oil. A 10cc syringe is an invaluable tool

One word of warning: don't do what I did which was to take the front wheel off with the bike on front (and rear) paddock stand. The nearside fork rotated slightly and nearly fell off the stand. Fortunately I had taken the precaution of looping a tie down strap around the handlebar and a beam in my garage.

That was a bit of a ramble I guess - hope you got the drift of it .

[Spanner Man]

Afternoon all.

Go for Hagons, can't beat 'em at around £64 with the oil.
Ditto the Squid regarding oil levels, you really do need the forks off for this.
Ditto Ejohnh, take your time and be careful & it isn't too bad a job.

Cheers.

[Mark_h]

So given I've only recently had my fork oil changed would it be possible to just leave everything where it is, take the FLANGE caps off fish out the internals swap the springs and reassemble. Or will I have issues with levels and various bits of fork going ping all over the garden once I'm de-flanged?

Although the oil level is supposed to be set fully compressed is there anything stopping me measuring it in situ before I start and making sure it's the same when I've done?

How much of an issue is it if the oil level is a bit out?

I know I should take it all apart, change the oil and do it all properly. Just want to know if the half-assed approach will be worth while or not.

Cheers,
Mark

Originally Posted by Mark_h

So given I've only recently had my fork oil changed would it be possible to just leave everything where it is, take the FLANGE caps off fish out the internals swap the springs and reassemble. Or will I have issues with levels and various bits of fork going ping all over the garden once I'm de-flanged?

Although the oil level is supposed to be set fully compressed is there anything stopping me measuring it in situ before I start and making sure it's the same when I've done?

How much of an issue is it if the oil level is a bit out?

I know I should take it all apart, change the oil and do it all properly. Just want to know if the half-assed approach will be worth while or not.

Cheers,
Mark

Ok, first thing you will need to do is make sure the springs are approximately the same physical length. Where I am going with this is you might need to cut the metal spacers a bit or make some slightly longer ones.

Even though the forks will be in the bike, that doesn't stop you from measuring the forks fully compressed. Just push the front wheel all the way up and get someone to hold it there!!

As the bike will be on a slight angle, measure the oil level at the front of the fork tube and the back of the fork tube, use the average figure as your level.

Then pop it all back together and measure your 'rider sag' ... lots of info on this if you search on here or the web Make sure that is acceptable and job done

Forget it. Chances are that you are changing to a new type of spring which probably occupies a different volume than the originals - so the required air gap with compressed tubes and no spring in will be different. Do it properly - you know it makes sense..