Fork oil options

[SV650rules]

Just replaced fork oil on 4 year old SVAL7 with Silkolene RSF10 maintain and first ride yesterday ( mind you new Avon Storm 3D tyres as well - so hard to judge 100% ) and bike felt great. Bike is stock suspension setup and I am just over 12 stone. Mind you I go more for comfort ( some of the roads in Shropshire can be shocking with potholes and even ruts ) rather than out and out cutting edge handling ( which would be wasted on me these days ), but I have to say stock setup and 10W is fine for me - and no excessive dive when braking hard.

[DickP]

Hi,

I weigh roughly 80kg (circa 12-13 stone) and often ride bumpy roads northern roads.

Is it reasonable to just change the fork oil (to say 15w for an example) whilst keeping the springs etc. stock to see what change that brings, before considering a spring swap?

Thanks,

[johnnyrod]

I'm 10 stone and the stock springs are too soft. They're the worst part of the bike by a country mile. Yes the stock oil is a bit thin but it's not a deal-breaker by any means.

[Adam Ef]

Originally Posted by DickP

Hi,

I weigh roughly 80kg (circa 12-13 stone) and often ride bumpy roads northern roads.

Is it reasonable to just change the fork oil (to say 15w for an example) whilst keeping the springs etc. stock to see what change that brings, before considering a spring swap?

Thanks,

Changing the oil will affect then speed at which things happen. The springs will affect how much they happen. Best off just doing the springs. But you may as well change the oil too if you're doing the springs.


K-Tech linear springs are good. Plenty compliant for road but much more reliable handling. You'd need a 9 or 9.5 weight spring.
Silkolene oil somewhere around 10 to 15 as mentioned already. (Get a 5 and a 15 and mix your own 10... leaving some left over to add if you want to go heavier after test riding... you can syringe some out and add a bit more 15 weight oil in instead until you get it right.)

[Dave20046]

Originally Posted by DickP

Hi,

I weigh roughly 80kg (circa 12-13 stone) and often ride bumpy roads northern roads.

Is it reasonable to just change the fork oil (to say 15w for an example) whilst keeping the springs etc. stock to see what change that brings, before considering a spring swap?

Thanks,

Fresh oil is undeniably a good thing. While you're there you may aswell change the springs. Even Hagon (or ktech) progressives are the easiest and cheapest if you're reluctant to spend cash & effort they'll be about £50 and take no thinking.
Linear springs take a bit of calculation but they'd be my choice if not going for a full blown front conversion.

I found bumpy backroads an utter pain in the **** on stock suspension.

[Sean_Morgan]

Ok, I'm home from work, my springs have arrived and the first fork is ready for rebuilding (I'm only removing them once at a time so I don't confuse myself). There are no instructions with the springs so my question is, what level should I fill the oil up too ?
The Haynes manual says 94mm, do I use that or is there a "better" option.
Many thanks
Sean

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[proze]

Bibio has recommended 100mm (without springs or spacers) in another thread. That's what I used.

[embee]

Oil level is a bit flexible. As long as it covers the holes it will give the same damping effects whatever the level, but the level affects how much air is left above the oil (air gap) which works as a secondary spring as it gets compressed. The bigger the air gap the less stiff the spring effect from compressing it, smaller gap means more pronounced air spring effect.

Set it to whatever is recommended for your model for a start, you can always change it a bit later.

Remember that the oil level is set by removing the spacer and spring, and fully compressing the fork. Held upright (in a vice etc is most practical) you measure the distance from the top of the tube down to the oil. You can use a steel rule or stick etc, various ways to do it. There are tools with an adjustable tube in a bracket which you can sit on top of the fork tube and use a syringe to simply suck out oil until it drops to the set level, they make it easy but are not necessary by any means.

You can usually get a fork oil change from a 1 litre bottle with a little left over, i.e. a bit less than 500ml in each side. It is really annoying when a particular bike needs just over 500ml per side.

Are your new springs the same relaxed length as the old ones? You may need to alter the spacer tubes to suit if they are not. You may also find the sag when you put the bike back on its wheels won't be ideal. With height adjusters in the top caps you can get a reasonable range, but you may need to alter the spacers if you can't get it right.

[Sean_Morgan]

That's the front end done (not just may I add, I've already had a shower and opened a beer !!)

Firstly I'd like to say, if you don't really know the history of your bike I'd look at changing the fork oil at least. Mine looked like it had been in there since it rolled off the production line.

Secondly, thanks for your input gents, you've all been very helpful. I decided to go with what the manual said for the oil level. It's the first time I have done anything suspension related so ive taken my time, someone else could have done it in half the time but I got there.

Tomorrow's job is to get the tape measure out and start measuring sag and setting the pre load.

Just bouncing the bike on the front brake feels like a massive improvement, it doesn't feel like a pogo stick any more.

I'll have a tinker with the pre load in the morning and hopefully get it out for a ride




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[Dave20046]

Originally Posted by Sean_Morgan

That's the front end done (not just may I add, I've already had a shower and opened a beer !!)

Firstly I'd like to say, if you don't really know the history of your bike I'd look at changing the fork oil at least. Mine looked like it had been in there since it rolled off the production line.

Secondly, thanks for your input gents, you've all been very helpful. I decided to go with what the manual said for the oil level. It's the first time I have done anything suspension related so ive taken my time, someone else could have done it in half the time but I got there.

Tomorrow's job is to get the tape measure out and start measuring sag and setting the pre load.

Just bouncing the bike on the front brake feels like a massive improvement, it doesn't feel like a pogo stick any more.

I'll have a tinker with the pre load in the morning and hopefully get it out for a ride




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I love tinkering with this stuff, you're going to get all the reward when you take it out for a ride.

re. fork oil age. I bet it is the original oil. No ****er ever changes it (apart from forum members!)