Hello team,

Recently, I found my bike getting pretty juddery in the front.
It still soaks up bumps (depressions) well, but humps (raised areas and corrugations) feel like I'm going to be thrown off the bike after a while.

I have Hyperpro springs, with the supplied oil (Don't quote me but I think it was 10W), half in each leg which I weighed exactly.

Forks are dropped 10mm through the yoke, and I have 20mm bar risers now.

They have done some mileage, I'm going to guess at around 18,000 miles.


I've experimented with pre-load. Currently the adjusters were wound all the way out to flush, and then 6 turns back in.

I'm thinking of changing to a heavier oil, would this be the way to solve the damping issue?
Or maybe I've set my pre-load too high?
I do like stiff suspension, but this has gotten a little dangerous, I feel.

I read that when changing the fork oil, I should be checking the height of the oil in the forks, obviously with the new springs this is different to stock, so I'm assuming it's just 500ml in each.

I realise suspension is personal preference, but any input would be much appreciated.

Regards,
Steve.

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Bike: 2013 XT660Z, TKC70 tyres

Mods:
Barkbusters, Scottoiler, DIY Tail Mod, DNA Stage 3, Power Commander V & O2 Eliminator, Exan X-Black Stainless exhaust, Tool tube, Ohlins linear front fork springs, Nitron rear shock, JT front and Supersprox rear sprockets, D.I.D. VX 520 chain, Adventure Spec bashplate, DIY USB Outlet, DIY chain guide, Kev's Throttle mod

http://www.facebook.com/onemooseonemotorbike

I found exactly the same sort of thing when I had progressive fork springs. Mine were Yacugar branded but they are made by Hyperpro. After much experimentation with oil, preload, fork position and sag I ended up ditching them for Ohlins linear springs which cured the issue.

My trials and tribulations are all explained in this thread:

http://www.xt660.com/showthread.php?t=19823

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As a quick hopeful fix, I'm going to experiment again.

Hopefully, it's just the fork oil degrading. As I said, it's a recent thing.

I'm going to try some heavier oil, since I've now discovered the original oil was 10W, I bought a litre of 15W and I'll give that a go before I try the Ohlins!

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Bike: 2013 XT660Z, TKC70 tyres

Mods:
Barkbusters, Scottoiler, DIY Tail Mod, DNA Stage 3, Power Commander V & O2 Eliminator, Exan X-Black Stainless exhaust, Tool tube, Ohlins linear front fork springs, Nitron rear shock, JT front and Supersprox rear sprockets, D.I.D. VX 520 chain, Adventure Spec bashplate, DIY USB Outlet, DIY chain guide, Kev's Throttle mod

http://www.facebook.com/onemooseonemotorbike

Sorry, I didn't mean try 'everything' in that thread!

Just trying highlight that a lot can be achieved by experimentation and some quality shed time. Trying different oil viscosities is a good starting point. Although it's worth checking the seals are still doing their job - have you lifted the gaiters and had a peak yet?

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