Finally did it!
Originally Posted by blacktiger
I had a fiddle with my forks whilst doing lots of other things to my bike. My impressions of the forks was that they were far too stiff. So, I got myself some 7.5W fork oil (Std. is 10W) and put that in the forks to a level of 140mm from the top of the leg with spring removed and leg fully compressed.
Why 140mm? Well, the Thruxton forks are filled to that level, whereas the Scrambler is filled to 123mm. So, if you're going to reduce the damping you also need to reduce the spring rate. The simplest way is to increase the air chamber above the oil.
I've just come back from a 100 mile ride to test it and I'm very pleased with the result. I rode a variety of roads from fast dual carriageway to bumpy back lanes covered in crap. The forks now absorb the bumps instead of crashing into them.
I have to say; I don't know if this would be too soft for dirt roads but if your riding is mainly paved roads and, like me, you think the forks come too hard, then you should give this a try.
7.5W oil to 140mm. You heard it here first.
EDIT, December 2009, I've done over 7000 miles with this set-up now including some pretty rough off roading and it copes very well with all conditions. IMHO this is almost as good as the forks could get for very little cost. Next step is to try 8.33W (mix 1 litre 10W with 1/2 litre 5W) at 135mm.
EDIT, May2010, next step is done and it is a bit better at giving more feel at the expense of ultimate comfort.
I bought the Fork Oil last year, finally while swapping the tires (now on Conti Trail Attacks) it seemed too good of an opportunity not to "upgrade" the forks. I went with the first version, 7 1/2 wt at 140mm and am very impressed thus far. Only one 30 mile test ride, mostly to scrub in the new sneakers but I realized that I was crossing some bumps in comfort and control that have made me cringe in the past. Interestingly, while perusing the shop manual for torque numbers I noted that in the general specs section they called for 120mm (maybe 123?) on the carbed Scramblers but 143mm for the injected ones. My bike is an '08, which in the rest of the world was injected but in the USA came with carbs. It makes me wonder what changes were made, I thought that the injection (and the different tank to fit it) was the only thing that was different.
I had intended to include a "Thank You" to Blacktiger for the mod, I apparently got distracted when I heard 'Your dinner is on the table' and forgot!
No one calls the Fire Department because they did something smart!
06 DR 650, Moose RS Holder, Handguards and Skidplate, ProTaper bars, Garmin 60CSx, Motech racks w/ 20mm Ammo cans, Renazco 08 Scrambler, Conti Trail Attacks and BlackTiger Fork mod, 05 FSE 450, 03 KLR 250, 02 FXDX, 72 WR 250 (again), 72 SL 350 K2 (again), 72 TR6R, 06 XT 225
Fire Escape screwed with this post 06-17-2010 at 06:51 AM