Converted front suspension to run 2.5W fork oil

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Freddy
Posts: 695
Joined: 06 Sep 2017, 11:06
Location: Sydney Australia

Re: Converted front suspension to run 2.5W fork oil

Post by Freddy »

750R wrote:Thanx foor the information - i'll try to contact them! will get funny wth my really bad English :lol:
W'll let you know what the answer was.
The spring for the 1100 can be a bit harder - 50kg more weight in the motorcycle (an don't ask for the driver ;) )

Greetings
The sonic spring calculator would have me (at 95Kg in gear) running a 1.00 Kg/mm front spring on an 1100. I'd certainly be reluctant to go any heavier than that, at least initially.

P.S. after a very long test ride I'd decided to increase the front rebound speed a little by increasing the single rebound hole in each damper rod by one drill size. Currently its 3/32 inch I think. One size larger would have me back pretty close to the original size (but one of the two original holes totally blocked). If the rebound proves to be too fast I can easily slow it back down by going up to 5W oil (or some appropriate mix).
Freddy
Posts: 695
Joined: 06 Sep 2017, 11:06
Location: Sydney Australia

Re: Converted front suspension to run 2.5W fork oil

Post by Freddy »

Finally got this project finished (well 99% as I'm sure I'll go on tinkering trying to squeeze a factor more out of the bike).

VERY please with the results. Final set up is ....
5W fork oil
One rebound hole in each damper rod
Cartridge emulator 1 slow speed compression bleed hole.
2 turns blue spring high speed compression damping.

Lots and lots of experimentation to arrive at the above. The main problem wasn't really with the settings I was trialing, the problem I was actually trying to sort wasn't even in the front suspension at all, it was in the rear suspension. It was inadequate compression damping that was making the rear give a harsh ride. Harsh ride, natural to reduce compression damping you'd think. No, needed to be screwed way up.
Freddy
Posts: 695
Joined: 06 Sep 2017, 11:06
Location: Sydney Australia

Re: Converted front suspension to run 2.5W fork oil

Post by Freddy »

Front fork upgrade now complete. WAY better than original, or previous effort.

Final configuration for anyone interested.

Springs - Linear, spring rate 0.90 Kg/mm for a 95Kg in gear rider
Fork oil - 5W Motorex (note fork oil weight varies across brands, there is no standard)
Fork Oil Height - 140mm
Race Tech cartridge Emulators set to: 1 bleed hole at 2.76mm, Blue springs set 2 turns
Rebound damping - One hole in damper rod, 2.76 mm
Front fork brace

Note: the 2.76mm is actually a 7/64" drill (think I remember than one correctly).

Total cost of the project if starting from scratch would be in the vicinity of US$400. I don't think it a stretch to say the final result is pretty much on a par in performance to stock modern forks.

P.S. I considered the stock damper rod forks not only very poor in performance, they were actually dangerous. So to me, doing nothing was never an option. It was just a matter of what modification represented the best 'bang for buck' and was viable from an engineering perspective.
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