Setting Front Preload on a '02
I took my ‘02 919 for its first real aggressive ride last weekend. I did a 400+ mile day that mostly consisted of spirited cornering (8-9/10ths pace). The week before, I mounted a stock '04 shock courtesy of another WT member. The ‘04 shock noticeably improved the rear end. With the shock in place, I was able to quicken the pace enough to reveal some shortcomings on ’02 front suspension:
1. Going into corners, the brake dive was a bit un-nerving. It unloaded the rear end to the point that it wanted to move around. This wasn't even hard braking, just adjusting corner entry speed
2. Also, when leaned to the edge of the tire, the 919 struggled to hold its line. With counter-steering and leaned pretty far off the bike it wanted to run wide in some high-speed sweepers.
I attribute both of these to the front being sprung too softly for my weight, (185lbs in full gear). So off to the garage…
I measured front (loaded) sag at 45mm, too soft for my tastes. I opened up the forks, removed the stock spacers, and cut some new ones out of PVC. Standard 1 inch PVC from Home Depot is the right size.
The stock spacers measure 150mm. I cut 2 lengths of PVC 160mm and 165mm, which reduced to 159mm and 164mm after filing, smoothing, and deburring.
I installed the 159mm spacers, put it back together, and torqued all the bolts to spec. The sag is now 36mm (9mm increase in spacer size reduced sag by 9mm). The front end was already lowered 7mm in the triple trees. I lowered it another 8mm to account for the increased ride height. So how does it ride…
A quick test ride showed that brake dive is reduced and the front feels a bit firmer, which is what I wanted. Hopefully, I’ll be able to hit the corners again this weekend to see how it handles.
It was a fairly easy mod and it only costs $3. Depending on the level of improvement, I may be buying some new springs…we’ll see.