My friend and I both rebuilt the suspensions on our sons' YZ85s recently. They both race Supermini and Senior classes and each have two different YZs for a total of 4 bikes. It was partly for periodic maintenence and partly to change the valving and springrates for the growing boys. I also installed Race Tech Gold Valves using RT's charts and recommendations, just like I had done years ago on my WR400. I happen to like Race Tech products if for no other reason than they don't treat you like you are too stupid to do something as simple as fork & shock rebuilds yourself. That's a long way from knowing what valving changes to make or being a suspension "expert", but their recommendations have worked well for both me and my son, and the changes themselves are simple to make. You also come away understanding the basics of how your suspension works and that helps greatly for fine tuning. The problem we ran into on 3 of the 4 bikes was not RT related. It was the shim/bushing that is found between the top of fork cartridge and the bottom spring coil. The "bushing" (there is no known official Yamaha/Kayaba name for it as I will explain shortly) lightly press-fits into the top of the cartridge using just finger pressure. It is "T-shaped" in crossection and provides a flat surface for the bottom of the fork spring to rest against while keeping the bottom-out cushion inside the cartridge and protects the cartridge itself from the sharp spring. It has a locator notch and cannot move or rotate when installed on the cartridge. Apparently, the spring DOES rotate a bit as it compresses, because the very sharp bottom edge of the springs on 3 of the bikes had chewed through the thin flat portion of the bushing. The damage extent ranged from minor to severe as a couple forks had the bushings dump out in pieces when we dumped the oil. Our bikes ranged in age from '03 to '05. Surprisingly, it was our oldest '03 that had no problems, while the '05, recently purchased from a very aggressive rider with (what I found out too late) a "zero-maintenence dad", had nothing but chunks and pieces floating loose in the fork tubes. No big deal. These are small, inexpensive wear items, right? We'll just order new ones along with the new upper and lower tube bushings and the seals. WRONG! Yamaha does not even list those bushings! Their parts list exploded view does not even show them! The ONLY way you can get those 50 cent bushings is to order $325 apiece entire cartridges!!! This is crazy! I tried to track down Kayaba's website, but only got Kayaba USA, which only manufactures automotive parts; not motorcycle. They referred me to Enzo Racing, the USA Yamaha/Kayaba team. "If they can't get them, nobody can." Enzo Racing replied to my email right away and said they would do what they could to obtain the proper bushings for me. They also said it wasn't a problem they ran into very often. But then, how many YZ85 forks do they actually rebuild? Maybe a bunch, but I'm guessing probably very few compared to the big bikes. Well, it appears they can't get them either since I have never heard back from them. The same went for Race Tech. I asked RT how they dealt with this issue since it must be fairly common if 3 of our 4 bikes had the problem to one extent or another. If you have ever dealt with RT, you will quickly learn to save your breath when calling the Tech line and just ask for the shop in the first place since you almost always get a salesman instead of an experienced actual technician on the tech line. The sales guy said they just make the customer buy new cartridges (??!!). The tech guy in the shop said to use a flat spacer bushing (fork spring shim included with RT front springs) on top of the cartridge to replace the bushing. Now, I can see where Kayaba should have done exactly that in the first place (placed a flat shim between the bushing and the spring bottom). That would have eliminated any chance of the sharp, rotating bottom edge of the spring galling and destroying the stationary bushing. But if we just use a flat shim now without the bushing, I can't help but worry a little there might be a slight chance of it somehow shifting enough to either interfere with the little bottom-out knob on the cartridge rod, or to allow the bottom-out cushion to ride up on that rod (that shouldn't matter too much though), from the way it looks to me. I am trying the "flat-shim" approach right now as the Race Tech techie suggested. So far, so good. And the suspension is much improved with the RT valving. I'll be taking the forks back apart in another month or so to see how the internals and flat shims are fairing. If anyone has any good ideas about getting the correct part, I'm all ears. I will NOT buy $650 worth of cartridges to replace perfectly good ones just to get those cheap little bushings. I strongly recommend that any YZ85 dads out there check their forks at least once a year and at least do oil/seal changes. That seemed to have saved our '03's bushings. While you have the forks apart, put in a proper-sized flat shim (used to adjust fork spring preload, but usually installed at the top of the spring betweem the spring and cap) between the cartidge bushing and the spring to absolutely ensure no future problems. You can get them from RT. It MUST fit with very little clearance between the shim outer edge and the fork tube inner wall to ensure it cannot slide around much. It also MUST have a large enough inner hole to allow the "knob" on the cartridge rod to pass easily through no matter how much the shim can slide sideways while at the same time being small enough inside diameter to not slide down over the cartridge. The YZ85 is the best 85cc bike out there and it's ultra-reliability and toughness is one of the biggest reasons why. I also like Race Tech products and the results we've gotten with them, and, if you are persistent enough, the tech support you can get from them, too, though that seems a little more difficult each year. It just ticks me off that such a simple wear item, like that bushing, cannot be obtained anywhere. I do not like feeling as though I am cutting corners or "making do" with flat shims when my son's safety literally rides on that suspension. Incidently, if you find the valving and spring recommendations given by Race Tech work well for you like it does for us, you should not be afraid to rebuild and revalve your own suspension on these bikes. I made the only special tool besides a fork seal driver and 12mm hex socket needed, a cartridge holder, myself, and, aside from having a shop do the nitrogen charge on the rear shock, it is very easy to follow the instructions and videos. No voodoo involved. If I had to cough up $350 to have a shop redo the suspension every time my son grows 10 to 15 pounds or gets more aggressive, it would be very expensive. He was 75 pounds when he started on the YZ85 and is now 117 pounds less than 2 1/2 years later and hitting a renewed growth spurt. As for the Race Tech bad-mouthing I saw in another post: Pay someone else to do your suspension and remain ignorant of what it really has done to it and what makes it work. You could do the same for top-ends and valve lash settings, too, if you have the money. Some of us like doing things ourselves or MUST do things ourselves to afford the sport. Who is "the best"? No one can possibly answer that question since no one has tried every suspension company and no two riders will like exactly the same thing. I actually had one local suspension expert, a good one, compliment me on how well my son's suspension looked to be working while watching him on the Supercross track. He even admitted he had never personally liked RT gold valving, but he sure couldn't argue with the results he was seeing on that bike and said he wouldn't pretend he could do it any better, though he did make a few clicker recommendations, which did help on that track. If and when the day comes when a suspension tuner guarantees significant improvement over the RT suspension for a reasonable price or my money back, AND the stopwatch and kid agree it is better; AND he is present at the track to actually watch the bike and kid together on all of the obstacles and fine tune it; I will take him up on the offer. Until then, the RT beats stock by a long ways.