Although we think that the Upper Only Kit is the best "budget" suspension/handling upgrade you can make to your stock quad, all of our YFZ and TRX450 kits come with the new "Quick Change Shims" to make your adjustments QUICK, EASY and DEAD ON ACCURATE... every time. When ordering your complete A-arm kit, be sure to ask about the "Quick Adjustments".

After extensive R&D;, we have discovered the Quickest Easiest most Reliable way to correct the twitchy steering in the YFZ450 and offer quick adjustment in the TRX450R.

The tendency for the stock front end to be unstable at high speeds or make sudden left and right movements when you hit a rock, tree root or bump in the trail is do to the AGRESSIVE caster settings from the factory. JD Performance discovered the problem, and FIXED IT!

The JD Performance Upper Only A-Arm Kit uses a simple system of shims that can me adjusted in 3 different settings to suit your particular need. By simply removing the pivot bolt and changing the location of the shims, you can make your bike go from a nimble MX champ to a straight shooting Desert rocket. Our GP and GNCC Woods riders have told us that this upper only kit is "the BEST upgrade I made to my YFZ".

YFZ Upper Only Kit

What does Caster do?
Caster refers to the angle of the front spindles. The "more caster" your bike has, the more the spindle is leaned either forward or back. This will make the bike turn "faster" or "slower". If you notice that the steering is rather twitchy or it takes only slight movement in the bars to make the bike turn, then you have "fast" steering (stock YFZ). If your bars have a lot of play in them before the bike turns, then you have "slow" steering. The YFZ is fast in the stock setting, while the TRX is rather neutral (the real MX racers will want to speed this up).

What other parts do I need for this kit?
NOTHING... Let's say it again. When you order the Upper only kit, you don't need to order, buy or modify any other parts for your quad. It's quick, easy and accurate.

Why not Heim Joints?
Many other companies are using heim joints on their A-arms. Although they are strong and a great way to design a system for a PRO mechanic, the every day rider/racer can't accuately adjust them. In order to adjust the Caster on a set of A-arms that uses heim joints means you much completely remove the arm, and turn the heim, then re-assemble. Turning the heim not only adjusts the caster, but it also changes the caster. What does this mean? It means you must adjust both heims (accurately) in order to achieve the desired affect. If you have tried it, then you know what we mean.