Z-Start Update
I wanted to let everybody know that we've put the z-Start on shipping hold and recalled all of the units in the field. We've had problems with the screws that hold the z-Start's friction disk coming out. The screws were a late design change to improve repeatability in manufacturing, we originally used pressed-in pins. Because these screws get no tensile load (no pull load) they are very susceptible to coming loose. My original solution was loctite, but it's just not working reliably. Most people are having no problems but the very aggressive riders have been able to get some loosening even with high temp loctite. Ultimately loctite looses strength with heat and clutches can get very hot (especially at the friction disk).
We are looking at a couple of different approaches to solving the problem. The first is solid rivets (what they use to hold ships and airplanes together). The advantage to solid rivets are strength and good repeatability in manufacturing (with the proper fixture). The downside is that the friction disk on the z-Start would no longer be field replaceable. You would have to send the z-Start back to us to install a new friction disk.
The other thing we are looking at is a technology called Sprialock. This is a thread forming tool that is designed to solve the problem of shear stress causing fasteners to come loose (precisely our problem). I am overnighting both the rivets and Spiralock tools so we'll be able to begin testing early next week. I'm also contracting with a fastener engineer to review the problem. I'm confident we can come up with a solution, I just don't want to rush things and make a bad decision.
Any Boise folks out there that are OMC members that'd like to take a CRF for some hot laps next week to help with testing, please send me a PM.
In other news... as I mentioned here before, we we're working on a new top plate with a pre heat treated material that would give better clutch lever manual override performance. The new top plate is done and does work much better than the previous version. However, I'd have to say that the clutch lever pull is still slightly stiffer than stock at higher rpms (although not much) and the bike will still creep at about 8K rpms but not much. I was able to hit the rev-limiter by holding the front brake with the bike in 2nd gear without any rear wheelspin. Everybody will be getting the revised top plate.
In more other news... the YZ/WR250F and YZ426/450F (including 01/02 250 2-stroke) have been started and machining should be done by the end of next week. I know I promised a lot of people to get the KTM/Husabergs versions done first but KTM has changed their clutch twice in two years and it's just more difficult to do. I will be doing it soon but I need to knock off a few easier ones first (the Yamahas are really easy). Also, the CR-250 2-stroke will be done next week, it just uses a different clutch cover spacer, should be done next week (everything else is the same as the CRF, I believe all the way back to '89).
Again, I want to apologize to my customers for the trouble of sending it back, especially to those of you that suffered from a screw poking through your clutch cover. We are committed to this thing 110% and we will get your z-Start back in your bike as quick as we can.
