Quote: Originally Posted by
kbruce130
I've got good news and I've got bad news. The good news is the kid went out to round 1 of the ITP Quad Cross and took 1st in the Open Expert Class. The bad news is within the first five minutes of our first practice following the race, the clutch basket went critical mass and detonated. It lost five ears and shredded two of the friction plates. Fortunately I don't think it did any other damage to the motor. Interestingly, upon inspecting the whole clutch assembly I noticed that all of the rivets connecting the drive gear to the basket were stretched and very loose. It literally had about 1/8 to 1/4 inch slack between the two. The rivets were very close to failure. In looking at the rivets, I wonder if the basket failed because it's a POS or if it failed because the slack in the rivets caused it to overstress and break? Anyhow, in case anyone is wondering, this is my dune bike and not our primary race bike (The primary is getting 3rd gear replaced). As such, this bike has less than 30 hours on it and has only been raced a total of 6 motos. As has been stated on this forum before, you just cannot tell how long these baskets will last. The irony is I was planning on replacing this basket in a few weeks. I was just waiting on getting the Son's bike back up and going before jumping into another project. Oh well, what's one more project.
On a very positive note, the kid pulled a nice holeshot with a stock motor against some very built up LTR's, TRX's, and YFZ's. Complaints about the performance of this engine are greatly exaggerated.
Wow! Well first glad he is ok! I was just talking to Warnert yesterday about this clutch we all know even the updated version is NO GOOD! Rivets are not as strong as bolts and they are in shear from high spinning torque loads, as you can imagine even the smallest piece of clutch plate hitting soft casted AL will fail every vertical wall in it's path and the longer it runs the worse it gets....glad you escaped internal damage. Ours failed about the same hours.
Make NO mistake thier is NO riding technique that will prevent this failure that results from a poor design. If you do not upgrade to a billet basket you run the risk. I'd recommend BCS since they use bolts vs rivets plus they put a surface hardening chem finish on that the pourous stock basket does not have, that coupled with a machine cold worked strong billet of a higher grade al will not fail no where near as easy from a plate impact in compression along with shear loads from the bolts on the basket web to hard steel gear interface.
We're running local expert today w/stock basket waiting for our BCS basket next week, hope it holds up.
BCS is just waiting for them to get done w/chem treat....they machine them themselves.