Rotor lapped and torqued still shears key
Posted March 01, 2003 - 10:34 AM
Posted March 01, 2003 - 12:17 PM
Posted March 01, 2003 - 01:11 PM
Posted March 01, 2003 - 04:44 PM
I believe it is a mistake to lapp this assembly. I have seen the service manual supplement and there was no mention of lapping the rotor. The problem is the torque applied to the rotor nut.
Posted March 01, 2003 - 05:01 PM
Yeah well yamaha corp. has listed 3 different torques 50 then 61 and finally 47. This was before anyone even took delivery! When I dykemed the crank there were severe high spots after trying the rotor. The only logical thing to do is to lap (one p) it. I don't need yamaha too "bless" something we've done for 35 years of racing. After looking futher at the rotor I think yamaha will find that it's too heavy (mass) for the taper and that's why it's shearing the key.
Posted March 01, 2003 - 06:19 PM
sounds like you did everything you could. Still broke. That SUCKS. I wonder how much the WR rotor weighs compared to the KTMs?
Posted March 01, 2003 - 07:14 PM
Posted March 02, 2003 - 02:54 AM
Adam I will weigh them this week.
Posted March 02, 2003 - 04:29 AM
something is causing the woodruff key to shear. What??? Nobody is 100% sure. There's a few things that haven't fixed the problem:-- Re-torque rotor nut to 47lbs.--Lap and check taper--Jet to 160m,48p,72s or whatever--Oh, and don't touch the throttle while starting???LOL.
I'm not saying the rotor is too heavy. But I'm not saying it's not. I'm not an engineer or mechanic. What do I know???
Posted March 02, 2003 - 05:09 AM
and I am sure Yamaha will make it good for you.
If you ever get the urge to sample the Northern Michigan woods give a yell, we will show you our super secret Scuba Steve world famous single line trail.
Posted March 02, 2003 - 05:43 AM
JB Weld is awesome. You know it's one of the most important inventions of the 20th century. Oh ya,You know it.. It probubly WOULD fix the woodruff key problem. Permanently. LOL.
Posted March 02, 2003 - 06:35 AM
is that up by wolverine ?????????????????????????????????
indian river ?????????????????????????????????????????
Posted March 02, 2003 - 07:08 AM
Bottom line is that all engines backfire sooner or later so jetting cannot be a solution - only a means to reduce the likelihood. And I know that most people do not enjoy riding a time bomb, it would drive me nuts to ride alone with a situation like that. I'm just suggesting that a methodical approach that includes listing bike id numbers could help isolate the problem if it is limited to "some" of the bikes delivered to the US - and it could help yamaha determine what bikes need a recall for those that may have not yet failed. Comparing failed parts (assume a flywheel, for example) to good ones is a simple and time proven troubleshooting technique - and yamaha has the means to do that. If, for example, it turns out to be a flywheel problem, they will know what flywheel production run matches the range of the affected bike ID's. More of a proactive approach I guess - you know the dealers aren't (can't) going to do the work - this forum is an ideal starting point. Just a suggestion.
Posted March 02, 2003 - 07:28 AM
our super secret Scuba Steve world famous single line trail
XR 600, We will show you. Wolverine/Indian river is OK, but we can show you better! ---Mike
Posted March 02, 2003 - 07:47 AM
It sounds like you tried valiantly. That really sucks to hear it still has a problem. I do have a question about the key itself. After lapping for a good contact fit between the rotor and the shaft, you had to install a new key. Is it possible that the key sticks up a hair too far and prevents a full-contact interference fit?
You might try torquing the gear to the shaft without the key. (Don't run it, of course). Just see how much force it then takes to remove it. It should take a lot. Maybe even some heat. If it doesn't, you still don't have a good fit. If it does take serious puller force/heat to remove, repeat with the key installed and compare how hard it is to remove the gear then. If it is any less, the key is preventing a good fit.
If that were the case, a little filing down of the top flat portion of the key might help. The key should just index the gear, not support any shear force. I always put a drop of red loctite on the shaft to gear mating surface as well as the nut on our similarly designed auto-clutches.
Having done all of these things; I would be at a frustrated loss and probably be tempted to reach for the mig gun... or, more likely, be parking it back at my dealer's...
Good luck! What Yamaha does from here is going to determine a lot of future sales, and I hope they realize that.
Posted March 02, 2003 - 08:54 AM
ive been riding in northern michigan since i was 12 , and ive never heard of it.
whoaaaaaa is me....i'm so unworthy.
Posted March 02, 2003 - 09:42 AM
Wonder if he has ever sheared a woodruff key???