WR 450 starter chaos
Posted January 26, 2003 - 06:44 PM
Posted January 26, 2003 - 10:05 PM
My mechanic, after he looked at it and found the key broke. He asked if it backfired at all? I told him that it did right when it broke.
Well, if the starter motor broke the woodruff key, the timing would be way advanced, this could make it backfire.
Funny he would say this efore I toldhim what had exactly happened.
Posted January 26, 2003 - 10:09 PM
Do you think they may have just forgotten to torque the nut at the factory and this is what caused the issue?
I doubt that is the problem. In an extreme case a loose, or missing altogether, flywheel nut may lead to a woodruff key failure.
However, if you stop and think about it for a minute you will realize that once the woodruff key breaks it is only a matter of time (a few seconds??) before the flywheel nut unthreads.
The starter spins the flyweel, the crank doesn't spin, and there goes the nut...
Posted January 27, 2003 - 05:32 AM
The thing you need to understand is that this has NOTHING to do with the starter, the starter gear or the mechanism that engages the gear. The starter turns the flywheel that turns the crank that starts the engine. If the flywheel is disabled so is the starter, obviously.
This problem could happen on ANY fourstroke, with or without a starter. Lets not blame the mishap on something just because it's new and unchartered.
I believe it has happened to the WR450 (twice?) because the bike is jetted so lean from the factory and it back fired uncharacteristically. Probably because of emission purposes. It just so happened to do it to this time during starting. Remember this bike makes a lot of horsies, so when it back fires it is changing those horsies from clockwise to counterclockwise instantaneously. Good thing only the key broke, and not the crank or rod.
All we need to do is richen up the jetting (pilot , clip, main jet) so that the bike wont back fire and cause problems. I think I may start caring an extra key or two in my fanny pack just in case.
Posted January 27, 2003 - 05:44 AM
Posted January 27, 2003 - 06:10 AM
It is the weakest part of the link between the two parts, it is designed to shear off in the case of bad things like a violent back fire.
Posted January 27, 2003 - 06:21 AM
Posted January 27, 2003 - 07:31 AM
Posted January 27, 2003 - 08:08 AM
Posted January 27, 2003 - 10:41 AM
The bike back fired and sheared off the woodruff key on the flywheel.
I hadn't considered that, it makes a lot more sense than my theory.
Starter engages flwywheel, motor "kicks back," woodruff key is lunched.
Posted January 27, 2003 - 11:28 AM
Posted January 27, 2003 - 11:53 AM
Posted January 27, 2003 - 02:14 PM
Posted January 27, 2003 - 02:30 PM
Posted January 27, 2003 - 03:31 PM
until this problem is solved ???????
Posted January 27, 2003 - 04:42 PM
I pulled the cover off and the fly wheel nut was backed off about 3 or 4 full turns. The key looks a little thinner
than most than most of the other bikes I have owned.Mine
seemed to have happened during starting although my bike
did backfire a few times during the ride