A 'timely' KDX story

[canyncarvr]

Shame on me. :o

It could happen to you. I found it by happenstance. File it in your 'symptom' drawer.

Last week out, my bike ran for crap. Couldn't figure it. A jetset I've run before (40-152-BEL/2-#6TV) that had worked as it should...no big hits, just smooth and fun.

My air filter SHOULD have been swapped out before I went. Had a couple rides on it. Nothing awful. The carb hoses were clear. No AS tweak fixed it. The bike didn't idle for diddle...even with the adjustment all the way in!!

I had to slip the dang clutch to get going in FIRST gear on a one-each uphill. My riding buddy asked if I had any rad fluid cuz I smelled 'hotter'n hell'. No rad gurgling or spitting. Wasn't that bad.

A couple of times on uphills, in first gear with a quick throttle flick and the bike would just crap out.

I changed from a 152 to a 150 based on the 'feel' of the bike. That was opposite of what it SHOULD have been based on what I'd run previously and the temperature of the day. It ran better!

So..I had too much heat (in the pipe, cuz the rads were fine), no bottom end, but the mid-top wasn't too bad. A drop in main jet was an improvement.

Last night I changed my timing. Done it many times. I know the effect a bit of retard º has. Sometimes I run it, sometimes I don't.
My steahly FWW came off with no surprises. The flywheel though was a bit of a surprise. It wasn't loose...but it wasn't stuck too good, either.

Looked for the key to make sure it was there. It wasn't there! Somtimes the key comes out when the FW is removed, but I didn't see it.

I found the key sitting between the two stators. Not jammed, but stuck to some degree. I could see a slight bluing on one end from heat and on the crescent shaped side I could feel an 'edge' with my fingernail.

It hadn't been in the crank from the last time I had the FW off!! The only thing that kept the flywheel in any sort of proper position was the steahly!! (it has allen set screws that tighten on the outside diameter of the FW)

I was amazed. I have experience with sheared keys (not my bike). Even with the FWW kinda' holding things together...how on earth did the FW stay in any position that could spark the plug at a time that worked at all?

It did. Obviously retarded some (all of the symptoms..in hindsight.. pointed to that).

Moral to the story??

When you put your FW back on, run a small allen (as an example) through the keyway!! It had better STOP where the key HAS to be!!

It's not tough to have the key back out as you put the FW on. Hey..it's not like the FW slips on like silk...the magnets make it kinda wonky!!

I'm aware that happens, took care it didn't......happened anyway!!

Be careful with it!

Oh..on/off with 1/2" pneumatic impact. No...I don't use a torque wrench. Wouldn't have mattered in this case anyway.

 

[G. Gearloose]

Thanks for the heads-up, CC!
Good thing it didn't wipe out the stators.

 

[David Trustrum]

I knew someone who used to routinely rely on the taper (which he cleaned up with grinding paste so it was a premo fit). He had a different ignition on an engine & would time it by moving the flywheel. I though he was crazy but it seemed to work. Not that I’d like to find out my timing had moved & fry the engine miles from anywhere (his wasn’t a dirtbike).

As you will know, often when the key shears the flywheel spins & the bike really won’t run but backfires when you kick it. Little stones make poor substitute keys no matter how hard you look for the perfect pebble sliver :( (don’t ask). My pump has a spare taped to it nowdays.

 

[Jim Crenca]

CC,

Thanks for the tip; have many hours trouble shooting this one?

 

[Moose95]

Originally posted by Jim Crenca
CC,

Thanks for the tip; have many hours trouble shooting this one?

 

Shoot yeah CC.  How much time trail side did it take you to figure that one out?  Daggon, that would have been a month long show stopper for a crappy mechanic like me:scream:

 

[canyncarvr]

No troubleshooting involved, thankfully. I just so happened to want to change the timing. Had I actually been working on the bike from the aspect of, 'What's wrong?'...well, it would have been a painfully long time before I got to the flywheel.

BTW... first ride with it fixed this past weekend. Correct timing is a good thing!! Quite a different personality from the week before. I use a close-by short uphill as a bit of a guage for AS set before I actually go anywhere. At the top there is a bit of a whoop. With a bit of a flick in 3rd gear I came close to a bit too much air under the frontend. A bit of a surprise.

Anyway, the bike hits like a ton of bricks! At the end of a rather mild 45-mile day, I had blisters on my calluses from hanging on!

...gonna have to jet that out.......;)