Lost power on a ride today

[DonnyV]

Hello all,

So I went on a ride today, bike was running great brought it in gotta drink of H2O then headed back out. Well a little bit into the 2nd ride the bike started knocking and had no power so I turned it around and slowly rode a few miles back to the truck. It felt pretty bad, haven't looked at it yet just wanted to ask here where should I start. It almost felt like the timing changed, it would still run but very rough, about 9 rides on new top end, new reeds. Any suggestions are appreciated

[Slick_Nick]

Bet your flywheel spun on the crank.

[KDXGarage]

2003 KDX220R??

Out of gas? :-)

I'd take the pipe off and look in the cylinder. If it gets to that point, do a vacuum test and a pressure test before disassembly.

[SS109]

Yup, check the flywheel key and the piston.

[DonnyV]

Yes 03 220
Not out of gas
I might have to buy some new tools, got a couple raining days and no garage so it might be later this week when I look at it, thanks guys for a good starting point

[KDXGarage]

Check the air filter.

Check the plug.

Start simple, then work your way up.

[DonnyV]

Well took the flywheel cover off and everything looks good there, while I had it off I grabbed the flywheel and no up and down movement but as I rotated it forward and back I could hear and feel a lot of slop internally, so either big end or small end. The rebuild/refresh continues. I'm just wandering if putting a new top end on a 18 year old bottom end did it in, thanks guys I'm sure I'll be talking to you on here for Q and A

[DonnyV]

Okay is there a different way of checking the big end bearing besides checking it with the jug off. Ugh I just really don't want it to be this bearing but from what I seen on YouTube and have read all signs are pointing there, I'm starting small and checking the easy points first. Thanks

[KDXGarage]

Did you take the pipe off and look inside with a strong light?

[DonnyV]

Not yet gonna do that now and will report back

[KDXGarage]

Yeah, start simple and work your way up.

Take the plug out and check it, too.

[DonnyV]

Okay so took the pipe off and everything looks like it should, piston looks new both rings in there groove. I took the flywheel cover off to rotate it and got on a good compression stroke and moved it back and forth while trying not to move the piston and there is definitely some play in there, maybe a bad wrist pin or wrist pin bearing. I think I'm gonna have to remove the jug.

[SS109]

Sadly, if you can feel play, and it's not the on the outside edge (main bearing) it's probably the big end rod bearing.

That said, do as KDXGarage said, check all the small stuff first. Also, pulling the flywheel cover won't tell you if you broke the woodruff key that holds the flywheel in proper timing. You have to actually pull the flywheel to know for sure.

[KDXGarage]

about how many hours are on the crankshaft and main bearings?

[Slick_Nick]

Chiming in here because I just had this happen, check your flywheel RIVETS. I recently had the two sections of the flywheel itself come loose and it caused all sorts of problems before the flywheel grenaded.

See here: viewtopic.php?f=86&t=25000

[DonnyV]

about how many hours are on the crankshaft and main bearings?

I don't know, I didn't get to talk to the original owner, my father-in-law bought it from an estate sale last year and put on a cheap petcock and new air filter then sold it to me. Everything was original besides a different headlight and trail tech endurance 1. From the looks of it when I got it I'd say a a couple hundred hours. I'm waiting on a flywheel puller now, will report back later this week.

[KDXGarage]

What did the spark plug look like?

[DonnyV]

What did the spark plug look like?

The spark plug was rich
Reeds looked good
Jetting
148 main
42 pilot
#7 slide

[KDXGarage]

No metal chunks on it or oddball issues?

[DonnyV]

Hey everyone sorry for the disappearance, kid's being out of school takes up almost all my free time. So I needed to put closure on this, long story short, that sneaky jet block gasket was the culprit. Funny thing is I had one for months now just never put it in. The good thing I got out of this is knowing my bike better and getting some new tools ie. Flywheel puller, compression tester and to take advise and use it, the "start small and work your way up" is huge. Thanks guys for all the advise and to anyone who hasn't changed this little kinda spendy gasket, just change it don't let it sit in the toolbox lol