Strange Engine Bogging

[evo550]

Watching the video, you seem to do alot of riding in a gear higher and slowly lugging the motor...not something a big bore mxer is designed for.Sounds like it's just loading up and needs to be cleared out.
If they are lugged to long the crank get full of unused fuel.
It;s a simple case of starting the bike and holding it wide open, eventualy it will rev out nice and clean. This can take up to a minute.
Does this happen when you are riding in wide open territory or just single trails?
I had exactly the same thing happen to my sons KX 60 when he was first learning to ride a geared/clutch bike.
Have you checked your reeds for wear.
or
You need to replace your clutch side hand grip

[opfermanmotors]

Actually, that's first gear and it is geared low.  I know the video makes it sound like it's bogging but it's actually pulling quite strong at above idle RPM, but it will lug pretty low.  I would like to say it's loading up or getting gased up like you say.  The only reason I don't go with that explaination though is because it didn't always do this and nothing changed.  Seems like it bogs and looses power where it didnt used to.

[evo550]

Ok, just watched the vid again and it's an '82 not '83 so disregard the reed statement
I still think it's just loading up, Why now and not before? not sure, perhaps engine wear.
Does it happen on the wide open sections or just the single trail sections?

[opfermanmotors]

The engine was completely rebuilt the year before, so only after a year of riding this occured.  But maybe it needs new rings, I guess it's possible since it is a weisco and not a Mahle.  Happens on hill climbs usually, which you can be wideopen on.  However, sometimes you can just be sitting idle and it just shuts off and this occurs.

It seems to me like it loaded up, just not sure why its not back firing and why its hard to clear out even with gas off.  Just seems strange to me like its fixible since it didnt occur before, definately feels like a power loss sometimes. 

[ford832]

Is there any chance your float needle is intermittently sticking open and your overflow tube is blocked?

[opfermanmotors]

Nope, would have to have occured at the same time on two previously working carbs, Mikuni (brand new) and Bing.

[ford832]

Any updates? 

[opfermanmotors]

Haven't riden the bike recently   My only thought is that I am hoping that it was the water sitting in the ignition cover.  I have to ride it to rule that out as the issue that either it was sucking in water there or the water was causing an electrical problem.  There was a good bit of water that was sealed in the ignition cover.

[SachsGS]

Wipe some grease around your magneto side crankshaft seal.If the seal is leaking your Maico will run fine until all the grease is sucked into the crankcase.