kx250 prob after rebuild

[KawasakiRipper]

Hey guys Ive ahd this bad 98 kx250 for a year now, i just got cylinder done at millenium, new piston and rings, new crank seals and bearings, but ever since ive got it back, it doesnt have the top end power it used too. It still has tons of low end power but its just not as fast and wicked, im guessing its either the KIPS powervalve or a dirty carb. Please help me out guys let me know what you think, im trying to rip silver lake sand dunes for the fourth! thanks!

[Foxx4Beaver]

though there are a few things it could be...
I would start with the KIPS, be sure they're opening/closing fully, and working correctly, if at all.
you can remove the plastic KIPS cover on the right side of the jug, start it up, and rev it a couple times to see if they're working. If the rod comes out when you rev it, you'll know they're working. Now you'll need to shut it down, remove the pipe, and look up into the exhaust port, and see if the side valves are fully closed...you can then manually pull on the rod easily on the side of the cylinder to see if they open fully.

Start with that, then report back.

[KawasakiRipper]

Ok thanks Foxx, this cover is what your talking about right?

[KawasakiRipper]

and also foxx when i look in into the exhaust port, i just give it throttle to see if its fully functioning? thanks

[Foxx4Beaver]

correct.
what I explained shouldn't take you much more than 30 minutes to do.

[KawasakiRipper]

Ok what about this one?

https://www.youtube.com/watch?v=FOIbhIo3GCU

[Foxx4Beaver]

and also foxx when i look in into the exhaust port, i just give it throttle to see if its fully functioning? thanks

you won't be able to have it running when you look into the exhaust port, because you'll need to have the pipe removed.
before you remove the pipe, start it 1st, with that plastic cover off, like you have shown in the pic...if that mechanism moves when you rev it up, you'll know it's working to some extent....but you won't know if they're timed correctly...that's when you take the pipe off, and look up into the cylinder while manually operating the KIPS by hand, and see if they're closed completely, and opening completely....and more importantly, correctly.

[Foxx4Beaver]

Ok what about this one?

https://www.youtube.com/watch?v=FOIbhIo3GCU

is that your bike in that video?
yes just like that...that appears to be functioning fully...but we don't know if they're timed correctly.

[KawasakiRipper]

No its not my bike but my bike has that same governor cover right there, i remember it when i was putting powervalve back together, i was just worried that a rod would shoot out or something once i take that cover off

[Foxx4Beaver]

nothing will fly out...and you want to see yours come out at least that far too when you rev it.

[KawasakiRipper]

ok so if doesnt come out the side of the cylinder that far, then the powervalve is put together wrong? So if one of the powervalve rods if off by like one tooth is that gonna hurt my new engine, seals or bearings? thanks soo much man!

[Foxx4Beaver]

ok so if doesnt come out the side of the cylinder that far, then the powervalve is put together wrong? So if one of the powervalve rods if off by like one tooth is that gonna hurt my new engine, seals or bearings? thanks soo much man!

having them timed wrong won't make it blow up, just don't rev it to the moon with that new top end, do it just like that kid did in the video....

it'll just have no sac in the upper revs...kinda like the issue you're having.

[KawasakiRipper]

Ok ill be at my parents house tomorrow with the bike and ill take pics and observations and report back immediately tomorrow! thanks foxx you the man!

[Foxx4Beaver]

I'm not guaranteeing the KIPS are gonna be the culprit...it's just where I myself would start.
I don't even know what a dirt bike is...I'm just guessing as I go

definitely let us know what you find.

[KawasakiRipper]

hahahaha thanks man!