New to forum, not new to kawis, have a couple old 2 strokes, they're easy. Got a couple scooters this spring that had been sitting for years, tore em apart, big bore kits, got em on the road. Looking to roll the profit into another basket case bike, that's always a good idea right?

09 klx250 posted for 1500 says "needs work" ask him what's up with he said it sat for years before he got it so needs tires, but he ripped it around as is for a few months and something blew up. He said "the dealership" said it needs "new cylinders" as they're "all scored up". He kept offering to start it to hear the noise but he wouldn't let me rip it apart or even take the plug out, there was somebody on their way that offered 1000 and I offered 1100 and said I'd be there first. Got it. I did start it when I got home, maybe 5k rpm tops, sounded like valvetrain noise but im new to 4 strokes didnt want to make it worse, was still assuming a stuck/broken ring. Already knew the ahl 299 kits were cheap so if it needed a cylinder, got a kit in the mail. New plastics in the mail. Manual cam chain tensioner in the mail.

Ripped it apart, top ends mint. No rings stuck or anything. 7500km Cylinders kind of glazed but not scored at all, no ridge. Chambers pretty carbony, top of pistons caked. A little worried I got lied to.
Rookie mistake, I flipped the head over to check how sooty the chamber and faces of the valves were, dropped 3/4 buckets/shims now not sure what went where. Shim kit and new feelers in the mail.
2 of the buckets have scoring on the face, both cams have visible wear. I see the buckets are $35us apiece on webcams.
I'm on a budget here, head stuff is intimidating. $6-700us for cams is >$1000cdn, that's what I paid for the bike believing it needed top end. I think the dealer has valve clearance at 1000km and 12000km, I guess this thing never got done at 1k or the auto chain tensioner slacked off. There's Chinese Loncon knockoffs of these things right? Anyone tried an aliexpress head?

Planning on reusing head bolts even though those 8mm hex had some stretch on them, reusing cam cap bolts too - i do know which ones went where and undone in stages in sequence. I think I'll wait til 299 kit shows up but I might bolt the cams into the head on the bench and see if I can test clearances that way. I have the service manual but im pretty sure even my layman self can tell by the visible wear these cams are tired. Local kawi dealers closed Sunday Monday

I'm really wishing I started with valve shims and/or scope inspection thru the plug hole instead of trusting the kid I bought it off that it had "scored cylinders". Kind of tempted to bolt it all back together with this base gasket until the 299 kit shows up but that's unnecessary stretch on the bolts.

I'm gonna go mic the shims and see if I can figure out what was where, I assume the 4 buckets are the same? Shim kits going to take a few days to get here. Center numbers worn off every shim but I see 2 0_5's, an 0_0 and a 1_0.

 

I measured my valve buckets and they were within a couple ten thousandths (.0001") of each other, totally acceptable to be considered identical. Thing is when doing valves the buckets wouldn't matter as long as they go back in the same place. If starting from scratch, which you are, it doesn't matter at all. Just once you started, keep them in the same place every time.

I don't know what the cams would be like when you say showing wear, or the cam caps either. You could run them and see how they go, maybe take some pics of the wear and ask here. I will tell you from what I've checked, the cams from any KLX250 or 300 from 1994-2022 can be used, although there may be ACR placement might differ on the kick start models vs the electric start, but then again if you leave the spring off of the ACR it doesn't matter. I will tell you the e-start will spin just fine without the ACR working. I have mine disabled and it has even cranked over and started at around 8°F so I know the ACR is unneeded. So if you find some cams it doesn't matter. Want proof, look up the part numbers here at Partzilla. I think one year there was a different cam in the 300, but still would work. Reusing the original cylinder bolts should be no problem, only being the second use. Two uses not uncommon.

I haven't replaced cam cap bolts either and am not too worried. There are two longer bolts that go in where the locating dowels are. One thing for sure - do not ever tighten the cam cap down until you have tapped it down totally against the head. If you try to pull the cap down with the bolts you may crack the cam cap, which means a new head and cam cap since they are machined together, no swapping caps. I will get the cap set down then tap lightly with a screwdriver handle to get the cap in place flush against the head surface. Then I snug all the fasteners, next torque to around 1/2 value, then full torque in the proper sequence of course.

I've never bought a shim kit, only buying the shims I needed after I measured and figured the ones needed.

I kind of wonder if your noise before tear down was the cam drive due to the automatic tensioner failing and the cam chain slapping around.

 

Ditto... I bought my '09 with 1800 miles on it and she sounded like she was going to come apart up above 5500 rpm. I swapped her over to a manual cam chain tensioner and she has been rock solid for the last 3000 hard trail miles (I stay off the roads as much as I can).

 

Haven't posted in here but been reading a lot about these things. Thanks for the help guys, I'm not used to valvetrain noise. I did take a video of it before I tore it apart, and like I said, I had the big bore kit ordered the day I bought the bike, before I took it apart.

No parts have showed up except shim kit, feeler guages, assembly lube. With the more accurate feelers I got the valve lash in spec but thats the closed end of the cams, manual says to replace cams if they're not 36.1xmm long and 3/4 of these cam lobes are in the 35.xxmm range, one is like 35mm. Visible wear. 2 of the bucket faces were scored but one was super rough, i sanded it down w 600/800/1000 and it still has some scores like low spots but nothing sticking out. Valves look great. Bike only has 7500km so what's that like 4500miles? I think this thing either ran out of oil or someone banged it around for a few thousand km with the auto chain tensioner stuck.
I bolted everything back together a few nights ago. Neither cam chain tensioner showed up yet. Runs fine, little noisy. Put 50km on it

manual tensioner still in the mail, auto tensioner still in the mail, 299 kit from Amazon still in the mail somehow. I almost bought a Chinese Loncin head but just got cams and buckets instead, but from China, en route. Black plastic in the mail. Another gasket kit because why not.

I bolted everything together with the same base and head gaskets, and ripped it around for most of a tank of gas. This things awesome and I can believe I got it so cheap. Kid said it needed a cylinder, I ordered a cylinder. I did nothing but take it apart and put ir back together but I did shim the valves. Intake only has a .009 to .014mm range and I only had 1 each of 3.10 amd 3.15mm but got it right at the .009 on one and like .13 on the other, another shim coming to go for .13/.14. Exhausts were easy. Cam chain tensioner has shiny spots where it was rubbing back n forth. Hoping replacing it quiets it up even more.

This things going to be sick w all black plastic and the 300 kit amd I'll be into it for like 2 grand 2500 bucks.

Got a 2000 kx125 I'm going to clean up and sell and that should pretty much pay it off, going to look into some supermoto wheels and/or Enduro tires, this will be my first road legal bike amd have a road test wednesday, this things going to see some highway intercity to save me truck gas this summer but I live in paradise, it'll see some dirt too. I had no idea parts were so cheap and interchangeable, maybe this thing will see some ferries and borders. Think im going to do luggage racks and a black gas can. Looking forward to racking km once I'm street legal. Already did fender delete and some better turn signals. Still feels illegal.