Posts
8
Joined
11/20/2023
Location
Fairmount, IN, USA
Edited Date/Time
11/24/2023 10:03am
2023 250 SXF with 70 hours, no problems prior. Checked valves and noticed this on my left exhaust lobe. Other lobes look fine. The surface is still completely smooth no grooving and cant feel it with a fingernail. Motorex 10w50 changed every 5-7 hours depending on terrain and usage. I am not hard on the bike at all. Completely "cosmetic" damage at this point but leads me to believe there is another underlying problem. Anyone had anything like this? Should I throw in a new cam and follower and keep an eye on it?
Have seen it before Keep an eye on it Dirty oil try sooner changes
Send those pictures to DQ at Spykes and see what he says. How does the finger follower look?
Haven't taken the cams out yet, but it almost looks discolored/ blued like it over heated.
It’s probably blued from low/dirty oil or no oil and generating friction. Does anything else in the valve train appear discolored from overheating?
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Just that one lobe, opposite exhaust is fine and both intake as well. I’m thinking an oil passage was/is blocked. It did have a good coat of oil on it when I opened it though.
Update from my local KTM dealer. "I can definitely see some scuffing on the cam, we see this quite often upon inspection, we have continued to use these parts even with the scuffs, oftentimes just taking a scotch brite to the cam lobe to clean off the transfer, I cannot see the wear on the rocker arm in the pictures. But they are DLC coated so id be surprised if it shows anything."
New cam and follower are on backorder until Feb, I ordered them anyway. I double checked my oilers were all clear and working. If I remember I will update this post after putting more hours on the bike and see if the problem gets worse. Going to run my oil no longer than 4 hrs now. Shame because it still looks brand new at 7.
“But they are DLC coated so id be surprised if it shows anything."
“DLC” coating smeared off the rocker arms and left the deposits on the cam lobes of my 18 450 SXF at 10 hours. Motorex 4T,changed at 1hr then every 5. Cleaned deposits off cam lobes with Flitz metal polish. 130 hours and no valve movement. I don’t believe it’s DLC. Maybe something to aid in break-in. Look at your rocker arm face. Bet it has no black coating.
Which dealer?
Spykes. I'm new to KTM so I don't know all the guys there. I just sent a service request with pics through their website.
I was very meticulous about break in as well. It is very odd how smooth the cam still is, but it would make sense if its a deposit that slowly transferred across parts. I am a bit weary to attack it with a scotch brite pad. Is there any technique you use to remove it with polish? My worry is creating high/low spots doing it by hand.
Chrome is very hard. Doubt that most polish is going to harm anything. I didn’t have to scrub. Just a light polish job with Flitz and it came off. Don’t think it would hurt anything to leave it either. Oil jet for the cams was squirting good.
They are pretty good and see a lot of race bikes there.
Do you lean bike over & fill oil filter cavity with oil during oil change? Wondering if maybe starving for oil on initial startup?
Yes. I haven't looked close at the oil passage diagram but maybe this cam is the last one to get oil to it? Just frustrating having this hiccup with a new bike. I let it warm up at idle before I ride and I haven't had any other issues.
Bumping since a few years have passed. I bought a new to me '22 MC250f that I found has the same wear when inspecting valve clearances. All in spec. Has anyone found a root cause to this or normal?
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