Posts
4
Joined
11/25/2023
Location
haslet, TX, USA
After a pretty long track day, I started my bike up and it is making a light ticking noise I suspect is coming from the top end. From my research it might be the cam chain tensioner failing or the decompression arm spring giving out. I checked the valve clearances and the only issue is that one exhaust and one intake are tight by .04~.05mm from in the middle of spec, and outside spec by only .01mm. If anybody has any knowledge or leads on what the noise could be coming from it would be greatly appreciated! I have a video of the sound, but I cannot attach it, so I can email or pm if the video is wanted.
Mine is doing the same thing. I have a manual cam chain tensioner. My guess is rocker arm play. Valves had not moved at 100hrs, now has 130. I will look into it when it gets colder along with a top end.
How long has oil been in it? Cam chain tensioner failing
probably about 5-12 hours, close to needing a change.
I just checked for rocker arm play and there is none. Valve clearances are all within spec. Decompression mechanism works fine and spring looks good. Maybe just a noisy engine like the early CRFs.
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All of our KTM/Husky's have made a ticking noise, and it's more pronounced on our 350. I've had a 16 400 XC-W, 18 FX 350, 19 &20 FC 250's nd now 23 FC250 and a 24 FC350. I have not paid enough attention to other bikes, but I think it is just the cam chain at normal tension. I guess best way to know if it's off, is go listen to some others next time you're at the track.
I had a 17' or 18' 350 xc-f come into the shop with a loud ticking noise a few weeks ago. Valve clearances were in spec. Cam chain tensioner fine. Realized that the lateral tolerance for the exhaust rocker arm was way too loose (knocking side to side). I found the spec online and I think it was .010. Here's the kicker, when I set that lateral (side to side) play, I torqued down the two 10 mm cam bolts properly then tightened the torx shaft plug that comes from the right side of the head. Started it and it was noisy like I made no change. Took the head cap back off and realized that the shaft plug had overcame the torque of the two 10 mm bolts. Tried everything and couldn't get that lateral play to stick after tightening the shaft plug. Finally took a suspension shim with the correct thickness I needed to fill the gap/leave desired tolerance. Drilled/sanded it to the right diameters and reinstalled. Boom, no noise. Weird story but it worked in my case. Also, I didn't notice any wear on the head or the rocker arm. There were plenty of questions but no solutions on the internet about this issue. Maybe that helps?
yeah thats what i believe it is. I also don't think that it is really a huge deal/will cause any catastrophic damage to the engine, as i'm not man enough or driven enough to fiddle with shims and spacers. Thanks man.
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