mcman56 Posted November 20, 2018 Report Share Posted November 20, 2018 I have a 2016 300 4T with maybe 75 hours on it, almost 35 since valve adjustment. It runs fine and starts easy. On the last few rides, I noticed that the top end seems to be noisier than before. Nothing sounds horrible but there is some "clitter clatter". Probing the head area with a mechanics stethoscope, it seems a little louder at the cam chain tensioner. Is this normal? See the video. It does seem to sound worse in the video than in person. The deep sound that comes and goes is it quieting down a little when pulling in the clutch. The engine was cold but I think it sounds the same hot. If not normal, any ideas? https://youtu.be/gk9x64aulWQ Quote Link to comment Share on other sites More sharing options...
mightychub Posted November 20, 2018 Report Share Posted November 20, 2018 Sounds like the chain slapping maybe tensioner is slightly worn or needs adjusting. My bro has one of these and it's really quite Quote Link to comment Share on other sites More sharing options...
tshock250 Posted November 20, 2018 Report Share Posted November 20, 2018 Don’t leave us in suspense, it’s really quite what??? Quote Link to comment Share on other sites More sharing options...
mcman56 Posted November 20, 2018 Author Report Share Posted November 20, 2018 I pulled the tensioner out. Teeth look ok and spring has enough tension to push out the plunger when off the bike. When it was out, I tried pushing on the red guide. It felt solid but I don’t know what it should feel like. It does sound much like a klx250 with bad tensioner I heard recently Quote Link to comment Share on other sites More sharing options...
feetupfun Posted November 21, 2018 Report Share Posted November 21, 2018 (edited) Wasn't there another forum string about this a few weeks ago? Maybe have a look back because your Beta 4T symptoms sound a lot like the other person's. I've just added a link to the string. It started in 2012 but was active again a few weeks ago Edited November 21, 2018 by feetupfun 1 Quote Link to comment Share on other sites More sharing options...
lotus54 Posted November 21, 2018 Report Share Posted November 21, 2018 Wow. I have a 2016 300 4T with probably close to 200+ hours. It is MUCH quieter. Take a look at the other thread- Billy showed a rocker that was very warn causing a very noisy top end. Mark Quote Link to comment Share on other sites More sharing options...
billyt Posted November 21, 2018 Report Share Posted November 21, 2018 Hi Mark. The reason it is much quieter is because it had the correct oil in from the get go. I miss her !!!! Quote Link to comment Share on other sites More sharing options...
section swept Posted November 21, 2018 Report Share Posted November 21, 2018 Does sound a bit rattle, as you have pulled the cam chain tensioner and confirmed it’s working the next move would be to re-set the valve clearances very carefully. The problem could be that the valve stem heads have worn. The noise is so regular that the cam chain may be the cause.The cam chain guides can wear as obviously can the actual chain. Don’t trust that tensioner it can look ok but the spring can go weak and there in lies the problem, re adjust the valve clearances and go from there. You can remove the camshaft and most of the valve operating gear without taking the engine out of the frame or removing the cylinder head it’s fiddling but doable? Quote Link to comment Share on other sites More sharing options...
carl ekblom Posted November 21, 2018 Report Share Posted November 21, 2018 Can be that the automatic valve lifter mechanism is stuck. Happened to me? 1 Quote Link to comment Share on other sites More sharing options...
mcman56 Posted November 21, 2018 Author Report Share Posted November 21, 2018 I appreciate all of the input. I did notice it oddly hard to kick over at least once. I pulled the valve cover and see nothing obvious. The decompressor spring does not look broken and the decompressor is free to rotate. Surface finish of the decompressor shaft is not that great and looks like it was worked on with a file. If it was stuck, I guess it is possible it got unstuck during disassembly. The spring force is very very weak but it is a tiny spring. Locked in the TDC position, it feels like the weight of the lever looking part provides the force for returning. I can't rotate the cam so assume that means the cam chain is tight. Looking down from the top I can see red guides are there but no detail. Cam sprocket feels bolted tight to gear. Rocker arms have some end play but otherwise feel tight. Rollers that run on cam feel OK as does the little pieces that meet the valve stems. I did not check clearances before pulling the valve cover but, by feel, nothing was grossly loose. There were a couple of very tiny flakes on the magnetic drain plug. Oil looked good. Nothing was in the two plastic oil filters. Any other suggestions? I'll look again but all I can think of is to loctite the gear to sprocket bolts, set the clearances and see what it sounds like before going deeper. Quote Link to comment Share on other sites More sharing options...
section swept Posted November 22, 2018 Report Share Posted November 22, 2018 18 hours ago, carl ekblom said: Can be that the automatic valve lifter mechanism is stuck. Happened to me? Isn’t that supposed to make a knocking noise! Quote Link to comment Share on other sites More sharing options...
section swept Posted November 22, 2018 Report Share Posted November 22, 2018 Did you set the valve clearances correctly? Were they done hot or cold? The cam chain tensioner spring can become weak even though it feels ok to you. The noise of your engine does sound very rhythmic as though it is tappet noise. I would go for resetting the valve clearances very carefully. Also fit a new tensioner and spring to be on the safe side. Follow the setting procedures for both from the manual. Keep us posted please.? Quote Link to comment Share on other sites More sharing options...
mcman56 Posted November 25, 2018 Author Report Share Posted November 25, 2018 Clearances were spot on. I rotated and looked at all parts of cam chain and it looked ok so I’m down to suspecting the cam chain tensioner. I hear the tap/ sound at idle but when I bring rpms up slowly to mid range, the sound is less noticeable or goes away. Quote Link to comment Share on other sites More sharing options...
thall1 Posted December 1, 2018 Report Share Posted December 1, 2018 Did you get it sorted?.. Just adjusted the tappets on my sons... Did it a few times but it's still a bit noisier than mine.. Just wondered if you found the cause of your noise? Quote Link to comment Share on other sites More sharing options...
mcman56 Posted December 2, 2018 Author Report Share Posted December 2, 2018 I put in a new tensioner today. First it was noisier so I manually pressed on the plunger while rotating the engine a few times. I reinstalled the spring and let it warm up. I think it is OK but as you listen to noises in an engine you can start to hear (imagine?) all sorts of things and I don't have another to listen to.. I made another video with the microphone not as close and out of an echo area. That specific noise is still there but it seems more in line with the other noises. Even when it was louder it went away or blended in as the rpms were bought ut to mid range. The tensioner is a ratchet design and tightens in steps. It seems logical it would get noisier as the chain wears but then quieter as the chain loosened enough for the tensioner to get out one more tooth. That could explain the difference between two bikes. The video is kind of vague because all you need to to to make it sound bad is turn up the volume. Quote Link to comment Share on other sites More sharing options...
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