vlj1216 Posted April 11, 2016 Share Posted April 11, 2016 So I have a knocking noise, not cct, coming from the front cylinders maybe. It's been there for a while, very intermittent. A recent thing I noticed and I'm not sure if it's always been like this or not; after I shut down the bike and I'm removing the oil fill cap there is a lot of air pressure, lots of air coming out. I can't remember if that is normal or not. If it is normal then I guess not related to my noise, if not normal then it might be related and what could cause it? I recently replaced my clutch and a leaking rear valve cover gasket. Other than that nothing new. Oh and the knocking sound was there before those repairs, actually been there for a good 6-7k miles or so. Link to comment Share on other sites More sharing options...
Member Contributer Terry Posted April 11, 2016 Member Contributer Share Posted April 11, 2016 What is the oil level like? I read elsewhere about knocking sounds as a result of very high oil level. The high oil level can be caused by a stuck injector that drips fuel into the cylinder then down into the crankcase when then engine is off. Link to comment Share on other sites More sharing options...
Member Contributer Switchblade Posted April 11, 2016 Member Contributer Share Posted April 11, 2016 Crack piston or a broken ring. Pull your PCV hose and make sure it's working. Link to comment Share on other sites More sharing options...
Member Contributer 3dcycle Posted April 11, 2016 Member Contributer Share Posted April 11, 2016 should not have pressure there, while bike is off. make sure crankcase breather not plugged at rear valve cover/ air box. Link to comment Share on other sites More sharing options...
vlj1216 Posted April 12, 2016 Author Share Posted April 12, 2016 I will check all these tomorrow. Link to comment Share on other sites More sharing options...
vlj1216 Posted April 12, 2016 Author Share Posted April 12, 2016 Oil level is good, same level as when I finished the clutch and did an oil change. Rear valve cover breather port isn't plugged and does have air coming from it. Even though it's not plugged and breathing, unfortunately the cracked piston/broken ring sounds like that might be it. Air leaking into the crankcase by the piston. Link to comment Share on other sites More sharing options...
vlj1216 Posted April 12, 2016 Author Share Posted April 12, 2016 Ha, I take that back the hose was plugged, Dunno how that got in there! No pressure at the cap now. I'll monitor the knock and see if the pressure relief will clear it up, hopefully it didn't cause too much damage. Link to comment Share on other sites More sharing options...
Member Contributer 3dcycle Posted April 12, 2016 Member Contributer Share Posted April 12, 2016 that will do it. Link to comment Share on other sites More sharing options...
wera803 Posted April 12, 2016 Share Posted April 12, 2016 That may have been the cause of your leaking valve cover gasket too. The pressure had to find somewhere to go. Link to comment Share on other sites More sharing options...
vlj1216 Posted April 12, 2016 Author Share Posted April 12, 2016 That may have been the cause of your leaking valve cover gasket too. The pressure had to find somewhere to go.I'll buy that! Link to comment Share on other sites More sharing options...
Member Contributer MaxSwell Posted April 12, 2016 Member Contributer Share Posted April 12, 2016 Please keep us informed. I'd like to hear what happened to the engine. Link to comment Share on other sites More sharing options...
vlj1216 Posted April 13, 2016 Author Share Posted April 13, 2016 Will do. I'll commute with it tomorrow 50 miles and see. I would have today but I killed a HUGE spider on it so I had to spray it down with bug spray. I don't do well with spiders at all and the thought of one running up my arm while riding kept me off her tonight Link to comment Share on other sites More sharing options...
Member Contributer Switchblade Posted April 13, 2016 Member Contributer Share Posted April 13, 2016 Crack piston or a broken ring. Pull your PCV hose and make sure it's working. Lucky man !!! Link to comment Share on other sites More sharing options...
vlj1216 Posted April 13, 2016 Author Share Posted April 13, 2016 No ride today. Started cranking and no start...I was like what now?! Checked the battery charge and found this...again 30 amp fuse hot and melting. Tomorrow I'll cut and solder/heat shrink it. Hopefully it was a shitty connection there from the last time I did it and not something else causing it. Man, a new VFR or maybe CBR is really starting to call me. Link to comment Share on other sites More sharing options...
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