Firstly, I bought this bike last summer with 10.5K miles on her and she is currently sitting at 13.1K. It was my first inline 4 supersport, so I don’t have a lot to go off when comparing it to other 600cc supersports. I do the routine maintenance, and I’m planning on checking the valve clearances this winter, but I’m in no way a mechanical expert. I did screw up the oil capacity and for the first 800 miles I owned it, she ran with ½ qt over full. I’ve had some mechanical sounds pop up recently and I want to get some opinions on whether I should just ride it like it is, or what I should dig into to try to trouble shoot.

1st- I had a sticky clutch cable that resulted in 4 miles of clutch slipping and a noticeable louder valve train, cam chain, and what sounds like a metal fan spinning when the rpms get to 5K when I got her home. I reset the automatic CCT and the faint clicking noise was gone, but the top end is still noisier than before this happened. The other noise is only audible around 5K rpms and drowns out around 10K, but it sounds like a vibrating metal fan. My first thought was that the radiator fan was running all the time, but it’s not. The speed of the sound increases as the rpms increase as well. It doesn’t sound like a tick or knocking sound. I’ll try to get a recording of it. She still pulls hard(in my very limited opinion), and she gets to red line in 1-5 without sputtering and idles pretty strongly. Is there common valve damage/top end engine damage that would sound like that? Where should I start?

2nd- I changed the spark plugs (NGK 6263 CR9E) and blew out the air filter(I think it’s OEM) and cleaned the airbox area. Now the exhaust is growling on decel when in gear and the intake is noticeable louder when accelerating. I can rev it in neutral and no pops or growls, but if I’m moving and the rpms are above 6K she growls when slowing down. I like it, but it’s never done this before the change. The bike only has a Jardine rt1 slip on(its what it came with) and there is no F1 light on. Should I pull the plugs again and see if it’s running rich? If they are white, what is the next thing I should do?

Last- In traffic or sitting at a red light on a hot day the radiator fan kicks on at around 212, and the bike will get up to 226 and then just stays there. It won’t go higher which is good, but it’ll pretty much just read 226 until I get moving again. Coolant level is good and was flushed in the spring. Is this normal?

I feel like the bike is still running strong, and maybe it’s just getting louder as she ages, but I have no other bike experience to go off of. I’ll upload it idling and figure out a way to record the fan spinning sound.

Here is the bike idling; sorry for the shake, I had the phone in the mount

Here is a a run on the bike... you can hear it best around the 10 second mark... I took it with an iphone, so the mic isn't great.

1). The clutch has zero to do with anything related to the valve train. Sounds like you have some tapping on the valve train.... Checking and adjusting the clearances is likely to correct that.

2). Go ahead and replace the air filter altogether. Blowing it out is better than nothing, now you're hearing what you are supposed to.

3). Normal.

Thanks! I’ll order a shim kit/filter try to get to it next weekend rather than waiting until winter. Would you continue to ride it for the time being, or should I garage here until checking? It must have just been coincidence that the sound happened after the sticking clutch cable incident.

I would not want to spend a lot of time at redline, until you have everything sorted. I've heard worse.

I checked the valve clearances today. Intakes were all within spec; pretty much .15mm-.18mm; Exhausts are all on the low side; .20mm-.25mm... Should I leave the intakes alone, or adjust them closer to the mean of .16mm?

There are as many opinions on this as there are people in this board.

My take? Leave what is in spec alone. Trying for an exact value within a +/- range can be extremely difficult without all of the tools being at the same level of accuracy. Your least accurate measurement tool, determines your overall accuracy.

There's a reason the engineers said this range is 'good enough'.

Update- Put everything back together, took it out this morning and it sounded/ran great for 30 minutes, then the sound came back. I noticed when rechecking the valves that there are some definite friction spots when I was spinning the crank/cams. Nothing that was binding, but definitely had some points that were sticky. Any ideas on what to check next? I'm going to check the oil pressure tomorrow,(No oil lights so far), but other than that I'm in a ride until something happens mode.

Edit** I'm going to make sure every nut/bolt is tight before I tear into anything. I just noticed that on the fuel tank diagram there are dampers that are under the tank... the diagram has them, but my bike does not.

so.. tightened everything and removed the radiator guard... the fan sound is gone, but the top end is way louder than before(possibly from the exhaust valve clearance adjustment) I was reading that the friction I felt when turning the crank was probably when other valves reached TDC and were opening. Is that true? I had to order an oil pressure gauge adapter, so once that comes in i'll make sure the pressure is good to go. I'm going to garage until it does. Any other things I should rule out before taking it to a shop?

Update 3- I believe there is a spun bearing on cylinder 1. On the downstroke I can hear play when I push on the cylinder head..... I'm going to drop the oil pan and prepare to take the motor out. Is it worth it to replace the bearing, or should I be looking for a new motor?

Common advice would be to buy a good, used motor. Unless you have experience doing major motorcycle engine surgery, it’ll be cheaper, and much faster than a rebuild.

I noticed you mentioned the dampers under the tank. They ARE NOT there for dampening! The way our bikes gas tanks are attached, they can wobble side to side, without those rubber blocks. Kawasaki threw them in as a stop gap measure. If that goes on for long enough, you will weaken the metal where the frame to tank bracket bolts to the tank. To the point where it pours gas through the little hairline cracks.

....ask me how I know....

Those little rubber blocks are less than $3 apiece. Completely remove the factory “adhesive”, and get some 3M double sided tape. You can get it at Home Depot. Black, with a red lining. The factory “adhesive” is comically weak, and you WILL lose those blocks if you don’t replace the adhesive with something more substantial. Again....ask me how I know...

Haha, I appreciate the reply. I ended up ordering new ones, but I found 1 between the valve cover and plastic heat cover, so I cut it in half and used that until the new ones came in. I'm just going to run it until she goes. Compression is within spec, oil pressure is good.. aside from tapping she still pulls really hard. Once it goes, i'll buy a new motor. I thought about trading it in next spring, but I wouldn't want any place to sell it to someone and tell them the sound is normal because it runs well.