CB160 engine noises - need some personal calibration

Snakeoil · Post by **Snakeoil** » Mon Oct 22, 2012 8:21 pm

My little CB160 runs great, pulls hard, does not smoke and is just a ball to ride. But the I believe the bottom end is a little noisy. Might be something like the clutch or primary drive as I've never really listened to one of these run before. I'm talking at idle. I don't want to say it knocks, but it does sound a bit like a knock.

There is no perceived noise with the engine under power or at high revs. It has 5K miles on the odo and that is correct. Engine has never been apart.

Can you give me an idea of just how noisy these engines are?

Thanks,
Rob

rrietman · Post by **rrietman** » Tue Oct 23, 2012 7:13 pm

Rob; they are really very quiet, usually. does the noise change when you pull in the clutch? shift into gear? if so might be trans related. I assume you have adjusted the cam chain. the primary drive is by gear and is very robust. might be time to pull the right side cover and clean the filters, have a look at the clutch, drive gears, and oil pump linkages (all right there once the cover is off).
Good luck
Randy

Snakeoil · Post by **Snakeoil** » Thu Oct 25, 2012 10:22 pm

Thanks Randy. I planned on pulling the side covers over the winter. Clutch release is a little sticky in spite of greasing it thru the fitting. Have not adjusted the cam chain so will do that and see if it quiets down. Had meant to do that once I got it running. But it ran so good I have to admit that I got distracted by just riding it.

Have put a few hundred miles on it since I got it so time to dump the oil anyway, since this is the first batch of new oil since I brought her back to life.

Can't believe with only 5K miles that it would have a knock. It does seem to go away with revs so might be something simple like the cam chain slapping. I don't have a lot of experience with vintage OHC engines like this.

regards,
Rob

Jlovvorn · Post by **Jlovvorn** » Wed Oct 31, 2012 8:33 am

Mine is so quiet that at stoplights I often worry it has stalled!

It gets loud at you wind it up past 5000, but below 2000 you can barely hear it with a helmet on.

Snakeoil · Post by **Snakeoil** » Fri Nov 09, 2012 5:31 pm

Winterized all the bikes today and when I got to the 160, I adjusted the cam chain per the manual and the engine seems to be much quieter now. Could be that chain had never been adjusted in it's life given there are only 5K miles on it.

Regarding the cam adjustment procedure. I assume that bringing it to TDC on the compression stroke is to have the valves closed so there is no pressure on the cam and hence the chain and inhibit proper tensioning of the chain. Is this a correct assumption. I cannot imagine any other reason for that step.

Thanks and regards,
Rob

Jlovvorn · Post by **Jlovvorn** » Sun Nov 11, 2012 2:13 pm

My owners manual just says loosen, and then tighten.

What procedure are you following?

I would like to do mine right if there is a better method than the manual.

Snakeoil · Post by **Snakeoil** » Sun Nov 11, 2012 8:37 pm

In the service manual it describes the adjusting procedure as follows. My words, not theirs.

Bring the engine to TDC and put the T on the alt rotor in line with the pointer on the stator. Then loosen the adjusting bolt.

I suspect that if you do it with the cams on the lead to the top of the lobe, the valve spring pushes the cam backwards with the engine off and would prevent the tensioner spring from taking the slack out of the chain. With the cam positioned on the bottom of the lobes, there is no moment trying to turn the cam in either direction.

This is not stated in the manual. It's what I surmise from the procedure and was asking if anyone could confirm.

regards,
Rob