[psgnw]

When I do a manual adjustment of my cam chain the bike runs nice and quiet for some minutes, but then the ticking comes back again. Runs like "new", but as soon as I button it up and get it running the ticking comes back. I have added a extra washer behind the cam chain tensioner bolt, but this does not fix it. Any ideas of what to do to fix it? The engine is not really ticking loudly, but enough to be annoying.

Doing the adjustment when idling just makes it more noisy. Manual adjustment seems to work fine, but only for a while.

I have done the part of gently pushing down on the tensioner, but that does not fix it either.

Valves have been adjusted. Balancer chain have been set and the bike runs smoothly, so that part of the equation should be fine.

Any tips or tricks/hacks for this?

 

[PoiPio]

Any tips or tricks/hacks for this?

Let's first look at a running engine. Pulse of the chain tightens on the power stroke. Can you close that down on the power stroke, no. That solves of never setting the chain running.

Trick I use is I don't need to take off a cover to see any marks needed, or what the book says to do. I place the bike in gear, back wheel is off the ground, hand is going to roll it in the drive direction, hand at 5 o'clock, the pressure moving it up to feeling it go thru a stroke or not, my hand is now at 3 or 2 o'clock, loaded so as not to move in either direction, the front chain rung is taught, the rear is at its most slack, now tighten the tensioner down with the other hand.

The x-ray seeing the chain's position is look at the chain and sprockets. Bottom rung is tight, top rung is loose. Pretty much what you're doing inside the engine without the covers off hand holding you that way.

Tick is usually valve lash. Set them loose. A sloppy .004" at the intake, and a .005" won't slide in, it's still a 4 and change. Same for exhaust. .006" for the ex, but a 7, no. Called the go-no go-system. See if the tick goes away.

 

[psgnw]

Thanks! The tick might be a valve, since it's more of a tick than a grinding sound. I'll do the valves again before I park it for winter. My valve cover is sweating a tiny amount of oil, so it has to come off anyway. It runs fine, starts right up and has the right amount of power. Might try a thicker oil next oil change and see if that improves things.

 

[DD23]

Are you saying that after a good cam chain adjustment and then engine run, but after a time cam chain goes slack ?

As if the cam chain adjusting/locking mechanism, may have slipped ?

Look at CMSNL.com or partzilla and understand the locking technique.

Pio is dead right.
Look at cam chain links on the cam sprocket and see the "play" movement by everso gentle crank movement back and forth half a degree. Always end by having the front run of the cam chain taught, then autotension happens, lock.

Although messy the engine will run with the cam cover off...

What oil you using may I ask and when we're the valve working clearance checked ?

Those small rocker shaft springs ok ?

Inspect cam chain...

 

[DD23]

Are you saying that after a good cam chain adjustment and then engine run, but after a time cam chain goes slack ?

As if the cam chain adjusting/locking mechanism, may have slipped ?

Look at CMSNL.com or partzilla and understand the locking technique.

Pio is dead right.
Look at cam chain links on the cam sprocket and see the "play" movement by everso gentle crank movement back and forth half a degree. Always end by having the front run of the cam chain taught, then autotension happens, lock.

Although messy the engine will run with the cam cover off...

What oil you using may I ask and when we're the valve working clearance checked ?

Those small rocker shaft springs ok ?

Inspect cam chain...

 

[psgnw]

I'm kind of unsure if it is the chain or tappet noise, see video:

Engine noise

Honda CB400N engine noise

youtube.com

The valves were set to:
Intake : 0,10mm
Exhaust: 0.15mm

I checked for chain play when I set the valves. There only a slight amount of play when rocking the chain sideways on the sprocket. Not possible to lift it up/forward/backwards. I have not checked the springs. Chain looks good.

I'm using 10w40 mineral oil.

 

[PoiPio]

Idle is too high. Does it smoke when you start it, smokes when you ride it, no? It's as good as it gets short of tearing it down or know the compression readings.

 

[psgnw]

Slight/normal smoke at cold start with choke. Not smoking when warm. Compression is good. Starts with a light touch of the button every time. I have ridden it a lot this summer without any hickups. Everything is fine except the slightly annoying noise.

 

[PoiPio]

Lower the idle, go to the side that seems noisy to you. Way too high an idle to notice if it's cam chain, rockers, basket. Does it go away if you just pull the clutch lever in? Noise goes away, there you go.

 

[psgnw]

Clutch lever does not affect the noise. I will lower the idle tomorrow and see if I can pinpoint the source.

 

[psgnw]

I lowered the idle and made another video:

Engine sound lower idle.

youtube.com

Pulling the clutch changes the sound a bit, but there is still some "tick". Valves/tappets? I don't think I hear the cam chain.

Phone recording makes it sound more "metallic" than it sounds in real life, but "ticking" can be heard.

 

[PoiPio]

Idle sounds just about right. I'd leave it there. Short of checking valve lash, sounds like it's not about to grenade. Clutch pull; changes not too much short of check throttle sync at idle. With the bike not smoking, it means the top end is in good shape.

The balancer chain might have slack to it. But how much noise you can get out of it, I'd adjust statically not running. Look at it like a drive chain. Turn and feel for the tight spot to adjust. Not walk up to it and make the adjust without that first move. How much tear down chasing the chain rung to go after? I wouldn't bother.

The better it stays together, you just let it break on its own. No parts you need to tighten the noise up like half the noise would be chain and cam sprocket. But chain is the only replacement.

Personally, I'd set the valves, check compression, ignore mechanical noise and ride it. Two types of approaches to moving parts: Fix it before it breaks/Fix it when it breaks. If you want to chase phantom noise, it's find what to look for? Just to freshen up the chain is splitting the cases. That takes gaskets and the majors you need like the head gasket

Signed,
Keep It Together & Ride Club

 

[psgnw]

Thanks! I'll do the valves after the season. The balancer chain have been adjusted earlier this summer and it got rid of a lot of vibrations and some noise. It used to rattle much more than it does now. As long as nothing sounds like it's going to break, I'll just ride it as it is. It runs fine, starts instantly both cold and warm. No smoke and pulls through the rev range. I guess some noise is to be expected for a 40 year old motorcycle

 

[DD23]

Little and often

How is oil light, instantly goes out and remains unlit when cold engine 10 second run then kill ign, how long does oil light stay off ?

Smartphone mike's are great but indoor noise ...

You absolutely certain head ain't loose and exhauts leak ?

Oil light come one when engine hot, low idle light flashes ?

Obviously all the easy stuff like filters etc. as per CMSNL view...

Does not sound like a sweet engine to me...

Pictures of cam areas...

Oil flow good up to cam including the centre feed by external pipe...

 

[PoiPio]

As long as nothing sounds like it's going to break

Baby it. Not the quietest engine, but runs.

I'll just ride it as it is. It runs fine, starts instantly both cold and warm. No smoke and pulls through the rev range.

I would. Money better spent on a later model. Start says clean carbs, and a solid ignition system. No smoke is another good sign.

 

[psgnw]

Oil light turns off almost instantly on cold engine start. Turns back on quickly after ignition turned off. Not certain there is no exhaust leaks, but can't feel anything around the headers. No leaks in the cylinder area.

Oil light has never come on when driving or idling. Airfilter changed in the spring. Changed oil and filter a month ago. Don't think there is a problem with oilfeed to the cam area. Have a slight weep from the camcover (going to fix it at the end of the season and do the valves again). Does not consume oil (checking oil level frequently).

 

[DD23]

You did say you added a washer to do with cam chain tensioner, on the outside of the engine ?

4 and 5ex thou cold but yours has the oil pipe...

Thump thump thump or a bang bang bang...some jingling and did I hear a noise similar to that made by starter clutches...russle from chain, tappety and classic whine...

Where was balance shaft dot when last inspected ?

 

[DD23]

You did say you added a washer to do with cam chain tensioner, on the outside of the engine ?

4 and 5ex thou cold but yours has the oil pipe...

Thump thump thump or a bang bang bang...some jingling and did I hear a noise similar to that made by starter clutches...russle from chain, tappety and classic whine...

Where was balance shaft dot when last inspected ?

 

[DD23]

Clutch usage change of sound involved, squeeeky sound flywheel area ?

 

[psgnw]

You did say you added a washer to do with cam chain tensioner, on the outside of the engine ?

4 and 5ex thou cold but yours has the oil pipe...

Thump thump thump or a bang bang bang...some jingling and did I hear a noise similar to that made by starter clutches...russle from chain, tappety and classic whine...

Where was balance shaft dot when last inspected ?

Washer on the outside yes. Just to try. I can hear the chain getting very rattly when I loosen the bolt, but it gets quiet when tightened, so I guess it works as it should (did so without the
extra washer as welll)

Balance shaft was reset, but the dot rotated within the limits, so it should be fine,

Was wondering if something came from the flywheel area. Always seems quieter with the cover off, but there are no marks or scratches inside tho cover or on the flywheel... The jingling sound seems to come from there.

At the end of the month I'll take the clutch cover off and inspect everything again (Did this in spring). Also valves + replacing the exhaust header gaskets as I have a new set.