Topic: Tappet Nightmares (video)

[Paganica]

Hi all. I've got a 76 cb550 with what sounds like some serious tappet noises. I have triple checked them and then triple checked them again and I cannot get the noise to go away.

Here are some quick bits of info:
-~12,000 miles
-The bike has cb500 carbs
-I've gone through and cleaned all the carbs including the emulsion tubes
-Changed spark plugs
- Adjusted cam tensioner
-Adjusted tappets (.002/.003), point gap , and static timing
-Changed o rings on intake manifold
- bench sync (haven't vacuum synced yet)

I don't know what else to do. I'm assuming it's tappet noise though I could be wrong. What else could cause this noise?

[enwri]

Are you absolutely sure that you did the exhausts and intakes for 2-3 the right way around? if you did the 2 step method,
if you do the four move way I think it's 1-2-4-3.
I hope it's tappets, that is loud.

[flybox1]

Forget to adjust your cam chain?
Do this ^^^ and a vacuum sync and then report back....

[Paganica]

I forgot to mention I had adjusted the cam chain as well... For the tappets I followed the service manual procedure turning to the "T" for 1/4 and adjusting intake and exhaust and then turning around to the 1/4 again and adjusting the remaining valves.

I'll do a vacuum sync and report back. thanks for the help so far.

[DaveBarbier]

I forgot to mention I had adjusted the cam chain as well... For the tappets I followed the service manual procedure turning to the "T" for 1/4 and adjusting intake and exhaust and then turning around to the 1/4 again and adjusting the remaining valves.

I'll do a vacuum sync and report back. thanks for the help so far.

Did you adjust the valves on any 2-3 tappets while on the 1-4 T mark? Maybe I'm misunderstanding you and it's just late and I need to go to bed but the faster I go to sleep the faster it seems work comes in the morning.


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1978 Honda CB550K

[Paganica]

I just followed the page in the service manual. Adjusted 4 valves then rotated crank shaft and adjusted the other four.

[enwri]

I've gotten mixed up with the intakes and exhausts on No.2-3. Got 1-4 ok, but did the 2-3 ones around backwards.
Didn't hear it running though, noticed the big gaps while turning it over.

[Bodi]

Take the tappet covers off and check the clearances by hand pulling up and down on the tappet nut - correct can just be felt as a tiny bit of movement possible when the valve is fully closed. Turn the engine over a couple of turns as you feel each one (not hard with plugs out). If you set one "wrong" the large clearance will be super obvious. I think we've all made this mistake - for me it did sound about like that.
If that's all good... exhaust leak?

[Paganica]

Not meaning to sound obvious, but you have checked your oil, right? It's full and not about 2 quarts low? I've seen guys service their bikes, get distracted, and run the motors for tuning without oil. Scratching their heads, "dang that sure sound loud now that I've adjusted the valves?" The reason shortly becomes apparent when the motor suddenly makes an obvious, abrupt stop.

Not a bad thought. Oil should be good but it can't hurt to double check. I'll also check the play in the in the tappets as calj737 and enwri suggested. The noise is  so loud I have to imagine I overlooked something or made a mistake somewhere along the way.

[b5rider]

mine made that noise after a valve adjustment and one of the tappets was loose. get a dedicated tappet adjuster tool which has a small, long screwdriver inside of a socket sleeve. It allows you to loosen the nut, tighten the tappet, and then tighten the nut without moving the crew out of adjustment.

[flybox1]

this works great.

https://www.denniskirk.com/284120.sku?utm_source=google&utm_medium=cse&gclid=CjwKEAjw5J6sBRDp3ty_17KZyWsSJABgp-Oa0xa9y_oOr6yOCzJuwg7ZE5TpJameOfkNpwhGjeTiCRoC60vw_wcB

[Tews19]

That sounds nasty. I can't put my finger on it but it does sound like you adjusted the cam chain but possibly in the wrong direction?

When adjusting the valves I read you did 4 at a time but curious of your exact procedure? The manual yes is helpful but people read and follow directions sometime differently than how it is written. Nothing against those but we all have been there. Here is a video that makes adjusting the valves very easy.

Than go to the cam chain...

[Paganica]

Alright so I went ahead and checked the tappets again... a few were a bit off so I adjusted them and checked them all twice. I watched the video again to make sure that I was doing them correctly. Went ahead and readjusted the timing after and made sure I followed the video to adjust the cam chain. Fired it up and got the same result.

I put a screw driver up to each tappet cover and noticed the intake tappet on intake 4 made a ton of noise compared to the others. I will wait until everything cools down and check that tappet again. I don't hear them as much when it idles but I certainly hear them a lot when i bring up the rpms. I have still only bench synched but I'm trying to run it for as little amount of time possible while I'm having this tappet issue. Checking the intake on 4 after it was hot measured .004". It seemed to be consistent with the intake on cylinder 2.

[DaveBarbier]

Checking the intake on 4 after it was hot measured .004". It seemed to be consistent with the intake on cylinder 2.

Shouldn't that be a cold measurement? If the tappet should be .002" when cold and it's .004" when HOT, what would it's cold measurement be?


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1978 Honda CB550K

[Paganica]

Ya I set it to .002 when it was cold and it measured .004 when it was hot. I can't remember if the gap is supposed to increase with heat or decrease but my definitely increased.

[Bootsey]

If you are certain that the tappets & cam chain are adjusted correctly, the rocker shafts having elongated the rocker cover may be worth considering? The '76 model has the short, unpinned rocker shafts from memory.

Found a couple of videos too if they help. Probably only worth considering once you've addressed the points raised by the guys above, and have ruled out all relevant adjustable bits

[DaveBarbier]

Ya I set it to .002 when it was cold and it measured .004 when it was hot. I can't remember if the gap is supposed to increase with heat or decrease but my definitely increased.

It's my understanding they should decrease. Lengthening of the valve stem from heat expansion. That's why there's a larger gap on the exhaust side...more expansion shrinking the clearance.


---
1978 Honda CB550K

[Tews19]

Where is your kick starter when revving the engine?  Does your kick starter work? Have you pulled your oil pan? I'm thinking.it could your your kick starter if the tappets are within spec. I've had the same noise with a 550 last summer. The electric starter did not work. Ended up being the starter clutch broke inside and the spring to the kick starter somehow shifted allowing the teeth of the kick starter to constantly grind. I will upload a video to let you compare the sound if you would like?

[Paganica]

Both the kick starter and electric starter are working. Ive been starting it with the electric mostly. I'm a little scared to check the oil after hearing all this noise.  I haven't checked the tappets yet since the bike has cooled down.

I am definitley a little confused as to why my tappet gap is increasing with heat.

[Tews19]

You tightened the 10mm nut once the valves were adjusted correct?

[b5rider]

Sometimes the rocker pivot pins wallow out the hole they fit into on the rocker cover. When this happens,  the valve spring pushes on the rocker shaft and your valves go out of adjustment.  Honda fixed this on later models by essentially pinning the rocker shaft with a set screw. 

[Paganica]

Sometimes the rocker pivot pins wallow out the hole they fit into on the rocker cover. When this happens,  the valve spring pushes on the rocker shaft and your valves go out of adjustment.  Honda fixed this on later models by essentially pinning the rocker shaft with a set screw.

I'm a little concerned this may be what is happening. I checked the valves and a number of them are out of spec after running the bike for about 5-10 minutes. I'll try again tomorrow and see if I get the same results.

Also, I did make sure that all the 10mm nuts were tightened after adjusting and they are still tight after running it.

[Paganica]

Here is a video of how I've been adjusting the tappets. This was before I ran the bike today and I went ahead and adjusted them all after the video so that each one was Go/No Go before coming up with the same results. To do the other four I just rotate the crank shaft to the T mark on the 1/4 again and adjust the others.

[b5rider]

Sometimes the rocker pivot pins wallow out the hole they fit into on the rocker cover. When this happens,  the valve spring pushes on the rocker shaft and your valves go out of adjustment.  Honda fixed this on later models by essentially pinning the rocker shaft with a set screw.

I'm a little concerned this may be what is happening. I checked the valves and a number of them are out of spec after running the bike for about 5-10 minutes. I'll try again tomorrow and see if I get the same results.

Also, I did make sure that all the 10mm nuts were tightened after adjusting and they are still tight after running it.

If so, send me a PM as I have the entire kit you would need

[754]

How loud was it before you adjusted?

If you do 1 and 4..do only the one where both valves are loose, the rotate 360 to do the next one.