Topic: Engine Tapping Sound? Valves or Tach gear?

[skishyishy]

Greetings!

Finished a rebuild on my '78 750 (w/ good help from the forum) about 6 weeks ago but now have what seems to be increasingly loud tap from the engine around the head. It may be getting increasingly loud with my increasing anxiety about it but it definitely wasn't there before the build and I dont believe it was there right after my final adjustment.  I had the valves and seats reground by a shop and re-installed in the head by them as well, but i, of course i did the final adjustment.  The tricky part is this... After the build i have been getting a slow leak (strangely light greyish) from the Tachometer gear at the tach cable connection on the valve cover.  The noise is definitely rpm related in that it gets louder and faster with revs and cant really be heard below 2500rpm.  Could the noise be something with this tach gear?  Could I have lost a washer or seal from it during the rebuild? Does this sound more like valve related?  If the springs were bad and not replaced (dont know if the shop checked them though theyre only 38K old) would this lead to a valve tap?

w/ faith in the masters...

[Bodi]

I would have a look at the valve clearances, I've had a tappet nut come loose (or did I forget to snug it up enough?) and the tappet loosen off. I've also had a nut come right off and drop into the engine. Good to find it loose rather than missing.

[Terry in Australia]

It's probably what Bodi said, and I don't want to frighten you, but 25 years ago I destroyed the top end of my K1 engine when both oilways to the head became blocked with silicon sealant, (no, I didn't do it, a Triumph "Mechanic" used it to reseal my alternator cover and globules of the vile stuff floated around my engine and came to rest in the afore-mentioned oilways) and when I eventually pulled it apart, it was full of (strangely light greyish) material, that was of course, the remains of my camshaft soft metal bearings.

I don't want to frighten you, but the failure was heralded by an increasingly louder tapping sound like..............

Once upon a midnight dreary, while I pondered, weak and weary,
Over many a quaint and curious volume of forgotten Honda lore,
While I nodded, nearly napping, suddenly there came a tapping,
As of some one gently rapping, rapping at my rocker arm inspection door.
"'Must be a loose nut gently tapping", I muttered, "tapping at my rocker door-- surely this, and nothing more?" (With apologies to Edgar Allen Poe)

I hope it's just a loose nut mate. Cheers, Terry.

[Bob Wessner]

(With apologies to Edgar Allen Poe)

You owe him more than that. 

[eldar]

Yeah, I hope it is not serious too. Pull your tappet covers and plugs and go through each one carefully. Hope you find one that wiggles a lot. I doubt it would be a tach gear as your tach would bounce like a belly dancers hips!

[Terry in Australia]

(With apologies to Edgar Allen Poe)

You owe him more than that. 

I'll wait until I get the final notice, ha ha!