OK, not too bad on your part. I'm a little foggy with some of your terminology 
but I think I get it. Yes, you can reseal the anti-foam chambers with a good 
silicone seal. Allow 24 hours before starting the engine. I always fill them 
with oil before re-assembly. With the silicone that may be a problem. Oil and 
silicone don't get along before the silicone sets up. At least put some in and 
clean the gasket surface with alcohol before the silicone is applied. How did 
the cam lobes look ? No scaring ? holes, pits ? 

--- On Mon, 4/27/09, tharrisn <[email protected]> wrote:
From: tharrisn <[email protected]>
Subject: [Nighthawk Lovers] Re: NOISE cont.
To: "Nighthawk Motorcycle Lovers!" <[email protected]>
Date: Monday, April 27, 2009, 9:14 AM

Dennis,

Update to the '83 CB650SC Nighthawk hydraulic valve adjuster
"tapping"
saga. It's been awhile since my last post but it's taken awhile to
collect this information...besides the weather has turned nice and I
was riding the thing. <grin>

I added Marvel Mystery Oil and then put several hundred miles on the
bike results:

- The intermittent clatter cleared up initially but now is pretty much
all the time
- With stethoscope isolated trouble to cylinder(s) 1 and/or 2 intake
valves

Since the clatter is all the time now that was a good sign for me
(makes it easier to diagnose). Anyway, decided to pull the cam cover
off and take a peek. Found a couple things.

- oil hole caps on intake and exhaust 1 and 2 cylinders in poor shape
- inspection and bleeding of all tappets revealed six of the sixteen
somewhat marginal
- visual inspection of everything else looks good

The oil hole cap on the intake was even out of place a bit leaving the
oil pocket open. (Of course the cap could have been dislodged when I
took the cam cover off but none of the others were. Anyway, the rubber
lips on both caps were cracked and broken in several spots. The intake
again was the worst.

Aha, says I. Since this oil pocket is supposed to keep the oil to the
adjusters from filling with air bubbles maybe this oil pocket cap
isn't doing its job?

Replacing the hydraulic adjusters was going a little overboard since
they really weren't too bad. I had some spares that tested a bit
better so installed them just for grins.

Ok, question...does anyone on this list have some spare oil pocket
caps? Do I need to replace these bad caps or maybe a good silicone
sealant will inject new life into the existing caps by sealing them on
the oil pockets? What do you think Dennis?

Thanks for all the help. This project is turning out to be kinda fun.

On Mar 16, 12:58 am, Dennis Hammerl <[email protected]> wrote:
> Good thought, however you used Sea Foam. That should have cleaned that up
if it works like they say it does. Do the MMO, I know what that does. At least
it will shift better.
>
> --- On Mon, 3/16/09, tharrisn <[email protected]> wrote:
> From: tharrisn <[email protected]>
> Subject: [Nighthawk Lovers] Re: NOISE cont.
> To: "Nighthawk Motorcycle Lovers!"
<[email protected]>
> Date: Monday, March 16, 2009, 12:26 AM
>
> What if there was a little varnish or other debris on the check valve in
the tappet. The varnish would allow the tappet to function "normally"
when fed pressurized oil but would "leak down" fairly easy thus
creating the clatter after a hot start. Just conjecture but interesting to think
about.  On Mar 15, 9:41 pm, Dennis Hammerl <[email protected]> wrote:
> If the adjuster had failed, no amount of oil pressure would make it SHUT
UP. If yours quiets down some times, what do you think ? > > --- On Sun,
3/15/09, tharrisn <[email protected]> wrote: > From: tharrisn
<[email protected]> > Subject: [Nighthawk Lovers] Re: NOISE cont. >
To: "Nighthawk Motorcycle Lovers!"
<[email protected]> > Date: Sunday, March 15, 2009,
9:08 PM > > Ok, it's get the oil pressure checked first. > >
It's gonna take me a bit to get back to this project. I'm helping >
escort a group of teenagers on a back packing trip. Should be fun...I > think
I'm the token old
>  guy? <grin> > > On Mar 14, 11:33 pm, Dennis Hammerl
<[email protected]> wrote:> A great question. Before we get into that,
I would call your attention to > > the location of the oil pressure
sending unit and the fact that the upper end > (cams, etc) are the last to
get oil. That's why I'm so aghast at gonzo > RPM starts. With that in
mind, it's not too difficult to see that the light > can go off (oil
pressure good) long before the critical upper end parts get > lube. Many
years ago  we would start a cold CB450 in the garage with no radio > on and
the door closed. At exactly 58 seconds after start-up, it would suddenly >
get very quiet. It took that long to oil the upper end ! Lets not speculate on
> any damage without a real pressure check first. I know that going anywhere
near > a dealer is like being condemned to hell, but suck it up and take this
variable > out of the equation.  In the end you may have to remove the head
cover just to > examine
>  the problem. Not yet. > > > --- On Sat, 3/14/09, tharrisn
<[email protected]> wrote: > > From: tharrisn
<[email protected]> > > Subject: [Nighthawk Lovers] Re: NOISE cont.
> > To: "Nighthawk Motorcycle Lovers!" > >
<[email protected]>> Date: Saturday, March 14, 2009,
11:02 PM > > > Would low oil pressure cause other noticeable problems
besides the > > tappet noise? > > > I know "idiot"
lights on cars are notoriously bad at indicating > > problems but what
about our bikes? I ask because the light comes on as > > it should when
turning the ignition on but promptly goes off when the > > engine starts.
> > > On Mar 14, 2:06 pm, Dennis Hammerl <[email protected]>
wrote:> > > This is starting to sound like > >
an oil pressure leakback, caused by #1 thin oil (from heat) or that #2
> >
>
 the Sea Foam has loosened up some grunge that is unable to escape from that part of the system since a I described, is not open-ended. Now on the #1 cause, I'd get a dealer to check its real oil pressure when hot. There is a screw in gauge that dealers have to do this.
> >
Shouldn't cost much to check. Low oil pressure can be many things. Don't panic. Since you didn't use anything on the second oil change we can't accuse anything of diluting the oil.  
> > > > > > --- On Sat, 3/14/09, tharrisn
<[email protected]> wrote: > > > From: tharrisn
<[email protected]> > > > Subject: [Nighthawk Lovers] Re: NOISE
cont. > > > To: "Nighthawk Motorcycle Lovers!" > > >
<[email protected]>> Date: Saturday, March 14, >
2009, 11:17 AM > > > > Doesn't sound like all the tappets are
noisy but a few and not > all the > > > time. They are the loudest
after the bike is
>  hot and sets for ten minutes > or so. > > I can almost
guarantee when I start it back up and take off the noise will > be > >
very pronounced until it eventually quiets back down after a mile or two >
> (quicker if I rev it a bit). They'll stay quiet until it idles for >
some time > > or I shut if off and start it again while still hot.
 I've changed > oil and > > filter twice now in 800 miles. The
first change I added SeaFoam (1/3 can). > > Second change straight engine
oil (Shell 5W-40 Rotella-T). I'll make > the > > next change using
Marvel Mystery Oil.  I've never used MM Oil before. > How > > much
can I safely put in the engine of this 83 650, or just follow > directions on
> > can?  Will it hurt anything if I continue to "soup up" the
> engine oil > > at each change with MM Oil no matter how long it takes
to stop the tappet > noise? > >  If I change oil at say 300 to 500
miles the next several>  times do > > I need to change the oil filter
>  too or can I skip to every > > > > > other change while
working on this problem?  I'm going to give the > engine > > every
opportunity to purge it's little gremlins before taking more > drastic
> > measures like pulling the cylinder head cover. But, I'm collecting
> some > > spare parts should I need to dig deeper.  You have helped a
bunch! Thank > you. > >  On Mar 13, 10:42 pm, Dennis Hammerl
<[email protected]> wrote: > > I > > guess I stirred
something up.  I did check parts sites and found no new > parts > >
available. (that puzzles me, I never used any) They don't wear out and >
you > > can purge them. There is a tool for purging the air that you
don't > need, > > just makes it easier. Let's start here; do
they (one or more) tap all > the > > time, some of the time, once in
awhile ? For the always and often cases, > you may > > have to remove
and purge. For the once in awhile, CHANGE OIL... then > change it > >
again. Get the nasties out. The
>  3K RPM deal is to force out the> > >  particle. In practice,
consider the adjuster like an oil pressure gauge. > > > > >
It's a dead-end that reacts to pressure. They do leak some out of the >
bore > > and back into circulation. I change my oil every thousand miles.
Comes out > like > > it went in. Seems a shame but the alternative
would be more so. My one > 700s > > started to tap on a trip and
without any option, I continued to ride it > home. It > > stopped some
miles later and I changed the oil next day. >  Never > heard from >
> again. Any top-end work and I remove them and place right-side up till I
> > reinstall. Somebody once tipped over a few and I had to purge them
before > > replacing in motor. If the problem persists and needs
attention, the > offending > > ones are easy to identify. To save time,
use a screwdriver as a > stethoscope and > > get a good idea of
it's general location. There should be no clearance > at > > any
valve. Since
>  they retain oil, the ones that are really hard to push > down are
> > good. Without oil, you are pushing against>  a spring only.
(still, a > > tough one) Now removing it is a chore. As I am > >
> > > want to do, I recommend to degree in the cams on any bike with
high > mileage if > > you have any reason to remove them. The results
are well worth it. > Bleeding the > > air out of an adjuster is a
simple process where you insert an object into > the > > hole in the
end and while holding it under in a bowl of oil, work the > piston > >
till the bubbles stop coming out. Hold upright and install. >  I once >
got a > > Hawk in that had been laying on it's side for a long time...
uh oh. It > > started and rapped like mad for about 3~4 minutes. Once it
quieted down, > we > > changed oil and filter, sent it on it's way.
You have to make the call > as to > > what you want to do / can do for
your problem. Everybody has thier own > snake > > oil, I'm going to
>  recommend Marvel Mystery Oil added to whatever you > use. > >
It's quite good at cleaning. One pint in my '86 700s does it for >
me. > > (that year has the largest sump) It is possible one could>
 fail, they > > are after all a mechanical device. That one would feel
> > > > > "not right" when purging. As in sticky, not
smooth.Or a broken > spring > > inside. > Any of this rambling help
?




      
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