92 750 Honda Nighthawk ticking

My bike has been making this ticking sound which sounds like its coming
from the top half of the engine on the right side. I tried to pin it
down as to the exact location but its inside the valve covers closer to
middle on the right I think. Just a tiny tick, tick, tick Im guessing
one tick per revolution. There are no performance issues that I have
noticed but the ticking noise has me concerned. Can anyone give me
some ideas as to what this may be?

 

In the past, when I've had this, it has always been a valve shim that
needs replacing because the gap has opened up,

But the Nighthawk uses hydraulic tappets, right?

If it's only at tickover (erm, as it were), it's probably just camchain
noise and I'd ignore it, but if it continues as the revs rise and keeps
pace with the revs, then I'd be tempted to have a look inside the top
end.

 

Ummm ... good point, same thing as a CBX750, right? The XLV used very
similar hydro tappets and did this occasionally ... I think it indicates
an eeny bubble in the tappet. The noise generally seemed to go away
when I changed oil & filter, but that might have been a coincidence I
suppose.

Worth keeping an ear on, though.

-----sharks

 

From what I read about the bike before I got it, there was some mention
of self adjusting valves. What this means in a mechanicly technical
term I dont know. The tic does follow the rpms to a point, the higher
the rpm the less evident the noise is, but maybe because the noise
drowns it out.
I made it to Laconia this weekend, a 400 mile round trip with no
problems.

spark plugs. Not sure if that has anything to do with it, but I'll
change the oil and see if that helps.

 

That's right - the hydraulic tappets are self-adjusting.

However, wear has been known - a friend ran an XLV750 (referred to by
Sharkey) and that started tapping from one cylinder. The cam followers
had worn and needed replacement.

 

Oh feck, just took my XLV for it's MOT[1] on Friday & it's tappy :-(

On the bright side, I've got another XLV for spares so I might even have
replacements waiting - but only might, the spares bike had sat in a
garden in Glasgow for 4 years & had a sump full of oily water. Still
turns over (after I freed off the seized back brake[2]) but I haven't
bothered connecting a battery to see if she'll start.

Bob

[1] Failed - leaky fork seal (was fine when I set out) & binding brake
(I just looked at the rusty disc & neglected to check further).
Annoyingly minor things but OTOH taking it for an MOT let me run it for
40 miles over hill tracks so I know the rest of it works. Not bad for
something that lay in a barn near Didcot for 5 years before I bought it
& only got a battery & some fresh oil. Might run some carb cleaner
through it next trip for an MOT.
[2] It's amazing - damn thing was seized solid, gear lever wouldn't even
move, dismantle back brake & it suddenly gained a complete set of gears
& would turn over despite all the water in it's innards

 

I *think* the Nighthawk has a fully automatic tensioner, actually.

 

I took the bike over to the dealer to get it inspected and I asked what
the ticking noise was while he was giving it a look over, "he said its
probably the timing chain and there should be a tension adjustment to
advance it a "click".
Anyone have a diagram that shows where this adjustment is?

 

I took the bike over to the dealer to get it inspected and I asked what

By some further investigation, i think the "timing" chain is the same
as the cam chain. If this is the case, than it is supposed to have an
auto tension spring to tighten the slack. The bike has 9000 miles on
it so I dont think the chain could have stretched that much, but I
guess I'll try to pin the tick down to a location with a stethoscope.

 

The timing chain is the camchain, yes. And it should be automatic, but
they do stick from time to time. Especially if the bike has been
standing for a long while.

 

Hmmm, odd. Wasn't oil-starved, was it? Might just have been unlucky, I
suppose. Most of 'em seem to die from exploded gearboxes or broken bigends.

The ticking my XLV had was no louder than, say, an Airhead BMW, and it
came and went ... for about 50,000km.

If this Nighthawk is _always_ ticking, it's possibly reached the end of
its adjustment though, as T.O.G. suggests, but with any luck it might
just need flushing or shimming.

This might be useful to the Nighthawk guy:
<http://teamrc17.net/tech/maintenance.html>

And this might be useful to Bob with the new XLV:
<http://zoic.org/sharkey/moto/xlv/>

-----sharks

[if I've just sent 107 copies of this message or something, it's all
Thunderbird's fault.]

 

If this Nighthawk is _always_ ticking, it's possibly reached the end of

I changed the oil but no change in the tick or more like a tack. It is
more evident in neutral I imagine because there is no strain on the
chain. I cant imagine the chain would have reached the end of its life
with only 9000 easy miles. Arrgh, and Im certainly not up to taking
the motor apart, maybe if I hang it upside down for a day.......

 

Chain? The camchain ain't slack just because you're in neutral ... and
the Nighthawk is a gear primary. There's an alternator chain too, mind
you, which has proved troublesome to others ...
<http://teamrc17.net/tech/projects/chains/index.html>
(I'm the hairy assistant in the first set of photos ... it's a small world)

If it's getting more tack than tick, I'd be planning to pull the
head cover off and have a look. Not terribly difficult, but you might
have to pull the motor out of the frame. At least then you'd be able to
have a look at the followers and flush the hydro adjusters out. Don't
get the hydros or their shim stacks mixed up though ... and yes, there's
16 of the buggers. A piccy of the XLV system is at
<http://zoic.org/sharkey/tmp/p21-6.jpg>
The CBX is similar, I think.

If you want more info, email me direct ... I'll quit rambling on about
this here!

-----sharks

 

Well, I got a second opinion from two other bike mechanics that dont
work for a dealer. Theyve been in the business themselves over 20
years. The guys said its very unlikely that its the cam chain due to
the mileage of the bike and more likely a sticky valve. They said to
try synthetic oil and maybe some additive to help clean the valves, and
possibly synching the carbs might help too. I wanted to get some other
opinions on this before I try it.
This may not have anything to do with it, but I remember when I changed
the plugs last year, thats when the noise started. Maybe some dirt
fell down in the chamber?
If I go with synthetic oil, should I go the full 3 quarts or just a
mix?
If I get an additive to clean the valves, what would work best?
Would a carb synch help?

Thanks in advance..

 

The so-called 20-year mechanics are ignorant arseholes.

hth

 

The so-called 20-year mechanics are ignorant arseholes.

I take it you dont believe them... Im gonna try some valve cleaner
anyway, certainly wouldnt hurt. I just dread the thought of taking out
the motor. I've torn apart a bunch of older 80's CB750 motors, but
they all had the cam chain adjustment doo-hickey just in front of the
carbs. Mine is all built in and if it is the chain and not just the
tensioner, I have a feeling I'll be selling the bike for parts......

 

Certainly won't do anything, either.

 

*looks back up thread* You mean "9000 easy miles" is the poor thing's
entire _life_? I just assumed it was a euphemism for "not serviced
since the speedo cable broke."

My money[*] is on a gummy hydro tappet. One possibility is to get into
the engine and look, but alternatively you can try changing the oil
completely for a good synthetic, Motul (mumble) worked well on the XLV.
Yes, change all of the bloody stuff, not just top it up. Do the
filter too you cheap bugger. A good hard run with nice, fresh oil might
degum the tappet, who knows.

Then flog the thing mercilessly until it either explodes or doesn't.
It's too young to die.

-----sharks

[*] Virtually speaking.

 

You speak truth, young sensei. Sticky valve, my arse.

 

Best wishes for a speedy recovery.

-----sharks .