Louder (than normal) valve noise at idle

[tunnelrider]

Hi everyone,

With the engine at operating temp in mid summer I'm getting a random loud metallic chatter from one valve on the right cylinder at idle, sounds like a valve hitting something alloy-ish.
The metallic noise comes on and off at random for 2-5 secs while idling, matches the normal valve rhythm, is very noticeable at idle but not at all while under load and produces a wee duff exhaust note if right up at the back of the exhausts pipes. It doesn't seem to be occuring under way or when the engine's cold.

I've checked and adjusted the valve clearances (the last time was 11,000km ago, gee, already?!), topped up the engine oil and opened up the idle mix screw a little, which have all had no effect on the problem.  The bike runs normally otherwise but I haven't checked the timing lately.

I feel a bit lame for posting this as I'd like to have investigated a bit further before posting, but I've got a licence test in a few days...!

Thanks for any advice,
Dan.

[Barry]

Rocker shaft end float ?  what's the adjustment method on an 85 are they shimmed ?

[tunnelrider]

Hi Barry, thanks for your reply.  Yes the '85 rocker arms are shimmed.  I measured the rocker arm end floats when I did the valve clearances. On the problem cylinder the intake end float was .229mm, the exhaust was nil.  Perhaps this should be more?  I haven't adjusted the rocker arm floats since owning the bike and put 20 000km on the clock.  The valve noise has always been pretty noticeable but there is a problem noise now (prob started approx 1000km ago).

BTW, the left side which doesn't have the valve problem have end floats of .254mm (intake) and 0.074mm (exhaust).

[georgesgiralt]

Hi,
I won't alarm you, but you should remove the valve cover.
Why I say that ? Because last time I had this noise on my R65 it was because I had broken a valve spring.
And I stop riding just before the valve broke due to that...
But YMMV

[tunnelrider]

Hi georges,

Yes so you're familiar with the noise.  Dammit, I didn't want to believe it would be a broken spring but you're right, I need to assess whether it is. I have to admit I've been riding her as fast as she'll go before this problem. I'll check tomorrow, thanks for your reply.

[Matt Chapter]

When I broke an exhaust valve spring, the performance hit was noticeable.  I did not notice any noise before hand, but I wasn't necessarily listening for it. The spring broke at start up, though.  Parked the bike at the office, was a normal (fast) commute in, going home was brutal.  Probably shouldn't have ridden it in that state.

[tunnelrider]

Thanks Matt for your input.  Unfortunately I didn't get a chance today to have a closer look at the rockers and springs, will try my luck tomorrow, if my better half doesn't mind me spending time with my other girlfriend in the garage on Valentine's Day...  
In reply though there hasn't been a discernible difference in performance or exhaust notes while riding.  But she's gonna be parked up now 'till I find the cause.

I need to buy an exhaust nut spanner too, anyone got recomend's?  I've avoided this so far as the postage to NZ will prob. be more than the spanner.

[georgesgiralt]

In order to check, you only need to remove the valve cover.  It takes 5 minutes each side. Then you can decide if you have to remove the heads or not...

[mrclubike]

This is the one I have
The  compact  size  may not be as bad to ship as some others
http://www.cycleworks.net/index.php?main_page=product_info&cPath=29_33_51&products_id=346

[Justin B.]

Why would the head need to come off for a broken valve spring?

[georgesgiralt]

Well IF it is a broken spring !
Once the noise origin ascertained, the OP will have a decision to make.
If the spring is actually broken, and he has ridden the bike, the valve and valve guide could have suffered (this is what I saw on my head). Then, if this hypothesis is correct, the head should come off.
But we are just speculating here.

[Justin B.]

What kind of damage did you see, George?  I've had to remove valve springs in a V8 and just needed to bring the piston up top to keep the valve from falling all the way in...  Actually, kind of stuff as much 1/4" nylon cord/rope into the cylinder then crank the piston up a little...

That being said, if you suspect damage on piston side of the head it would need to come off.

[mrclubike]

Even if he doesn't need to remove the head at  this time .
 It is still a good idea for a Airhead owner to have some of the basic special tools handy.
The exhaust nut wrench is one of them.
The rotor removal bolt and swing arm bearing  socket are others.
I almost forgot the heat gun

[tunnelrider]

Hi again,

Mrclubike that's right, an airhead owner should have an exhaust nut spanner.  I've been meaning for a while to sort out the low compression on this cylinder, which was existing before the noise.  If it was winter I'd be getting right into the barrels.  I want to replace the piston rings, the base gasket O-ring is leaking and I've expected something to be done with the valves.  But anyway with the rocker cover off there was the following:

- The R65 on the centre stand is able stay upright through a 5.7 earthquake centred 10km away (no s&%t!)

- The valve springs are not broken although the exhaust spring has been installed up the wrong way, with the painted end towards the rocker cover.

- There were a few metal filings, magnetic, on the rocker arm support blocks, mainly the intake side.

-  The intake rocker arm has a larger shiny area where it is pushing on the valve, due to the larger axial play, than the exhaust (see photos).

- The exhaust push rod has a few marks along it but no gouges have been worn in.

I'm thinking my next step should be to order a few shims to reduce the intake rocker arm axial play and see if this makes a difference.

Because the four nuts holding the valve rockers are off, oil has weeped out of the barrel base o-ring gasket.  Can I just tighten up over this?

Cheers for all of your input, you guys are great.
Dan.

[tunnelrider]

Uh oh, the brutal (big up's Matt) ride back home, the ride from hell where you just want to ride into a hole and come back out with a broken shoulder to think about rather than a broken bike!  I now know what it's like...

Against all good wishes (and thanks for your advice George) I bloody put the rockers back on and took her for a test ride up a hill so I could sit my full bike license today. After starting alright I clanked back home at 40km/h.  Well I knew I was asking for trouble but kinda hoped I'd be lucky!

So I'm gonna get stuck into the barrels, just like it was winter! But I cant tell what or how bad 'till I get an exhaust nut wrench. I can see by looking down the spark plug hole that it's very oily in there, I'm expecting a whole lotta trouble. I'll probably post again when I'm climbing out of the hole, hopefully without the spade.