SF3 sudden tappety noise

M

macavity99

Full member
Location
Bedfordshire, UK
Another problem, not a happy motorcycle.

On way to work today, overtaking hit a false neutral at about 40mph. Over-reved a little but not too much. Then a new noise appeared, sounds like a very loose tappet. Turned around and rode bike home. Not smoking, performance not bad so think both cylinders are firing. Put SF in garage, got on Honda and went to work.

Difficult to speculate but anyone experienced anything similar and can offer any ideas what's happened? If I'm lucky it could actually be a loosened tappet adjuster? Realistically, I'm expecting an engine out job.

Ideas?

Cheers, Steve in UK
 
Same thing happened to Craig on the way to the Alpine Rally a few years back.  Revved the snot out of it up a hill close to the rallysite, suddenly started making tappety noises just before pulling up.  The locknut had come completely off the adjuster, but was just sitting in the valley in the head just below.  Was diagnosed and repaired before the first beer was finished, literally in less time that it would have taken you to write your message.
Go take all the tappet covers off and have a look, takes no time at all.  There isn't much else that usually goes wrong, only the camshaft key (or more correctly loosening cam flanges since the key should only be for initial alignment) but that usually comes on more gradually.  If the tappets are ok then take the cam end covers off and feel both sides while someone else winds the engine over, you'll feel one side move in relation to the other if the flanges are gone.
 
agree entirely with Steve, but don't fall into the trap that I did on my SF1 a few years ago.

Exactly the same scenario, I rode to a place of safety and took off (by chance) the correct rocker cover, a tappet is an item that follows a cam, but who cares they always get called tappets, and found one very loose adjuster, so took out the plug , found TDC (ish) and readjusted the clearance, all looked good and I rode on, but the noise very slowly returned, so I reset and again the same happened, around four times and then ceased. It was not until some years later that I was stripping the complete motor that I found the cause! the hardened tip of the valve in question was lying in the bottom of the crankcase and that valve had burred over and would not pass through the valve guide without assistance from a 4.5 inch grinder.

So check carefully that the adjuster thread is poking through the rocker at roughly the same dimension as the other valve of the same type.

CLEM
 
Just removed all the rocker covers and yes, the LE tappet adjuster and nut are missing. (Surprised it can run that well in that condition, these old bikes are tough!) Have retrieved the nut. Have fished around with a magnet but cannot find adjuster, maybe washed down camchain tunnel by oil?

Here is a valuable lesson in not missing out scheduled maintenance. I missed the last service as I couldn't be bothered, and here is retribution. End of lesson from Saint Steve.

Next step drain oil to see if the adjuster comes out of the sump, unless you guys can suggest anything else first?

If it doesn't I really do not want to strip the engine to find it. Just order some spares and hope it never gets anywhere it should not.

Cheers, Steve in UK
 
Help me out here. Remembering when I took cyl head off for a rebore job and looking at the engine drawings, the adjuster cannot fall down the camchain tunnel. Correct?

The L-camshaft/camchain/R-camshaft are in three separate compartments. There are walls between left camshaft/rockers and camshaft sprocket, and between right camshaft/rockers and camshaft sprocket. The left and right camshafts pass through bearings in the dividing walls but there is no other communication between the three compartments.

Therefore the missing adjuster MUST be in the left camshaft/rocker compartment. Yes?

Cheers, Steve in uK
 
Goodo.

But I really do think it's impossible for it to fit through the small drain hole under the inside cam bearings anyway, so it had to be there.
 
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