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[Old Plonker Mike]

Just as it was all going so well, That noisey valve gear got so noisey that I had to adjust it. It had milimetres of clearance. (not sure whether that is senility taking effect on assembly or whether it had worked loose, but I have my suspicions).Wth the tappet so loose, I thoguht I needed to investigate, so uncovered the rockers, and noticed there had been contact between a pushrod rim and the armpit (for want of a better word) of the rocker. I dressed back the lip of the pushrod, and had a look at the rocker. it was a bit far round in its starting position. I think I have changed the valves and failed to check all the dimensions afterwards, and it could now do with a few milimetres off the bottom of rocker block. Anyway that all replaced, and valve clearances set, I did an oil and filter change. What nice pretty oil - with a sparkly metalic gold look, like one of those fancy shampoos. Anyway with everything set up sensibly I took it out for a ride again, and tacka tacka tacka, the noise starts as the engine speeds up around 2000 revs I guess, and goes away again at idle. At 70 though you cant hear it at all.

is the answer
A - always ride at 70mph,
B - buy ear plugs,
C - blame it on piston slap,
D - stop hiding from it and just get a new big end fitted,

I guess the valve gear is relatively quiet on these even when badly adjusted.

[Adrian]

Is one of your valves missing a valve stem cap? If you had a failed big-end it would be knocking at all rpm, though a failING big-end that hasn't fully gone would be shedding metal particles - were they magnetic or non-magnetic? With that going on check your rocker feed pipe and rocker assembly oilways for blockages caused by said particles, the gauze strainers fitted to the crankcase plugs only filter out the bigger chunks. Blocked oilways on the rocker side will put extra load on the scavenge pump, ultimately causing the oil pump worm drive to fail leaving you with no feed to the big end (and cylinder wall) either.



If the primary chain needs adjusting you may well have the adjuster screw head clattering against the primary case, quite a racket but not always present.



A.

[Leon Novello]

I would blame Global warming, and go down to the pub.

[Alan R]

Hi Mike,

Oh dearie me...the saying "All that glitters is not Gold" comes to mind here..... as it's probably Bronze flakes that you are seeing....Whitemetal flakes from the big end tend to be silvery in colour...(unless you have a Bronze bush big-end instead..)

What bike model are we talking about here ?..In any event ADRIAN's advice about checking your oil feed pipes etc is sound...If it's an Iron barrelled Classic then ALL the scavenged oil is passed up to the rockers via that external pipe, unlike other Brit. designs where a tee-piece tapping off the scavenge return feeds a small amount of oil to the rockers etc.. You already know what you must do }--- Head and Barrel off and check-out con-rod lift etc..

---only then can you go and join LEON down at the Pub as he's getting the first round in !!

[Beezabryan]

Regarding the valve problem two things come to mind -
Adrian has a good and very likely suggestion "Is one of your valves missing a valve stem cap?"
If it is exhaust valve and it is an older iron barrel engine with soft valve seats then I might suggest valve seat recession.
for the other problems Adrian advice is sound as is Alan R

[Bullet Whisperer]

Hi Mike, the noise could be backlash in the timing gears. If the engine is quiet when cold and quite suddenly gets clattery when it gets hot, it could well be the cam gear teeth that are responsible. Taking the timing cover off while the engine is hot could verify this. Fitting eccentric cam spindles can fix this, but I don't like them much myself. Regards, Paul.

[Old Plonker Mike]

I am glad I posted this, everyone is making me think - something I have obviously become unaccustomed to. The valves I think are some of those that don't have caps fitted (unless I goofed). I never checked with a magnet to see if it liked any of the bits in the oil, as they were a lovely golden bronze colour, and I assumed the big end was a bronze bushing ? Some of the crud from the oil tank/sump actually managed to block the strainer in my funnel while bottling the oil. The bike is an Indian built 500 Lightning. I never thought what the bearing was made of. Are they normally white metal ? I dont' believe this bike has ever been in the hands of someone who would swap the big end. It has done around 10k recorded miles (plus speedo broken miles). I didnt see anything too scary when I cleaned the strainers in the sump and oil tank. Watching the rockers while running the engine showed lots of oil being pumped out, so not too worried about oilways being blocked. It has big oil pumps too. I think I should take it for a rattle again to remind me just how it goes. I am inclined to agree with Leon - first hurricanes and now big ends, scrap that diet and get some beer in before the end.