Nasty tinking noise on warm engine

[cgrigson]

Dear all,
I bought a rather nice '79 strada recently, it's a very clean low mileage import. I drove it home and it pulled very well, better than my old K2 as I recall but the clutch was dragging at idle and there was no play at the lever. If you adjusted some play into the lever the clutch would not disengage. On inspection the clutch plates were glased and the thin friction plate had been replaced with a thick one. I fitted a new clutch pack but still could not adjust the clutch. Out came the clutch center and I found there was no washer or shim behind it! The raised rivets on the back of the clutch center had been happily wearing away the metal of the clutch basket! Luckily no visible damage had occurred to any supporting surface but what the primary drive thought about all that end float I just don't know. I noticed one of the clutch spring pillars had also been replaced but the clutch pressure plate lifts smoothly and evenly so this seems ok. Anyway I reassembled the clutch properly and shimmed it up. There was some rock to the basket, about .5mm at the edge with the clutch center removed, but very little afer shimming.

I have also cleaned the carbs and adjusted the tappets to 0.1mm, they were all about 0.25mm. The bike now runs ok and you can almost select neutral at a standstill. However as the bike warms up a tinking noise develops whenever the bike is not under load that is clearly audible at some distance. The noise seems in time with the engine and sounds like a very loud tappet. I have made the noise disappear occasionaly by operating the clutch but it soon returns. Using a screwdriver as a stethoscope the noise seems to come from the upper primary drive area but this is not a very reliable method. I have a Ducrappy and the noise doesn't sound anything like the horrendous clutch on that or like the clutch rattle on my old K2.

I've fitted new carb inlet rubbers and air filters. I was surprised that the engine no longer responds to the idle mixture screws unless you make it run on that cylinder alone when they set best at about 3/4 turn out.

Can anyone suggest any solutions?

Maybe I should write this up as an article for the mag... The pics of the damaged drum are rather good!

Thanks

Chris

[trianglevee]

First sign of a gudgeon pin machining a groove into the bore after failure of circlip? Best to assume the worst and check.

Stuart Tallack gloomy as always

[cgrigson]

Stuart,
Are you kidding me for worrying about a little noise or do you speak from experience? Please do share...

Chris

[trianglevee]

I am afraid it did happen to me once. I sold a Strada about twenty years ago and a couple of years later, it turned up locally owned by somebody with very little mechanical sympathy. I bought it back and rode it over to see Jon Barnden who was then editor of ATG. It was making the faintest tinkling noise and we discussed what it might be, Having decided on the basis of no evidence and a lot of ignorant optimism, we agreed I should ride home. By the time I got there, it sounded like somebody in the next room tapping two teaspoons together. At that time, I stripped down anything if it gave me an excuse so I took the barrel off. One scored... no! grooved... barrel. A milling machine could not have done it better.

I blamed the previous owner's cack-handedness, but I suppose it was my fault. The golden rule is that if you take a noise seriously, it will have a cause which is of no importance at all; if you ignore it, it will be the first sign of terminal disaster.

Always happy to cheer people up. Actually, if the noise does not get louder or change its nature, it is not likely to be the pin. On another make, a broken gear selector spring sounded as though it were coming from the cylinder. Have you tried using a metal bar as a stethoscope?

Stuart Tallack