Tappety Noise

Torontonian said:

Mine blew at 12000 kms . too . Limped home slipping the clutch in 2 nd . gear .
Always replace the bearing on the layshaft if it's an unknown history bike . Roller is my choice .

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Mine blew at 12000 miles not kms.

Hi again,

I've reconditioned the gearbox with new bearings and bushings (two of the bushings were pretty knackered), and started putting the bike together again. However, I then decided to try turning the engine with a crank, without the primary and gearbox connected, and guess what.... there is still a "dock-dock" noise....

It occurs at exactly the same position, every two turns of the crank, so it must be something cam-related. There is nothing suspect under the timing cover, so I suppose I'll start pulling the head and cylinders...

Cheers

Esben

Before you remove the head, Take off the valve covers, so you can see if there is any erratic movement as the vales open and close, You could put a finger on each rocker arm as it travels the full range of motion to feel or hear any change in the sound,.

Just taking things apart "blindly" can hamper finding a solution. Once I had a strange noise in my MK3, Lucky I tracked it down to a bent tach drive gear. Without me being lucky or clever or both , I could have taken the engine apart and never figured it out.

Have a helper turn the engine back and forth at the place where the dock- dock is and go around the engine with a listening device and track the location down.

I did check various things first, including the tach drive, but then pulled the head and barrel.
The LH piston must have seized at one point, because it's completely toast. The RH looks almost brand new....
Also, it's 74mm, so max oversize.
Oh well, new barrels and pistons it is.

On the positive side, the engine does have Carillo rods!

Cheers
Esben

Fastback-DE said:

I did check various things first, including the tach drive, but then pulled the head and barrel.
The LH piston must have seized at one point, because it's completely toast. The RH looks almost brand new....
Also, it's 74mm, so max oversize.
Oh well, new barrels and pistons it is.

On the positive side, the engine does have Carillo rods!

Cheers
Esben

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Jim Schmidt does 74.5mm forged pistons for standard length rods. Choice of CR too…

DennisMo said:

The Fiat 124 was a 5 speed double overhead cam which was quite something for its day. It had a timing belt, not chain, that needed changing. Two barrel Weber and cruise control consisting of a knob on the dashboard that was a throttle cable. One pulled it out and twisted the knob to lock it! I added an electronic ignition which was a new thing in that

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DennisMo said:

The Fiat 124 was a 5 speed double overhead cam which was quite something for its day. It had a timing belt, not chain, that needed changing. Two barrel Weber and cruise control consisting of a knob on the dashboard that was a throttle cable. One pulled it out and twisted the knob to lock it! I added an electronic ignition which was a new thing in that day.

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My mate had one , it was a beautiful car , I always wanted it but he wouldn't sell. I ended up with a Lancia HPE (with no rust !) that was a great car for me

could you have engine pinging instead of something loose I've just developed a similar noise on my 71 750 roadster. I'm checking my timing and if that is OK i will drop the fuel and refuel with some octane booster. At the moment Australia is accepting fuel from anywhere in the world and may not be the same quality as we are used to.

Fastback-DE said:

Maybe... I haven't dared giving it the beans....

Apparently, the engine had been rebuilt not that long ago by a specialist here in Germany, but I only havr a handwritten note to prove that. But it included Carillo rods, forged pistons etc.

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Your forged pistons likely, 4032 will have more clearance,than cast these are good though.

Fastback-DE said:

I did check various things first, including the tach drive, but then pulled the head and barrel.
The LH piston must have seized at one point, because it's completely toast. The RH looks almost brand new....

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What was it that caused the "dock-dock" noise? Just curious.

- Knut