She was getting very noisy with the din obviously coming from the tappets.
Reset Tappets to .004” and .006” with engine cold.
Success, quiet as a guzzi is expected to be.
2 days and 50 miles later, rattle was back.
Further checks to pushrods for straightness, belling at ends, no obvious faults or wear.
Deeper investigation to camshaft and followers needed.
Put Triking onto build stand.
Drain oil.
Remove engine leaving gearbox in situ.
Remove heads and cylinders to give access to cam followers.
Cam followers found to be worn to concave, which in turn had rounded over the cam lobes.
Before stripping the timing gear to remove the camshaft, I made up a flywheel locking toothed plate to set the engine to tdc compression on left cylinder, the cyl used for valve timing. (Also needed to lock engine for torquing crankshaft and camshaft sprocket nuts back on)
Remove oil pump nut.
With timing marks on sprockets lined up, it was possible to remove the timing chain and sprockets all in one lump, thus avoiding a struggle setting up later.
Remove camshaft retaining plate to remove camshaft.
Cam followers worn and pitted concave.
Cam lobes slightly rounded over.
Oil ways in rockers spindles totally blocked.
The amount of oil getting to the rocker spindles was sufficient to keep them lubricated but not enough flow to run down the push rods and lubricate the cam and followers.
Engine oil and sump clean, filter cut in half, nothing adverse noted.
Cam bearings all ok, pistons, rings and barrels fine with no wear.
Reason for blockage.
Rocker spindles are held in place by M6 x 14 bolts. 3 were 16 long and 1 was 18. The 16s didn’t block the oil way but the 18 was a baddy.
The main reason, I believe, someone had used a sealing compound on the oilway junction between head and rocker assembly casting. This had squeezed into the oilway, enough being flushed through to the smaller holes in the rocker spindle starting the blockage.
Moral here: Don’t use any sealant on metal to metal oilway junction.
To clear the completely blocked spindle, I drilled out the peened over aluminium end plug, these turned out to me M5 threaded. 2 came out easy with an ‘easy-out’ others had a 4mm drill in them then M5 tap to clear.
Re-plugged with 5mm ally dowel, threaded M5 long enough to bottom out in hole without going too far into the M6 threaded cross hole. Screwed in tight using grips, threadlock used, saw off 1.5mm long then peen over with hammer. Check M6 hole clear and clean up with tap.
Good set of cam followers acquired.
Spares needed.
Oil filter
Sump gaskets
Cylinder gaskets
Head gaskets
Set of head bolt O-rings
Rocker box gaskets
Timing cover gasket
Crankshaft/timing cover oil seal (No. W14911027 28-38-7)
5mm ally dowel for rocker spindle plugs
4 M6 x 14 Hex bolts + Schnorr washers
Re-building went ok, only special tools needed is a long 32mm socket for the crankshaft/sprocket nut. Here’s one I made when I was a boy, doubles up as the adaptor for the allen key used to torque the socket head cyl head nut.
With the cam drive chain held together in the correct position, with timing marks aligned, the crankshaft sprocket is located with a woodruff key, camshaft with a round dowel which makes alignment much easier. The oil pump has a square key which can be pushed in after sprockets are on.
With the toothed plate still locating the flywheel, torque the crankshaft and camshaft nuts to 110 ft/lb.
Leave the timing gear exposed till the next day, then torque down again.
Fit a new oil seal in the timing cover, for £5 it’s not worth skimping on this.
When fitting the barrels, don’t forget the O-rings go under the cylinders on the short head studs and on top of the heads on the long ones.
T make things easier, tilt the engine to one side so that piston is pointing vertical when fitting a barrel. I put 2 pieces of 10mm square timber under the piston skirt for support, then with suitable ring clamp, lower the barrel on.
Fit the heads and torque down to 30 ft/lb.
Don’t be in a rush to fit the rockers, leave till the next day then torque head bolts again. Probably go another 5-10deg.
Remove the toothed plate from the flywheel to rotate engine for rocker fitting.
Conclusion.
With an engine that may be 20-30 years old, someone may have been in there before you. When checking the tappets, may be worth removing the rocker spindles and checking the oilways. Just saying.
Constructive criticism welcome.
