hello from a state of disassembly.
- Thread starter lindie
- Start date
OK Sorry. It had not sunk in that they were the nine holes. If they are on the same PCD as the holes in a C3 then you could be right but if so check what is left of the plate for hardness. It is not the way I did it. Cheers
not to worry. the o-ring trick doesn't sound like a bad idea while i've got her in pieces.
got the bulk of whats to be painted in final primer awaiting a spare few minutes of my painter mates time.
and i've started cleaning up some of the alloy and it's responding nicely as you can see in the contrast to the centre piece:
not expecting miracles but she may at least wind up presentable.
got the bulk of whats to be painted in final primer awaiting a spare few minutes of my painter mates time.
and i've started cleaning up some of the alloy and it's responding nicely as you can see in the contrast to the centre piece:
not expecting miracles but she may at least wind up presentable.
heads and barrels are now off and disassembled for decarbonizing and a general clean up. could someone in the know tell me what compression ratio i'm dealing with via the cast numbers in the piston skirt please? specialloid slugs with h96 in the inner wall.
Compression ratio
I think that H96 is the casting number - differently machined, the same casting was used for several ratios. The number you need is stamped on to the piston crown, about 1/16" high letters. If you can find them they'll tell you the cr and the oversize. I have a set of original 7.3 pistons (E7/7AS) but those were Hepolite. Specialoids were E7/6 (standard rapide, 6.45:1) or E7/8AS, 8:1. At least that's what the spares list says. Bikes didn't always leave the factory exactly standard. I could take some basic measurements if the numbers have disappeared due to earlier decarbonising.
(When I got to this stage I fitted oversize liners, taking the opportunity to go back to + zero bores, and had sealed valve guides fitted. The bike was absolutely transformed, although the +20 pistons i replaced had only done a few thousand miles. The muffs slacken both with mileage (heat cycling) and with time: mine was rebored in 1969, next started in 2004.)
I think that H96 is the casting number - differently machined, the same casting was used for several ratios. The number you need is stamped on to the piston crown, about 1/16" high letters. If you can find them they'll tell you the cr and the oversize. I have a set of original 7.3 pistons (E7/7AS) but those were Hepolite. Specialoids were E7/6 (standard rapide, 6.45:1) or E7/8AS, 8:1. At least that's what the spares list says. Bikes didn't always leave the factory exactly standard. I could take some basic measurements if the numbers have disappeared due to earlier decarbonising.
(When I got to this stage I fitted oversize liners, taking the opportunity to go back to + zero bores, and had sealed valve guides fitted. The bike was absolutely transformed, although the +20 pistons i replaced had only done a few thousand miles. The muffs slacken both with mileage (heat cycling) and with time: mine was rebored in 1969, next started in 2004.)
had another fun day today. pulled and cleaned the gearcluster and it's housing for inspection while i've got the primary off. no apparent damage and all the inherent black goop that settles at the bottom of the housing is now gone. i like the nice user friendly slot they provided for the camplate, and ease of reinstallation.
out of interest, are the main cylinder studs prone to oil seepage past the threads as there was no visible sealant on them.
out of interest, are the main cylinder studs prone to oil seepage past the threads as there was no visible sealant on them.
Prudent, minor, gearbox improvements
What is strongly recommended is that one makes sure that the camplate pivot G34 is 1) tight in the casting, and tightened down fully, and 2) is wired up once it is fully tight. If it slackens, the (not particularly robust) boss it sits in has been know to break. I do know someone to whom this happened. There's quite a lot on this, problems and solutions, in Forty years On. Or maybe ATY. The spring G54 is not essential. And if you don't have it, it won't break.
What is strongly recommended is that one makes sure that the camplate pivot G34 is 1) tight in the casting, and tightened down fully, and 2) is wired up once it is fully tight. If it slackens, the (not particularly robust) boss it sits in has been know to break. I do know someone to whom this happened. There's quite a lot on this, problems and solutions, in Forty years On. Or maybe ATY. The spring G54 is not essential. And if you don't have it, it won't break.
the spring is still there and springing nicely. the wiring up aspect has me a little confused. the previous assembler had simply filled into the cavity where it threads into with some form of wonder sealant that was a pig to remove and precluded any movement. would punch locking and/or perhaps a thread locking medium do?
where would one feed the wire?
all the g2 and the g37 fasteners were wired but theres room around them for such.
where would one feed the wire?
all the g2 and the g37 fasteners were wired but theres room around them for such.