speedrattle
Well-Known Member
nice start
1972 T120v Disassembly
- Thread starter saig55
- Start date
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You cannot, the cam follower part of the tappet is much larger than the part through the tappet guide block.
Yes. See the indentation around each tappet? Before lifting the cylinder block off the crankcase, put either a rubber band around each tappet or one band around both tappets.
You're going to have to change the bearings, which means splitting the case anyway. That level of corrosion inside...
This is one of the cleanest inner primaries I've seen on a bike displaying otherwise typical grime/grunge/rust/sludge/skank everywhere else...
So, have you measured for up/down play in the main bearings? What about rod 'shake' or side-to-side movement, measured at the rod at its highest portion--where the wrist pin goes through?
With roller bearing big ends, as on my '51 FL Harley, at this stage you measure up/down slop at the top of the rod (or piston crown), then rod 'shake' from side to side, at either the highest point on the rod you can with pistons fitted, or at just below the wrist pin hole if not. Specs are provided for each measurement. (On my 73-year-old engine, those were within spec, so I just honed the cylinders, installed new rings, and rebuilt the top end.)
However, the shop manual for this bike has no such diagnostic methods or specs (that I've found, anyway--someone can pipe up and show them to you if I've missed them).
If that's right, the only diagnostic method I'm aware of is checking oil pressure, which with shell-type bearings reflects the clearances at the bottom end--if a somewhat gross go/no-go measure. But of course you can't do that until your engine is running--a bit of a catch-22 at this point.
The shop manual does have a useful passage for this stage, if you're going to reassemble without taking apart and measuring the big end bearing clearances--or rolling the dice, as it were: "Prior to refitting the cylinder block, pour approximately 1/4 pint of oil into the crankcase."
This is purely my predilection, but since you've gone this far and the bike has sat for so long--and given the visible wear on the pistons and bore, and corrosion you've found, plus the silicone residue at the cylinder base mating surfaces--I'd dismantle it and start from scratch. Bearings are cheap. You might measure and inspect the cam lobes and oil pump, too. All it needs is a very cheap ball and spring rebuild kit, if the sliding drive block isn't worn out.
speedrattle
Well-Known Member
dont ever trust that the bottom end was actually rebuilt. or maybe it was, and done wrong.
you want to get the crank out to clean the sludge tube.
you want to get the crank out to clean the sludge tube.
Lordmac
Well-Known Member
Wow, what a project. I am pleased though, to see yet another humble and tired and dead Triumph being brought back from the grave. I personally love restoring seemingly impossible projects - far worse than yours - and having the joy of firing the rebuilt engine and going for a spin. No new bike gives more satisfaction. It's bliss, I tell ya.
Amen. To each their own, of course, but new bikes leave me cold. Give me a 50- or 70-year-old bike, a fistful of wrenches, some shade and a cuppa coffee, and I'm happy as a clam.
speedrattle
Well-Known Member
my newest bikes are a 17 year old 250 ninja my kids race and a 27 year old tube frame buell. beyond that theyre all at least 50 years.
the new bikes are spectacular and amazingly competent machines but they dont do what im interested in.
its like in racing. i line up at the racetrack behind machines that i watch do 240 mph in the mile. then i pull up on something almost 60 years old that struggles to pass 135. i am vastly more interested in hunting 140 mph on a 650 triumph than i am going 200-plus on a ZX14.
the new bikes are spectacular and amazingly competent machines but they dont do what im interested in.
its like in racing. i line up at the racetrack behind machines that i watch do 240 mph in the mile. then i pull up on something almost 60 years old that struggles to pass 135. i am vastly more interested in hunting 140 mph on a 650 triumph than i am going 200-plus on a ZX14.
Lordmac
Well-Known Member
Yeah, what I'm sayin. Recently I test-rode a 2023 Bonneville 900 and though it was nice enough, my "78 Bonnie just does it for me. I've had her completely disassembled twice-and-a-half since I bought her new, and there is not much I don't know about her workings. With the exception of this one, every bike I ever owned was got as a basket case.
Lordmac
Well-Known Member
I agree. As long as one's got the thing fairly disassembled, it really isn't much of a stretch to go all-out and be absolutely sure as to what has, or has not, been done to the bike. Some parts don't wear much while others gotta go; timing side ball bearings being one, in my experience.
