Triumph Rat Motorcycle Forums banner
  • Hey everyone! Enter your ride HERE to be a part of this month's Bike of the Month Challenge!

1 - 20 of 20 Posts

·
Registered
Joined
·
118 Posts
Discussion Starter · #1 · (Edited)
The engine (`70 T120R) cranked over very easily while everything was together. After removing the head I found a light rusty surface in one cylinder bore but still, it cranked over very easy. Now I'm trying to remove the cylinder block and about when the piston skirts reach the bottom of the cylinder sleeve things start to stick. Moving the pistons back up some I can feel maybe 1/2 or 3/4 inch of the bottom of the bores and they feel smooth. Also, everything is pretty well lubricated with Kroil/PBBlaster. I've gotten only about 5mm of the piston skirts to show below the cylinder sleeves.

Anyone have any idea of how I should proceed? Patience? More Kroil? Use force? (and if so, what kind and how much?)

Thanks.

-- alonzo
 

·
Registered
Joined
·
1,547 Posts
Carbon?

I take it the barrels are off the crankcases but pistons won't come through.
It sounds like there is a carbon build up behind the rings keeping then out, as you are getting to the best/unused bit of the bore the rings won't go in far enough to let it pass. A couple of eggcups of diesel above the pistons, then slowly work the barrels up and down you might have to pull quite hard, not blue in the face hard though:D
plenty of rags around your con rods will soak up the diesel that gets past the rings, which is what you want.
 

·
Super Moderator
Joined
·
13,271 Posts
Lift the jugs & slugs as high as they'll go, stucc a bunch of rags all around the rods and down into the crankcase, then stand on top of the crankcase and give 'em a mighty yank. They'll come off.

You're going to need new pistons and a rebore anyway, you can't hurt them by yanking on them, only by prying on certain things.
 

·
Registered
Joined
·
118 Posts
Discussion Starter · #5 ·
Success!!

stand on top of the crankcase and give 'em a mighty yank. They'll come off.
Thanks everyone. I did all the above. Used diesel and Sea Foam. Both seemed to help but I don't know which was better. Thought I was going to need twin 800lb gorillas to 'yank' them off but I just kept at it and it finally happened.

Any suggestions on how to clean and paint the cylinders? Should I do this before boring?

I had a good stroke of luck yesterday. While at my local BMW, Triumph, Ducatti, Vespa dealer I mentioned that I had just acquired the Bonnie and they told me about the guy who works on old Triumphs. Seems he was the local Triumph dealer back in the `70's & `80's till the old Triumph went out of business. I talked to him and it sounds like he has many engine parts and can get most anything else. He also has a machine shop.



-- alonzo
 

·
Registered
Joined
·
1,547 Posts
Great stuff

I'm glad they came off for you alonzo and hello. the easiest way is to get them blasted (before you rebore) but you should make some wooden templates in such a way that you can put 1 on top and 1 below and hold them together with a long through bolt, this will keep the grit out of the bores. You can also make some to cover the tappet block holes (remove tappet block first) and block your oil hole up if you have one then paint with "pot Black"

edit your bores and pistons don't look too bad! could you get away with a glaze bust and a set of rings?
 

·
Super Moderator
Joined
·
13,271 Posts
I wouldn't re-use those heat-stressed pistons; I'd re-bore next oversize and go all new. I mask with tape on the spigots, tappett blocks and head face, and paint with Rust-O-Leum gloss black.

While many swear by powdercoating the jugs, I believe it holds in heat; I don't like it.
 

·
Premium Member
Joined
·
2,895 Posts
I wouldn't re-use those heat-stressed pistons; I'd re-bore next oversize and go all new. I mask with tape on the spigots, tappett blocks and head face, and paint with Rust-O-Leum gloss black.

While many swear by powdercoating the jugs, I believe it holds in heat; I don't like it.
I would agree with you GPZ, not a good idea to powdercoat the jugs. There is a VERY GOOD specialist in Wales (next to england) called SRM Engineering, I remember reading an article on how they rebuild a triumph engine and one of the remarks was that they do not powercoat due to heat build up. (this is a place where it will set you back approx. £ 3000.00 GBP for a triumph twin rebuild!)

Webby
 

·
Registered
Joined
·
118 Posts
Discussion Starter · #11 ·
That's a lot of heat on those rods and pistons, could be inadequate oil flow, I'll bet your sludge tube is LOADED with solidified grit.
OK... Where's the sludge tube? Is it a "split the cases" kinda deal? The other rod small end didn't have that discoloration and the one that did cleaned up somewhat with BrakeClean. I wondered about that but thought it was just 'varnish' buildup rather than overheating.

I haven't measured the piston/cylinder clearance yet but am definitely inclined to re-bore.

then paint with "pot Black"
Pot Black... Oh, yeah. I'm sure my neighborhood hardware store will know *exactly* what I'm talking about. I'll be in England week after next. Maybe I can pick up a can of "pot black" to bring home (on the plane ;-)

-- alonzo
 

·
Premium Member
Joined
·
2,895 Posts
Srm

Hi Plewsy,

Sounds like a fair price for that amount of work.
I thought of sending my head and crankshaft to them, in the end I decided against it due to the cost of shipping (the down side of living in France)
Once I've finished my engine, we'll see if it was a good decision to do the work myself (valves/valve guides and bottom end)
If it smokes/burns oil and runs like sh*t I'll know what to do next time :) - Take a flight to Wales with some very heavy baggage!

Webby
 

·
Registered
Joined
·
1,144 Posts
Alonzo, The sludge trap is a "split the case" kind of thing.

In my view there is absolutely no reason not to split the case at this stage. Why spend all that money and time on the top end just to ruin it with a full sludge trap. I had 24,000 miles on my engine and the trap was completely full. It's "false economy" as Hughie says!
 

·
Registered
Joined
·
1,144 Posts
Alonzo, that plug (#4) is usually indented with a drift to stop it from backing out. You need to drill out the indentation and then unscrew it. An impact driver will help.
 

·
Registered
Joined
·
1,825 Posts
sludge tube plug removal.

I have found that a bit of heat from a torch around and on the plug helps. Maybe it softens the lock tight. The last one I pulled out wouldn't budge until I applied some heat, then it loosened on the first wack with the impact driver. Just don't heat so much you damage the crank structure.
 

·
Registered
Joined
·
118 Posts
Discussion Starter · #19 ·
Well,,, ok.... I was hoping to avoid parting the cases as the bottom end feels tight but you all have convinced me to do so.

So much for my original idea of bringing the bike home, washing it off, putting in a battery and fuel and riding off into the sunset feeling like James Dean..... ;-)

Thanks everyone for the help and info.

-- alonzo
 

·
Super Moderator
Joined
·
13,271 Posts
I am not guaranteeing that your problem is the sludge tube.

However, I guarantee that if the problem IS the sludge tube, and you DON'T clean the sludge trap out, you WILL end up spending a lot more money very soon when you lose a rod...

...and you'll then HAVE to clean the sludge trap!
 
1 - 20 of 20 Posts
Top