I remember how I entered into such the problem you described well. I had to reassemble all the top once again not really undrestanding what the reason for leak has been more because I trusted to "original" parts and sizes needed. The head hasn't been skimmed much except a bit but I even compared the other spare head . That all really took me too much time that was absolutelly not nice. Thanks Michael, for the explanation and quite useful video.
Hi, During my career, I encountered a 633cc 9 stud pre unit Triumph engine in a racing sidecar outfit which was fitted with the 500cc pre unit Tiger 🐯 100 💯 one piece crankshaft with the 80mm stroke (650cc stroke is 82mm). These crankshafts, although of identical appearance have a figure 5 stamped onto the timing side crank web which is the way to tell them apart. A check with another cylinder showed that that cylinder hasn't been decked. The owner decided to replace the crankshaft knowing he could get a good 😊 price for the 500cc item. The replacement crankshaft was sent off for balancing, sludge trap cleaned and journals measured which were still fine.
If the thinnest seals are needed you should also check if the head has been skimmed, if it has then you need a thicker head gasket and to then restart the gap checking process to find the right thickness seals.
Finally a good example of how to do this, but how do you measure what to order in the first place? For some of us, it can get very expensive and take a very long time to get new parts.
Don’t use silicon goo on the seal joints fit dry. I’ve used gas PTFE tape and it works great instead of the silicone stock ones when I didn’t have seals to hand for the top tube joint with a bit of well seal. Still leak free. The standard design bends the head and does encourage leakage across the two cylinders losing power out put.
I use a thick o ring on bottom and thin one on top of tubes. Both are the white o rings. As stated it all depends on how much head rock you get. Any one use gasket sealer or install dry? I would think dry is OK.
@@bonkeydollocks1879 correct. 750s also have a slightly different sealing arrangement for pushrod tubes - the top seal is an o-ring, and there is another o-ring in a groove machined into the bore at the bottom of the tube, as well as the flat silicone ring squashed underneath and retained by the "wedding band". Mine have always sealed ok with the standard set up (for a few years, anyway, until they don't)
@@rickconstant6106 yes, I was doing it of memory, what makes it hard for me is mines got a morgo 750cc big bore kit, and a 750cc mick hemming big valve head, all on a 650cc engine so I'm all over the place
Very helpful. Thanks!
I remember how I entered into such the problem you described well. I had to reassemble all the top once again not really undrestanding what the reason for leak has been more because I trusted to "original" parts and sizes needed. The head hasn't been skimmed much except a bit but I even compared the other spare head . That all really took me too much time that was absolutelly not nice. Thanks Michael, for the explanation and quite useful video.
Wonderfully explained process of fitting these!
thank you. Learning more all the time..
Well done, very helpful.
Hi Mike,
That was great help
Hi, During my career, I encountered a 633cc 9 stud pre unit Triumph engine in a racing sidecar outfit which was fitted with the 500cc pre unit Tiger 🐯 100 💯 one piece crankshaft with the 80mm stroke (650cc stroke is 82mm). These crankshafts, although of identical appearance have a figure 5 stamped onto the timing side crank web which is the way to tell them apart. A check with another cylinder showed that that cylinder hasn't been decked. The owner decided to replace the crankshaft knowing he could get a good 😊 price for the 500cc item.
The replacement crankshaft was sent off for balancing, sludge trap cleaned and journals measured which were still fine.
My 900 year old seals are getting pretty tired, I have to do this and check out what size I need to get.
If the thinnest seals are needed you should also check if the head has been skimmed, if it has then you need a thicker head gasket and to then restart the gap checking process to find the right thickness seals.
You might have to break down and ‘ make ‘ you some custom length pushrod tubes
Looks like you just made it with those skinny seals
Finally a good example of how to do this, but how do you measure what to order in the first place? For some of us, it can get very expensive and take a very long time to get new parts.
He Dosent know this by the look of it..
Most gasket kits come with several sizes of those seals , round and flat.
Don’t use silicon goo on the seal joints fit dry.
I’ve used gas PTFE tape and it works great instead of the silicone stock ones when I didn’t have seals to hand for the top tube joint with a bit of well seal. Still leak free. The standard design bends the head and does encourage leakage across the two cylinders losing power out put.
Do you use sealant on the pushrod tube seals? Or a dry installation?
I'm a first time builder, I have a 72 T120 with a 63 cylinder head, what pushrod tubes and pushrods should I get?
I use a thick o ring on bottom and thin one on top of tubes. Both are the white o rings. As stated it all depends on how much head rock you get. Any one use gasket sealer or install dry? I would think dry is OK.
Tiny bit of the correct silicone
Wow. looks like the right amount? I don't doubt your expertise, but stick a feeler gauge in there & give us some kind of chance.
30 thou gap is what you need
OK shall we just guess the gap then because it's a bit hard to guage when in the bath watching this
Sure that's not 750 head the depth for push Rod tube is different only owed triumph for 35 years
I thought that but it's a 9 stud head by the look of it. I believe 750s had ten studs
@@bonkeydollocks1879 correct. 750s also have a slightly different sealing arrangement for pushrod tubes - the top seal is an o-ring, and there is another o-ring in a groove machined into the bore at the bottom of the tube, as well as the flat silicone ring squashed underneath and retained by the "wedding band". Mine have always sealed ok with the standard set up (for a few years, anyway, until they don't)
@@rickconstant6106 yes, I was doing it of memory, what makes it hard for me is mines got a morgo 750cc big bore kit, and a 750cc mick hemming big valve head, all on a 650cc engine so I'm all over the place