Ever wonder how a classic British bike engine works?

If everything else is done right, you shouldn't need the sealant. As a last resort, it works.

If it DOESN'T work, you may have an abused head (they typically leak at the top, when they leak).

Also, there is a possibility that the front and rear may have slightly different gaps, so measure carefully and use the closest thickness seal for each one.
 
"For what it's worth"

In over 25 years working on Brit bikes (40 years on bikes of all sorts), I haven't had a single oil-related failure, no blown cranks/cases, not a catastrophic engine failure of ANY sort. In fact, the worst failure caused by my mistake was a spun rod bearing requiring only cleanup, new bearing shells, gasket set and some incidentals, all paid immediately to the recommended mechanic local to that client. (the mistake was not fully seating a Triumph sludge tube in the crank, which blocked off oil flow to the rod journal)

That's in AT LEAST 19 restorations, 12 custom builds, 3 salvage restorations, 19 major refurbs, 18 overhauls, and at least a dozen other serious rebuilds over that 40 years.

So, I let the record speak for itself.
 
72 bikes? whatever
Get into the hundreds or thousands over 46 yrs then come back
 
1 out of 72 failures works out to less than 1-1/2% (.014) failure rate.

The fact is, I've never grenaded an engine, and never had a catastrophic mechanical failure like a lock-up that tossed a rider.

Add to that no significant failure of ANY sort related to sloppy, shabby, hamfisted, or any other less-than-acceptable practices.

I light smear of silicone sealant is not the same as globs of gook that ooze out of the joints and plug up oil passages.

Going back to the cut-and-paste criticism, NONE of those items discussed resulted in an actual failure.
 
GP, Suggestion - Let it go. The man that never made a mistake has never been born.

The first cause of leaks on old triumph push rod tubes is the wrong combination of parts that allows a gap between the seals and mating parts. Second is damage to the push rod tubes or mating surfaces on the rocker box or tappet block. I have never needed to use Gasket goo on those seals so maybe I got lucky. Using a head gasket that's too thick or thick rocker box gaskets or machining a lot off the barrels or head are all potential problems that need to be addressed with thicker or thinner seals.

And that assumes that all the parts are within tolerance. For example, imagine the effect of fitting replacement tappet blocks that were machined slightly lower on that sealing surface or are marginally too small diameter. Old engines are always a challenge. Some fall together and others fight you all the way.
 
I'm well aware of tolerance stacking, my engine has 43k miles. From the factory this was an issue. An identical Triumph was sold off the floor, the same time as mine, 4k miles and the leak appears on the front tube on it as well. I can see the factory mixing up parts easier to keep the assy line going. I'm just going to have to use the engineering specs for heat, crush, and dimension. Parker has a book I can pick up, it's $150 to make a special die if needed. In my line of work I have to deal with chronic issues all the time. An engineer will make a drawing, submit it and then the bean counters will say cheaper, cheaper have you checked the China vendors?
 
teazer said:
GP, Suggestion - Let it go. The man that never made a mistake has never been born.

The first cause of leaks on old triumph push rod tubes is the wrong combination of parts that allows a gap between the seals and mating parts. Second is damage to the push rod tubes or mating surfaces on the rocker box or tappet block. I have never needed to use Gasket goo on those seals so maybe I got lucky. Using a head gasket that's too thick or thick rocker box gaskets or machining a lot off the barrels or head are all potential problems that need to be addressed with thicker or thinner seals.

And that assumes that all the parts are within tolerance. For example, imagine the effect of fitting replacement tappet blocks that were machined slightly lower on that sealing surface or are marginally too small diameter. Old engines are always a challenge. Some fall together and others fight you all the way.
yep old engines when i got my goldstar it had a real issue even trying to kick it over using the correct procedure
the guy i got it from said yeah its got a harley piston.well to me that sounded just like an old horseshit tail....finally after i done a compression test coming out with 230+lbs i realized this aint right .i tore it down it was a brand new bore never had been run new piston after mucjh head scratching and research turns out indeed it was an afermarket hi comp sportster piston ,totally unsuited of course !!
 
Careful now. I'm an engineer and a bean counter and I happen to like going to China.... :)

Good point that who knows where parts were sourced for the last few years of Triumph production or how good the parts were. I think the only thing coming out of China at the time were little red books.
 
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