Vestigial parts

Looking for a list of vestigial parts in a 1970 t120 build. Didn’t get a lot of response on the other board, and since nortoneers are more accepting of improvements, figured I’d ask here…. Lotsa stuff in a 650 triumph that looks vestigial to me, i.e. could be left out… examples I thought of

Sludge trap (gotta keep the plug, ditch the sludge tube, cartridge oil filter kit)

Weird chain oiler thingamabob in primary

Primary crank oil seal? 70 has the 3 lil holes drilled into the primary, effectively un-sealing it anyway…

Transmission main shaft bearing oil seal? New bearing came sealed on the one side…

Two obnoxious flat head screws in crank cases around pushrod tubes? I heard they were deleted at some point further down the line but I might have made this one up…

Oil pressure release valve?

Ok I put that last one up just to see if you were still paying attention. But seriously though- what can be or is better left out? My commando has all the trick mods- enlighten me on this 650 lump!

You got twenty replies.

no way will I be blamed for telling somebody to leave parts off their bike

I’ll comment on a couple of your points:

Sludge trap (gotta keep the plug, ditch the sludge tube, cartridge oil filter kit)…
Kinda controversial, but has been done before. Crank will need re balancing.

Weird chain oiler thingamabob in primary…
Yes. Was defeated by the factory later.

Primary crank oil seal…
Yes, this oil seal was deleted on later models that breathed through the bearing. But some like a dry primary for a belt, or a separate primary to run ATF.

Two obnoxious flat head screws in crank cases around pushrod tubes…
Yes, these can be left out altogether without any issue.

I know I'm not the only one.
Word of the day, Vestigial

Triton Thrasher said:

You got twenty replies.

Vestigial parts?

Howdy! Norton man here confused about a couple things on my newly exploded triumph 650. Motor is a feb. 1970 t120r… so what’s the deal with the pr...

www.britbike.com

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Kinda… in a week it turned into a ‘what is a sludge tube’ thread and I couldn’t tell what the heck the Aussie guy was on about. Couple hours on a Norton forum and I got actual answers…

Fast Eddie said:

I’ll comment on a couple of your points:

Sludge trap (gotta keep the plug, ditch the sludge tube, cartridge oil filter kit)…
Kinda controversial, but has been done before. Crank will need re balancing.

Weird chain oiler thingamabob in primary…
Yes. Was defeated by the factory later.

Primary crank oil seal…
Yes, this oil seal was deleted on later models that breathed through the bearing. But some like a dry primary for a belt, or a separate primary to run ATF.

Two obnoxious flat head screws in crank cases around pushrod tubes…
Yes, these can be left out altogether without any issue.

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Thanks for the reply! I kinda thought some of this stuff was redundant.

MichaelB said:

I know I'm not the only one.
Word of the day, Vestigial

VESTIGIAL Definition & Meaning | Dictionary.com

VESTIGIAL definition: of, relating to, or of the nature of a vestige. See examples of vestigial used in a sentence.

www.dictionary.com

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The benefit of a college education- useless words, impure thoughts and job in the trades after all!

tompkins said:

The benefit of a college education- useless words, impure thoughts and job in the trades after all!

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Superfluous might have been a better word. Triumphs (and other makes) have a lot of superfluous cycle parts but not many in the engine / transmission / gearbox. I know that sludge trap tubes can be left out but I don't understand why anyone would want to, unless they're fitting a strengthening tube in its place.

Tigernut said:

Superfluous might have been a better word. Triumphs (and other makes) have a lot of superfluous cycle parts but not many in the engine / transmission / gearbox. I know that sludge trap tubes can be left out but I don't understand why anyone would want to, unless they're fitting a strengthening tube in its place.

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I think the first reason is that it could be argued that the sludge traps function is largely undermined if using modern high detergent oils, as the oil will keep the sludge in suspense. A paper filter added into the system will then capture it.

Another argument is that the sludge trap bung in the timing side cheek creates a weak spot in the (otherwise strong) Triumph crank. The very course threads cut into a rough face creates potential stress risers to my mind. Then add in some over enthusiastic centre punching (perhaps several) and I think a stress riser is inevitable.

Machining the threads out to leave a smooth hole and welding in a press fitted plug would strengthen a Triumph crank a lot IMO.

I’ve never done it though, so this is all just armchair conjecture on my part !

My Triumph's sludge trap had a surprising amount of sludge after ten years of riding, exclusively with a Commando oil filter kit on it, and modern oils in it.

Going through all the trouble of building a Triumph motor to leave out a 10 gram part that is expressly designed to stop the whole going "BANG!" (reciprocal weight or not) is an interesting choice of how to spend one's time. On the other hand, life's a gamble, why not up the ante on everything?

Particles of carbon black are too small to be completely removed by a full flow paper oil filter. Some of it will always plate out in the crankshaft, whether there’s a tube or not.

t ingermanson said:

My Triumph's sludge trap had a surprising amount of sludge after ten years of riding, exclusively with a Commando oil filter kit on it, and modern oils in it.

Going through all the trouble of building a Triumph motor to leave out a 10 gram part that is expressly designed to stop the whole going "BANG!" (reciprocal weight or not) is an interesting choice of how to spend one's time. On the other hand, life's a gamble, why not up the ante on everything?

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Different horses for different courses I suggest.

The sludge trap helps those wanting to reduce wear for tens of thousands of miles of riding comfortably within the stress tolerances of the stock crank.

Removing and welding is more for those wanting to increase the stress tolerances of the crank to avoid a blow up due to building an engine and riding it in such a way as to render standard stress tolerances inadequate.

Fast Eddie said:

Different horses for different courses I suggest.

The sludge trap helps those wanting to reduce wear for tens of thousands of miles of riding comfortably within the stress tolerances of the stock crank.

Removing and welding is more for those wanting to increase the stress tolerances of the crank to avoid a blow up due to building an engine and riding it in such a way as to render standard stress tolerances inadequate.

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Sorry for the lag. Been busy, just want to make clear what I meant. I realize you may have taken it the wrong way.

Welding the crank and removing the sludge tube are two very different things in my mind:

Removing the sludge tube as a superfluous item to the function of the trap is (in my mind) tempting fate of passing undesirable items down the line. The tube seems to keep things in place better than no tube.

Welding the crank is attempting to fix a weak point in the crank, no? I'm not an owner of a Spintron, so any experimenting must be done by straddling my experiment. Fussing with the metallurgy of a 7000 rpm lump of iron and/or steel, by introducing heat affected zones on a three piece crank is undesirable when a two piece crank is readily available as an oem item. Triumph cranks are generally well regarded as pretty robust, aren't they? I'm sure there's horror stories out there as there is with anything.

t ingermanson said:

Sorry for the lag. Been busy, just want to make clear what I meant. I realize you may have taken it the wrong way.

Welding the crank and removing the sludge tube are two very different things in my mind:

Removing the sludge tube as a superfluous item to the function of the trap is (in my mind) tempting fate of passing undesirable items down the line. The tube seems to keep things in place better than no tube.

Welding the crank is attempting to fix a weak point in the crank, no? I'm not an owner of a Spintron, so any experimenting must be done by straddling my experiment. Fussing with the metallurgy of a 7000 rpm lump of iron and/or steel, by introducing heat affected zones on a three piece crank is undesirable when a two piece crank is readily available as an oem item. Triumph cranks are generally well regarded as pretty robust, aren't they? I'm sure there's horror stories out there as there is with anything.

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Yes, you are quite right, the leaving out of the sludge trap tube for no real reason, is indeed a different topic to leaving it out in order to modify the crank.

Regarding the latter… Welding of cranks is very common. If done by a skilled operator, there’s no need for heat related worries. Even less so these days with the advent of laser welding.