TTi Gearbox.

SteveA said:

I have fitted 3 larger balls to one, you can easily measure that there is indeed more lift with the part in your hands, but have yet to fit it to the bike and test it!

Click to expand...

Ok, so 3 smaller balls should have the opposite effect, I have more lift than I need and even though the lever pressure isn't a problem, I may have a play, A lighter lever is always welcome.

Fast Eddie said:

The PSP hydraulic lifter gives more lift, with lower lever pressure. If I needed more lift, and originality is no issue, this would be my choice.

Click to expand...

Might not get away with a hydraulic clutch in classic racing.

Fast Eddie said:

But I gotta ask... Why do you need more lift?

Click to expand...

Because with the Norman White clutch I have, I don't have enough lift! If Brooking shows up some time soon, he has had the same problem with a different clutch.

Norman White clutch has fewer thicker friction plates.

I have fitted a 33mm pivot lever (expensive Domino/Tomasselli part), which improved it over more common 27mm pivot type.

It drags when warm....difficult selecting neutral and engaging gear.....it is a pain on the start line...I have to select neutral rolling on to grid...then after engaging gear....I have to hold the brake on or risk a jump start!

I ordered the part from MX24 in France anyway! Means I have two possible solutions to try during forthcoming winter/spring prep.

I honestly don't find the diaphragm clutch heavy! But I don't ride through traffic in first!

SteveA said:

Because with the Norman White clutch I have, I don't have enough lift! If Brooking shows up some time soon, he has had the same problem with a different clutch.

Norman White clutch has fewer thicker friction plates.

I have fitted a 33mm pivot lever (expensive Domino/Tomasselli part), which improved it over more common 27mm pivot type.

It drags when warm....difficult selecting neutral and engaging gear.....it is a pain on the start line...I have to select neutral rolling on to grid...then after engaging gear....I have to hold the brake on or risk a jump start!

I ordered the part from MX24 in France anyway! Means I have two possible solutions to try during forthcoming winter/spring prep.

I honestly don't find the diaphragm clutch heavy! But I don't ride through traffic in first!

Click to expand...

Interesting, I imagine the plates must be expanding with heat? Fewer plates, running dry, should need less lift.

I've never measured the TTI lift and compared it to stock Norton, do you know how they compare?

SteveA said:

Norman White clutch has fewer thicker friction plates.

Click to expand...

Crazy isn't it, I have always though that the less plates the less lift needed, and in my experience that is usually the case. I guess the reason is, any drag caused by distortion in the plates is multiplied by the number of plates.

Obviously not the case with you, and I recently pulled the slipping clutch assembly on my T150, whilst it was apart, I machined the carrier and dropped over a pound off that, I fitted a new sintered plate (just the one) and machined all the relevant surfaces parallel, I then made sure the clamp plate lifted square using the paper method and then I made sure it was balanced.

Guess what, it drags!!!

It is a real pain to get to the clutch on a T150 so it has gone on the back burner for now, it is useable but heavy. The two things I will be looking at are, whilst the diaphragm is lifting square at the point of lift I guess it could change as it lifts higher, and 2, the diaphragm is not going over centre as it releases, a small machining job will sort this and I believe as the pressure come off the clutch cable it will provide a tad more lift anyway as cables do compress or stretch more with higher tension.

In my time with my Commando (46 years). On my mates bikes I have come across a few things that cause clutch drag, I have seen diaphragms that don't lift square, the bit the clutch cable fits in not providing enough movement, warped plates, grooves in the inner or outer drums etc, but the ones that were not sending the pressure plate over centre when pulling the lever were most common and usually cured by adding an extra plain plate, not only did it cure the drag but it also made the clutch nice and light.

I am guessing with your background in racing all that might be like teaching my Granny to suck eggs but !!!!

After years of suffering a heavy clutch not disengaging properly on my Trident, I eventually had the castellated parts of the clutch drive ring machined down by 40 thou. It's now acceptable. Neil Beadling has told me they are all different and must be individually seen to. My other Trident clutch is just fine, as are both my Commandos.

storm42 said:

..........a few things that cause clutch drag, I have seen diaphragms that don't lift square, the bit the clutch cable fits in not providing enough movement, warped plates, grooves in the inner or outer drums etc, but the ones that were not sending the pressure plate over centre when pulling the lever were most common and usually cured by adding an extra plain plate, not only did it cure the drag but it also made the clutch nice and light.

I am guessing with your background in racing all that might be like teaching my Granny to suck eggs but !!!!

Click to expand...

Bear in mind I had a long break from all bikes, and a longer break between Nortons....I will listen to anything sensible I can recognised is based on experience...

My guess is that the diaphragm centre coulbe be better, I don't think it lifts as square as it should.....and the addition of a plain plate might be works considering...

I have just replaced the plates and only done 3 race starts with the new ones...I noticed that as the plates bedded a little is was marginally better....

When the plates on the Norman White clutch are badly worn the spring touches the pressure plate (Norman pointed out it might and when I checked I found witness marks). No issue with new plates, but having an extra plain one right at the back might help in a couple of ways as it would move the relationship of the steel plates with the drum which has some minor notching. (the drag issue existed before the notching became apparent and I don't think it is enough to be the root of the problem.

trident sam said:

After years of suffering a heavy clutch not disengaging properly on my Trident, I eventually had the castellated parts of the clutch drive ring machined down by 40 thou. It's now acceptable. Neil Beadling has told me they are all different and must be individually seen to. My other Trident clutch is just fine, as are both my Commandos.

Click to expand...

Yes that is the next job when I have time, I will keep reducing the castellated posts 20 thou at a time until it goes over centre at about half travel, that and make sure the plate lifts square throughout its travel. My T160 was alright so I know I can do it.

SteveA said:

My guess is that the diaphragm centre coulbe be better, I don't think it lifts as square as it should.....and the addition of a plain plate might be works considering...

Click to expand...

Here is one that caused some problems back in the day (I don't throw much away)

As you can see the centre where the diaphragm tangs go in are staggered, I assume this was to give a lighter feel to the clutch by only lifting every other finger on the initial pull and bring the rest of the spring off the pressure plate as your hand was in a better position to finish the pull, all well and good but this spring needed a lot of lift to clear the plates. You can also see the pressure plate witness marks on the fingers are not uniform, just a bad spring.

Changing the spring cured the drag this gave, unfortunately it is so long ago, I cannot remember if the centre on the replacement was staggered the same.

SteveA said:

I will listen to anything sensible I can recognised is based on experience...

Click to expand...

Be careful, I have never been accused of being sensible, or experienced.

The issue I had with clutch drag in the TTI 5 speed in my race bike was resolved after I met an Australian guy who had a racing Norton. He had found the clutch actuating pin (part number 57-1710) which is common throughout the Triumph unit construction gearboxes, the face where the clutch rod acts against had not been hardened properly in a batch so was creating wear at the same diameter of the rod in the end face of the pin, hence creating drag after some use.
I bought a few pins , put in a new one with the same three balls the gearbox came with and no more problems.
Regards Mike

storm42 said:

As you can see the centre where the diaphragm tangs go in are staggered, I assume this was to give a lighter feel to the clutch by only lifting every other finger on the initial pull and bring the rest of the spring off the pressure plate as your hand was in a better position to finish the pull

Click to expand...

https://www.accessnorton.com/NortonCommando/diaphragm-spring.29290/#post-449764

Sometimes if the rod through the centre of a gearbox is the wrong length, it changes the angles on the cable or lever and makes the clutch heavier when used - even if all the adjustment is used to take up the slack.
I forget what is in which box these days, but in at least one of them - when the angle of the cable with the lever is either too obtuse or acute, the clutch can feel heavy. I use a piece of 6mm unhardened mild steel rod which I can shorten easily. Wear on the ends of the rod is not a problem - just file them up nice and square.

You guys have given me a conscience. It is now almost cool enough for me to get into my shed.

L.A.B. said:

https://www.accessnorton.com/NortonCommando/diaphragm-spring.29290/#post-449764

Click to expand...

Ha, well I never!! That JML chap goes on a bit doesn't he.

storm42 said:

Might not get away with a hydraulic clutch in classic racing.

Click to expand...

I raced with AHRMA for years with a hydraulic clutch on my Norton.
They called it a control which can be modified as desired.
But of course my hydraulic clutch will not fit in a TTI.

comnoz said:

I raced with AHRMA for years with a hydraulic clutch on my Norton.
They called it a control which can be modified as desired.
But of course my hydraulic clutch will not fit in a TTI.

Click to expand...

Over here they use the term "free from restriction" but for my class the controls must be of a type and style used in the period. To race the bikes we have to have eligibility certificate which must be reapplied for if any changes are made.

There are no real checks made at the meetings re eligibility but I guess if you were winning with a dodgy bike it wouldn't be long before somebody was complaining. And rightly so.

The clutch action with my TTI box, it better than it ever was with the Norton box. But I don't use the Commando clutch. I use single row primary with Manx clutch and floating Jawa engine sprocket. It is cheap, light and easier to adjust gearing. The Manx clutch has been used behind 100 BHP Vincent motors in drag bikes - it won't slip.

In Australia, if there are eligibility issues - the argument ' it could have existed' is used. That is the reason most of our historic bikes are shit.

storm42 said:

I pulled my (5 speed XHD) TTi box apart last night and thought there may be some interest in just what is inside these boxes.

Click to expand...

storm42 said:

View attachment 14281

Click to expand...

Hello Ralph,
I have a 5 sp XHD gearbox on order with TTI. Can you please tell me what the bore seen at the casting where they have machined clearance for the selector drum is for? Is there a boss on the outside? The wall thichness is rather small for holding a bolt or another threaded item.

I am discussing with TTI how to integrate a neutral switch at their transmission. My order is for a Mk3 variant and I want to keep the neutral switch which is std fitment on the Mk3.

-Knut