A TTi gearbox related query

Schwany, which effect do you strive for by including a ball bearing within the mainshaft? I thought the ide was to stop the clutch rod rotation? In view of the rough mainshaft bore,
a two-part clutch rod is likely to keep rotating, despite the central ball bearing. One effect you may hope for is reduced driving friction torque due to the shorter rod.

The situation at the actuator end needs more research. Stationary steel to rotating steel transmitting pressure across a small surface is obviously not a good solution, even in the presence of oil. I wonder if a cap made of bronze would offer an improvement? (Less friction, reduced risk of abrasion)

- Knut

mdt-son said:

Schwany, which effect do you strive for by including a ball bearing within the mainshaft? I thought the ide was to stop the clutch rod rotation? In view of the rough mainshaft bore,
a two-part clutch rod is likely to keep rotating, despite the central ball bearing. One effect you may hope for is reduced driving friction torque due to the shorter rod.

The situation at the actuator end needs more research. Stationary steel to rotating steel transmitting pressure across a small surface is obviously not a good solution, even in the presence of oil. I wonder if a cap made of bronze would offer an improvement? (Less friction, reduced risk of abrasion)

- Knut

Click to expand...

Simply put I want the pushrod to rotate with and at the same speed as the adjuster when the clutch is actuated. Any wear would be against the very centers of the pushrods on the ball bearing. With the single rod locked up at the other end for whatever reason it happens and pressed against the adjuster in a situation where I am stuck having to hold the clutch in multiple times for a hour, a stationary rod eats the clutch adjuster.

For all I know and what usually ends up being the case on the internet is that I am the only person on planet earth that has ever had a problem with anything related to Norton ownership. Everyone else does things perfectly and they never have problems. Obviously, I'm kidding, but I have no idea what is actually going to happen with the two piece pushrod and ball setup.

If I could have my way, I'd like to simply roll a ball bearing into the bore then slide the pushrod (length adjusted for the addition of the ball bearing) in and have everything function like it should, which is more or less how the AMC setup works. Unfortunately, I have no idea where that ball bearing would end up if I rolled it in the TTi mainshaft bore. It might drop into a black hole of total destruction.

I be done talking about this today.

Don't forget that since the thirties all Nortons basically has a wet clutch. The Norton oil bath primary. Except the Manx and belt drives which are dry. So some oil can find its way to the rod end . The early gearboxes had a mushroom left rod and no adjuster. The older gearboxes and the TTI obviously has the same design flaw when running a dry clutch. So why not a proven more than 60 years old simple fix? Race riders back then was very good mechanics and problem solvers. Because they had to.
Stripped an old Manx clutch with three rods and a couple of balls and rollers.

Schwany said:

Simply put I want the pushrod to rotate with and at the same speed as the adjuster when the clutch is actuated. Any wear would be against the very centers of the pushrods on the ball bearing.

Click to expand...

Not quite. Let's assume first gear is engaged and the clutch is actuated. The mainshaft will not rotate, while the clutch basket including adjuster rotates at about half the engine rpm. The (shorter) clutch rod is now partially restrained by friction towards the rough mainshaft and excitated by the clutch adjuster. As the lifter pressure is raised, friction between clutch adjuster and rod will overcome surface friction at the rod and the clutch rod will spin up. There is hardly any friction between bearing ball and rod due to absence of rotational speed at the rod center. Thus, you may expect friction marks at the rod surface and the rod end towards the adjuster, and at the adjuster itself. Rate of abrasion depends on usage and available lubrication.

The best remedy to avoid problems is fitting a thrust needle roller bearing at the clutch adjuster. A scrapped engine valve can be modified to act as partial clutch rod.

- Knut

Knut, EXCEPT,.... there's really nothing wrong with the clutch, rod, or the adjuster nut. The problem stems from not having an easy time finding neutral on a TTI box, combined with it's use in the urban stop and go in traffic.

Schwany, I wonder if you think you'll eventually just get the feel of finding neutral or is finding neutral really feel that imperceptible??... I also wonder what other TTI box users opinions are about finding neutral. I bet they'll say that you eventually get used to how it feels and the problem goes away...

I always thought my AMC box's neutral is tricky to find, but I am used to how it feels so it's not an issue. I don't give Non-norton riders much chance of finding neutral on my bike when it's running. For those few who have ridden my bike, I would never expect them to ride it in stop and go traffic. They would stall the bike numerous times, where I would never stall it from missing neutral. I bet the TTI box issue will go away as familiarity with it's feel develops...

o0norton0o said:

Knut, EXCEPT,.... there's really nothing wrong with the clutch, rod, or the adjuster nut. The problem stems from not having an easy time finding neutral on a TTI box, combined with it's use in the urban stop and go in traffic.

Schwany, I wonder if you think you'll eventually just get the feel of finding neutral or is finding neutral really feel that imperceptible??... I also wonder what other TTI box users opinions are about finding neutral. I bet they'll say that you eventually get used to how it feels and the problem goes away...

I always thought my AMC box's neutral is tricky to find, but I am used to how it feels so it's not an issue. I don't give Non-norton riders much chance of finding neutral on my bike when it's running. For those few who have ridden my bike, I would never expect them to ride it in stop and go traffic. They would stall the bike numerous times, where I would never stall it from missing neutral. I bet the TTI box issue will go away as familiarity with it's feel develops...

Click to expand...

Youz got to ride with a TTi gearbox in a Norton frame behind a Norton engine and determine for yourself really. My experience could be unique and irrelevant.

It is easy-ish to find Neutral if not in stop and go unpredictable traffic. Coming up to Red light with some time it is relatively easy to find. Coming up on a quick change Red light at speed is really tricky if in 3rd. Coming to stop signs is the easiest. One can see a stop sign off in the distance and take their time making the touchy shift into neutral when they get close, or just hold in 1st gear for a second and take off if there is no cross traffic.

The TTi slides into Neutral from 1st or 2nd with a very light touch, but no feedback on the toe of the boot. Shifting up and down through the other gears the shift lever stops at each gear. It is also easy to downshift from 2nd to 1st with a blip of the throttle. Neutral is the only odd shift in either direction. I've owned and ridden a lot of motorcycles. This TTi gearbox is unique for use in a street only motorcycle.

My experience says the TTi gearbox is nothing like the AMC gearbox that was in my P11, which really was nice except it stopped going into 3rd from 2nd without dancing a jig on the shift lever and cussing in my helmet. I could not count on that 2nd to 3rd shift, and it made the bike a lot less fun to ride. I played with that goofy pawl spring many times. I probably got it right when the TTi box showed up on my doorstep. Didn't want to find out if the last adjustment was perfect.

Racers have a totally different environment to ride in. Finding neutral on a race track would be counter productive unless crashed out. Racers are very likely all going to praise the TTi gearbox. Besides I think disagreeing with me is trendy here regardless of the topic. lol

The 2 piece shaft and center ball bearing are in the mainshaft bore. Test ride later.

Before I installed the two piece setup, I cleaned out the mainshaft bore with my 22 rifle cleaning kit.

mdt-son said:

The best remedy to avoid problems is fitting a radial needle roller bearing at the clutch adjuster. A scrapped engine valve can be modified to act as partial clutch rod.

- Knut

Click to expand...

Except that you should have written axial, not radial.
The combination of a TTI gearbox, traffic jams and a Commando clutch, especially if a belt drive, is a good recipe for adjuster wear. Only took me a week to figure out why.
Best solution is to minimize friction at the adjuster. Limited space makes it hard to find a ball, roller or needle bearing with enough axial load capacity. Not to mention how to assemble.
If the ball between rods fix don't work, I'd try a bottom hole drilled into the adjuster and ball bearing press fit into the hole. Ball diameter probably 5/16 or 8 mm. Leaving enough adjuster meat to keep the ball in place.
A smaller ball will give higher contact pressure.

Mike40M said:

Except that you should have written axial, not radial.

Click to expand...

I stand corrected. I think "thrust bearing" is the commonly used term.

Mike40M said:

Except that you should have written axial, not radial.
The combination of a TTI gearbox, traffic jams and a Commando clutch, especially if a belt drive, is a good recipe for adjuster wear. Only took me a week to figure out why.
Best solution is to minimize friction at the adjuster. Limited space makes it hard to find a ball, roller or needle bearing with enough axial load capacity. Not to mention how to assemble.
If the ball between rods fix don't work, I'd try a bottom hole drilled into the adjuster and ball bearing press fit into the hole. Ball diameter probably 5/16 or 8 mm. Leaving enough adjuster meat to keep the ball in place.
A smaller ball will give higher contact pressure.

Click to expand...

RGM do a thrust bearing kit for the commando clutch. I do it a little different by making my own as in the photo. Components are made from hardenable steel.
The two piece pushrod and ball in the middle, will cause the pushrod assembly to bind in the mainshaft. Think of it like leaning on a broom handle, now cut the broom handle in two and try and lean on it, It will want to move sideways, much like a compression spring will always want to spring out sideways when compressed.

o0norton0o said:

Knut, EXCEPT,.... there's really nothing wrong with the clutch, rod, or the adjuster nut. The problem stems from not having an easy time finding neutral on a TTI box, combined with it's use in the urban stop and go in traffic.

Click to expand...

That's a question of semantics, probably.

I understand why the problem occured. Here we have a gearbox developed for racing which is being used in a street bike, with components attached for which the manufacturer (TTI) takes no responsibility. Buyers (me included) are now facing a problem, because the components don't work well together.

In a mechanical system, components rarely work independently - they need to work well together.

You are right: There is nothing wrong with these components on their own, yet they do not work well in combination. We have a system failure.

There are two ways to resolve this:

One is to adapt usage to the limitations of the system, as you suggest. This works in racing, due to the excessive maintenance those machines are subjected to.

For a road bike, I for one won't accept this policy. The machine has to serve my (normal) usage, not vice versa. The design principle "Form follows function" applies here.
(FfF is a design principle that states that the shape of an object should primarily relate to its intended function or purpose.)
For me, the TTi gearbox with a clutch of choice has to work equally well to the stock components they are replacing. I won't accept a scenario where I am forced to do close inspections of wear and possibly replace parts every 500-1000 miles. If I can't mitigate the system failure, all of these components are useless to me.

- Knut

dobba99 said:

RGM do a thrust bearing kit for the commando clutch. I do it a little different by making my own as in the photo. Components are made from hardenable steel.
The two piece pushrod and ball in the middle, will cause the pushrod assembly to bind in the mainshaft. Think of it like leaning on a broom handle, now cut the broom handle in two and try and lean on it, It will want to move sideways, much like a compression spring will always want to spring out sideways when compressed.

Click to expand...

No pic ?

Hopefully now showing

dobba99 said:

Hopefully now showing

Click to expand...

Brilliant! Well done. It looks like an integral container in which the thrust bearing is located?

dobba99 said:

RGM do a thrust bearing kit for the commando clutch. I do it a little different by making my own as in the photo. Components are made from hardenable steel.
The two piece pushrod and ball in the middle, will cause the pushrod assembly to bind in the mainshaft. Think of it like leaning on a broom handle, now cut the broom handle in two and try and lean on it, It will want to move sideways, much like a compression spring will always want to spring out sideways when compressed.

Click to expand...

Observation not a criticism. Looks to me like your solution in the pic would still require a 2 piece pushrod. Difference being the pushrods would meet closer to the clutch rather than in the middle of the mainshaft bore.

I'm not going to worry about the two piece broom handles and ball bearing I have fitted until it fails. Then I might do something else or buy another clutch. I was aware of the RGM needle roller part, but didn't purchase it. Looked like another failure point to me. It does get kind of dusty in the primary which isn't great for exposed bearings.

dobba99 said:

The two piece pushrod and ball in the middle, will cause the pushrod assembly to bind in the mainshaft. Think of it like leaning on a broom handle, now cut the broom handle in two and try and lean on it, It will want to move sideways, much like a compression spring will always want to spring out sideways when compressed.

Click to expand...

Your displacement model would be correct if the rod was acting in open air. It is not. Lateral support by way of the mainshaft inner wall ensures there will be no movement sideways, provided the rod is given approx. the size of the mainshaft bore. I do agree there will be binding, but not due to lateral displacement.

- Knut

Schwany said:

It does get kind of dusty in the primary which isn't great for exposed bearings.

Click to expand...

Dust will mostly collect at the outer perimeter of the clutch basket (chainwheel); the pressure plate will confide most of the dust to the clutch interior (assuming a Commando type clutch is used). By enclosing the thrust bearing in a container, I think it's sufficiently protected against debris.

- Knut

mdt-son said:

Dust will mostly collect at the outer perimeter of the clutch basket (chainwheel); the pressure plate will confide most of the dust to the clutch interior. By enclosing the thrust bearing in a container, I think it's sufficiently protected against debris.

- Knut

Click to expand...

If you would have seen what I've seen in that clutch adjuster housing, you might think otherwise. Kidding. My clutch was not operating as it should. That housing had dust and metal shavings in it.

Since I'm not about to make what dobba99 made, I might get one of those needle bearing kits from RGM.

I also thought about the 2 pushrod binding before it was brought up. If I had the right tools and a way to polish a small cup in the end of the 2 pushrods where they meet on the ball bearing, it would be an improvement.

What I would like to know from the guys that have had the TTi gearbox apart is if it is possible to roll a 6mm ball bearing into the mainshaft without it dropping out at the pushrod operating lever end. That would be helpful for my endeavor to preserver.

mdt-son said:

That's a question of semantics, probably.

I understand why the problem occured. Here we have a gearbox developed for racing which is being used in a street bike, with components attached for which the manufacturer (TTI) takes no responsibility. Buyers (me included) are now facing a problem, because the components don't work well together.

In a mechanical system, components rarely work independently - they need to work well together.

You are right: There is nothing wrong with these components on their own, yet they do not work well in combination. We have a system failure.

There are two ways to resolve this:

One is to adapt usage to the limitations of the system, as you suggest. This works in racing, due to the excessive maintenance those machines are subjected to.

For a road bike, I for one won't accept this policy. The machine has to serve my (normal) usage, not vice versa. The design principle "Form follows function" applies here.
(FfF is a design principle that states that the shape of an object should primarily relate to its intended function or purpose.)
For me, the TTi gearbox with a clutch of choice has to work equally well to the stock components they are replacing. I won't accept a scenario where I am forced to do close inspections of wear and possibly replace parts every 500-1000 miles. If I can't mitigate the system failure, all of these components are useless to me.

- Knut

Click to expand...

I respect your opinion Knut, and respect that you acknowledged my point about finding neutral more easily would mitigate some of the wear on the current design.

We had a thread in the forum recently about sitting at a traffic light in gear with the clutch lever being held for the duration of the light, with some guys saying that they always do that so they can make a fast get away in any situation. Those people expect a clutch to do that duty without damage as "normal duty". When I learned to drive a car, my dad taught me not to "ride the clutch" and that I had to learn to take it in and out of gear because sitting at a light holding the clutch in was not good practice and it put an undue load on the clutch's throw out bearing. So I don't think a clutch is supposed to be held on continuously like that. I don't think it's a flaw if the part fails like Schwany's clutch center did because I don't expect it to be used that way...

With a car, the throw out bearing is an actual ball bearing which seems like a better design to be held for longer periods of time than a hardened pushrod and hardened adjuster of a motorcycle. The standard user practice in car manual transmissions is not to ride the clutch. I'm sure some still do that, but I wouldn't expect their throw out bearing to last the same length of time as mine.

So is excessive wear on the throw out bearing/adjuster which makes a part fail an inadequate part? or a user inflicted premature wear?? From Schwany's description, I sort of got the impression that his part failure was purely an isolated case which happened because he hadn't gotten comfortable finding neutral yet because the box was newly installed, so he held the clutch in excessively to keep from getting mowed down in city traffic...

If the same adjuster wear is a common problem to many TTI box users (you included), then I would conclude as you do that the parts/design should be improved to work better. Is it a common problem for TTI users??

Schwany said:

What I would like to know from the guys that have had the TTi gearbox apart is if it is possible to roll a 6mm ball bearing into the mainshaft without it dropping out at the pushrod operating lever end. That would be helpful for my endeavor to preserver.

Click to expand...

Why wouldn't you do a 2 piece clutch rod and have the ball bearing captured inside the shaft by a rod length on each side of the ball? You could even have a groove turned in both rods to mount "O" rings so you could grease the ball bearing and the "O" rings would hold the grease in place inside the hollow shaft with the ball bearing. If you want to try that simple design, I could turn the rod parts to cut the grooves for the "O" rings and polish the ends of the rods if you like... This doesn't seem like a hard job at all if you want to try it.

I am guessing that excessive wear on the RGM clutch adjuster is not an issue on race bikes. Most of the issue was probably me adjusting the clutch like I usually did with the AMC gearbox that incorporates a ball bearing at the pushrod operating lever. I had too much lever and it was probably over lifting and under a lot of stress in the heat holding the clutch in.

Thanks for the offer on the machine work but I want to see how what I've done works first using a looser adjustment with the 2 piece pushrod and ball bearing and a 9 mile loop ride isn't enough testing. I'm currently taking care of a very long overdue HoneyDo. Wife has been waiting patiently 10 years for me to get her car in the garage.