tti gearbox

a friend brought over a TTI gear box for a 71 Norton. While trying to install it I came up with 2 problems.....
1) it will not fit through the cradle without removing metal either on the gearbox or on the cradle.
2) it requires removing the motor.
It would have been nice if we were forewarned.
Also, top mounting point does not use the 3/16 washer that Commandos have so that is an issue, too.

Any idea what oil is used?

300 ml of Syntrans 75W-85

The bottom bolt is in a different place and the diameters of both holding bolts are bigger. You need to re-drill the holes for the bottom bolt. You might find the gear-shift direction is Triumph pattern. Bruce Verdon will send you a shift drum which reverses the pattern.

Hi Seattle
On a Commando cradle you will find that you have to remove material.
All my gearbox holes are
A) in the same place
B) the same size

Looks like Chris beat me to it.
The oil I use in my TTI box is Motul 300 75-90 which is one of the 2 TTI recommended. I get it off Amazon, Motul 105777 Gear 300 Gearbox Oil-75W90-1L 317811Motul 105777 Gear 300 Gearbox Oil-75W90-1L 317811

Contrary to acotrel ‘s post, the AMC Norton, Quaife and AMC TTI casings all have the same size mounting holes and locations – I’ve fitted all 3 interchangeably in the same engine plates at various times. The Quaife also doesn’t use the 3/16 top washer and it didn’t seem to cause a problem with fitting it into a Commando cradle.

I believe there have been posts on this forum where people have described their problems in fitting the TTI into the Commando cradle and they did involve metal removal. I’ve never done this exact swap so couldn’t really comment on that aspect. Similarly, I think I remember that you can get the gearbox into the frame without removing the engine but it does involve removing some engine bolts and head steady and tilting the engine and cradle to get enough room.

acotrel said:

The bottom bolt is in a different place and the diameters of both holding bolts are bigger. You need to re-drill the holes for the bottom bolt. You might find the gear-shift direction is Triumph pattern. Bruce Verdon will send you a shift drum which reverses the pattern.

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You keep saying this Al despite being corrected.

To be clear, the mounting holes on a TTI box are NOT different to Norton.

seattle##gs said:

a friend brought over a TTI gear box for a 71 Norton. While trying to install it I came up with 2 problems.....
1) it will not fit through the cradle without removing metal either on the gearbox or on the cradle.
2) it requires removing the motor.
It would have been nice if we were forewarned.
Also, top mounting point does not use the 3/16 washer that Commandos have so that is an issue, too.

Any idea what oil is used?

Click to expand...

Yes, actually metal needs removing from both sides of the cradle. It’s quite a PITA and would be VERY easy for TTI provide a template for this to both forewarn and make the job easier. If you search on here someone did sketch out the areas where removal is needed. When I did mine I just did it ad-hoc / trial and error, fitting and removing the box a gazillion times till I was happy. Remember, some of the external hardware is dummy, and can be removed to ease fitting through the cradle holes.

I did mine with the cradle removed and still thought it was a PITA but I do not believe the motor MUST be removed.

However, the cradle to motor mounts do need undoing. You are correct in that the top spacer is not fitted with a TTI box, but it’s easy to spread the cradle sufficiently to facilitate fitting if motor mounts and primary case stud are undone.

TTI boxes normally come with a 1/4 sprocket, so don’t let that catch you out.

I use Bel Ray fully synthetic gear oil in all my bikes (I use the one suitable for wet clutches too, so if any does migrate through to the clutch, it’s no issue). TTI are very specific in stating NOT to use shockproof oils. I ignored this and tried it, the shift is notably smoother with the Bel Ray (a common theme I am finding) so no more shock proof for me.

See below:

Fast Eddie said:

You keep saying this Al despite being corrected.

To be clear, the mounting holes on a TTI box are NOT different to Norton.

Click to expand...

Nigel, I had a normal Norton gearbox before I fitted the TTI into the Seeley. It was not a straight swap. The bottom bolt was in a different position - a bit further back If it fits without re-driliing, the box is probably not vertical.

seattle##gs said:

a friend brought over a TTI gear box for a 71 Norton. While trying to install it I came up with 2 problems.....
1) it will not fit through the cradle without removing metal either on the gearbox or on the cradle.
2) it requires removing the motor.
It would have been nice if we were forewarned.
Also, top mounting point does not use the 3/16 washer that Commandos have so that is an issue, too.

Any idea what oil is used?

Click to expand...

Email TTi & they will send you details of the metal to be removed.

Martyn.

acotrel said:

Nigel, I had a normal Norton gearbox before I fitted the TTI into the Seeley. It was not a straight swap. The bottom bolt was in a different position - a bit further back If it fits without re-driliing, the box is probably not vertical.

Click to expand...

Fair enough Al, but your bike isn’t a Norton, the engine and gearbox plates aren’t Norton. It sounds like your gearbox mounting holes were most likely in a different place (compared to ’standard’ Norton) to start with.

As far as I know, no one fitting a TTI to a Commando has had to alter the mounting hole positions.

If anyone knows this to be wrong, please do say so.

thanks everyone. It sounds like I have a long afternoon ahead of me. All I have is a disc grinder and some files. We are in the process of assembling his bike, just got the motor in and discovered the trans no-go problem. It won't be that difficult to remove the motor, just frustrating that I didn't install the trans first, had I known. In a perfect world this could have been done on the bench with the cradle locked up in a vice

Go slowly on the metal remove from the cradle. I did it on the bench. The sketch Bruce sends isnt a template. When you are done you will see that the bottom forward of the cradle is pretty attenuated. 10k miles and no issues but I won't be surprised if we have a crack problem in this area.
BTW it is a great box I love it.

I saw that the bottom front will be thinned quite a bit but not a lot of material there. Hoping to split the difference with the top rear.

Try to get as much as possible on the top as the bottm is a known issue

As Nigel states, no need to change bolt hole pattern or size for standard Commando cradle, I have a 5 speed in my racebike.
Just a bit of gearbox fettling to get it to fit , and no top washer. I made a wooden wedge to spread the top of the cradle during fit up.
Regards Mike

Things going smoothly. The left side of the cradle needs a 1/4" strip maybe 3" long removed so the box can be shifted forwards and backwards for chain tension.

Here's a link to the TTi gearbox engine plate mod diagrams, in case you don't have them.
Bruce never supplied them to me either.. Luckily I lived pretty much next door to TTi.
Cheers
John.

johnfitzw said:

Here's a link to the TTi gearbox engine plate mod diagrams, in case you don't have them.
Bruce never supplied them to me either.. Luckily I lived pretty much next door to TTi.
Cheers
John.

Norton Commando TTi Gearbox Engine Plate Modifications · Thursday, May 10, 2018 📸

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Nigel - you were very terse with me. I was sure fitting the TTI box was not just a straight swap,because I can remember taking the bike apart and redrilling the bottom holes.

Al
I've got 5 bikes & have swapped gearboxes between all of them! Standard Quaife 4 & 5 speed standard & reinforced Quaife shell. Plus the TTi box. I have never had to alter the mounts or redrill them for bigger bolts. However I have always had to shave various parts of the engine plates. Eddie pulled you up because you have stated the same wrong information, even after you have been corrected on this.

Chris said:

Al
I've got 5 bikes & have swapped gearboxes between all of them! Standard Quaife 4 & 5 speed standard & reinforced Quaife shell. Plus the TTi box. I have never had to alter the mounts or redrill them for bigger bolts. However I have always had to shave various parts of the engine plates. Eddie pulled you up because you have stated the same wrong information, even after you have been corrected on this.

Click to expand...

Approx how much does a complete 5 speed cost?

acotrel said:

Nigel - you were very terse with me. I was sure fitting the TTI box was not just a straight swap,because I can remember taking the bike apart and redrilling the bottom holes.

Click to expand...

I didn’t mean to be deliberately terse Al, but I did want to be very clear. As Chris says, you keep repeating the same incorrect information even after being corrected.