TT Industries gearbox

If you are racing, the gearbox is the next most important thing after the front brake. Engine power is less important.

acotrel said:

I think the position of the bottom bolt is in a different position on the TTI box and both top and bottom bolts are larger diameter. My box is rigidly mounted and I think I had to re-position the holes in the plates for the bottom bolt, and widen the adjustment slot.

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Neither johnfitzw nor fasteddie have mentioned this in the thread above. The TTI g/b shell was modelled as close as possible to mimic an AMC-Norton g/b shell, and it would be daft of them to miss the bolt positions. Also, there should be no need to increase bolt sizes.

As for me, I just wouldn't accept the spindly shafts of the AMC gearbox. I will be running a hotted up full bore 850 cc.

- Knut

Is a neutral indicator available for the TTI AMC type gearbox? I would like to retain that feature for my Mk. 3.

-Knut

I got an offer two days ago to swap my TTI for a Quafe.
Tempting but still don't know how much I'll have to pay for that.
In my opinion the TTI box is a piece of crap.
First problem was that it did not fit in a Manx. After milling off some metal it didn't interfere with the frame.
Second problem was that clutch came loose, even though nut tightened to correct torque.
Third problem is that the clutch release mechanism isn't geared for a standard Manx. Very heavy to pull.
Fourth problem is gear shifting. Heavy combined with long throw. If it decides to shift at all. Kind of lottery. Sometimes a false neutral, sometimes no gearchange and occasionally correct gearshifting.
Also had no success trying to communicate with TTI.
Even the dolls head gearbox in the 16H, the Arrgardh five-speeeder that was fitted to the Manx, my laydown gearbox in the ES2 and the AMC boxes I've had are much better,

Internals of the TTI gearbox, for future reference.

Yve's TTI gearbox including the PSP-001 hydraulic slave cylinder.

Studs location and size was a direct fit with mine.

Disappointing to hear Mikes complaints above, I certainly wouldn’t be happy if I’d suffered similar! Apart from the box not fitting in the cradle I personally have had no issues even with the output from my 920 motor. So, despite the annoyance of the cradle issue, I’m personally still very pleased with mine.

9/1

tonybsa said:

Unfortunantly TZ750 sidecars bring a whole new load of problems instead.We are out on ours at the weekend.

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Maximum quote 10
Koenig: 4/10
Yam TZ 750: 9/ 10

Yves

Oh, just remember that I had to ream the bore for the top bolt and file away some aluminium to be able to adjust primary chain. But that was minor problems, easily forgotten. Quite normal when fixing Brit bikes.
The factory workers that assembled the British bikes was called fitters for a reason.
Old Swedish proverb translated: Fitting an English motorcycle is only dependant on size of the hammer.

The last time I raced, I was using the close ratio 4 speed AMC box. With the high first gear, I could not get a decent start except for the last race when I revved the tits off the motor to get going. I revved it to about 5000 RPM and dumped the clutch. When I did it, I was very worried that the box might explode and I could be hit from behind. However it did not let go and I entered turn two behind the three leaders. I simply rode under them and was leading when the fuel line came loose. The clip is right up under the tank.
I have the 6 speed TTI box installed. If I get the opportunity, I will have another go - next time will be different. If I get where I got last time, they wont see which way I went. After turn two there is a sweeper and several tight corners, By the time we get to the straight bits, I will be impossible to catch. Winton is a riders' circuit, and the Seeley is a better bike than I am as a rider.

I remember drilling new holes in the engine plates for the bottom bolt of the TTI box. I also had titanium top and bottom bolts made which were of larger diameter than the usual. I did not ream the mounting holes in the TTI box.

When I spoke to Bruce Verdon, he told me the TTI box is a copy of a Quaife. I would expect the modern materials used in the TTI box would be better. However getting decent alloy steel is always a problem. A lot of it is too high in sulphur and phosphorus content.