gearbox considerations

RE,a reply to Comnoz's work. Well thanks for your reply Jim. I had no idea it was done on a CNC. They make the impossible easy dont they. You play a bigger game than me Jim, i only have access to manual machine tools , some of them not that new either, so I do with what Ive got.

Perhaps you could help me out here, Jim, with all the references to 90/100HP and 7500 rpm bikes, how do the poor old gearbox stand up to all this power. I have broken gearboxes trying to drag and play street missle during a misguided youth and this was with standard engines..

I am curious as to how everyone keeps theirs together with all that power. would it be worth getting a thread going on gearbox modification particularly tooth profile changes and other design considerations. Tooth design is a complicated subject and i am not an expert in gear design at all. I know just enough to get myself into trouble on this subject, but have a huge interest in gearbox improvement. I read a thread somewhere where there is a mountain of shells not usable due to loose bearings or cracks in the shell between the bearings. Am I wrong in suggesting we keep replacing the same ol shells and keep getting the same ol problems.

i have seen a lot of boxes with severe pitting on the pitch line yet kept going without tooth breakage. is there a modern box already available that is designed for 90/100HP. Is there a shell that has an increase in shaft centre distance to put more metal between the bearings. There are lots of areas for improvement here. With all the forums accumulated knowledge and facilities, , what is the likely hood of a collaboration producing a replacement box that fits into the standard frame looks similar but takes 100/110 HP. Has this already been done. I am very interested in this subject . advice appreciated
Bradley

Here is one option, been around a long time, but $$$$$.


http://www.quaife.co.uk/shop/search/results/norton

http://www.quaife.co.uk/shop/products/a1h100a

the quaife does NOT really address the trouble with the standard gearbox. the first main and 4th lay are to small and are the high load gears in the std box and quaife box. as was asked the main shaft to lay shaft are to close together and trying to stuff a 5 speed in the same space is not a fix. it would take a MAJOR redesign to fix the short comings as there is more than just the internal gears. the other issues are with the over hung clutch ass. with no real support either. Kenny drear did some nice work with moving the output to the right side and was a MAJOR redesign in the right direction. this is just a short answer!!!

bwolfie said:

Here is one option, been around a long time, but $$$$$.


http://www.quaife.co.uk/shop/search/results/norton

http://www.quaife.co.uk/shop/products/a1h100a

Click to expand...

bill said:

the quaife does NOT really address the trouble with the standard gearbox. the first main and 4th lay are to small and are the high load gears in the std box and quaife box. as was asked the main shaft to lay shaft are to close together and trying to stuff a 5 speed in the same space is not a fix. it would take a MAJOR redesign to fix the short comings as there is more than just the internal gears. the other issues are with the over hung clutch ass. with no real support either. Kenny drear did some nice work with moving the output to the right side and was a MAJOR redesign in the right direction. this is just a short answer!!!

bwolfie said:

Here is one option, been around a long time, but $$$$$.


http://www.quaife.co.uk/shop/search/results/norton

http://www.quaife.co.uk/shop/products/a1h100a

Click to expand...

Click to expand...

For those of you who don't know Windy ("bill" on this Forum), I tend to hang on everything he says....the guy has dedicated his life to keeping our machines on the road. It's the definitive case of "been there, done that, thought about it, and here's the way it is"....just sayin'.

This gearbox is designed to look very similar to the AMC Norton box and handle the type of power you are describing. Its made in Nelson NZ. Today it would be regarded as the best box for racing.

Bruce Vernon is the owner and designer and is well known to many people on this site. He races his own Manx and was in USA rcently at Barbour ans Daytona. I know him reasonably well and have one of his 6 speeds with magnesium cases in my Dommie race bike. It is a very very good box. But not cheap. Still an Ozzie $ is about the best in the world at the moment and very strong against the Kiwi

John

http://www.ttindustries.com/

johnm said:

This gearbox is designed to look very similar to the AMC Norton box and handle the type of power you are describing. Its made in Nelson NZ. Today it would be regarded as the best box for racing.

Bruce Vernon is the owner and designer and is well known to many people on this site. He races his own Manx and was in USA rcently at Barbour ans Daytona. I know him reasonably well and have one of his 6 speeds with magnesium cases in my Dommie race bike. It is a very very good box. But not cheap. Still an Ozzie $ is about the best in the world at the moment and very strong against the Kiwi

John

http://www.ttindustries.com/

Click to expand...

I'll have to second this as I have several race seasons on two of his six speeds and several others I know in Vintage road racing in the states are using his boxes. I have yet to hear about a failure or a necessary rebuild; they are tough and shift like a modern Japanese machine; it does not get any better.

You really need to take a hard look at the application before buying into one of these boxes. If it is a road race application then TTIndustries boxes are the way to go, no question about it. Truely cost effective for the serious Vintage road racer.

Thank you johnm and Dances with Shrapnel. You have hit the nail on the head.

Having viewed the photos at Trans Tasman industries i have had my questions answered. But i have no need for such a magnificent box. I was merely coming from an engineering viewpoint about the shortcomings of the standard box and i keep hearing about these high power high RPm engines and was very curious about the standard box performance and possible alternatives.

These are truly magnificent design boxes adressing the major shortcomings. The photos show plenty of meat between the main and lay shafts. Also all pinions shows increased tooth thickness, possibly due to long addendum pinions or increased pressure angle. Either way the problems have been solved. No point in re-inventing the wheel.

Thank you both again for your informative replies

Best wishes to all and kind regards
Bradley

This concerns me as my 1st Combat tore up everything in the drive line, though not all at once. It was my excitement in heated moments that caused most of them. The now dead drag racers I talked to said at ~100 hp level the AMC box spills its guts on the track. They all adapted Harley gearboxes after that. One of the biggest issues I ran into was long times at hi rpms in lower gears, I don't think there is any way lube can flow into the sleeve bushes slinging it all out above oil level so a ceramic abrasive forms in the melt. Has ITT given thought to this or is it a non issue in their design? I'm saving for a basic wide ratio 4spd.

hobot posted about wide ratio gear cluster. do you by any chance mean close ratio. that is admirable but the basic problems remain for high HP or harsh acceleration.

the shafts are too close together on a standard type shell regardless of what the casting alloy is. not enough metal between bearings. you mentioned trouble at long bursts in lower gears, that is because as bill pointed out the pinions are too small. over run makes matters worse.

the DP would only be 12 or so(I havent measured yet), the pressure angle looks to be the old 14 /2 degrees and any pinion less than about 17/18 teeth has a tendency to undercut, even when hobbed.

have a good look at the 14 tooth pinion. close examination reveals that the tooth space exceeds the tooth thickness, and you can see the undercut.so if you use a standard type shell you still have the design faults. most of the cluster exhibit this tendency. compare 14 tooth pinion shape to the sleeve gear and you will see what i mean. the sleeve gear profile is what all teeth should look like.

The close ratio cluster has the smallest pinion at 17 teeth so that would be some small improvement as far as tooth strength goes, but still room for improvement..

Dont seem to be able to get away from the fact that a box designed for 35/40HP cops at least 58 and sometimes those horses are Clydesdales, not Shetlands.

guess mere mortals just have to live with it. thousands of bikes still on the road attest to the fact they do last a bit with all their faults. Only go bang under torture, as would I.
kind regards to all
Bradley

Kenny Dreer effectively used an aftermarket Harley box, which is what is being used in the Donington bikes now. Though I hear the gears are now made in England, not taken from Kenny's source. Perhaps though not knowing who Kenny's source was.

B.Rad said:

RE,a reply to Comnoz's work. Well thanks for your reply Jim. I had no idea it was done on a CNC. They make the impossible easy dont they. You play a bigger game than me Jim, i only have access to manual machine tools , some of them not that new either, so I do with what Ive got.

Perhaps you could help me out here, Jim, with all the references to 90/100HP and 7500 rpm bikes, how do the poor old gearbox stand up to all this power. I have broken gearboxes trying to drag and play street missle during a misguided youth and this was with standard engines..

I am curious as to how everyone keeps theirs together with all that power. would it be worth getting a thread going on Bradley

Click to expand...

The answer to your question is that standard Norton gearboxes were never made to handle this power, as the John Player Norton race team found out at Daytona, in the 1970s.
Their solution? One was to fit an outside bearing to the gearbox drive shaft; there where no details, as far as I am aware, on what they did to the interior gears.

If anyone does go with the TT box be sure to go through your options with Bruce.

There are a wide range of gear ratios -. more than listed on the website. There are three lenghts of mainshaft, Commando, Manx and Dommie. You can have normal and reversed shift camplate. 4,5 and 6 speeds. Magnesium and alloy casing. Kickstart or not. There are very heavy duty options for sidecars but I dont think these are available in 6 speed - no surprisingly - no space.

There are probably more options so ask. You will be talking to the owner, designer, main builder and rider developer.

Only issues I have heard of is the diameter of the clutch push rod. Make sure you use 6 mm not 0.25 ". The larger diameter can mushroom and rotate, even seize I understand. Kenny Cummings mentions this on his New York Norton website and a guy in NZ had the same issue. And I know of one example where a kickstart failed to mesh properly. Fixed by rocking the bike back and forth through the gears. This is something which may be sorted by now because the box was built for racing and I doubt many kickstart boxes have been made.

On the plus side anybdy who is anybody in Australasia uses them and they are in many of the top bikes in Europe and the US.

John

Bernhard said:

B.Rad said:

RE,a reply to Comnoz's work. Well thanks for your reply Jim. I had no idea it was done on a CNC. They make the impossible easy dont they. You play a bigger game than me Jim, i only have access to manual machine tools , some of them not that new either, so I do with what Ive got.

Perhaps you could help me out here, Jim, with all the references to 90/100HP and 7500 rpm bikes, how do the poor old gearbox stand up to all this power. I have broken gearboxes trying to drag and play street missle during a misguided youth and this was with standard engines..

I am curious as to how everyone keeps theirs together with all that power. would it be worth getting a thread going on Bradley

Click to expand...

The answer to your question is that standard Norton gearboxes were never made to handle this power, as the John Player Norton race team found out at Daytona, in the 1970s.
Their solution? One was to fit an outside bearing to the gearbox drive shaft; there where no details, as far as I am aware, on what they did to the interior gears.

Click to expand...

If you were to stay with the standard box, one modification that is a must do for racing and higher power is to remove the steel kick start sleeve on the inner cover and replace it with a steel sleeve that holds a proper roller or ball bearing to properly support the RH side of the lay shaft.

I ran this set up in a Commando road racer for a few years as a newby racer and it took considerable abuse without incident. I picked this up from a fellow vintage road racer.

ZFD said:

Kenny Dreer effectively used an aftermarket Harley box, which is what is being used in the Donington bikes now. Though I hear the gears are now made in England, not taken from Kenny's source. Perhaps though not knowing who Kenny's source was.

Click to expand...

Probably someone like Baker.

No typo, I seek a very wide 4 ratio for Ms Peel, 1st as granny creeper instant slow wheelie or spin out for getting over axle high objects and dicing between a tree and hard place hook backs on slopes, 2nd to use instead of first for tarmac take offs up to 100 mph, then 3rd kinda close ratio to 2nd for up to 140 then 4th for easy cruise and who knows how fast. Rear hub sprocket is an easy order and install on Peel to shift base line for the occasion.

I note the upgrade to RH lay shaft bearing and would appreciate a private ping or details here to impliment before I can afford an ITT bullet proof box.

I still wonder about the length of time any sleeve bushed design can take hi rpm load below 4th w/o any lube getting in between, only thrown right out until stopped again to allow oil to flow back in. As bushes and steel melt and abrade the clutch basket gets too wobbly to keep a belt on. My temporary help in AMC box will cryogenic temper and dry friction coat, to repeat now and then as wears off.

I figure about $4500 for what i seek in an ITT box. Only about twice as much as the rear shocks I want too.

One of the remedies to high tooth loading in race application AMC gear boxes of the era was to increase the speed. This may have been mentioned earlier or in another thread. As mentioned above, replacing the RH lay shaft bushing with a roller or ball bearing went a long way with reducing the layshaft effective span, thus reducing bending.

There is another option which is the Dave Nourish NRE gear box conversion. I recall hearing he no lnger makes the parts but there are a few floating around; I have one available for sale.

Dave Nourish made an alloy shell and main shaft which would accomodate a Commando style clutch basket and fit in a Norton gearbox cradle. The internals and inner and outer covers came from a Triumph five speed. You could purchase the shell and shaft from Nourish and source the balance yourself or purchase as a turn key gear box. It took some modification (trimming and polishing) of the inner and outer covers to make the fit.

I have yet to see or hear of one break under race use and the quality (feel) of the shifting was a great improvement over the old AMC arrangement.

Say What, using obvious Triumph items to beef up a Norton, that'd be like putting in Ford running gear and tail lights in a classic Chevy, ugh. Vintage - "upgraded" :roll: road racers don't get to spend much time in lower gears or dicing tight twisties for most an hour in red zone at a time against bikes twice the hp performance in the opens, so maybe me and the Manx guys are the only ones concerned about sleeve shaft bushes starvation in real life. Of course with enough grunt only need top gear load transmission, which still bows shafts into candy cane shape. I've hunted down hydraulic infinite variable ratio but they are very heavy to handle 100 hp and torque and limited in rpms tolerance too.

Weakest gear I've found is the 3rd set that tends of loose teeth if snicked in at too low of rpm on WOT. The crank TS pinon gear for Cdo's is like 1/8" thinner than Atlas version. Ask homeslice about that little weakness to prevent ahead of time. When I got my 1st Combat in '99 it was the vender's test ride bike and only hot shots ever owned it or worked on it, so was had rather spunky performance if leaking a 'bit', on entering my hwy steep climb out I'd snick 2nd to hear a chirp/squealing with hesitation in full thrust, thought the worse but turned out was just tire spin, so eased up on the 1st>2nd shift loads a bit.

Question on this post:
<If you were to stay with the standard box, one modification that is a must do for racing and higher power is to remove the steel kick start sleeve on the inner cover and replace it with a steel sleeve that holds a proper roller or ball bearing to properly support the RH side of the lay shaft.>

How is it that this helps? The kicker shaft only moves when you kick to start.
The layshaft turns inside the kicker on the bushing. Ive read where the bushing
has been replaced by a needle and can understand that. Also realize there may
be sense to the comments on having to grind the layshaft down to fit available
needle causing loss of strength of layshaft.

Im in my box now and it is surely a crapulous POS from design to execution.
Look longingly at TT five speed and trying to rationalize total cost of said
gearbox over the number of rebuildings , even replacements, over the life of
ownership. TT looks life a fine unit but terribly dear.

Re the Triumph gearset in an AMC case- this may be the answer for moderately tuned bikes but has its limitations.
I have recently been corresponding with Roy Robertson, longtime Vincent racer and well known in that community.Roy races and sprints this bike (11 second et) He also holds a couple of UK speed records with it, so the trans gets very hard use.

His 1272 Egli makes 96 hp at the rear wheel and has destroyed 5 triumph 5 speeds to date. Cases are Nourish AMC style, not sure how they have held up.
His Vincent motor is chopped to accept the Norton gearbox. This was quite popular at one time because the Norton box was a better shifting unit than the Vincent. Now that Surtees Quaife makes a very nice shifting 5 speed gearset to go in the stock Vincent cases, most hotrodders go that route instead.

Glen

Onder said:

Question on this post:
<If you were to stay with the standard box, one modification that is a must do for racing and higher power is to remove the steel kick start sleeve on the inner cover and replace it with a steel sleeve that holds a proper roller or ball bearing to properly support the RH side of the lay shaft.>

How is it that this helps? The kicker shaft only moves when you kick to start.
The layshaft turns inside the kicker on the bushing. Ive read where the bushing
has been replaced by a needle and can understand that. Also realize there may
be sense to the comments on having to grind the layshaft down to fit available
needle causing loss of strength of layshaft.

Im in my box now and it is surely a crapulous POS from design to execution.
Look longingly at TT five speed and trying to rationalize total cost of said
gearbox over the number of rebuildings , even replacements, over the life of
ownership. TT looks life a fine unit but terribly dear.

Click to expand...

Rather than a grind down of the RH side of the layshaft I used a this walled steel sleeve and carefully peened one side to keep it from sliding out. From what I can tell, under the stock configuration the layshaft has a wider span of support (can slide back and forth a bit). With the ball/roller bearing replacement it is a reduced span and the shaft is not able to slide back and forth as much. This is my recollection. Best if seen side by side.

The end result is no kick start spindle and no factory riveted paul plate and sleeve on the inside cover, only a steel bearing carrier held in place by one or twe allen bolts. The spindle hole through the outter cover was sealed with an o-ring and press fit aluminum plug with a shoulder.

As for the decision to go with a TTIndustries or not, you should take a look at total expected costs. For racing one may consider such things as the lilely cost of missing a race because of a broken gear box and the likelihood of that happening (expected cost), the likely costs of serious injury or worse as a result of a broken gearbox and the likelyhood of that happening and so on.

For serious Vintage racing I am convinced that the increased reliability, safety and durability of the TTIndustries option is the way to go.

I have no stake in TTIndustries.

As for the Vincent and Triumph gears, that is drag racing. To me, that is a whole different application of power and torque than road racing.