Which Direction Does the Commando Engine Rotate?

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I don't know how Ducati are able to easily reverse the direction of rotation of the Panigale engine. When that was mentioned in the video I watched, it sounded as though they did it after the bike had already been manufactured.

 
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acotrel said:
In most bikes with geared primary drive, the input and output shafts of the gearbox are not on the same centre. so the output shaft turns in the opposite direction to the input shaft. The clutch is on the input shaft. With any bike with a chain primary, everything except the gearbox lay shaft and the idler timing gear usually runs in the same direction as the wheels, unless there is a Japanese type gearbox fitted - which is unusual in older bikes.
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I had given little thought to the gearbox with non chain primaries before posting.
Unlike some (spacer), I left my post there instead of deleting it, a little embarrassment can be good for you.
 
The direction the Japanese gearbox shafts turn, means it is not easy to adapt one to use in an old British bike. You would actually need an extra pair of gears on the end of one to get the final drive sprocket to turn in the correct direction.
 
acotrel said:
The direction the Japanese gearbox shafts turn, means it is not easy to adapt one to use in an old British bike. You would actually need an extra pair of gears on the end of one to get the final drive sprocket to turn in the correct direction.
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The TZ350 Yamaha has a gear on the end of the crank that drives the clutch drum and the gearbox input shaft....conventional Japanese approach for twins and singles and some multis, crank rotates in same direction as the gearbox output shaft and therefore the rear wheel!

The TZ750 Yamaha has a central gear between two cranks that runs on a countershaft that drives the clutch drum, crank rotates in opposite direction to the wheel, clutch and gearbox input shaft rotate same as TZ350.

Some people think of the TZ750 as two TZ350s, it isn't quite, due to the crank rotating backwards, apart from other things, cylinder and piston/ring wear patterns are very different!

Do remember gear driven clutches are normally mounted on a gearbox input shaft, feeding an output shaft. Norton and other British gearboxes with chain/belt driven mainshaft mounted clutches have input and output on same shaft centreline, the mainshaft, and intermediary gears drive through the layshaft, except for top gear which locks the ouput sleeve gear to the mainshaft for 1:1 drive!

You don't need an extra pair of gears, you need a countershaft behind the crankcase with an input to connect to the crankshaft and an output to carry a drive gear for the gearbox input shaft. And you need two big sturdy gears to mount the shaft on.....and some sturdy castings to stop the bearings from moving!

Easy innit!
 
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I thought it might be possible to put a gear where the sprocket usually goes on a Japanese gearbox , and transfer the drive through another gear with a sprocket turning on the input shaft, to reverse its direction.
 
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Bernhard said:
2 x 350 do NOT add up to 750 do the Maths!!!!:(



https://www.bing.com/images/search?...E63A0340799F357960E16C65AC91DBF59&FORM=IQFRBA

The TZ700 came first before the TZ750!!!! Oh yes it did!

Removed broken link
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Bernard, I think you are responding to something I didn't even say!

As for your assertion, well go tell Yamaha, because if you ask Yamaha there was no 'TZ700', from the start they called the production 'TZ700' the TZ750A! There was no TZ700 'model', it is just called that because we know the early bikes were 700cc. The A model is distinguished by being twin shock. The production TZ750B was a full 750cc with cantlilever monoshock suspension. (Let's not even get into works OW numbers).

Pretty clearly Yamaha used two 'TZ350' cylinders on the early bikes, but too suggest the motor was two 350s bolted together ignores the crankshaft and rotation stuff. The bottom end was unique. The barrels were 'adapted' and pistons had to be suitable for the reverse rotation and thrusts as they run over the ports.

Of course private runners did all sorts of things that Yamaha didn't, indeed some people (John Williams comes to mind from late '75 at Brands) rode TZ350s fitted with TZ750 barrels in the 500 class, so you 'do the maths' and tell me exactly what capacity they were? I have no idea what actual pistons he used!

(Nominally they were 375cc, but they weren't quite.)

And before we go any further, sorry, were are a long way from the OPs question!
 
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I was offered a 750cc Guzzi race bike. It came to Australia from the US, where somebody had been killed while riding it. I suspected the torque reaction of the motor had played a part so I did not buy it, even though it was pretty cheap.
 
SteveA said:
Bernard, I think you are responding to something I didn't even say!
As for your assertion, well go tell Yamaha, because if you ask Yamaha there was no 'TZ700', from the start they called the production 'TZ700' the TZ750A! There was no TZ700 'model', it is just called that because we know the early bikes were 700cc. The A model is distinguished by being twin shock. The production TZ750B was a full 750cc with cantlilever monoshock suspension. (Let's not even get into works OW numbers).
Pretty clearly Yamaha used two 'TZ350' cylinders on the early bikes, but too suggest the motor was two 350s bolted together ignores the crankshaft and rotation stuff. The bottom end was unique. The barrels were 'adapted' and pistons had to be suitable for the reverse rotation and thrusts as they run over the ports.
Of course private runners did all sorts of things that Yamaha didn't, indeed some people (John Williams comes to mind from late '75 at Brands) rode TZ350s fitted with TZ750 barrels in the 500 class, so you 'do the maths' and tell me exactly what capacity they were? I have no idea what actual pistons he used! (Nominally they were 375cc, but they weren't quite.)
And before we go any further, sorry, were are a long way from the OPs question!
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Humble apologies for misunderstanding your reply.
FYI the 700 did have piston ported, whereas the 750 was reed valves. The 700 and 750 barrels could be fitted to a TZ350 crankcase, thought you will have to open up the crankcase mouth to fit them-size was about 375cc. The 700 engine became popular with the sidecar boys& gals. Long before the 750 came along, there was available, offset crank pins for the 350 to increase the capacity to 351 to enable it to be ridden in the 500 class, but some race scrutineers clocked onto this and would measure up the engine size to check that you had it done, those that were caught out with a 349cc engine had simply changed the blue number background for a yellow Fablon sticky back plastic 500 one – hence the term having a “Fablon crank” was talked about in the race paddock!
 
My friend rode for Millege Yamaha in Melbourne in the 70s. I was told that he had tried using two TZ350 barrels in a TZ700. However when I asked him about it in recent years, he denied it. A TZ700 would be a horrendous bike to try and race with, if it did not have the reed valves. The TZ700 might have been called the TZ750 by the Japanese, but we always knew them as the TZ700. The 750 version was quicker, depending on the rider - the monoshock suspension was a major improvement. In fact when I said to Bob that I remembered him riding a TZ750, he corrected me and said 'it was a TZ700'. He was still almost impossible to beat.
With my silly two-stroke project, the motor consists of three RD350 barrels and heads on an H1 Kawasaki bottom end to give 600cc. The port timings are TZ750. The frame is a copy of the 70s Egli frame that Graeme Muir used with a TZ750 motor, to win a round of the Swann Series at Sandown in about 1978. The running gear of my project is Suzuki RG250. I have run into a lot of very silly minor problems, so I have lost enthusiasm. One day I will complete it.
 
acotrel said:
My friend rode for Millege Yamaha in Melbourne in the 70s. I was told that he had tried using two TZ350 barrels in a TZ700. However when I asked him about it in recent years, he denied it. A TZ700 would be a horrendous bike to try and race with, if it did not have the reed valves. .
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Yes, the TZ700 was exactly that as it had a very sharp powerband, that is why Yamaha made the 750 with reed valves and a little more " rider friendly"
 
I am fairly certain the TZ700 had reed valves. I can remember my friend riding it. It never grabbed him by the throat. A TZ700 with TZ350 barrels would be a bad joke. A TZ350 on it's own is a very savage bike. Later Yamaha production racers all have reed valves and are designed to deliver more torque, so they are actually faster when raced. And most of them are 250s or 500s, not 350s. The three cylinder 350cc Yamaha that Ferry Brower was involved with, was faster than the 500cc four cylinder two strokes. Many people believe that the bike with the most power, wins. But torque wins races. You can have tons of top end but go nowhere. In drag racing, it might be different.
 
I never rode the Egli 700 that Muir rode in the Swann Series, but my friend rode it at Calder. He said he saw the end of the front straight get extremely narrow as he approached it.
 
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