Any interest in a re-production of the front and rear primary gearing?

I have seen a similar scenario to that described by Cam, this was a 120 with two simplex chains and had lost drive, on opening the case a similar avalanche occurred, but what is different here is that those chains did not simultaneously fail, one will have broken first and the other then carried on, maybe not for long but carry on none the less, both chains had about 80% of the rollers missing but no broken pins, and fractured side plates to make the fail as Piet says, a total engine strip was needed, but didn't happen.

It is seriously annoying when people ask for help or advice, and I willingly give it, but its not taken or adhered to usually out of tighfistedness and sometimes out of me being an amateur prat and getting it wrong, but I am training to be a pro.
CLEM
 
That tightfistedness leads to much larger bills down the track a little way. But by then the scrimpers pass it on to some poor sod and we get to read about the DPO on here!
 
I found a split roller on the cam chain when I stripped the engine for a rebuild several years ago. Was a Regina chain.
Use only Andy's chains these days
 
I seem to remember talk about an advantage available in spinning the gearbox either faster or slower,don't remember the details.
 
Vince said:
I seem to remember talk about an advantage available in spinning the gearbox either faster or slower,don't remember the details.
Click to expand...

Gearbox output and torque delivered to rear wheel are governed by your road speed and acceleration. These are pretty much determined by driving conditions which you only have limited control over, at least while riding on public roads if you want to keep your licence.

For a given torque at the rear wheel, the torque input at the clutch (and therefore the load on primary chain) is lower for higher engine speeds. So if you wanna reduce the tensile load on the primary chain, keep the engine revs up. But with high chain speeds the dynamic loads increase. So it's all a compromise. The best advice for all of your engine and drive system components is to just drive sensibly. Don't lug the engine in a high gear or rev the guts out of it in a low gear.

 
No I was talking about changing the number of teeth in the primary to alter the speed the gearbox spins at compared to engine speeds. I don't remember the advantages or any context, maybe when Batto was having broken primary drive issues with his twin race bike. Maybe that belt drive had a different ratio to the chain drives.
This all stopped with Andys duplex chains being so much stronger.
So any advantage to changing the gearing in the primary
 
If you change the primary drive ratio to spin the gearbox faster, then the torque transmitted to the gearbox is reduced. You could use a larger crankshaft sprocket, or a smaller clutch sprocket. But then you have to compensate by increasing the reduction ratio in the final drive with a smaller gearbox sprocket and/or larger wheel sprocket.

Kind of sounds easy but isn't so straightforward due to the fixed distance between the crankshaft and gearbox input shaft.

Cheers,

bazzee
 
bazzee said:
Kind of sounds easy but isn't so straightforward due to the fixed distance between the crankshaft and gearbox input shaft.
Click to expand...

Yeah, I agree Baz. If you do the arithmetic, the shaft centre distance is exactly what it should be for the sprocket sizes and chain pitch. What little slack there is in the chain is down to the small clearances between chain components. Any other sprocket sizes would throw that relationship out the window and the tensioner slipper would have a whole lot more slack to take up. That's if you could fit different sized sprockets in there. There's bugger-all space to go up or down in sprocket diameters.

PS:
What would be possible is to switch to a different type of chain. A 3/8" pitch Morse HyVo type chain runs on the same pitch circle diameters as roller chain, so the shaft distance would work. It's been talked about on this forum before. I did some drawings (see attached) and I think Red came close to building a prototype, but shelved the idea when Andy came up with the Merc duplex chain.
 

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  • Toothed chain with case & follower.jpg
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A 750 clutch could be adapted, but would need a special sprocket to get the chain in line though.

Already been done, sort of, with a belt drive.  The 750 clutch was used to be able to close it off from the oil-filled primary drive cavity to run it and the belt dry (sorry, no pics).

piet
 
Hi all,

Contrary to common belief, there are none available. I have contacted all the various sellers all over the globe that I could think of, and they are not for sale, no longer available, nla, as a factory made new 120 set with two teeth rows and in the slimmer 120 spacing and with O-rings.

I reintroduce the list of interest here once more, and if there's enough interest, I'll have them made by a specialist company who do this sort of production.

So, if you want a set, write here, and we'll see if there's enough people to make it resonable. We can let it run for a while, as I Peder and I are in no hurry.

My set at least, will be cryo-treated to alternate the molecular structure.

1: Jacques Keller
2: Peder Heise
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Kind regards,
Jacques
 
Okay, so no interest showed, so list is closed. There will not be a reproduction of RGS series primary gearings.
I am speaking about the narrow chainline o-ringed RGS series gearings, with one outer, one inner row, not the wider near similar 180 version, which by the way also appeared on a very early RGS sample in the USA.
I'll have a set or two made my myself, as I have some plans to try out.

Kind regards,
Jacques

List closed.
 
sfcpiet said:
A 750 clutch could be adapted, but would need a special sprocket to get the chain in line though.

Already been done, sort of, with a belt drive.  The 750 clutch was used to be able to close it off from the oil-filled primary drive cavity to run it and the belt dry (sorry, no pics).

piet
Click to expand...

Found a pic.  Possibly of some interest to somebody...

piet
 

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  • Neu_prim?r Tuscher.jpg
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I don't reckon that drive belt would last very long under racing conditions.

Looks like the engine out of that monoshock custom bike that was built in Germany a few years ago. It was all over the internet back then, but I can't find it now. Only thing I remember about it was that it had a swing arm out of an Aprilia RS125.
 
Yes, built around 10 years ago in Bavaria.  Based on a RGS motor, I re-phased the crank to 180?, the rest is the brainchild of Hans Tuscher.  Not intended for racing.  AfaIk, the primary drive has not thrown up any issues.  Alternator driven by o-ring from the drive sprocket, Aprilia RS125 swing arm, twin spark ignition driven by points(!) at the LH end of the ex. cam, home-built frame.

piet
 
Is that the original outrigger arm, or a new one to suit?
I am asking because I have bought another original arm, which I will modify.

Kind regards,
jacques
 
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