Future for Zane bikes?

Miguel,

Rest assured, it is NOT 05B (do you really think we hadn't checked that?). Pitch and width are not the only things defining a chain, especially roller/bush dimensions play a MAJOR role. 05B, 06B/2/3 etc are standardised chains. You can regard the C107HC chain as custom-made.

Next problem will be tooth count, ideally it should be uneven/even, ie 15/30T, to spread chain and tooth wear evenly. When using even/even, ie 14/28T, the chain links will run on the same teeth over and over. Guess this can be neglected to some degree, no great milages will be spooled off and having a readily available chain, it can be replaced at shorter intervals.

Like I stated, nothing is as easy as it first seems.

piet
 
michipons said:
The problem comes when changing the sprockets, as the old diameter will be modified, so the earlier chain lenght calculation is not valid anymore,
Click to expand...
Yes, you're right, I've removed my post . Although theoretical pitch diameters of the C107 vs 06B sprockets were v-e-r-y similar, so the difference would be small.
If you're working it out then I suppose you don't really need to know the exact dimensions, since you only care about the difference between one option and another. Cam spacing is pretty easy to measure with moderate accuracy, crank to cams just estimate with a tape measure up against the engine (should get it within a couple of mm). With that and the pitch diameters of the sprockets (which are known) draw up the chain run and measure around it. Compare that against the theoretical chain length (pitch x no of links). Lets say the chain run is 5mm shorter than the chain for the C107 option - consider this is the 'slack'. Now redo it comparing the length of the 06B chain with the chain run around 15/30 06B sprocket pitch diameters on the same centre distances - how different is the 'slack'? This should give you a fair idea of whether it will work using stock tensioners etc.

But for sure the best and much more easy way to go is to find a suitable chain from Regina or elsewhere! :) I do not have a Zane or a 500 so don't know the exact dimensions of the chain. Surely someone would have tried the 05B by now if it were suitable? Or was the solution just hiding in plain sight? :)
 
sfcpiet said:
Miguel,

Rest assured, it is NOT 05B (do you really think we hadn't checked that?). Pitch and width are not the only things defining a chain, especially roller/bush dimensions play a MAJOR role. 05B, 06B/2/3 etc are standardised chains. You can regard the C107HC chain as custom-made.

Next problem will be tooth count, ideally it should be uneven/even, ie 15/30T, to spread chain and tooth wear evenly. When using even/even, ie 14/28T, the chain links will run on the same teeth over and over. Guess this can be neglected to some degree, no great milages will be spooled off and having a readily available chain, it can be replaced at shorter intervals.

Like I stated, nothing is as easy as it first seems.

piet
Click to expand...
sounds like marriage ... not easy
 
I honestly think we will get there and its a good project, Miguel can count on me for any machining work needed etc, and Im looking at other chain manufacturers for the moment to. Its not always about volume... sometimes its just enough to have a project that requires a little soul
 
OK, given the specs that have been bandied about, I've done a few quick calculations. The numbers don't model the system perfectly because I made a couple of minor approximations with the geometry, but they should be pretty close.

114 links of the original C107HC chain wrapping around a 15/30T sprockets gives a shaft centre distance of 362.65mm assuming no slack in the chain. That would have to be pretty damn close to the actual centre distance otherwise the tensioner would have a to deflect a long way to take up the slack.

Looking at a couple of alternatives compared against the C107HC original, 05B with 14/28 teeth and 06B with 13/26 teeth look like the most promising. I tried a few other combinations but those two are closest fit to the original sprocket diameters and centre distance. What I did was to work out the optimal centre distance the alternatives needed for zero slack, then used that to work out how much slack there would be in that setup when the shafts were pushed together to match the original centre distance. It seemed like a logical approach to me, but mathematicians might come up with a simpler way to do it. It was no good just looking at chain length, because the chain length for the 05B option is actually kess than the original because the sprocket PCD's are smaller.

C107HC05B06B
Link pitch (inch)
0.307​
0.375​
Link pitch (mm)
7.80​
8​
9.525​
Small sprocket teeth
17​
14​
13​
Large sprocket teeth
34​
28​
26​
Chain links
112​
112​
96​
Ratio
2.00​
2.00​
2.00​
Small sprocket PCD (mm)
38.17727​
35.95167​
39.80099​
Large sprocket PCD (mm)
75.93625​
71.45123​
79.02159​
Chain length (mm)
904.875​
896​
914.4​
Optimal sprocket centre dist with no slack (mm)
362.6459​
363.5633​
363.7978​
Actual sprocket centres in engine (mm)
362.6459​
362.6459​
362.6459​
Difference between optimal and actual centre distance (mm)
0​
0.917432​
1.151949​
Slack in chain at original centre distance (mm)
0​
1.834864​
2.303898​
Tensioner deflection to take up above slack (mm)
0​
18.2632​
20.47136​

One of the approximations I made was to assume a single point tensioner like a small idler wheel. The deflection would be a bit less for a curved blade type tensioner. I dunno what sort of tensioner the Zane bikes use and I didn't bother looking it up on a parts diagram because I'm not doing an actual design here, just some ballpark calculations. If someone wanted to take this further I could build a more accurate mathematical model.

The 06B option might require a bit of machining to the cam chain tunnel because the sprockets are a wee bit larger than the originals.
 
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Cam,
Changed some figures in your table above, Link pitch, small and large sprocket teeth, amount of links on a 500

Dimensions are
Main bearing 72mm OD/2 = 36mm
Bearing recess to top of Crank case 51.50mm
Base gasket 1.0mm
Barrels overall 85.0mm
Head gasket 1.0mm
Head thickness 111.50mm

Total crank center to camshaft center 286.0mm

Cam centers Inlet to Exhaust 100mm

500 has a blade type tensioner, rubbing block on the front similar to a triple

HTH
Red
 
The only caveat I'd have to those calculations is that the layout is a triangle with all the slack taken up on one run.
Which infers that the less slack the better as a tensioner of whatever type doesn't have a lot of room to move
A blade even less - thanks Red.
 
Thanks Red. So from your shaft centre distance, I assume the 500 engine has different dimensions to the Zane engines. Otherwise 114 pitches of C107HC would be way too long for a 500. If it uses the same chain then I've wrongly interpreted the chain path.
 
GregT said:
The only caveat I'd have to those calculations is that the layout is a triangle with all the slack taken up on one run.
Which infers implies that the less slack the better as a tensioner of whatever type doesn't have a lot of room to move
A blade even less - thanks Red.
Click to expand...
Fixed ;)

By triangle, do you mean the return run of the timing chain goes around an idler sprocket (or roller) that deflects the chain a long way off the straight line between the two sprockets. If that's the case then it makes sense (to me) of Red's shaft centre distance. In my arithmetic above, I was assuming straight runs between the sprockets on both sides of the chain.
 
I understood we were talking about DOHC motors....Red's supplied the vertical distance crank to cams, but the actual run distance is the hypotenuse of the triangle of which we know two sides, Crank to cam CL 286mm, and half the distance between cams = 50mm.
But that is of course center to center, not the actual length of chain over the sprockets.

PB2 - you've got it.

Edit - well, yes, it tells us how long that run is as part of the full calculation when you're varying sprocket sizes.
 
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piranha-bro2 said:
Isn't the triangle the profile between the two camshafts (in and ex) and the crank centre?
Click to expand...
Ah. Of course it is. Is there a smacking forehead emoji?

I was thinking in Breganze 750 twin mode. I forgot the Zane and 500 twins are DOHC. Most of my arithmetic is wrong then.

I suppose the only relevant bits are the relative lengths of cam chain. Forget my dumb calculation for shaft centre distance. Now I understand Red's shaft centre numbers. I can re-calculate if someone can tell me the centre distance between the two camshafts.
 
Dellortoman said:
Thanks Red. So from your shaft centre distance, I assume the 500 engine has different dimensions to the Zane engines. Otherwise 114 pitches of C107HC would be way too long for a 500. If it uses the same chain then I've wrongly interpreted the chain path.
Click to expand...
that is correct, 500 uses 112 links, Zane 114 links as Zane cylinder head is thicker

I stated the camshaft center to center at 100mm in my reply above
 
michipons said:
Of course Piet, I was confused because Breganzane had writen that some bikes could have had 8mm which is 05B. A missunderstanding.
Click to expand...

My meaning was that I didn't know if the original C107 chain was an 8mm pitch or 5/16". Still don't. Which is it?

Separately to this topic, I've learnt something interesting during this discussion. Standard chains change from metric to imperial throughout their size range!! 04B=6mm pitch, 05B=8mm, 06B=3/8", 08B=1/2" etc. Totally bizarre. Imagine a screw thread standard that had millimetre pitches below a certain size and TPI above?
 
My actual head hurts, but I love this. And not a sketch is sight. Well done you imaginative types. Good thought experiment
 
500, 600, 650 and 668 use the same chain, ie, 112links. Zane 750 uses 114. Differentiate between air- and liquid-cooling!

If this is to be carried on to the 750s, there is about 1.5mm clearance between the cam sprockets, cams are a lot closer together because of the smaller included valve angle.

At a guess, I'd say the air-coled cams are about 150-170mm apart...

Looks like quite a few ambitions have been woken.;)

piet
 
breganzane said:
My meaning was that I didn't know if the original C107 chain was an 8mm pitch or 5/16". Still don't. Which is it?

Separately to this topic, I've learnt something interesting during this discussion. Standard chains change from metric to imperial throughout their size range!! 04B=6mm pitch, 05B=8mm, 06B=3/8", 08B=1/2" etc. Totally bizarre. Imagine a screw thread standard that had millimetre pitches below a certain size and TPI above?
Click to expand...

And if it's an orphan size chain, what's the roller diameter please ?
 
Guys,

Been reading this thread with interest. Before venting too many opinions and guesses, please get the facts; read the documentation. It is out there.
The Regina C107HC was a bit of an odd child but neither orphan nor custom. It's just that Laverda and Guzzi were the only ones to buy it at Regina and so only Regina listed it as a known application. And Regina focuses on bikes, much less on cars or industry in general.
Given the costs involved with setting up production and tooling no way it would be limited to just a couple of thousand Laverdas and Guzzis. Neither Regina nor Laverda would have been that foolish. So there is a normalised size / series behind it and thus other people must have used and produced it.

It is partly metric; 8 mm pitch. Unfortunately chains are still very much dominated by medieval stuff like inches and 11/128" conventions. Old standards don't die out quickly. Oh well.... ;)
The 8mm pitch series was introduced around then to offer cam chains for the European automotive industry that would be more compact (lighter) and at the same time take higher revs than the bicycle derived inch-series that were available before. Just the thing for the new fast running small Laverda 500 engine.... well let's use that!

As per Regina specs the sizes are:
pitch: 8,00 mm
roller dia: 4,77 mm
roller width: 5,72 mm
average tensile strength (ats): 9,5kN
# links: 114 (750), 112 (others)

8mm pitch chains are pretty common in European and Japanese car engines, and they seem to be popular in small mopeds and minibikes too. Thing is to get one that will cope with the uneven load of driving a cam. Most of these have a slightly smaller roller width though; around 4,6 - 4,9mm.
No idea why someone decided to go with the oversize width, might be that tooling for 5,2mm sprockets was available so less investment there. Or they wanted to share sprockets between models. Anyway, that's what they did.


There is at least one producer with an exact match on all aspects, but I'm not sure about their quality. It's a chinese factory: may be good, may be rubbish. You could buy some and pull them apart on a bench and see. Alternative would be no chain at all.
Must check some more catalogues to see what's available.

Another option is to go with a current cam chain from a well known supplier but slightly narrower. That would mean shaving 0,25mm off of either side of the original sprockets. Still a cam and crank out conversion but no need for a bespoke crank centre pin (heat treatments anyone?) and cam sprockets. I will be happy to go that route when time comes; 4,7mm is wide enough for this sort of application.

Will be back.

cheers
Tom
 
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