primary chain replacement

andychain

Hero member
As the song says, I can see claerly now.

These could be machined from a triplex plate wheel.

Paul by the way you have small pin single chains :D :D :D :D :D :D

Andy
 
P

paul-haggis

Guest
Hi Andy, the chain in the photo had done 16k enthusiastic miles when replaced. There was no great noticeable 'slop' in it when it was replaced. It was replaced with IWIS - which turned out to be the blue plated / greased industrial spec. I'm sure the blue plater is up to the job, but I would have liked to have tried one of your optimised simplexes. I would have liked to try the Merc duplex, but my middle row of teeth have since disappeared in a cloud of swarf. P.
 

andychain

Hero member
Paul as stated before both the Regina and iwis simplex chains are a good product with standard pins I just like the security of the pig pin no roller chain.

Andy
 

andychain

Hero member
Just to make it clear, when the pin turns in the outer plate as it has done this destroys the pressfit tolerance between the pin and plate. When this happens it is only a matter of time before it lets go.

Andy
 

sfcpiet

Administrator
Staff member
Location
Germany
Tom Eatman said:
If you need the clutch sprocket I have several lurking in the man-cave. Give me a buzz.

Thanks, Tom.  

I also have a couple..... Gijs asked me to try the steel chain wheel about 3 years ago, I can now report that it has stood up well.  Apart from the bending/mashing of the teeth tips from when the chain jumped the teeth and jammed against the casing, there is no evident wear.

Andy,

I'll check out the DID before I fit one.  OCT has sold and fitted dozens over the last year, no bad reports to date.....  Messrs Ehinger/Heyne use one in their race triple.... while they are cursed with DNFs, there has never been a primary chain issue.

The duplex MB chain has a major advantage though, one row of teeth can be deleted! :D

piet
 
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paul-haggis

Guest
Yes, Andy, completely agree. I was not at all questioning you comments in the suitability of the small pins in anyway. With the new-found knowledge you have kindly provided, I would like to go for the big pin jobbies next time. Maybe not needed, but I just want the best for my bike - as you say that bit extra security. Paul.
 

CLEMTOG

Hero member
what Haggis buy some thing that is 7 gramms heavier than the item to be replaced ? only if he can spark erode a .004mm hole straight through every pin.
CLEM
 

andychain

Hero member
Clem

Nice one mate but I think you will find it is about 90 grams.

G67WZ..............296 grams
G67HP...............386 grams

And that is per single chain.

Comparing the triplex.

06B-3...............789 grams
D67HP (Merc).....687 grams

The small pin chain is the lightest I will grant you but the Merc duplex comes a close second and pisses all over 06B-3 in terms of weight.

Going for a lie down in darkened room.

Andy
 

Dellortoman

Hero member
Andychain said:
Just to make it clear, when the pin turns in the outer plate as it has done this destroys the pressfit tolerance between the pin and plate. When this happens it is only a matter of time before it lets go.

Andy

Thanks Andy. That's a very handy warning sign to be aware of. Maybe we should call you Handy Andy  :wink:
Dead easy to check for turned pins when the primary cover is off. If any have turned then the chain goes in the bin.

Cheers,
Cam
 

sfcpiet

Administrator
Staff member
Location
Germany
Andy,

Turned out my chain is a German product, made by Arnold & Stolzenberg, a company that happens to be the Renold representative in Germany...    I had bought it from OCT.  Roger hasn't had any reports of others having issues with these chains.

Checked the DID triplex today, dimensions of pins and link plates identical to my busted chain......  so I guess I'll take you up on your offer.  You have a pm!

piet
 

andychain

Hero member
Piet

Once again it is a case of a big company being a little misleading. Renold own Arnold and Stozenberg, A&S, they purchased the German firm some years ago along with Brampton in France in and effort to get into the European market place. They succeeded. Once agian I leave myself open to critism and I point out that these are my personal views, but A&S was never one of the top quality chains. Germany had many chain producers including Wipperman and Kobo and I would maintain that iwis was always top of the class. It is interesting to note that on the fall of "the wall" many companies, including iwis, took the oppertunity to take over companies in the "eastern bit of Europe. There were many companies in that sector making chains for the Eastern Block and due to the regime both political and financial most were crap. Very much in the same way that chain from some areas of the world need changing almost as the machines arrive in Europe.

As I have previously stated it is almost impossible for end users to know who has produced which product and where, as a time served chain engineer, not a laptop chain rep, it saddens me that the original name for the product "Precision Chain" has been left behind due to acountants and companies putting price before quality. Chain is being sold as you would a can of beans and even the large companies take little note of some grey haired fat old English guy who predicted the situation many years ago.

Morning rant over.

And take note class there will a test later.

Andy     
 

andychain

Hero member
Nope just a bitter old guy that does not like modern business practices.

Dad is 86 and an old Renold guy and I am 60. I sincerely hope that my grandsons or even one of them will take up the fight and it looks very likely. I have been outspoken and misunderstood but to date no court cases. The reason I love this site is that despite early flack now people appear to understand my motives not only that but the knowledge regarding Laverda on here is superb. I read every post and the technical abiltiy from seats to Valves and just about anything is a joy.

Keep it up.

Love yer lots..........even Tim who appears to have come off whatever he was on.

Andy

Piet on the way mate. 
 

Dellortoman

Hero member
Chains arrived, thanks Andy. Took 3 days from UK to Australia. Couldn't have done it much quicker if you'd bought 'em a seat on a plane and taxi each end!

It's interesting comparing different chains.

I have 4 different primary chains in front of me: An original Regina triplex, an IWIS triplex, an IRIS triplex, and the IWIS (Mercedes) big pin duplex.
Of the tripex chains, the most heavily constructed is the Regina. It weighs in at 922 grams on my (non calibrated) digital kitchen scale, compared with 804 grams for the IWIS, and 802 grams for the IRIS.

Being only two rows, the duplex is obviously much lighter in total weight at 670 grams, but its construction looks about the same as the Regina - big pins and hefty side plates.

Comparing the apparent construction got me thinking (a dangerous thing). If you take the weight of the IWIS (Merc) duplex and manipulate it through some complex arithmetic* to estimate what a triplex chain of the same construction would weigh, the answer comes out to 975 grams. So the IWIS duplex is actually built more heavily than the original Regina chain. It?s a pity they don?t make it in triplex.  :sad:
* The complex arithmetic isn?t simply multiplying the weight of the duplex by 1.5. It?s a combination of multiplying the weight of the rollers and pins by a factor of 1.5 and the weight of the plates by 1.429 (380 plates in triplex / 266 plates in duplex). The trick is to know the weight distribution between plates, rollers and pins  :wink:

Andy, I know you said the choice of primary chain is a ?no brainer?. I must have no brain because I?m hard to convince, but I think I?m now tending towards your opinion that the big pin duplex is the best primary drive option out of what?s available today.

I also have an old Regina cam chain and a new IWIS equivalent in front of me.

For what it's worth, I've made some observations in the tables below. Dunno whether any useful conclusions can be drawn from this. Note that the figures are approximate - dimensions measured roughly and rounded to one decimal, and weights from my crappy cheap kitchen scales.

Cheers,
Cam
 

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andychain

Hero member
You must have too much free time Cam.

Unfortunately I do not work in "ifs" or "what ifs".

I work with what is freely available. Triplex as a quality product and I doubt if any manufacturer will divulge where their brand is actually made. Given this the Merc chain is obvious. If it had been freely available in the right lengths and more importantly known of by the manufacturers of the time , Triumph, Norton etc it would have been fitted.

The iwis cam chain is light but it all goes back to a well known fact to old guys.......low revs = high torque, high revs = low torque. The idea of high reving race engines using big chains is wrong. The Aston race engines use a tiny 8mm chain similar to old bike cam chains 219.

Thanks for your comments and remember the most important part of the chain is the steel. Get an old iwis down to your local uni and get it tested.

Andy 
 

Dellortoman

Hero member
I must have too much free time. Here's another product of my idle mind...

I was looking at the primary chain on the 3C I'm working on, wondering how much work it had done. I figured there had to be a simple way to measure the stretch in the chain, so I dived headlong into a bit of theoretical geometry. The bloody geometry wasn't as simple as it first looked, so it took a lot of head scratching and number crunching, but I eventually got it licked and came up with the chart below.

The shaft centre spacing of 176.5mm on Laverda triples is no accident. That's the exact spacing required for the 76 pitches of 3/8" chain to have zero slack. Well, that's the theory anyway. In practice, the chain will have a little slack because of the manufacturing clearances in the chain links. Anyway, the amount of slack in the chain can be measured by pressing down on the middle of the top span of chain and measuring how much sag there is. It's easy enough to measure - just lay a straight-edge across the two sprockets, press down on the chain and measure the amount of sag with a steel rule or vernier. You don't have to be super accurate, the nearst millimeter will do.

Look up the sag on the horizontal axis of the chart, and the % stretch (in excess of the theoretical chain length of 76 x 3/8") is on the vertical axis. If you prefer using a formula, this is a near enough approximation:

% stretch = 1.69 x Sag2/1000

Incidentally, the 3C had 9.5mm of sag which is equvalent to 0.15% stretch. Using Andy's rule of thumb that 1% stretch is a serviceable limit, the chain should be good for a while yet. Mind you, 1% stretch means a sag of about 25mm. I don't know whether the tensioner shoe has enough travel to take up that amount of slack. I think I'd pension the chain off long before it got that sloppy. Maybe around 12 or 13mm (1/2") sag will give a good safety margin. That's about 0.25% stretch.

Now waiting for Andy to load his gun with experience and practical know-how and shoot holes in my purely theoretical analysis  :D

Cheers,
Cam

 

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Dellortoman

Hero member
Here's a more practical version of the chart with a maximum range of 1% stretch.

I did this for Laverda triple engines. I don't know the specs for the 750's primary drive.
If the 750 has the same basic geometry (25/51 teeth, 76 pitch chain) then it'll work OK.

Cheers,
Cam
 

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andychain

Hero member
Very good.

The max tolerance on a new chain is +.13% at a load of 15lb.

As for chain claculation on length for given centre distance, there are some very complicated equations. Much simpler to download the free chain calculation form the Renold web site. Put in the values for a Laverda and see what comes up :D :D :D :D :D.

Andy

PS The allowable deflection on any chain drive is 1% of centre distance although on a bike I would go for 1-2%.
 
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