Triplex v. simplex primary chain

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<DIV>Hi Phil,</DIV> <DIV>with the help of Photoshop (cos' my sore eyes) I enhanced a bit brightness and contrast of Piet's pic. I saw a bump in the cover where the pump sprocket axel should be. So I guess the pump is still in place (maybe modified).</DIV> <DIV>Don't know if Piet is allowed to confirm this ;))</DIV> <DIV>Cheers</DIV> <DIV>Heiko (the spy)</DIV>
 
<DIV>Hi Heiko - Nice bit of detective work - I  still reckon that Piet's got a belt driving the pump with  the motor  running backwards and an extra idler in gearbox<IMG height=19 src="/forum/msnemoticons/emwink.gif" width=19> - regards - Phil</DIV>
 
<DIV>Hi fellas!</DIV> <DIV> </DIV> <DIV>Guess I've got you stumped, huh?</DIV> <DIV> </DIV> <DIV>Phil, the pump is still gear-driven but the entire lube system has been modified with an external spin-on filter fitted to the front of the crankcase.  </DIV> <DIV> </DIV> <DIV>I'll ask if I may show pics of the complete bike, I assure you it is mind boggling!</DIV> <DIV> </DIV> <DIV>cheers,</DIV> <DIV>piet</DIV>
 
And the clutch? Is converting a wet clutch to a dry clutch as simple as draining the case of oil?
 
<DIV>Just to split off from the clutch examination thread, and to put aside belt drives as they are rather rare and expensive, does anyone have a strong technical argument (or experience!) one way or the other?  I know both are readily available from your local transmission factor, and that 2 x simplex are much cheaper than 1 x triplex at my Renold dealer, but what is best??</DIV> <DIV> </DIV> <DIV>NickNZ</DIV>
 
This is my own belief....

The two single chains have a lower drag than a triplex. It also seems to make sense that if they are alligned properly they will drain less power from the crank to the clutch...

Anyway that might get the conversation flowing !!

Tim
 
<DIV>I seem to have a history of weird problems with my bike but at one stage I had quiet a lot of noise from the primary,the chains got missed from being changed during the 1/2 dozon engine rebuilds resently,the noise turned out to be lots of slop in one of the chains,the adjuster worked on only one of the chains and the other was flaying about,dont know why one would wear more than the other,it now has a tripalex and all is good.</DIV>
 
<DIV>The original spec was  a Regina item. Regina brought out a simplex chain which, when used as a pair , had a higher rating than their Triplex. There are subtle differences in the construction of the pins and rollers and the thickness of the side plates which give these various chains their characteristics. </DIV> <DIV>I have quite few original, brand new Regina chains for twins and triples. If anybody wants some please drop me a line off the list. The price is usually less than the cost of a pattern item.</DIV> <DIV>Ray Shone has fitted some Cosworth chains to his Jota which look very trick to me. I think they had some spacing issues which needed a little work to get them to fit. Ralph Allen at Motalia has a source for these....they ain`t cheap though.</DIV> <DIV>Bob</DIV>
 
<DIV>When it came time to replace the chain on my RGS I replaced it with simplex chains as original along with the clutch rubbers. After it was done I wondered why it was still made noise at idle as compared to my 3CL. So as an experiment I took off the simplex chain and put on an old used triplex chain I had laying on the shelf. It got rid of the noise. OK I thought why does the simplex make noise? Putting them back on and inspecting everything it was apparent the simplex chains were not the exact same length so one chain had more slack than the other. So I ordered a new triplex chain and that is how the RGS runs now.</DIV> <DIV> </DIV> <DIV>Bruce</DIV>
 
Interesting thread this. In those cases where the duplex chains caused problems, let me ask a stupid question: were the chains identical? Purchased at the same time from the same supplier?
It's time I thought of replacing the primary drive chains on my triples, so this discussion is very timely and interesting.
Some time back I acquired a belt drive kit but lost my enthusiasm for this "upgrade" when both Wolfgang and Andy Wagner reported they were failure-prone. I've heard that the belt material continues to be improved, so once again I'm pondering installing that.
Anyone with recent experience with a primary belt drive?
 
<DIV>If memory serves, the explanation given at the time was that two simplex chains were quieter than a triplex.  The factory had to do a lot of work to enable the RGS to meet noise regulations - as an example, Massimo cited the work that went into the airbox trumpet design to keep airflow 'supersonic' and minimise induction roar; also the clutch outrigger bearing redesign.</DIV> <DIV> </DIV> <DIV>A more cynical view is that two simplex chains are cheaper than a triplex!  From the Renold website for a given size & type, two simplex chains are stronger than a duplex but 25% less strong than a triplex.  They also refer to the need for matching chain stock that is used in tandem arrangements.</DIV> <DIV> <A target=_top href="http://www.renold.com/Renold/web/site/Products/TransmissionChainSprockets/TransmissionChainIndexPage.asp?menuID=39">http://www.renold.com/Renold/web/site/Products/TransmissionChainSprockets/TransmissionChainIndexPage.asp?menuID=39</A> </DIV> <DIV> </DIV> <DIV>Whilst there are horror stories about snapped chains, I'm not aware of any causal link with simplex/triplex fitment.  Problems are usually explained by overdue replacement, incorrect adjustment or use of poor quality chain.  Misaligned sprockets don't help, either!  </DIV> <DIV> </DIV> <DIV>Just to throw another thought into the pot, would fitting a triplex in place of 2 simplex result in accelerated wear because the centre strand was running on previously unused teeth, compared to the outers?</DIV>
 
<DIV>given the choice between having a primary chain let go and punch holes in the cases while locking the back wheel at speed and threatening my life, or having a belt disintegrate and clog up the engine with debris, I'll take the belt.</DIV> <DIV> </DIV> <DIV> <DIV>the Primary belt drive sets John Scerri makes are about $400 U.S. or so. Then there is, I believe, a German (?) company also selling a belt drive kit? Tons of these belt drive primary conversions running successfully on vintage British bikes. What is the present price of a new Triplex primary chain AND matching sprockets? I really don't know, but would be interesting for comparison purposes.</DIV></DIV> <DIV> </DIV> <DIV>there are a few 'horror stories" about primary belts failing. As Brad mentioned, there are also the "horror stories" of primary chains letting go, but I agree with Brad that there is typically a reason for a failure, often as simple as owner failure to replace a worn chain, failure to adjust the tensioner as required, etc. However, what about worn primary sprockets?</DIV> <DIV> </DIV> <DIV>I have always wondered about the wisdom or possible stupidity of installing a new primary chain on obviously worn primary sprockets. Shouldn't the primary sprockets be replaced at the same time as the primary chain, same as when you replace a drive chain? I would never install a new drive chain on old sprockets, waste of money, as the new chain will wear out quickly, possibly wear abnormally and break, and in my opinion, a safety hazard. Obviously the front and rear drive sprockets wear out with the chain, I don't see how the primary sprockets are any different, yet people do not appear to be replacing the primary drive sprockets, just slapping on a new chain. I expect pretty much most of the bikes running around out there are still on their factory original primary sprockets, more than well worn by now, don't you think? </DIV> <DIV> </DIV> <DIV>Regards</DIV> <DIV>Paul LeClair</DIV> <DIV> </DIV> <DIV> </DIV>
 
<DIV>Hi all</DIV> <DIV>        Just a few comments - the clutch and primary drive sprocket have extremely hardened teeth - hence lack of wear as per normal secondary drive sprocket. Can't buy into risking life if primary chain snaps - just pull in clutch as per piston etc seizure - gearbox seizure another matter - Regards - Phil</DIV>
 
<DIV>Hi Paul,</DIV> <DIV> </DIV> <DIV>Four or five years ago I spoke to the 'No 1 belt drive designer' in UK about the possibility of fitting a belt drive to a 750 SF. He said that belts should never be run 'wet' as the oil gets trapped and pressurised between the belt and the cog eventually snapping the belt.</DIV> <DIV> </DIV> <DIV>He said he had worked with several Laverda owners to try to achieve a 'dry' primary drive on a Laverda but never succeeded. It may be that belt technology has moved on, but I feel that most kits available here are for 'open' primary drives.</DIV> <DIV> </DIV> <DIV>I can't wait for somebody to shoot me down in flames!</DIV>
 
Hi Paul
I think the different wear rates of primary sprockets vs rear drive can be explained by several factors:
1) Clean environment inside the cases vs outside road debris, etc.
2) oil bath vs dry/dirty outside
3) constant geometry vs swingarm movement generated changes
4)torque direct from crank vs multiplication thru gearbox.
5)sprocket/roller size (many rollers in engagement at same time) vs just a few on the countershaft sprocket. BTW, this is the biggest killer of rear chains
6)Higher precision and harder surface (more expensive sprockets) vs cheaper stuff that they know won't last much longer even if double the price

The reason there are very few rear drive belt systems is they can't handle the torque multiplication from the transmission. Harley with low HP runs a very wide belt, the only way to increase the capacity. There is no space to run a 4 inch + wide belt on a big sport bike! But, they can be used in the primary drive since it is direct from the crank. Works better with more cylinders/cc, since the power pulses are weaker.

With the increased technology in chains, breaking primary chains should not be a problem, if they are made with newer spec materiels. Chains are WAY stronger than the ones made back when these bikes were new. So, NOS chains may not be a good thing, IF new replacements are made with current spec materiels. Some research may be needed here.

Will
 
<DIV>Buell 100+ HP plenty of torque35mm drive belt!!!!!!!!!!!</DIV>
 
<DIV>Well, in 35 years of ownesrhip of various bikes, I have never broken either a primary chain or a primary belt (knock on wood), yet, I defer to greater wisdom and experience. Interesting comments, especially from Phil, I guess I didn't think it through as to what would actually happens if a primary snaps and locks up the clutch basket - pulling in the clutch obviously would free the back wheel to continue to rotate.<IMG height=19 src="/forum/msnemoticons/emembarrassed.gif" width=19></DIV> <DIV> </DIV> <DIV>If the primary belt breaks on either the 1200 or the RGS, I'll put a primary chain and chain sprockets back on. Till then, I am happy with the light, silent, belt primary.</DIV> <DIV> </DIV> <DIV>I put a lot of miles on my highly "built" Harley with no problems with its belt drive to the rear wheel. I do acknowledge that my Harley ran a primary chain in the "wet" primary, and the various Harley belt drive primary conversions available all appear to run "dry", which I suppose should tell me something. Hmmmmm.............<IMG height=19 src="/forum/msnemoticons/emidea.gif" width=19></DIV> <DIV> </DIV> <DIV>Regards</DIV> <DIV>Paul LeClair</DIV>
 
"I have always wondered about the wisdom or possible stupidity of installing a new primary chain on obviously worn primary sprockets. Shouldn't the primary sprockets be replaced at the same time as the primary chain, same as when you replace a drive chain? I would never install a new drive chain on old sprockets, waste of money, as the new chain will wear out quickly, possibly wear abnormally and break, and in my opinion, a safety hazard. Obviously the front and rear drive sprockets wear out with the chain, I don't see how the primary sprockets are any different, yet people do not appear to be replacing the primary drive sprockets, just slapping on a new chain. I expect pretty much most of the bikes running around out there are still on their factory original primary sprockets, more than well worn by now, don't you think?"

gee Paul, with this argument you'd have to think about replacing cam and crank sprockets with cam chains. ;)

cheers,
scott
 
<DIV>Hi Scott</DIV> <DIV> </DIV> <DIV>I am sufficiently anal that in fact I have THOUGHT about replacing the cam sprockets with the cam chain, easy enough to change out the cam sprockets at the same time, changing the cam chain sprocket on the crank, on the other hand, would be going a little too far even for me....... <IMG height=19 src="/forum/msnemoticons/emdgust.gif" width=19></DIV> <DIV> </DIV> <DIV>All in good fun.</DIV> <DIV> </DIV> <DIV>Regards</DIV> <DIV>Paul LeClair</DIV>
 
<DIV>As far as I know the primary chains were replaced at the same time by the local distrbuter with the right grade chains,the bike then in about 10 or so years did maybe </DIV> <DIV>10,ooo km till the huge spate of rebuilds in the last couple of years,its posable that a differant more worn chain was installed during one of these rebuild by mistake but thats highly unlikely,more likely is a differant wear rate between seperate chains,thats why I like the origanal tripalex and am happy Wolfgang has them,anyone know what type and grade the 2 sperate chains Jim Eades were using in the late 80s,the reason they were fitting 2 chains I was told was the tripalex was not being produced anymore.</DIV>
 
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