Stubborn 750 cam chain fitment

Yup - we realised that pretty soon on. Tensioner bolts wouldn't do up and no way we were going go crank down hard on them. I'll take a picture in a bit.
 
This spacer must be about 8mm thick. It allows the tensioner to push under spring tension only by a mm or so. The idea was to run it like this until the new rollers are worn then remove but it makes me uncomfortable
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That is insane. The wheel and/or rubber block must be way over size. It is now such that nothing we buy can just be fitted without thorough checking and modifying.
 
Closed up a 750 top end today, chain installation was a pain and effortless 3-minute affair. Customer supplied a NOS Regina chain and standard pattern gaskets by Centauro. Head will be re-torqued tomorrow and chain tensioner fitted with new seal, rubber and roller. All looking good.

Can't believe 3 pages have been scrawled on the topic over the past week.

piet
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It took way longer to sort my rear light bulbs on my Atlas, finally Andy in NZ sent a picture and I suddenly noticed the slots were the bulb fitted were so tiny I thought they couldn't be right. Communicating via text and pins is hard work.
 
I can only say that the Regina Extra cam chain that came with the bike at 15K miles is an extremely tight fit with barely any flex when I press on it thru the tensioner opening. I counted 88 pitches which I understand is proper spec. But thank you all for your help- raising the motor to level and firmly grasping the chain ends while the motor was slightly advanced back and forth seated in the chain. The trick was to make sure that the timing marks on the cam sprocket stayed at 12 o'clock, along with the timing marks on the case and flywheel aligning.

I may heed others advice about doubling the tensioner gasket, but I've lubed up the tensioner plunger so it slides back and forth. I replaced the worn roller and hard "bumper".

Again, this Forum has been very informative and helpful.
 
No yellow inserted nuts Piet, come on mate you can do better than that! (ps if you find a source of them I will buy 250)

"seems a right old faff when it should be straight forward." I couldnt agree with you more EB, I bought my SF1 brand new and had no end of trouble fitting a new cam chain when Slaters were in their heyday and supplied factory parts, the reality is this.... at the time I thought I must change the internal engine chains, all three of them due to the mileage, which was at that time 25,000K's. I now know that this advice was probably due to the deal that Moto Laverda had with their chain supplier, who knows, just a guess, but there was no way that cam or primary (or even starter) chain needed changing, I kept them and used them for decades later after re-fitting, my triple gets far more use than my 750 these days and the same applies, the triplex primary will last a lot longer than manufacturers spec changing period, My son david (who is an engineer in ordance and explosives with MOD) did a clinical wash and measure of a triplex chain with more than 50,000 kilometres on it and a brand new one (same make) straight out of the box, and the difference was miniscule, read whatever you like into that.
CLEM
 
CLEMTOG said:
No yellow inserted nuts Piet, come on mate you can do better than that! (ps if you find a source of them I will buy 250)

"seems a right old faff when it should be straight forward." I couldnt agree with you more EB, I bought my SF1 brand new and had no end of trouble fitting a new cam chain when Slaters were in their heyday and supplied factory parts, the reality is this.... at the time I thought I must change the internal engine chains, all three of them due to the mileage, which was at that time 25,000K's. I now know that this advice was probably due to the deal that Moto Laverda had with their chain supplier, who knows, just a guess, but there was no way that cam or primary (or even starter) chain needed changing, I kept them and used them for decades later after re-fitting, my triple gets far more use than my 750 these days and the same applies, the triplex primary will last a lot longer than manufacturers spec changing period, My son david (who is an engineer in ordance and explosives with MOD) did a clinical wash and measure of a triplex chain with more than 50,000 kilometres on it and a brand new one (same make) straight out of the box, and the difference was miniscule, read whatever you like into that.
CLEM
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Sure Clem, of course I could...

I do have a personal stash of freshly plated ones, ear-marked for those 120% restorations that I might get around to performing one day.

Manufacturers/outside suppliers need to reckon with the stupidity and ignorance of future users, hence the rather short specified change intervals. With the gentle use and low mileages these bikes see these days, along with the old codgers at the bars, chains will definitely last much, much longer than originally specified.

Never found any mention of timing chain replacement in Laverda factory literature. Guess Massimo never expected them to be used for much more than the 70-80000km the chains are at least good for, before being dumped for the next shiny toy. Even the service booklet for the RGS ends at 48000km. There, the primary chain change is specified at 24000 and 48000, no mention of timing chain except inspection thereof, but the tensioner blade was to be replaced every 16000km, along with a top-end de-coke! I do remember reading in a later factory publication that pistons were to be replaced at 60000km, apparently the factory was aware of the top ring groove wear issue.

I advise my customers to observe the short change intervals (chains and oil) as well. They'll swear on their mothers' grave that they will stick to running-in procedures, to stay under rev limits, etc, bla, bla, but I know for certain that some individuals don't care a rats arse about good (any!) advice and will gleefully murder their engine and come sulking back.

I too have managed to break a triplex primary chain. 2nd. to last lap on the Sunday of the 2010 Bikers Classics... not much damage, thankfully. Turned out it was from a incorrectly supplied batch that OCT ordered, chainman Andy later confirmed it to be of inferior quality. To be fair, it did hold up to 2 years of road use as well as 2 track weekends. Been running Andys' IWIS primary in the 3C since then, all others run on DID products.

piet

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olly said:
This spacer must be about 8mm thick. It allows the tensioner to push under spring tension only by a mm or so. The idea was to run it like this until the new rollers are worn then remove but it makes me uncomfortable
View attachment 95156
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This is exactly what I did about 20 years ago and it's still there and behaving perfectly. There must be a photo somewhere.
 
Tippie said:
Those were also used on primary chain tensioner on SF2 and other motors after that.
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I've seen the squared-off type of nuts on primary tensioners of all model years, can't remember finding anything else, other than the occasional bodge-job.

I actually prefer the steel-capped cylinder head nuts over the yellow ones, they don't stick out like a sore thumb in conjunction with some paintjobs. Yellow does clash brutally with some colours... the steel caps are far less obvious. The ones I use have an integral plastic sealing/securing component, just like the originals. Available in zinc-plated or stainless.

piet
 
Pretty sure I saw some later triples with a rounded dome nut on the primary, but my memory is not to trust (if it ever was). The yellow head nuts are a bit like Laverda signature hex bolts aren't they?
 
piranha-bro2 said:
And square top all-steel ones only on SF1's (I think). The replacements i got from Wolfgang are domed all steel - pre-SF1?
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Correct, (most of) the SF1s had 8 of the nuts that you find on the primary chain adjuster. Some SFCs that were built in 1972 had them too.

Before that indeed the steel cap nuts were used, and before that, on early 750s, regular nyloc nuts.

Marnix
 
Just in case some reader doesn't know... The engineeringly-correct solution here is always a capped nut - otherwise there is an oil leak path, past the threads and eventually onto your lovely garage carpet. i.e. the cap is not just for decoration.
 
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