Laverda Parts

Good points Cam. BTW, the 750s (post 1971???) all use the curved slipper primary chain tensioner.

I actually sourced a used duplex sprocket with rubber cushioning from somewhere decades ago (out of some car engine from memory - no longer have it but it did strike me as a suitable alternative to the plastic wheel. Would the steel sprockets be a lot noisier?
 
MarnixSFC said:
You mean the toothed tensioner wheel for the camchain, Rob? Found one in a 1974 SFC with various factory racer parts. Bit of a crude creation, but works fine.

Marnix
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Yes Marnix, both the tensioner and the guide, steel with teeth. Must have a look for them and post a pic. Hopefully I still have them, it's been like 40 years.

." BTW, the 750s (post 1971???) all use the curved slipper primary chain tensioner."
Don't quite understand what your talking about Q. You saying it has a similar set up to the triple tensioner, IE. long curved blade type

Anyway here is a pic of a worn SFC set and a new set for the SF series
 

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motoddrob said:
." BTW, the 750s (post 1971???) all use the curved slipper primary chain tensioner."
Don't quite understand what your talking about Q. You saying it has a similar set up to the triple tensioner, IE. long curved blade type
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Just getting mixed up between cam and primary, Rob. Cam thought I was talking about cam chain tensioners:

"Yes. Triples have a curved tensioner blade for the cam chain. No rollers."

I was trying to find out if triple PRIMARY chain slipper tensioners were the same as 750s. Cos I need one and the NSW Lav club might be able to help me ... if it fits. I'm familiar with triple and 750 internals but not to that extent.
 
piranha-bro2 said:
How do i use my lathe to make one of those slipper primary chain tensioners with the rubbery coating, Steve?! Maybe the old GT style ones with the roller but not mine. Is it possible to have the coating replaced on a worn one? If Red's guy can make kevlar clutch plates surely this is doable?
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The ones in the thread's initial picture and comments are the early type, hence I assumed that's what you were talking about. The slipper style are available from any Laverda parts source, pretty sure they're the same twin and triple, someone will be along shortly to confirm.
Dellortoman said:
Ooh, 10mm smaller wouldn't pass the rivet counter test Steve, unless you're trying to replicate a worn one.
What species of plastic do you use Steve (assuming you use plastic)?

My Kawasaki has a plastic sprocket as a cam chain tensioner wheel. I dunno what kind of plastic it is but the bloody thing wears away at a prodidgious rate. Last time I replaced one (was not actually on my bike that time), I considered making a new one out of steel, or maybe bronze, but I didn't have the equipment to cut the sprocket teeth. Maybe Kawasaki (and Laverda) chose plastic so it's sacrificial and doesn't wear the chain.
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I used some nylon, can't quote you the grade. The slightly yellow off-white if that helps.
There are no teeth on the Laverda ones - at least when new! They are ridged so as to run on the rollers. All that stuff that wears off most likely ends up in your slinger plates. Making the camchain one a bit smaller really helps with the chain which always seems too tight. Craig Mac made a 6mm spacer between his tensioner housing and barrel, same sorta vibe.
I would generally convert to the later style primary tensioner on an early twin, however the tensioner screws in from the inside and on the bike I had here a while ago the outer end of the thread was damaged (quite common according to Piet) so it was sort of 'captive' unless I put an angle grinder through it. I just put a new wheel on it in the end, the first had lasted the one-owner bike from new till 2020, so it seems unlikely he'll wear out the new one. :)
 
Dug these out from deep storage.
IIRC circa 1980 they came out of a SF3 I brought in Melbourne
Minus a front end.
 

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olly said:
We just made a set with https://www.dupont.com/brands/delrin.html
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Delrin machines nicely and has decent bearing properties.

We used to use Ertalyte for heavier loads and abrasion resistance at a scientific instruments manufacturing firm I worked for.

Consequently, it might be better for the later type tensioner that rubs.

Interestingly, my old MKII Ariel Square Four had a hard faced solid steel wear shoe for the duplex timing chain.
 
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