Has anyone tried it? Regina duplex timing chains are now in the hen’s teeth category - I recently had to order one from a private seller on ebay Italy because no dealer across Europe seemed to have one. Not even secondhand ones. I probably missed a few main dealers… Gutsibits’ solution to the duplex chain problem is to sell you a simplex chain, camshaft, crankshaft and oil pump sprocket. Expensive and a lot of work to fit.
I was out in my garage tonight looking at a simplex oil pump drive sprocket from a V35 when I spotted some odd machining marks on the body. It looked like the forward row of teeth had been machined off. That grabbed my attention and I set about checking and measuring the V35 simplex timing assembly (crankshaft, camshaft sprocket, oil pump sprocket) against the Monza’s duplex timing assembly. I am, at this point, fairly well convinced that it’s possible to run a simplex chain on a duplex assembly.
If only the chain has worn it’d be possible to find out the pitch of the old duplex and likely most good industrial bearing & transmission suppliers would be able to get a chain of the correct length, plus either a rivet or clip joining link to suit.
I realise this doesn’t address worn sprockets, however it would be a ‘life extender’ until these were sourced.
Wish I had access to a lathe and milling machine; I could take commonly available sprockets and size them for Guzzi crank/cam shafts!
There’s also the mix’n’match possibility; change just the oil pump and cam sprockets and run the chain over the rear set of teeth on the crankshaft. This is getting interesting; shame I don’t have my own bike to work on.
I’d try Mercedes W123 - we used to use worn off cam chains in our 'sixties bikes for primary gearing with great success, could be that Guzzi will accept it as well.
Gutsibits’ solution to the duplex chain problem is to sell you a simplex chain, camshaft, crankshaft and oil pump sprocket. Expensive and a lot of work to fit.