loop frame dizzy advance

[NoSprk]

so here in the great state of commifornia we have shit fuel. I run 91 in my bike but still have some pinging. I've backed the timing off and it's helped for the most part but climbing some bigger hills at somewhat heavy throttle I've heard a little.

I think someone mentioned before using matching advance springs to keep the weights in till higher in the RPM range.

I'm assuming it's the tighter one not the one with oval shaped end.

[Antietam Classic Cycle]

First try new springs. The old ones will have stretched and become weakened from 50 years of use. If that doesn't work, then use two of the "normal" springs (no oblong end).

How many miles on it? Too much valve-to-guide clearance will allow oil to be sucked into the fuel mixture diluting it's octane. May be time for a head rebuild if over 30k and it hasn't already been done.

[NoSprk]

when I got the bike the previous owner had already replaced the springs. even my brand new Harley pings on the 10% corn mix 91 here. I have no idea on how many miles are on the bike. when I got it the speedo said 37k but by the time it rolled over it changed to 58k within about 2000 miles so who knows. I do know my bike has iron liners. I wonder if someone replaced them with later 1000cc jugs and pistons and never rejetted. it runs pretty damn well for an old 850.

I'll put the smaller spring on and go from there. I definitely need to check the timing

First try new springs. The old ones will have stretched and become weakened from 50 years of use. If that doesn't work, then use two of the "normal" springs (no oblong end).

How many miles on it? Too much valve-to-guide clearance will allow oil to be sucked into the fuel mixture diluting it's octane. May be time for a head rebuild if over 30k and it hasn't already been done.

[guzziart]

I replaced the distributor springs on my '72 Eldo with whatever Guzziology had recommended at the time but Charlie's recomendation sounds good too.  Additionally, I re-shimmed the distributor at the same time...as I recall it had a lot of end play which can also play havoc with ignition timing.  I got the shims and roll pin from McMaster-Carr to the best of my recollection.  Sorry if I sound vague but it was 8 years ago when I did that work on mine.

[Antietam Classic Cycle]

I replaced the distributor springs on my '72 Eldo with whatever Guzziology had recommended at the time but Charlie's recomendation sounds good too.  Additionally, I re-shimmed the distributor at the same time...as I recall it had a lot of end play which can also play havoc with ignition timing.  I got the shims and roll pin from McMaster-Carr to the best of my recollection.  Sorry if I sound vague but it was 8 years ago when I did that work on mine.

Good advice to shim the end-play - I've seen them so loose that the carbon contact in the center of the cap gets worn out quickly. Also a good idea to replace the felt "seal" as well. The original shrinks from age and no longer does the job.

https://www.thisoldtractor.com/moto_guzzi_loopframe_distributor_rebuild.html

[pehayes]

How many miles on it? Too much valve-to-guide clearance will allow oil to be sucked into the fuel mixture diluting it's octane. May be time for a head rebuild if over 30k and it hasn't already been done.

+1 on Charlie's advice.  It doesn't take very much oil to seriously degrade the combustion mixture.  You won't notice oil consumption or smoke, but you will notice the pinging.  New guides should do the trick.

Patrick Hayes
Fremont CA