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New to loops and trying to set mine up to eliminate detonation(pinging)

Tubehead

Just got it firing!
Joined
Apr 27, 2017
Messages
19
Location
melbourne Australia
Hi
I am new to Moto guzzi's the loop is my first one and with a shed full of Ducati's I have to say I am pretty smitten by this old bike.I ride it everywhere and has it quickly become my go to ride.The only fault I can find is the detonation that seems to be an accepted fault with these bikes and this is just the way they are?
Can an electronic upgrade get rid of it?

First off I have set the valves correctly tapped the inlet manifolds to take some adaptors so the carbs are now balanced .Set the points to spec and adjusted the timing with a strobe and the the advance is correct and timing spot on.I am running 98 ron .Compression in both cylinders is with in spec as it should be with a rebuilt top end by the previous owner.The points and condensor are new. A plug chop shows a nice tan color both plugs.The bike runs fantastic set up like this but pings it's head off once it's hot especially off the bottom of the rev range which I fixed by retarding the ignition timing until it stopped.
I am hoping I don't have to ride it like that permanently because I like it much better set up to spec.
Am I missing something? IMG 3642
 
Do you know what cylinders were used in the rebuild - Nikasil or iron liners? In my experience, those with iron liners tend to run a bit hotter and are more prone to ping.

Years ago Mark Etheridge @ Moto Guzzi Classics suggested using two "normal" advance springs (the lower one in the photo) to cure ping issues. I've used that setup to good effect on several customer bikes. It slows advance considerably, making the curve more progressive.
12715442b5443.jpg
 
Thanks
Gilardona cylinders so nikasil.
I read the initial advance to 2500 rpm is quite aggressive so will give this a go if I don't go electronic.
There seems to be a couple of choices there but would be mad not to try your suggestion first before parting with $500 Aud .
Can I buy the spring from you?
 
Going electronic wouldn't change the advance curve as far as I know. It still uses the mechanical advance of the distributor. Amboman's suggestion is excellent. Some time ago, a US dealer made plates go to between the cylinders and block to drop compression and thus reduce the "ping". I would only look at that as a last resort.
 
Thanks
Gilardona cylinders so nikasil.
I read the initial advance to 2500 rpm is quite aggressive so will give this a go if I don't go electronic.
There seems to be a couple of choices there but would be mad not to try your suggestion first before parting with $500 Aud .
Can I buy the spring from you?

I can supply the springs (would need to buy two sets to get two "normal" ones) but it would be just as easy to buy from MG Cycle.

An electronic ignition is only going to help if it doesn't use the original advance unit and has advance curve that can be changed. Paul Crowe (I think that's his name?) at C5 Performance made a limited number of complete new distributors incorporating their programmable ignition system. IIRC, it was around USD 500, so not inexpensive.
 
I can supply the springs (would need to buy two sets to get two "normal" ones) but it would be just as easy to buy from MG Cycle.

An electronic ignition is only going to help if it doesn't use the original advance unit and has advance curve that can be changed. Paul Crowe (I think that's his name?) at C5 Performance made a limited number of complete new distributors incorporating their programmable ignition system. IIRC, it was around USD 500, so not inexpensive.
I will give the springs a go first and take it from there .Thanks for advice.
 
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