82 GS550M Ignitor box

[Safra]

Anyone ever used a 82 GS550m ignitor on any other aircooled lumps I have 2 to play with only reason I bring this up is because I've read its got 5 degrees more electronic advance than my GSX750 unit which has a 15° BTDC below 1500 r/min and 35° BTDC above 2350 r/min

Will the extra 5 degrees advance at above 2350 r/min make a difference or will it be negligible 

Rolling roads or dynos for motorcycles are rare as hens teeth on my side of the world so my preliminary results will be conducted via ass dyno

 

[Poldark]

I don't think 5 degrees extra advance would make too much difference, but be sure to check for signs of ignition knocking.  Factory ignition advance settings assume: a new factory spec engine, factory carburetor settings, and the fuel available at the time.  Fuel burns faster under higher compression, if your engine is a little worn out, a little more ignition advance can help compensate for a small loss of compression.  A slightly too rich fuel mixture will burn a little slower; a little extra advance can help compensate.  I don't know what the fuel formulation is where you live, but that can have an impact too, especially considering the formulation has likely changed in the past 40 years.  The 550 is a smaller, higher revving engine than the 750, so it would need more advance.  I'd say go ahead and try it, just be looking for signs of premature ignition.

[Safra]

Interesting enough both the 550 and 750 have redline at around 9500 to 10500 as max I dont plan on revving my bike to the moon I dont trust 30 plus year old valve springs

Edited August 29, 2023 by Safra

[prutser]

Which gsx750 are we talking about? The first generation 16valves (ET/EZ/EX models, built till '81 or '82 i guess) has mechanical advance at higher Rpms. At least my 81 EX does.

If i recall correctly, the '82 550m has "full electronic ignition" meaning it has electronic advance, correct me if im wrong.

Mixing mechanical with electronic advance will advance way too much probably?

The 2nd gen 16valves (ES, EF, 1983 and up) moved on to fully electronic as well, i assume.

But, to confuse all of the above even more, the first gen 16valves were still called GS in the USA, but GSX in pretty much anywhere else in the world.

[Safra]

On 8/30/2023 at 2:48 PM, prutser said:

Which gsx750 are we talking about? The first generation 16valves (ET/EZ/EX models, built till '81 or '82 i guess) has mechanical advance at higher Rpms. At least my 81 EX does.

 

I dont know why I thought mine was digital I also have a 81 model 750 oh well must of been tired when I wrote that

[Poldark]

Here in the US, they went to fully electronic in 83.  Earlier ones had mechanical advance.  My 82 GS750E (16 valve) has mechanical advance.