81'GS-450 and 81' GS-550

[doggies]

Will coils and other electronics interchange?

[snark]

I beleive the ignitor might. Your best doner would be a 250. Pretty much everything swaps there as the 450 is more or less a bored out 250.

[mriddle]

Which one are you trying to fix ?

[bwringer]

If you look closely, there are some important differences between these engines...

But if you're trying to get the 550 ignition stuff to work on the 450, you could probably achieve that simply by cutting off and capping one spark plug wire on each coil.

The 4 cylinder ignitions fire 1/4 at the same time and 2/3 at the same time. (One spark is always "wasted", since it's firing on the exhaust stroke, but it simplifies the ignition wiring and only requires two coils instead of four.)

So the only real difference between the twin and four cylinder ignitions is the number of spark plug wires on each coil.

[mriddle]

If you are going the other direction, your 450 coils will not work on a 550. You could find coils from a later model Suzuki 4 cylinder on Ebay for not too much money.