81 GS550 Are coils are interchangeable?

[Guest]

Hi, all. Just joined the forum today. Looks like a good place to exchange info on these older Suzuki models. I have an '81 GS550T that I bought new for about $1500 in Seattle in "82. Over the first several years I put on about 30K miles then it sat for many years (15+). Got it running last summer and have been bringing it up to date in different areas since. Would like to ask if anyone knows if the two ignition coils are interchangeable? I know they have numbers on the wires indicating the corresponding cylinder (1 & 4 or 2 & 3) but I'm thinking (hoping) they can be used on either side.
Thanks, looking forward to the information this site has to offer and contribute where I can.
Michael

[tom203]

The coils are identical . Coils are pretty durable, so be sure to check plug wire connection at plug cap and cap itself for high resistance.
Welcome, glad you are getting it going again. Try this link for good info

http://members.dslextreme.com/users/bikecliff/images/GSR_Greeting.html

[GSMichael]

Thanks for the reply, Tom. I figured they might be the same.
Was able to find a couple relatively cheap and listed as new but both were for 1 & 4. The existing ones probably don't need changing yet but seems like a good buy.
After a little research here I don't think the problem is electrical anymore. She's got low compression in all cylinders (85 - 100) and the lowest one does not combust on a cold start. Determined by touching header pipe. Used to be 2 & 4 did not get hot till it warmed but after a valve adjustment all but one get hot. Which doesn't make sense because I didn't need to make any adjustments to #4 valves.
Maybe just need to take it on a long cruise and burn out the crud built up over the many stagnant years.

[Nessism]

Have you kept up with the valve adjustment and oil changes over the years? Is the bike stock with a good stock air filter. If you answer yes to these questions, then there is a very good chance the compression will come back to normal after some good miles. If you neglected the valves, or ran the bike lean using a header and/or pods without proper jetting then the engine may have suffered more than necessary. Good luck and hope the answer is the former, not later.

[GSMichael]

Hi, Ed. The bike is bone stock except I just installed a K & N filter less than 50 miles ago. I know that these can cause problems especially on carbies but I have not noticed any difference thus far. I may go back to stock as I am sure at the higher RPMs it will run leaner. And I am very attentive when it comes to oil changes.
Only 2 of the 8 valves needed adjusting so I was looking pretty good there. As you said...may just need some good miles.
Thanks

[tom203]

Put some miles on to wake it up, but make sure that you got 12 volts to coils and ignitor.After 30 years corrosion could cause a drop off. Power goes thru main fuse, up to key switch,back to ignition fuse, up to kill switch, then on to coils- it's a long path.

[GSMichael]

Put some miles on to wake it up, but make sure that you got 12 volts to coils and ignitor.After 30 years corrosion could cause a drop off. Power goes thru main fuse, up to key switch,back to ignition fuse, up to kill switch, then on to coils- it's a long path.

Will do, thanks!