Bad coils?

[Anonymous]

I'm having ongoing trouble with my GS. Bought a repair manual and started trying to eliminate things. I checked my coils to see if they were ok here's what I got on BOTH coils the primary winding is fine, checked with ohm meter, now for the secondary windings, I can't get a reading at all. Checking from neg. connector to spark plug cap. I don't know if I'm checking them wrong or if the secondary winding on BOTH coils have gone out. Also I tried checking my reg/rec and got absolutely nothing off of it, but it seems to be working perfect, 14.5 v to the battery at all times.
Any ideas? What else can I do to eliminate whats wrong and whats not?

 

[SqDancerLynn1]

Your post is confusing Does your bike run??? What kind of problems are you having?? 14.5 volts is great, I would still redo all of the reg/rect connections.

 

[duaneage]

coils

coils

The secondary side of the coil is going to have a higher resistance than the other side, your meter may not be able to read it. check coil output with a sparkplug.

Pull the boot from your plug in the engine and attach to another plug that hangs in free air. Connect a short piece of wire from the threads of the spark plug to the metal of the engine. Crank ( or start) the bike. You should see a nice big blue spark. If it is orange or weak or missing then you have a bad coil.

If the bike runs at all the coils are probably OK.

 

[AOD]

also check the spark when the engine is good and hot and been run a while. generally the coils will get weaker as they heat up, which is most noticeable when you try a hot-start and it requires a lot of cranking to fire over.

~Adam

 

[duaneage]

one more thing

While you have the plug out to test the spark, check the gap against the recommended gap for your bike. A mis adjusted spark plug gap has caused many " carb problems" over the years. THis happens sometimes on bikes that were just tuned up or when new plugs are dropped right in thinking the gap was preset, they seldom are.

 

[Anonymous]

Sorry SqDancerLynn1 I didn't go into everything thats wrong with the bike because I've posted them in previous questions. The bike cranks fine hot or cold, checked the spark, hot and cold, good spark. Set the gap,all that stuff just curious as to why I couldn't get a reading on the secondary. I'm trying to eliminate problems and starting with electrics. Signal generators good, reg/rec is about 2 months old. but like I said not getting a reading on it either.Prob just not doing something right.

 

[earlfor]

Well, it would make things a little easier if we knew if you were working on Maytag, a Boeing or a Suzuki.

Would that be a 737 or a lint free, full cycle? LOL

Earl

Sorry SqDancerLynn1 I didn't go into everything thats wrong with the bike because I've posted them in previous questions. The bike cranks fine hot or cold, checked the spark, hot and cold, good spark. Set the gap,all that stuff just curious as to why I couldn't get a reading on the secondary. I'm trying to eliminate problems and starting with electrics. Signal generators good, reg/rec is about 2 months old. but like I said not getting a reading on it either.Prob just not doing something right.

 

[Anonymous]

Ok here it is again, 82 GS 300L starts fine won't take gas, idles fine I know it could be a list of things just had a question about ohm reading on coils

 

[earlfor]

OK, and 82 is going to be electronic ignition. Resistance between the primary connectors on the coil should be 3 ohms. Usually, it will be between 3 and 4 ohms. Anything up to 5 ohms is acceptable. Resistance of the plug caps should be 5k ohms. A 300 is a twin, so I assume it has two coils, each with one spark plug wire. On a dual spark plug coil, resistance between the two caps on a coil should be between 30k and 50k ohms. Logically then, resistance on one wire and cap should be between 15k and 25k ohms.
The only way I can think of to check that on a single wire coil is to unplug the spark plug wire. Most stock coils did not have removable wires though.

Earl

Ok here it is again, 82 GS 300L starts fine won't take gas, idles fine I know it could be a list of things just had a question about ohm reading on coils

 

[Anonymous]

yep, thats it. I checked resistance in primary and is fine,as stated in opening question. The manual says to check secondary between what it shows to be the neg. side of the coil, and the actual end of the plug cap,the metal connector inside not thr rubber housing. When I do this I get no reading at all, just wanted to know about that. I'm sure that the coils are fine now. Moving on to carbs next. Thanks for all the info.

 

[earlfor]

I have made that check also. The only reading I have ever got was zero.

Earl

yep, thats it. I checked resistance in primary and is fine,as stated in opening question. The manual says to check secondary between what it shows to be the neg. side of the coil, and the actual end of the plug cap,the metal connector inside not thr rubber housing. When I do this I get no reading at all, just wanted to know about that. I'm sure that the coils are fine now. Moving on to carbs next. Thanks for all the info.

 

[KEITH KRAUSE]

Sounds like the classic damaged diaphragm.
A leaking diaphragm(s) will let the bike idle all day, but it won't accept any throttle, or barely any.
It could be other things too. The diaphragm comes first to mind.
What's the condition of the carbs? Have they been sitting dry? What attempts to repair them have been done?

 

[duaneage]

THere are three stages on these carbs, idle, low speed and high ( this is the oversimplified story) and the engine makes transitions from idle through slow speed untill there is enough airflow to meter fuel from the high or mains. The idle circuit gives way to the low speed and high circuits as the throttle is opened and air increases through the carb. In you case your not getting off first base it seems.


I would get another set of carbs either from ebay or another friendly GSer and swap them out and see what happens. The Clymers book has some good troubleshooting tips for carbs, the GS resources web site has a great carb rebuilding series found on the main page.

Good Luck!