rookie do-it-yourselfer

[Anonymous]

I have a 1977 GS750 that is only running on cylinders 1and4.
When I take plugwire 1 or 4,put a screwdriver in the plugend,
hold it close to the engine and whirl it over,I get a blue-white
spark that will SNAP across a good1/4 inch gap.If I do the same
thing to plugs 2 or3, I get a blue-white spark that will only jump
1/16 inch at most, and does not SNAP.I have cleaned and regapped the points,(I believe they were ok, so this was
precautionary). I would like to know how can I determine
between a coil problem or a condenser problem. Are there any
quick easy test or signs a rookie do-it-yourselfer can do or
look for. Any help would be appreciated.

[Anonymous]

Wire joints and plug hats

I had a similar problem. Cylinders 2 and 3 were cold and even the hot cylinders gave a weak spark.

I took my electric meter and started searching for the spot were the promlem was.

My solution was:
- Poor contact on the wire joints leading to coil. I changed the couplers to new ones and it brought cylinders 2 & 3 back to life.
- I also resistance measured the plug hats and found out that they were unservicable and got new ones with the correct resistance. This incresed the power of the plugs.

If you have an electric meter you should try and find out wether the coil of cyl 2 & 3 gets the right amount of electricity.

Good luck

[Anonymous]

To start with, I replaced my points/condensor/mechanical advance with an electronic ignition system. Boyer Brandsen, its fantastic, it eliminates all kind of potential problems and only needs setting up on installation. Its worth considering. However, I think the easiest way to discover your problem is to swap parts. Cylinders 1 and 4 fire, so you know you have one good set of points, one good condensor, one good coil, 2 good leads etc etc. Swap parts over one at a time and see which part the fault follows. Not very scientific I know, but I find it to be the most conclusive way. Also, check your carbs out. Are you sure you are getting fuel into 2 and 3. And your coils, one coil fires 1 and 3 and the other fires 2 and 4. so I think if you had a coil problem it would be 1 and 3 or 2 and 4 that had the problem.

I hope this is of help

[Anonymous]

my mistake

Ignore what I said about the coils firing 1 and 3, 2 and 4. What was I thinking !!!! One coil fires 1 and 4 and the other 2 and 3. So swap over your coils and see if the problem follows to the other two cylinders. If so, theres your problem. Sorry for the misleading information, I had a mental blockage .....