So I made it out to the bike this afternoon and found the ignition coils were hooked up properly. Left was for 1 & 4 and the right was for 2 & 3.

So the next step was to see if the problem followed if I switched 4 for 1 and 1 for 4.

The result was the same. Cylinders 1 & 3 ran just fine as evidenced by the hot pipes.

This leads me to believe that the coils are fine, but I might have a wiring issue somewhere else on the bike.

I took off the coils to get them cleaned up and noticed a lot of corrosion where they attach to the bike via bolts to the frame along with a couple of ring terminals used for grounds.

Do the coils "ground" through the frame at all?

I will get out there and check all the other wiring too while I am at it to be sure.

Recap:
Carbs are clean and getting fuel just fine
Does not run on all 4 cylinders with the aid of Instant Start
Runs on 1 & 3 regardless of position of plugs (switching 1 & 4, etc...)
Fully charged battery every time I go out to give it a go

it's not clear from your post whether you swapped the plugs for 1 and 4 or the plug wires from 1 and 4.

if you swapped the plug wires and nothing changed, then you've ruled out any electrical problem.

if you swapped the plugs and nothing changed, then at least you know all your plugs are good.

i'm not sure if the coils ground through the frame - an ohm meter should be able to help you answer that question. an ohm meter will also tell you if your coils are bad.

first thing i would do is pull one of the plugs that is not firing, plug back into the plug wire and ground to the engine while spinning the engine over. do the same for the other one. if they spark then you are not getting fuel to the cylinder, or the mixture is severely incorrect, if they don't spark then you have bad plugs, replace them, easy fix - since 1 and 3 are firing, your coils are good and you ruled out the wires/caps by swapping plug wires between 1/4, did you do the same for 2/3 with same results? (caps are worth replacing anyway if they are original/old)

another thought, what kind of shape is the engine in? could be stuck valves or something....

I swapped plug wires around and there was no change.

It is possible that the mixture is incorrect and causing problems.

I will do the test against the cylinder head/block my next time I am out there.

I will also look up the specs on the coils and do the ohm test. I have all that good stuff to test this and other electrical problems.

I would hate for it to be a fuel problem, but I got the rack off once, I can do it again. I set the float levels properly to be sure. But I didn't touch the mixture screws from what the previous owner used. The PO had it running once about 5 years ago, but he never told me how it ran (quality wise).

As far as the engine condition, I have no idea. Should I pull the valve cover and tap (lightly tap) each valve and turn it over and see if all of them are moving?

another thought, when you pull the plugs to check for spark, take a look at the plugs themselves and tell us how they look. another thing to try is swap plugs 1/4 and see if that changes things (as opposed to just swapping wires).

when you do the ohm test, do it with the caps off and check the caps themselves too (they screw on/off the wire), not sure again for your bike but most (i think) should be 5k +-10%.

a compression test will tell you if the valves are sealing.

i'd be praying it was bad spark plugs right about now.

Have you checked the fuel/float levels? Was this bike running ok previously? What is the background please?

I set the float levels myself right after doing the carb cleaning. I did the 17mm setting that everyone recommends for these Hitachi carbs. But I didn't check the fuel level due to seized screws in the bowls.

The history of the bike is that it was running once...about 5 years ago. Prior to that, it was registered in PA back in 1994 and I assume that is when the bike started to sit.

Currently, it runs on 1 & 3 no problem but not the other two. Oh and the plugs looked just fine. A little dark if I had to describe them. I will check the gap while I am at it too.

I need to get out there and try swapping plugs around and see if I get some luck out of that.

pull the plugs first. if they are wet then they are getting fuel. and the plugs aren't firing.

if the plugs are dry. chances are they are firing. and there's no fuel. to which youi can check by pulling the drain screw out of the carb for that particular cylinder.

just becuase the plugs spark on the outside of the motor don't mean they are firing on the inside of the motor. 140 lbs compression is a lot harder to fire then standing air. compression offers more resistance.

FYI - i've had plugs that will spark just fine when removed from the cylinder and grounded against the engine - but would not spark inside the cylinder (compression in the cylinder creates more resistance across the gap). in my case, this was due to a coil that was on it's way out - it still made spark, but had open loop (infinite) resistance from one wire to the other.

Are we sue that Spark Plugs which fire -- Outside -- the Engine don't fire once they are screwed -- Inside -- the Engine.

The Higher Compression in a Cylinder is make it more likely the Cylinder -- WILL -- fire.
As Compression rises the Mixture can Ignite without a Spark.

This may be a couple of problems feeding the other.
If it coughs or tries to run on Starting Fluid, ...
The problem is going to be Fuel Delivery.

RickCoMatic wrote:

Are we sue that Spark Plugs which fire -- Outside -- the Engine don't fire once they are screwed -- Inside -- the Engine. The Higher Compression in a Cylinder is make it more likely the Cylinder -- WILL -- fire. As Compression rises the Mixture can Ignite without a Spark. This may be a couple of problems feeding the other. If it coughs or tries to run on Starting Fluid, ... The problem is going to be Fuel Delivery.

not to hi-jack this thread - but, for clarity's sake - are we in agreement that compression in the cylinder makes it harder for the plug to actually produce a spark?

gasoline needs a spark to ignite. deisel fuel needs compression to ignite.

automotive basics 101.

i can't see compression having any negative effect on the quality of spark, if anything i would think compression of the ionized fuel (and lacking that, simply the humidity in the air) would actually make it easier for the spark to discharge...

snowwy66 wrote:

gasoline needs a spark to ignite. deisel fuel needs compression to ignite. automotive basics 101.

Except that theoretically if a gas engine could be built with enough compression, it wouldn't need a flame to ignite.

Physics 101