Cylinder 1 & 3 stop running

Hi
It's been a long time that i ask your help, I often just had to read old treads, but now i don't know what to do.

Yesterday, cylinder 1 didn't work, but since the beginning of the season it was actually working.

Little bit of history...Last year cylinder 3 was working SOMETIMES, but rarely. Before the beginning of the actual season, i changed old coils for the Dyna, and the coils upgrade of M.WG was already done. When i changed the coils, all cylinders was working, but the sparks never seems to be that fat to me compair with the old coils.

So, yesterday after my 300 meters ride with just 3 cylinders, i checked primary and secondary resistence, and was showing respectively 3.5omhs on each and 14600omhs as well on each.
I checked pick up coils = 460omhs
Battery voltage = 12.9V
Coils Hot wire = 12.2V

I also remove the carburator cause spark plug no.1 was wet, not the other. I checked the float, the needle, the jets, everything looked fine. By the way, i reduce the hight of the floats 'cause all my spark plugs are black and sooty since forever.

This morning, i put the carbs on and now the cylinder 1 and 3 doesn't work.

Why cylinder 1 decide not working all of a sudden? Maybe #3 stop for the same reason.

Thank you for your knowledge and ingeniousity
Pat

You didn't mention new plugs but I'm assuming that you are changing them or switching them around.

Of course you know that 1 and 3 work off of different coils.

Post edited by: mrbreeze, at: 2007/05/24 14:45

Yes, they have been switch around and they are not on the same coil. Both generate a spark.

I may be off base, does the bike have points? if so look at them, put a new set of plugs in it, I have messed with fouled plugs way too many times.
last check the wires they may be bad

To answer the last reply, its pick up coils not contact points on this bike.
I changed spark plugs this morning and cylinder 1 works, #3 is starting but after 4 seconds it stops.

After this start, i checked the plugs, and #1 looked black and sooty, #2 and #3 looks just like they never been used and #4 looks brownish.

So i did 2 compression tests, one dry, and one with a table spoon of oil in the cylinders:from #1 to #4
dry and cold: 120-120-120-140
wet and cold: 140-130-140-150
And there is a spark comming out of the #3 spark plug.

What conclusion can i make out of this? Yes, my rings are probably worn, could this be the reason why cylinder #3 doesn't work?
Tell me your conclusions
Thanks

Post edited by: pat, at: 2007/05/25 11:06

I'll just repeat what is now drilled into my head from cruising this site all the friggin' time:P

When you're doing the compression test, it's best to make sure the engine is warmed up so they rings are sealing optimally as they would while riding. Also make sure you have the throttle wide open when compression testing.

Am I learning guys?:woohoo: :woohoo:

check the plug wires, you may have a bad one.
does it start to fire if you rev it up ?
may even try to swao the coils to see if you might have one going south

I rode around the block with the bike, and cylinder #3 didn't worked. It just work when i start the bike, then it stoped. I checked the fire again and while the bike was idling, i was holding the plug connect to is wire, touching the engine and a good spark was coming out of it and the cylinder was moving when you check from the spark plug hole.
If the electricity is not the issue and there's compression, i guess the problem is the carb #3, but it's clean just like the other, and why would he stop working suddenly?
I'll remove the carbs again and do i don't know what...

Why does this bike works fine just for the first 2 weeks of the season, and then the cylinder #3 screw up the rest of my summer? It does that the past 2 summer but i was working all summer in the bushes, so i never had to use it neither the time to repair it in the fall. But i want to ride my bad a.. bike this summer!!

Thank you all for your help.

Post edited by: pat, at: 2007/05/26 12:45

All right, it's fine
The float of cylinder #3 was a bit to low (still at the same hight as the others...). Now it all works.
Sorry, i'm still learning
Thanks a lot to all the participants of this site, it's always very very helpful.
See ya for the next problem...in a million years.
But sooner for ajustments
Thanks