Cyl 4 noFire

So I just so happened to change my oil today, put in some 20w50, figured itd be better for the older engine... Anyway, as im lettin the bike idle i get the notion to just pull the plugs, make sure that not all the work is being done by one or two cylinders (makeshift sync test untill my mercrometer comes in) Anyway turns out that Cyl 4, cylinder opposite of petcockside, when plug is pulled has no difference in engine tone, not even a sputter. Im getting spark , even when im holding just the shielded wire and touching the bike im getting mildly shocked.... and i just cleaned the carbs yesterday....



So...?

 

Had that happen to me once so put plug 4 into 1 and plug 1 into 4.

Misfire miraculously swapped sides. Plug still sparked but died under pressure for some reason. Looked clean but was wet due to not firing. New plug and she ran sweet.

Hope it's that simple for you.

 

Oh and For all of you having those petcock leaking issues that have been goin around as of late.... Open up the petcock on the vacuum side. Take out the spring from a clicker pen, cut off 3/8" of the spring. Stick the shortened pen spring inside the larger spring, smear a SMALL amount of RTV or silicone around the sealing areas and put it back together.

 

I dont know i dont think thats it. For me the left hand side of the bike has a 1 foot cable that extends over to cyl 4, then a shorter, say 9" cable, that goes to cyl 1, then cyl 2 and 3 come from the right side coil.

Besides If cyl 1 and 4 are both coming from the same coil it wouldnt matter.... though i guess if i swap them and then cyl 1 doesnt fire i guess ive eliminated the problem down to spark, not fuel...

 

And the cable for cyl1 wont reach to cyl 4 anyway.... Guess i need to pull the plugs tommarow....

 

set the plug on an engine nut or some other ground while its turnin over... other than that for a plug check maybe your not getting fuel?...hmmm now im curious... let us know what happens tommorrow

 

I'll have to agree with everyone else, also check that the plug in there is not only good but also gapped properly. This seems to cause problems for some bikes.

 

no fuel. Float stuck up.

 

Darn conceited floats. They think they're so special!

 

Ok, again.... that was just another problem. Still no fire in cyl 4 AND 2.


Whats the firing order on these? 1 and 4 fire and 2 and 3 fire? thats how my spark plugs are wired to the coils. Left side controls outside plugs and right side controls inside plugs. or should it be 1.3 and 2.4, which would explain these 2 dead cyls...

 

Funny Eblo, I laughed! One coil services two cylinders through a process called the "lost spark" method. That coil fires on both the compression stroke for #2 as well as the exhaust stroke on #4, hence the term lost spark since it does nothing in #4. This means the coils fire as often as a regular coil would but service more than one cylinder. If your loosing #2 + 4, two things could have happend. Either your pickup coils died for that bank (look at your reluctor plate under the right side cover) or the coil died. Could be a loose connection either way so play with it and see what happens. The coils should ohm out at less than 3 ohms primary and I forget how many ohms exactly for the secondary (high tension lead compared to the - side of the coils primary inputs) but I do remember it being around 5,000 ohms. Oh yes, to answer your question what the firing order is, the coils fire on opposite cycles. first 1 + 3 then 2 + 4 and so on.

 

Can't find my manual but the primary reading is 2.5 ohms and the secondary is either 11k or 11.5 k with the resistor plug caps off.
On stuck floats it is either gum in the float seat holding the float valve in or rust on the float hinge and pin. First fix is to soak the float seat in carb cleaner which means pulling the carbs. Without pulling the carbs you can do a seafoam treatment by adding half a can to one gallon of gas, pouring this into a near empty tank and starting the bike. When it smokes like a forest fire kill the engine and let it sit over night. In the morning fill the tank with fresh gas, start the bike and ride to test the results.
Best way to fix a float pin and it's seat in the float hinge is to remove both and insert the pin into a dremel tool. Coat it with Mother's rubbing compound or a diamond lapping paste and slowly spin it "in the hinge section of the float" This polishes both surfaces so they work together smoothly.

 

Ok, ive been taking the carbs on and off 4 times now, cleaning them. Soaking. Making sure eveyrthings OK. Swapped coils twice.



Yea it was the pilot jets. The manual i have said 2.5 - 3 turns out. I had to go to over 4. I guess the manual i had was for the hitachi carbs, not the minuki. I feel like dumb. Cant wait to get some colortune plugs... ugh.