Sluggish and Popping…

[MaxMidnight]

Coils are good. Not sure on the wires and boots. I found an older forum in reference to plugs and wires and found that you can order an NGK SB05F and get 7mm copper core wire at auto parts store. When the boots arrive Friday, I’m gonna build me a set and put it on the bike to see if that fixes my problem.


The front plugs look excellent.

I know that this is not the correct way, but I did a cold compression check with a compression tester and got 120 psi on every cylinder. I’m terrified to continue running it to get a warm compression check because I don’t wanna further wash down the rear cylinder walls. The oil smells like gasoline.

My next question for the experts is would a faulty CDI box, allow the front two cylinders to get adequate spark and weak spark for the rear?

As it has a single pick-up then the signal to the ICU will; be the same for all cylinders. I don't have the detailed knowledge to answer your question but as the spark is generated when the current is switched of my best guess is that it either works or it doesn't(?)....but I stand to be corrected.
As the leads and plug caps are some 28 years old(?) then it would make sense to change them and eliminate one potential problem area.

Do you have or have you checked that the float chamber needle valves are OK and that the float heights are correct?

 

[JBryan91]

Hello all,

Life has gotten in the way along with waiting for parts. Went to move the bike and the clutch lever had no pressure. Found out the original slave had went bad. Waited for a new one and replaced it. I replaced the rear plug wires, boots and cleaned all grounding points .The bike started up and immediately sounded different. The famous V4 sound…took it for a ride and it barked the rear tire. Kinda made me fudge a little….

Been riding for a week and been to lining the carbs. I went back to 152.5 mains chasing a loss of power and breakup in the mid range when not giving it WOT. I cannot cruise in 5th gear at 45-75mph without breakup. If I pull in clutch lever at highway speed and rev it the bike chokes. When I slow down and downshift while giving generous throttle the bike responds perfectly.

Today I shimmed the needles to add fuel to midrange with no difference. I’m kinda stumped. I will attach pics of plug chop.

K&N Air Filter
Delkelvic 8” slip ons
Stock carb jets and needles.
Needles have 1 M3 SS washer installed per carb.

Any ideas??

 

[JBryan91]

Fixed! Sorry FireMedic…

 

[Fire-medic]

Hm, looks like the rear plugs aren't seeing much gas.

I had to write down the cylinders, because my simple mind has trouble when you swap the way you name them, between the two pictures. To do it like the factory does, print the capital letter 'N' starting at the left rear. That's cyl #1.


Left front (2) Right front (4)

N

Left rear (1) Right rear (3)