Topic: Mismatched Spark Plugs?

[jayrdee]

So, I'm slowly chugging away at a 3k mile service on my 77 CB750K. I noticed it runs a little rough in the lower rpms so I figured now would be a good time to go through everything. I bought the bike last year but never got around to tinkering with it until now (this is also my first bike, like ever, so I'm learning as I go haha)

Anyways, I took the spark plugs out today and noticed they were mismatched. Cylinders 1 and 4 had NGK DR8EAs and cylinders 2 and 3 had Champion RA6HCs. I wanted to check to make sure the plugs were good so I measured the resistance through the electrodes. NGK's measured around 5k ohms, and the Champions measured 10k? 

What are some symptoms these mismatched plugs could cause?  Correct me if I'm wrong, I'm still new to this stuff, but if the plugs have too much resistance, that leads to a weaker spark, right?
I did notice theres not as much power coming from cylinder 3. I could feel the air coming out of the exhausts, and 3 was the weakest. Come to think of it, cylinder 2 was weak too, but not as bad as 3.

Regardless, I will buy new D8EA plugs since that's what the standard was.

[BenelliSEI]

Jay..... get the new plugs on, valve clearances, points gap, ignition timing, then sync the carbs. You’ll be amazed how it smooths out. Good luck, looked at your older posts/ pictures. Lovely bike! Clutch still slipping?

[jayrdee]

Jay..... get the new plugs on, valve clearances, points gap, ignition timing, then sync the carbs. You’ll be amazed how it smooths out. Good luck, looked at your older posts/ pictures. Lovely bike! Clutch still slipping?

That's the plan!

And thanks! I'm in love with it. But unfortunately yes, its still slipping. Its not too bad as long as I'm easy on it, so cruising around town is no issue. I want to get the motor running healthy then do the clutch.

[BenelliSEI]

Jay........I’ve said it before, and I’ll say it again; K7/8’s are so under appreciated and such great looking bikes! Make sure your clutch cable and lever are correctly adjusted and the operating arm is totally slack and disengaged before ripping it apart. What oil are you using? Synthetics can have a bad effect on clutch plates......

[DesertKyorugi]

I pulled the plugs off my 71 that sat for 39 years last week before firing it up the first time and it had 3 different plugs.

Jay..... get the new plugs on, valve clearances, points gap, ignition timing, then sync the carbs. You’ll be amazed how it smooths out. Good luck, looked at your older posts/ pictures. Lovely bike! Clutch still slipping?

I got the first two done along with cam chain tensioner and the bike is already purring. I will get to the last 3 this week before going for a test ride.