Wrong spark plugs

Hey guys so i ordered some new plugs and decided to try out B8ES instead of B7ES. However the plugs came today and they're BR8ES. I understand that the r is for resistor but would it hurt anything to use them?

Why did you decide on the the B8's?

You can use resistor plugs as long as you do not have resistor caps or resistor wires.

Price wrote: Hey guys so i ordered some new plugs and decided to try out B8ES instead of B7ES. However the plugs came today and they're BR8ES. I understand that the r is for resistor but would it hurt anything to use them?

If your KZ650 is tuned properly you will find the B8ES plugs to be too cold and they will tend to foul. The KZ650 should use B7ES or (even better) ND W22ES-U plugs. If your bike is not tuned properly changing spark plugs is not going to fix the problem. Ed

Sorry for not getting back for a couple days, works been crazy. I switched to the B8s because i've been taking my bike out to the mountains and riding it pretty hard on a daily basis. The b7s I had were white and blistered and my understanding is that B8s are better for that kind of riding

It sounds like the carbs and/or ignition timing isn't tuned properly. In the past I ran my 1977 KZ650 extremely hard and had no problems with the correct plugs. Ed

Give the B8s a shot.
Write down your findings in a notebook just in case you have to refer back at a later date.
Carry your old B7s and spark plug wrench on the first couple of rides just in case the B8s get testy.

From what I have learned about reading plugs is, the temperature range is determined by looking at the earth strap. There will be a color change from a gray to black. If the point of change is close the the tip it’s to cold. If the color change is near the bend it’s in the correct temperature range, and if there is no color change or it’s at the point where the earth strap is welded the the base ring then the plug heat range is to hot.

Here are my plugs from a few months ago you can see the color change on the earth strap. I agree with 650ed. You need to look at tuning as the problem. White plugs are a result of a lean condition. Heat range will not correct for bad jetting or timing.

www.enginebasics.com/Engine%20Basics%20R...20Spark%20Plugs.html