super dupper dumb spark plug question

Hi all, just looking to replace my spark plugs (trying to resolve a non start issue) and see I need a NGK BP7ES spark plug, well I have taken out a
NGK BPR8ES !

Can anyone tell me what is the difference, and should I go for one type or the other? (might that contribute to my starting issue or just wishful thinking)

Its an 84 750 FYI

 

"R" means resistor in the plug and 8 is one heat range hotter than 7.

Do you have spark? did you test compression? and have you tried either in the air box to see if it will fire?

MN

 

Thanks for the info on the plug, now I Know (should I go back to the original 7 as recommended?)
I have rubbish spark and dribbles out orange excuses, coils within spec. Was running a little but now nothing (trying to get it back on the road after 12 years (PO)
Q- can you explain the last bit about trying them in the air box to see if it will fire, don't know what you mean.
Thanks

 

He said either, meant ETHER - - starting fluid.

You buy hotter plugs to correct a problem that you observe.
Buy the "stock" plugs, and keep the hot ones (clean 'em)

These bikes won't fire if the voltage is down a bit, boost your bike from a non-running car. Spray a whiff of ETHER in the airbox, smile as it barks to life.

"have rubbish spark and dribbles out orange excuses" At best, it's a 7,000 volt spark - - not a 50,000 v high energy spark from a car. That's all you get.

After 12 years of neglect you'll need valve lash check, carb clean-up, tires, brakes, check all service points.

 

Sorry about the spelling iPhone auto corrects to wrong words sometimes

 

If your bike has been sitting for that long, it's going to need serious maintenance before you can expect to put it back on the road. Get a service manual and do all of the required maintenance and replace the tires. Make it safe so you don't get hurt.

 

NGK numbers go opposite. Original is a 7. I went to a hotter plug which is a 6 on the part number. My plugs were fouling every 5k miles. So far so good.