Plugs and Oil Questions, HELP please

I have just purchased a 1981 XJ550 Maxim

Was going to do tune up and oil change but have one problem.

In the Haynes manual it says the standard plugs should be NGK D8EA, in the bike right now are D7EA should I be using D8EA plugs as the book says?
What is the difference between the D7EA and the D8EA?

Also the Haynes book asys the oil should be 20w40?
Store has motorcycle oil 20w50 is the closest you can get, is there 20w40 oil or is this a misprint in the book?
If there is where can you get 20w50 oil?


Thanks for your help,

Don

 

20w50 motorcycle oil is good unless you live where it's currently very cold then you'd want a thinner oil.

The differance in plugs is the heat range of the plug. Probably should go with what the book says.

Welcome to the site! Check your rear brake shoes for delamination.

 

For info about the heat ranges, check here:
NGK Plugs

But in short - using a plug one number away from the specified is just fine - shouldn't be a problem at all.

As for oil, the specs that were printed were 30 years ago. Most of us find 20w50 is just fine for most weather. If you really like to ride in the cold - as in below 5C / 40F - then you'll probably want to run 10w30. However - any oil is better than no oil. Avoid "friction modifiers" in the oil -- some people find it causes clutch slippage.

 

if i remember right. 20w40 is what was being used back then. now it's 20w50.

 

Welcome !!
Check your tire date codes too !! Eight years + is time for new skins.

 

The number on the plug is really just a marking of its "heat grade". If I recall correctly, the higher the number the hotter the plug (although I know it varies between brands).

One number off should work just fine, may run a little hotter that's all. But should definitely run.

Also, 20w50 oil works just fine as long is its JASO certified. Anything else has synthetics or additives and might cause your clutch to slip.

 

D8EA are correct for the 550.

You can run 20W50 as long as it's Motorcycle oil not car oil; I use Castrol 4T.

20W40 IS still available, you just have to search a bit. I currently stick to 20W40 in one of my 550s and 20W50 in the other (out of curiosity) but so far have not been able to tell any difference.

 

Thanks, assistance appreciated greatly