NGK BR9ES spark plugs no longer fit

Hey all.

My 1985 XJ700 was not firing the first cylinder, so I pulled the plug and found it a bit wet compared to the others. It's been sitting for a long time, and figured at the very least it could do with a new set of plugs.

I picked up another set of the same plugs that are currently in it now (NGK R BR9ES) and see that the heads on the new ones are thicker, and will not fit into the spark plug wires. The only difference I can see at all on the plugs is that the old ones have a tiny "M 1 x 9" stamped on the hex part, and the new ones have "M 3 Z 8" stamped on them.

Has anyone run into this issue before? The ones in the bike now I had bought about 5 years ago when I first got the bike, and just used the BR9ES part number from the plugs that came with the bike. Tried to do the same thing this time around and its clearly a different head on it, and will definitely not fit. Is there a different plug product number I should get instead?

Thanks

 

Those are the caps on it.

I found out the hard way as well. I ended up destroying one of the wire terminals pulling the magical hidden plug out.

Take the top of the plug and unscrew the cap. ( Then you'll have the threaded piece you'll want. )

 

If these are caps, then they aren't coming off. I threaded one of the plugs into the bike to act as a vice, and then put some pliers on it to unscrew the cap, and it ended up pulling out the whole metal length of the plug down to the bottom. Looks like it might have sheared, I'm not sure exactly. But it all looks like one piece; I can't even see a ridge where the cap would be a separate part from the threaded piece underneath.

 

I don't know the difference from NGK BR9ES and NGK BP7ES

 

However, I assume the idea is the same, there are threads underneath the cap.

Thank goodness I had an old spark plug to demonstrate, and a newer cap.

I'd guess the plugs haven't changed since they were last replaced, but would you upload a photo of the old and new plug?

 

http://video.oreillyauto.com/v/22811/ngk-spark-plug-terminal-types/

Watch this video.

Turns out some spark plugs come in the solid and removable caps. You may have picked up the type with the solid terminal, that doesn't have any removable caps. That is why you probably were not able to remove the terminal.

Trip back to the autoparts store.

 

The fiche says the proper plugs for an '85 XJ700 (aircooled) are NGK BP8ES, at least for the USA. Those should have removable caps.

 

Yeah, these are definitely the solid terminal variety it turns out. I didn't even know they came in more than one type. I'll go back to the store and see if they have them in the stud or loose type, and if not try to see if they carry the BP8ES plugs. Thanks everyone for all the information!