Are you running crush washer or taper seat plugs?

[Ronnie_D]

I pulled the spark plugs on my 79 XS1100 and noticed the cylinder has a taper seat for the plug to cylinder seal. The plugs in it were crush washer type.

I called NGK and he gave a part number for Iridium plugs.
TR6IX, or 3689.

The Iridium plug conversion on NGK website goes from BP6ES to BPR6EIX, or 6637. This is a crush washer seal type.

I am going to order the TR6IX plugs and try them out.

cheers,
Ron.

[Bax]

Hi Ron, There is a 1mm difference in the thread reach between the two and the factory gap setting is set different as well. The hex is also one size smaller. Probably not going to make a bit of noticeable difference IMO.
---Bax

https://www.ngk.com/ngk-6637-bpr6eix...-ix-spark-plug

https://www.ngk.com/ngk-3689-tr6ix-i...-ix-spark-plug

[DiverRay]

Unless someone has machined the head, you should be using crush washers on the plugs. That is what the machine was designed to use. I've not seen an XS that used taper seat plugs, and I worked on my first XS in 1978.

[Ronnie_D]

Thanks for the info. I will use the crush washer type of plug.
I will buy some Iridium BPR6EIX.

cheers,
Ron.

[Bax]

Ron, Just suggesting that you purchase from an auto parts store directly. eBay and Amazon are full of counterfeit NGK iridium marked plugs. ---Bax

Post by Madmax-im

https://xs11.club/forum/idle-talk-forum/xs11-xj11-discussion/858872-amazon-is-selling-counterfiet-parts-buyer-beware