Spark Plug Tune up 2002 F650

I have spent a lot of time on the info pages for my F650GS. I had read that a projected tip Iridium spark plug would improve the slight surging that it had. Well... I installed an NGK DPR8EIX-9 Iridium IX Spark Plug during the annual service and it's like a different bike!! That $8 plug lets it run smooootthly up through the 2500-3500 rpm range. It does 50mph in high without a stumble and will pull from there like I hoped it might if I installed a $250 gismo to fatten up the fuel or something. I ran it up to 85 once and no problem there either. If you have any issues with this common complaint try one (found on Amazon). I now hear the Denso (5372) IX24 Iridium Spark Plug is supposed to be even better! I have one in my cart for the next order! I haven't had time to fully appreciate this change as I have only taken one ride so far but what a change.

I think this mostly suggests the previous plug was worn out.

I hear ya

lkchris said:

I think this mostly suggests the previous plug was worn out.

Click to expand...

Kent,
Yea I would think the same... except.
The bike had an annual service about 750 miles before done by the PO. The "old" plug looked "new". The recommendation on F650.com FAQ has many other owners with similar results. I posted it because, like you, I couldn't believe it would make any significant change. I'm not a believer that cures come in cans or that the engineers at a major manufacturer got the plug wrong. I have had a chance to ride it more and the results are real. If the plug stuck out the side like my R bike I would buy a new BMW plug and put it in JUST to finish the experiment, but this plug change requires the faux tank to be removed and the air box taken off etc. Not worth it as I now have a bike that is significantly better. All said, you can be right, and your observation would have been mine too.

How much winter riding is 50 degrees and above there?

It certainly wouldn't be the first time they picked a poor plug... Part of their choice is no doubt driven by paper-pushers and cost-cutters.