2021 700i Uxv spark plugs

[loftisman19]

Last year during the winter, it had trouble cranking and was backfiring like crazy. Finally got to where it wouldn’t run. It was still under warranty so I took it to the shop and found fouled plugs. Here recently I’ve been driving it in low, to me it rides smoother not so jerky for my evening cruises putting around the farm. I’ll put it in high every now and then when I catch the need for speed. Well, the other day the motor bogged down and backfired really loud. Now intermittently, whether I’m in high or low, it’s wanting to backfire or just bog down and knock off. Sometimes it runs just as smooth and no issues, and the next it will knock off 3 times in half a mile. I’m figuring it’s the spark plug again, has anybody else had these issues? What plugs are you guys using? Are the OEM plugs just that bad or is it another issue causing this? I’ve always used non-ethanol gas in it and I don’t abuse it by any means. Any help would be greatly appreciated.

[Bratman2]

I had that problem more with my MXU 450i new than my UXV 700i. Both take the same NGK CR7E sparkplug. On my MXU I replaced the NGK CR7E with an NGK CR6E. That is a one-step hotter plug. That greatly reduced the stalling on it. I would suggest trying the one step hotter CR6E plug.

This may not have anything to do with your current problem, but I will mention as a possibility. I bought a pair of NGK spark plugs off Ebay. They were stamped NGK and came in what looked like NGK boxes. They were for my grandkids atvs. A Kymco 90 and Chinese 110. Both of those plugs started failing with very low hours. When I say failing, I am talking about missing, running rough and finally not at all. Like maybe 5-8 hours of riding. In hindsight I believe they may have been counterfeits. Mainly because I bought the same plugs from somewhere else and have had no more problems with 4-5 times the hours on the atvs now. Just a thought!