Is it normal to have bad spark plugs from time to time?

[a6lns]

Hi all is it normal to have bad plugs go from time to time or am I doing something wrong I am on my 3rd plug now with the zenoah 29cc

 

[Mick Boomer]

How often? And are you using cmr7h ngk plugs?

 

[a6lns]

Yes I am using cmr7h it was a new engine so I put it down because it was new summer time the last plug had the engine in jan last year

 

[RcJunkie13]

yea just toss in a new one

 

[motocam360]

what kind of spark plug gap do you run with that plug and that engine? I've got the same setup that I'm trying to get going. It's a used engine, but new to me.

 

[a6lns]

Ngk cmr7hi I never shock gap just put them in don’t think the plug should go bad that often that’s me fuel mix 25;1 think I might change to 33;1 that’s me though

 

[a6lns]

hi went to track today with 5t but only done 3 runs because plug failed again I changed from putoline with 25:1 now using motul oil 160 mils to 5 litres now a plug ant lasting can’t understand it