Spark plug

[Fletcher Hildreth]

So I think my spark plug malfunctioned and I got a couple different ones from auto parts store. Neither seem to work. The engine might sort of run and backfires the entire time. I just took the chain off and peddled home. Help

 

[crassius]

always check for gasket leaks first, they're common

after that, it may be just loose wire or bad CDI unit

 

[Frankenstein]

So I think my spark plug malfunctioned and I got a couple different ones from auto parts store. Neither seem to work. The engine might sort of run and backfires the entire time. I just took the chain off and peddled home. Help

You may have lost your woodruff key under the magnet, pull the magneto cover and see if you can rotate the magnet without it turning the crank, or better yet loosen the nut a bit and then try.