Hi there just wondering how many miles needed for a good spark plug reading ?? Now I have just up jet after the air filter drilling modifications gone up from a 96 standard to a 98 main jet now I have been going out to check out any difference and it's better on the get go and thought the gear's a bit more responsive no top end different still bog standard still not made the 50 mph but Hay l never been trying to go faster just a bit quicker on the get go and l think this may have solved the issue just need to make sure that I have the sweet spot running condition any advice most welcome soulmate