Triumph street twin diagnosis,poor running,rough running.blowing head gasket?‪@jbsworkshop‬

I had this triumph street twin in for diagnostics,when I picked it up i could it was dark but i could here & feel gas blowing near the cylinder head gasket area so was thinking the worst. When i got it back to the workshop in daylight things began to look a bit clearer after i found the damaged spark plug,what i could feel was the combustion gasses escaping up past the broke plug & coming out the spark plug weep hole. Luckily the plug removal was nice & easy,i cleaned the drain holes both sides of the engine & replaced both plugs & the problem was solved. I then gave it a full service & road test & all was good.