How would loose guides cause build up of gunk in the intake ports only. Is it keeping the valves open constantly thus allowing some exhaust to flow back into the intake mixing with the incoming fuel causing the build up ?
the clearance between the guide and the vavle get loose due to poor machining or worn out, then excessive oil can get suked into the intake port causing build up...
hope that made sense becasue we dipped into the bottel of jack otonite!