This is my 01 Quadrunner 250, I have 30 hours on this rebuild. 1.5mm over, Namura piston, TP rings. The connecting rod bearing felt nice and had no play in it (these are roller bearing big ends). I've run semi-synthetic 10W-40 in it since I rebuilt it and changed it twice.
It runs great, some carb issues aside, compression is great, 175psi, and burns no oil. But when I stuck my borescope down there the other day, this is what I saw. The resolution on the pics from the borescope is terrible so it's hard to tell, but the crosshatch is still visible under most of the aluminum transfer in all but a couple areas. The only thing I can think of is when I rode on the beach last year I happened to be riding with the wind which meant that there was limited airflow over the engine (even with the fan running) and I saw CHTs around 425-435, usually it's in the mid 300s. From what I read though that should be fine for short periods of time and it wasn't noticeably down on power or anything.
I don't want to pull the head again if I can avoid it because it's a major pain in the rear, but should I worry about the aluminum transfer? Since the compression is still great and it's not burning oil I would think it should be fine, these old Suzukis are just about as bulletproof as old Hondas. Worth the headache of pulling the head and cleaning it up with some muriatic acid or not?
It runs great, some carb issues aside, compression is great, 175psi, and burns no oil. But when I stuck my borescope down there the other day, this is what I saw. The resolution on the pics from the borescope is terrible so it's hard to tell, but the crosshatch is still visible under most of the aluminum transfer in all but a couple areas. The only thing I can think of is when I rode on the beach last year I happened to be riding with the wind which meant that there was limited airflow over the engine (even with the fan running) and I saw CHTs around 425-435, usually it's in the mid 300s. From what I read though that should be fine for short periods of time and it wasn't noticeably down on power or anything.
I don't want to pull the head again if I can avoid it because it's a major pain in the rear, but should I worry about the aluminum transfer? Since the compression is still great and it's not burning oil I would think it should be fine, these old Suzukis are just about as bulletproof as old Hondas. Worth the headache of pulling the head and cleaning it up with some muriatic acid or not?
