Joda76

Pauls320 thank you so much for your comment. If I did not inspect head grooves I would of slammed it back with a new o-rings and afterwards would be like🤔 I was suspicious though, because when disassembling I figured by the head bolts that the head was done before, and when I inspected o-rings they were flexible an in like new condition. Previous owner must of bin frustrated for not fixing it and sold it

I have found two, next to a muffler mount (photo1),it was almost invisible util I started digging into it.... next one in line further away from muffler mount (photo2).

Great point! Thank you for advice. I will inspect. I was just checking if the head is flat, while waiting on o ring shipment. Managed to take a head off no problem. Accept Ossa manual says that the bolts are T20 and they are T25. Also wanted to comment about a muffler. I mean, even though I really respect Ossa's designe team work in many ways, making muffler into a prying tool for an engine head is such a bad idea. I am seriously considering doing some mod to dissconect muffler fron an engine.

Hello good people. I bought my self a cheep defective Ossa. It is in a rather good shape, only inner head gasket is blown. After cranking it pops like a champagne when opening a radiator cap. Coolant that I have drained smells on gassoline. As I can see 4 side bolts will be the problem to torque with my Nm torque wrench because of a frame interference . Should I use some special tool , or release engine in front and pivot it a bit to make some clearance? One more thing. I read that inner oring is better to be silicone than NBR one, any oppinion on that? Many thanks !