I tore down my rn sj motor to freshen it up with paint, new gaskets, new bore and a factory B pipe limited chamber. The motor is 62t/62t currently running 85mm wiseco pistons, thinking about going 85.5mm. But when I pulled the cylinder I noticed the ports looked hacked to me. The motor actually ran good, very reliable, pretty powerful with a 10/16 hooker on stock pump. I wanted to know if I can save this cylinder? Or is it to late? Also the cylinder measures 4.688 from top deck to bottom deck. Is this normal or was it decked? Thanks in advance for any help.
Need help with a 62t cylinder.
- Thread starter Drock_707
- Start date
Not sure of the guys name but the ski and motor were purchased on pwc today as a complete package. Not much info about the motor was passed on. I didn't even know it was bored, I was just told it was a 760. Also this is my first SJ so could've been my lack of knowledge. I've been trying to learn more an more about these skis and motors. So can I clean the ports up to make them smooth and match the casting to the sleeve ports? I also put a Ada head 38cc domes with girdle kit on, which means if it was decked I need custom domes? Thanks
BruceSki
Formerly Motoman25
- Location
- Long Island
It looks like someone put rocks in the cylinder and shook it around to port it. Lol
If it's a 64x casting it starts at 85mm.
If it's a 62t casting it starts at 701cc and was bored to 85mm or 760cc.
If it's a 64x casting it starts at 85mm.
If it's a 62t casting it starts at 701cc and was bored to 85mm or 760cc.
BruceSki
Formerly Motoman25
- Location
- Long Island
BruceSki
Formerly Motoman25
- Location
- Long Island
I would suggest asking someone who has experience porting motors.
Most guys like to start with a clean slate instead of fixing a botched job.
You can always take material off but it's very difficult to add it if it's missing.
Most guys like to start with a clean slate instead of fixing a botched job.
You can always take material off but it's very difficult to add it if it's missing.
- Location
- Denver, NC
760 cylinders start at 84mm actually (701 start at 81mm). Also, all 760 cylinders are cast with 62T markings, just like the 701. The 760 does have larger outside diameter sleeves than the 701, sorry I don't know the measurement off hand though.
Sent from my iPhone using Tapatalk
4.688 is fine on deck height for stock ada domes to work
4.682 would be your limit before custom cutting domes
don't go by too much visual on the porting
its best to measure them
any good porting shop can clean them up to look nicer
cylinder honing finish looks worse than the hacked porting to me
4.682 would be your limit before custom cutting domes
don't go by too much visual on the porting
its best to measure them
any good porting shop can clean them up to look nicer
cylinder honing finish looks worse than the hacked porting to me
waxhead
wannabe backflipper
- Location
- gold coast
Port job is quite rough. The bit that worries me the most is they have ground the bottom of the transfers and not the top. There is a really sharp edge where the ring is running this can be seen by the line above the port on the cylidner wall. The ring is crying every time it goes over that. The exhaust port walls also have alot of indentiations. It really needs to be cleaned up. The cylinder can be fixed no problemn at all but you really need to have it bored and to remove the horizontal hone marks. make sure they put a small bevel on it to allow the rings to be guided back after the port