Port timing question

[mwiley]

So the cylinder that is on my bike I bought off a guy like 15 years ago and don't really know what it was originally ported for. The guy I bought it from raced mx and I occasionally would trail ride with him. I have no idea where he is now. So, I just checked the exhaust port timing and it came in at 183 degrees. First question would be does anyone have an idea of what type of application this might have been ported for? My next question is how much of a difference would another 5 degrees of port timing make? I have another cylinder I could get ported but just wondered if it would really be worth it on a small bore motor? Thanks for your help.

[Langbolt]

Looks like it's been kept STOCK......Or atleast the roof of the Exhaust port is anyway. Did you use a Degree Wheel to check your Timing ? Or Calculate it ? Giving it another 5 degrees would really wake it up....if you wanted a MX style motor....188 degrees.....but then you'll want 126 degrees of Transfer timing to give you 30 degrees of blowdown..  What are your Transfer timings ? Do the ports look like they've been made wider ? Maybe just cleaned up. What you have would be good for trail riding-woods. Neil or Arlan could help you out if you want it Ported.

[mwiley]

I checked it with a degree wheel. I have no idea what the transfer timing is, mainly because the motor is still in the bike and the head is on. It definitely has been cleaned up and maybe I just need to send the cylinder out for further inspection to someone who can really tell me what I have.