Which Porting is that

[uts]

Hey dirtosaurs,
Maybe someone can give me some inf. I have an 86 CR250. It is a great bike. I had the bore done a while back and the guy said " gee this must have some power, someone has done a great porting job on this". But I didn't know about porting and didn't ask what kind. Maybe someone can fill me in. Info:
Power hits hard right off the bottom and pulls hard through the mid range, then seems to have another hit at the top of the mid range but very top rev range is a bit flat. If I use 91 octane fuel it detonates bad, 95 octane detonates a little down low, 98 octane no detonation and excellent performance. I don't know much about performance mods (obviously) but maybe this sounds familiar to the knowleged.
just curious really. When I get the cylinder off for a top end next time I will ask the guy more, but that won't be for a while.

 

[Eric Gorr]

Thats stock! They were great tractors but the big problem is that the exhaust valves clog with carbon and get stuck closed or worse, half open. Try checking the valves by removing the left cylinder cover and making sure that the valve move 15mm

 

[uts]

Hey Thanks Eric,

Stock eh, that's awesome. I hope the goose that did the bore knows what he is on about then. It runs great, perfect for trails and stuff with the tractor effect down low as you said. I keep a close eye on those valves as I have hear of the problems with them. Last time I checked they were moving nicely. I use the motul 800 which doesn't seem to mess things up much. Hey maybe you know of a good 2 stroke guy down in Aus. Is there anyone you can suggest for bore work etc.
Thanks heaps

UTS