From Florida Vintage MX News:

As I See It by Peter Villacaro


As vintage motocross continues to grow, our sources of parts seem to become more of a jungle. Exhaust pipes for two-stroke race bikes in particular, is an area that can really make you want to scream.

Prior to the recent race at Reddick, I considered switching to the CIRCLE F pipe, however, my skeptical side stopped me. After two holeshots and 2nd and 1st place moto finishes for first overall in the 250/500 Masters class, I decided to test the new pipe at the end of the day.

Examining the pipe, the first thing to get my attention was the first-rate workmanship. All the welds are gas-fusion (almost a lost art) - not a drop of braze is used, and the rolled cones mate perfectly. OK, so it looks nice, but how does it fit? Better than stock! My only beef at this point is the lack of a rear hanger to help the feeble main mount on the Honda frame.

Firing up the bike, I was provided with a pleasantly subdued note, and warmup showed crisp response. Into first gear to pull away produces an impression of good low end. Running it up through gears feels real strong, but it's out on the track to see if there is an improvement where it really counts.

On the circuit the CIRCLE F pipe continued to impress me with seemingly "electric" power delivery, smooth and predictable. Power output was up in the bottom and midrange. Using a gear higher on most sections of the track seemed to bear this out. Top end, you ask? Absolutely. The engine was more than willing to rev, and rev some more. Was it too lean? Five laps later, a "plug chop" showed just a nip on the rich side - plenty safe. Ten more laps showed more of the same behavior - just happy and strong. To give you an idea of how, in my opinion, this pipe stacks up in relation to its competitors, every time I have tried another aftermarket pipe, I always ended up going back to the stock pipe!

About the test bike: The engine is stock with a six-petal reed valve and 38mm Mikuni. Piston-port CR's should respond in a similar manner due to the fact that the reed-valve engine liked the same stock pipe that testing has shown the piston-port engines respond best with.

In review, oustanding craftsmanship, excellent fit, and great performance mark the CIRCLE F CR250 Honda pipe a winner in my book . . . . As an additional side benefit, you can get the transmission drain plug out with pipe on!