To Pipe - To Know Is To Start

The Question - I am looking for some port info for a 250r. Mainly what duration works the best for a strong overall power band. Right now I have a exhaust duration of 186 degrees and the transfers are stock just the casting flaws cleaned up. I am wondering how much I should raise the transfers and how wide should I go with them. secondly I am looking for info in the new FTZ pipe and how it compares to the LRD team B pipe.

The Response - If you're wanting overall power, stay put with the 186. Your transfers, I imagine just thinking about it, should be somewhere in the 126-129 range to match up with the exhaust - but that is only a very basic answer. I would calculate further to obtain exacts. I had the LRD pipe and HATED it. I went through all sorts of pipes, and eventually ended up with a Whale pipe, just before I was going to have a custom-built one. I love this pipe. But, my motor happened to be ported in such a way that this pipe really complimented it well. Could be very different in your case. From what I have seen & heard on the FTZ pipe, it is identical to the Whale.

Trax310

Me too. I have had a shelf full of (almost) useless pipes, or pipes that were completely wrong for the kind of porting my motor had. It's too broad a statement to say that a pipe is High Output or Torque, or Mid Range. What the manufacturers of the pipes need to do is to start publishing precise data about their products. In the four stroke automobile world, cam manufacturers publish information about the lift and duration, operating range, maximum RPM and sometimes even much more specific information.

This aids greatly in cam selection.

Differences in the available 2 stroke pipes could be compared more easily if this kind of information was available. I dare any manufacturer to publish the design specification of their pipe along with the advantages and disadvantages of its use. Include the most amount of information possible, and let the user make the choice from that. Additionally I'd like to see 2 stroke porting shops tell up front what specs they'll be cutting their customers motors ports to.

Its not hard to find out these things if you really want to know though. Many racers and enthusiasts who need to have as much information as possible at all times have taken a few pictures of various quads or bikes with their pipes attached to be used to reverse engineer the product. Since we know the overall dimensions of a given quad, we can scale our drawings from them with extreme accuracy. Angles of divergence/convergence are constants - the wonderful thing about pictures.

Open up a road race magazine and look at the pictures of pipes attached to a 250cc racer. The way they hang there its very easy to scale them and find out a whole lot of information about them. It's also very easy to find out other specifics about those bikes this way. The wheel sizes, tire aspect ratios, steering head angles, even spring rates and many, many other interesting factors which make these 2 stroke masterpieces the most powerful (per liter) naturally aspirated gas burning engines in the world. A hundred HP from a 250cc motor translates into 400 HP per liter - OUCH - that's gotta hurt those 4 stroke techies...

Rick

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