RGV 250 Build: Engine plans

I mentioned in my last post that we would talk about plans for the engine in the next post.  Before I get into that, I want to share a few bits and pieces that have been acquired in the last week.

• Extra set of wheels (no discs)
  I was able to find an inexpensive set of wheels on Ebay without discs.  They are black and a little beat up and my plan is to take them to a local powdercoater to be blasted and coated white to match my current wheels.  I am also considering a shade of blue to match the blue in the decals.

• 

  Upgraded stator, regulator/rectifier, and CDI for the Banshee The Banshee does not come with a battery or charging system and it’s built in stator is barely sufficient to power the stock lights on the Banshee.  The upgraded stator brings out an additional wire which is need for the rectifier to convert AC to DC power.  The stator will feed the ignition system directly and then feed the 200W rectifier/regulator which will charge the battery and power the rest of the bike.  Depending on the motor I end up with, I will will also be looking for a flywheel.

• RZ350 Transmission spares
  The RZ350 transmission is more suitable for street/track use with its taller gearing.  The shift forks are a little different as well which provides for smoother shifting from what I am told.  I am hoping to close a deal on the bottom end of a RZ350 motor that also includes the transmission.  In the meantime, I was able to snag a partially complete transmission to use for spare parts.  The spares include one complete output shaft, a partial output shaft and a partial input shaft.

  	Banshee	RZ350
  1st	2.461	2.571
  2nd	1.812	1.778
  3rd	1.500	1.318
  4th	1.250	1.083
  5th	1.045	0.962
  6th	0.875	0.889

  Comparison of Banshee to RZ350 transmission ratios

The Banshee Engine

I’ve been doing a lot of research into performance mods for these Banshee engines.  Since my current plan is to buy a complete bottom end and build the top, I lots of freedom in how it gets built.  I’m still reading and learning a lot, but I have narrowed my options down a bit.   The 2 Smoked website has been a great resource as it is geared towards RZ350 mods which are more relevant to what I am trying to do.

• There is the inexpensive option which involves using the existing crank and Athena cylinders.  With 68mm cylinders, Athena cylinder head, pistons, studs, and gaskets and 392cc displacement, I could get into this for less than $700.
• A medium priced option would include new Cheetah Cub cylinders and a Pro Design Cool Head.  There are Cheetah Cub options that allow for keeping the stock stroke (54mm) so the crank doesn’t need to be replaced. They also don’t require any machining of the crankcase. It looks like the most displacement I could get with this setup is 392cc (same as the inexpensive option but higher quality components).  That is the kit pictured above.
• The top shelf option is limited only by your imagination and pocketbook.  There are Cheetah Super Cub cylinder options that could take you all the way up to 553cc with 72mm bore and 68mm stroke. This would obviously require a new crank as well as machining to the crankcase to accept the oversized cylinders.

More research still needs to be done, but in the meantime I’ll start tearing down the chassis and coming up with a game plan.  More on that next…