A championship-winning Honda CL175 road racer is being auctioned with the proceeds benefiting the AHRMA Safety Fund.

The Story

Built for speed, comfort and beauty. The custom aluminum racing tank and pop-up cap was hand-crafted by Stephen Gillen. It’s super-light and the shape is perfect for racing. – Photo Credit Mike Polkabla

During 2010, Mike Polkabla and Mike Riddle, two AHRMA racers from the SF Bay Area, chased and won the 200GP national championship.

The two friends were actively involved in building, racing and developing Honda CB160s. Riddle, in particular, became legendary for pushing the technical and performance boundaries of these machines. He developed CDI-based ignition systems and pioneered the use of large-diameter pistons that resulted in machines capable of winning not only 200GP championships but also being competitive in the 250GP class.

Polkabla has retired from racing and has mothballed his race bikes. Riddle tragically and unfortunately passed away a few years ago – his passing left a massive void in the CB160 racing community. Polkabla wants his championship-winning CB160 to find a new home – ideally with someone who will return it to the track and wants to support AHRMA. Per his request, the bike will be auctioned off with the proceeds supporting the AHRMA Safety Fund via a donation made in Mike Riddle’s name.

The Auction

A “hybrid” auction will begin July 1 and will end July 15 during the AHRMA Classic MotoFest™ of Monterey. The winning bidder will be responsible for transporting the bike from WeatherTech Raceway Laguna Seca.

On July 1, the virtual auction will begin using the GalaBid system. Bids may be placed by clicking the button below.

Top-to-bottom, this bike is a champ: Custom fiberglass Airtech half fairing, fender and seat, racing clip-ons, levers and controls, custom foot pegs, aluminum mounts and linkages based on modern Suzuki GSXR components, and a custom fiberglass belly pan with quick-release Zeus fasteners.  Photo credit Mike Polkabla

At approximately 6 p.m. on Friday, July 15, the highest bid from the virtual auction will be the starting bid for a live auction during the “One AHRMA” party at the AHRMA Classic MotoFest™ of Monterey. If there are no bids during the live auction that exceeds the highest bid from the virtual auction, the bidder from the virtual auction will be the winner.

The winning bidder will pay for the bike, accessories and spares by making a contribution in the amount of the winning bid to the AHRMA safety fund. The winning bidder is responsible for arranging transportation of the bike from WeatherTech Raceway Laguna Seca.

Questions: Please contact AHRMA member and volunteer, David Stark, at davidstark.ahrma@gmail.com

The Bike

Polkabla’s Honda CL 175, affectionately known as the “X-Bike,” was campaigned in AHRMA’s GP200 and GP250 Class from 2008 to 2010. He rode the bike to the AHRMA 2010 National Championship in GP200 and placed second in the in GP250 Class the same year.
Following the 2010 championship, Polkabla cleaned and stored the bike inside his home. It is essentially in race-ready condition.

The bike will be on display at the AHRMA booth during the MotoAmerica event at WeatherTech Raceway Laguna Seca July 9 and 10 and during the AHRMA Classic MotoFest™ of Monterey July 15 and 16.

In the engine room you’ll find a CL175 based “sloper” motor and transmission with a racing head ported and flowed by Patrick Ho, re-phased Falicon polished 180-degree crank and Megacycle X9 roller bearing camshaft. The Wiseco Racing Pistons are a 3mm overbore legal for the AHRMA GP200 class. The custom oil cooler based on Suzuki GSXR components keeps everything cool. Photo credit Mike Polkabla

Chassis, Wheels, Controls and Brakes:

  • 1968 CL175 based chassis with black powder coated lightened frame (extra tabs removed)
  • 30mm Ceriani aluminum racing forks and triple clamps and springs
  • Works Performance custom rear shocks
  • 2-inch extended and sleeved swingarm
  • Akront WM1 alloy wheels with stainless steel spokes and nipples
  • New racing wheel bearings and custom aluminum spacers
  • CB450 Spec polished and lightened front brake hub and drum
  • CB175 Spec polished and lightened rear brake hub and drum
  • HRC hollow aluminum rear axle and nut
  • Primary drive chain conversion to modern GP125 chain and sprockets
  • Aluminum racing clip-ons, levers and controls
  • Custom foot pegs, aluminum mounts and linkages based on modern Suzuki GSXR components
  • Custom fiberglass Airtech half fairing, fender and seat with aluminum mounts
  • Gustafsson acrylic fairing shield
  • Custom fiberglass belly pan with quick-release Zeus fasteners
  • Stephen Gillen custom aluminum racing tank and pop-up cap
  • Motion Pro double (push-pull) throttle and clutch cables
  • SRA Scitsu Sheffield electronic Tachometer
  • Dual kill switches

Engine Modifications:

  • CL175 based “sloper” engine and transmission
  • Aluminum dome racing head ported and flowed by Patrick Ho
  • Re-Phased Falicon polished 180-degree crank
  • Custom aluminum breather case valve
  • Megacycle X9 roller bearing camshaft re-phased to a 180 degree
  • Riveted cam chain and custom racing cam chain tensioner
  • Wiseco Racing Pistons 3mm overbore (legal for the AHRMA GP200 class)
  • Copper Head gasket and spares
  • Patrick Ho Racing stainless valves and titanium valve caps
  • Racing Valve Springs and guides
  • RDL electronic ignition rephased to 180-degree firing
  • Custom RDL dual under seat exhaust with aluminum collars and mounts
  • Exhaust ports matched to exhaust
  • High flow dual petcocks
  • Keihin VM26 Carbs
  • Custom oil cooler based on Suzuki GSXR components
  • Custom tuned Bateman carb intake ports and velocity stacks
  • K&N High flow filters
  • RDL and Poneleit spec coils and electronic ignition
  • Motul racing oil and lubricants were used exclusively during it’s time on the track

Spares and Accessories

  • Front and rear stands
  • Arias racing pistons
  • Rear sprockets and countershaft sprockets for race tracks from Daytona to Seattle
  • New-in-box racing primary chain and cam chains
  • Assortment of copper head gaskets
  • Larger oil cooler for long/fast tracks like Daytona and Willow Springs
  • Kehin VM 22 carbs
  • Complete transmission spares
  • Spare foot and hand controls
  • New-in-box Falicon Polished 180-degree crankshaft

The Cause

The AHRMA Safety Fund provides financial support for a variety of track and racing related safety programs. The fund has been used to support important safety measures such as Air Fence equipment at AHRMA races, along with other initiatives. Contributions to this fund are used strictly for safety related equipment and project work.

Questions: Please contact AHRMA member and volunteer, David Stark, at davidstark.ahrma@gmail.com