CB175 Project for 200GP and CB160


After racing at NOLA and Talladega, the bike was not running well enough to bump start. Further troubleshooting revealed that the left piston was hitting and shorting out the spark plug. This did not happen with a brand new spark plug but did with every subsequent installation such as after checking for carb jetting. We decided to tear down the engine and learned that the left intake valve was not seating properly. Perhaps a result of gravel ingestion from Barber

Bike Hopefully Now NOT Under Reconstruction...

Before Barber in October 2012

After Barber in October 2012

Ready for engine removal

Spark plug marks on left piston

Used spark plug indexing bad

New spark plug indexing good

Some scoring on left cylinder


Head and engine sent to Auto Machine in St. Charles for valve cleaning, cylinder honing, and measurements.

Leaking left intake valve confirmed.

No other problems, now indexing plugs.

Switched to Bore-Tech FS-10GL electronic ignition for MUCH stronger spark. The left cylinder now has combustion. Added 1.3AH battery under the seat. Removed (clutch slipped)and then added 6th clutch plate (no apparent slippage) and changed clutch lever for increased clutch range, Happily it reasonably bump starts. Ready for Road America and Grattan in about 2 weeks.

It is finally running PERFECTLY. Yeah !!!