Honda CR80 Engine Tuning and Tech Tips for Shifterkart Applications

I will be very honest, most of this information I extracted from www.swedetechracing.com, as I was an employee with the company for many years.  Before being an employee of the famed Shifter Kart Engine builder, I was a customer while I competed in the Northern California Region in both the Honda 80cc Shifter and the Modified Honda CR125 classes.  It was before the internet, so you have to take me word for it.

I will continue to add information to this webpage as I information requires updating.  If you have suggestions, please contact us with your added information or tech tech tips.

Honda CR80 Break In Techinical sheet from SwedeTech Racing for Modified Honda CR80 Engines built by Swedetech

CR80 Engine Break-In

Always warm-up the engine on the stand and do a walk around of the engine and kart, check for loose bolts, water leaks, etc.

• Break-in water temp. should be 150-155 degrees
  • Water Temp Sensor should always be located between the head water outlet and the radiator inlet.
• Normal running water temp. 130-135 degrees
  • (Take the reading anywhere between the cyl. head outlet and the radiator)
• New engine break-in 15-20 laps
• New top end break-in 8-10 laps
• Increase main jet 1-2 sizes for the break in procedure

On a 30 second track slow the pace 4-5 seconds per lap. Always drive with either full throttle or zero throttle. Do not limit engine by using partial throttle, as this causes a lean condition. Shift through all of the gears and when exiting corners, and allow the engine to fully rpm. On the straights, short shift the engine to keep the RPM’s low and to create a load. The load is needed to properly seat the ring and break in the piston.

Oil

Motul Trans oil 10w30 or 10w40 Expert (never use ATF) for the gearbox on transmission
New engine - 600ml
Use 50ml less for routine oil changes
Motul Kart Grand Prix or Maxima 927 - mix 24:1 for break-in and regular use.  This must be added to the racing gasoline or fuel.  Non Oxygenated, 110 or 112 octane is preferred.  Do not use less than 98 octane.  Do Not Use Pump Fuel

Spark Plugs

NGK BR10EG or R7376-10

Jetting

Standard Mikuni Flatslide
160-200 main
30-40 pilot
5DP39 needle 4th or 3rd clip from top

Above recommendation is when using a dual fuel pump system called a pump around

Miscellaneous

There are 2 water spigots by the water pump. The one in front is where the hose from the bottom of the radiator connects. The one behind it connects the hose to the inlet on the back of the head. Be sure not to mix them up!

Top End

SwedeTech always has top end parts in stock. You can order by phone or by internet at www.shopswedetech.com . When ordering, please have the base gasket thickness measurement available.

You will want to achieve a squish of 0.029”- 0.032” when installing a new piston. You will achieve this by using different thicknesses of base gaskets. Use 0.040” solder when checking the squish. We also have this available.

Bookmark the Honda Category on Extra Kart Parts for updates and new items.  As always, EKP's inventory is always revolving, so if it's not posted yet, send us a descriptive note of what parts you are looking for and there is a good chance it is in our inbound department waiting for photos and to be placed online.

Honda Parts on Extra Kart Parts

Keep in mind, we offer additonal discounts on items that are not yet published online.