Himalayan 500cc


Backyard Bodger
Staff member
477 Owner
After playing with the idea bigger and bigger Pistons and building a 511cc which required a Spacer to raise the Barrel and a Longer Cam chain ( both thanks to @barima) and succeeding in making the "Worlds Largest Himalayan" ( yet to be contradicted or confirmed) I have decided to go back to 500cc.
For that I needed to modify the Piston to create clearance for the larger Valves fitted.View attachment 1696

View attachment 1697
Determining TDC.

Deck height measurement.
Some people ( I wont say who) prefer Riding their Himalayan to working on it.
Having just suffered a couple of Heart attacks and 2 operations (that I hope have sorted things out) , I am resting on Doctors orders and not allowed on the road for the time being.
Hense the seemingly pointless spannering!
IMG_20240521_121441.jpgthis is not going to fall in the Engine again!
Case widened without removing from the Frame.
Over size Valves need over size Ports!


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Started up a bit hesitantly and required idle adjusted up to hold it.

First ride it reved freely but with a couple of "flat spots" and some hesitation from idle.
Checking the Map it was very lean and when I showed @Sasa a pic of the map recognized that it was the original map!

Bike has been sitting 3 months with the battery disconnected perhaps it had reset to factory settings :unsure: