Honda XR500 big bore 591 cc

Full on power

 

The journey down the road of building several trick XR500 had to lead me to the mother of all motors. As the saying goes, "if you need power, there is no substitute for displacement".



So, on an expensive day of 2013, I decided to request from Engine Dynamics to provide a 591cc big bore kit for the XR500.



These things are not exactly sitting on shelves waiting for the next customer of the day. So I had to be patient.



From my stock of parts I selected a nice cylinder jug, a good strong cylinder head that I fitted with helicoils all around, a rockers cover, a good inlet pipe.


I sand&soda blasted everything nice and clean and shipped to EdCo in Petaluma, CA.

unnamed_edited.jpg
unnamed (2).jpg
unnamed (1).jpg

Carillo rod and balanced crankshaft

     A big piston.      97 mm diameter for 591 cc.

And the nicely prepared cylinder-head.

 

My instructions to EdCo were:

  • On cylinder: 591cc kit including sleeve, piston, rings, pin, gaskets, clips

  • On cylinder head

    • full race porting (exhaust at 29mm to match exhaust pipe please)

    • valve spring kit inc. guides and titanium top retainers

    • 1mm oversize stainless valves

    • new valve guide seals

    • high lift Megacycle cam

    • (Please remove the bolt that is still there, I did not manage to extract it, thanks)

  • On cam cover: please confirm what happens here

  • On inlet pipe: port as per inlet for a 38mm Mikuni carburetor

 

But there was more

My project was more than just making a 600cc out of a 500cc.

While EdCo was building the top end, I turned to my stock of parts to build the bottom part of the business. I intended to go for the full enchilada.

  • XR (PE01) cases

  • Tight innards from a low mileage XL500S

  • Removed the balancers and chain (1.74 kg less)

  • Carillo rod fitted to balanced crank

  • Billet aluminum clutch basket

  • New Barnett clutch plates and springs

  • NOS cam chain and guides

  • Flywheel from a XL250S (700g lighter)

  • And a whole bag of new bits and pieces.


Before the assembly can begin, I need to replace the now-absent rear balancer wheel with a suitable spacer.

 
IMG_20130416_160234.jpg
IMG_20200304_192637.jpg
IMG_20200304_185452.jpg
IMG_20200304_181655.jpg
IMG_20200304_174957.jpg
IMG_20200102_160711.jpg
IMG_20200102_160718.jpg
IMG_20200102_171205.jpg
IMG_20200102_160004.jpg
IMG_20200102_155958.jpg
IMG_20200102_155951.jpg
IMG_20200102_155355.jpg
IMG_20200102_155949.jpg
IMG_20200102_155347.jpg
IMG_20130421_191740.jpg
IMG_20130421_191611.jpg
IMG_20130416_174602.jpg
IMG_20130416_174624.jpg
IMG_20130416_181552.jpg
IMG_20130416_164111.jpg
IMG_20130416_160255.jpg
IMG_20130416_160425.jpg
 

©2020 by XR500 Only. Proudly created with Wix.com