There aren't too many Gen I Virago 750s around, but we haven't forgotten them. Here's a choice of compression - 12:1 or 13:1 for your consideration. The 86mm bore will take your machine out to 805cc, and if you are really brave, this can be expanded to 87mm and 823cc - not recommmended. Your engine will gain power throughout the powerband, both from the displacement bump and from the greater compression. 12:1 will stress your starter: see our comments on starting elsewhere. If you opt for 13:1, always run the highest octane fuel that you can find; most municipalities usually have at least one station that sells 100 (or higher) octane fuel. And run a performance cam to mitigate the cylinder pressure. 823cc at 13:1 would make for a potent "duck hunter." But you might have heating problems on long rides. Our recommendation is 805cc at 12:1 - spunky yet stealthy. Run anything from 34mm VM carbs to TM38s - the bigger, the faster - at the expense of off-throttle manuevering.

The kit comes with two pistons milled for maximal lightness, rings for all, two pins, four clips, and a pair of pure copper head gaskets. In either size, any compression (11:1 to 13:1), these go for $700 for a kit consisting of two pistons, two sets of rings, two pins, four clips, and two solid copper head gaskets. If you want ceramic caps on the pistons and a slippery coating on the skirts, it comes to $850. The max is 86.5mm (813cc) at 12.5:1 (13:1 if you are really brave) and to be able to warranty these I must charge a little more. If you are nuts and don't care about warranties, we can come up with 87mm (823cc) at 13:1. Note: boring this big will probably completely remove the inner "fire ring" and it leaves the sleeves very thin. It is also very hard on the rod eyes (the small-end) where the piston pin resides. If you really want this kind of power, split the cases and run a crank out of a bigger bike. You'll get the bigger piston pin bores and you can even bore and stroke to as big as (at least) 1483cc. Reckon on about $15 for shipping. Sorry, I don't have access to these cylinders, so having your originals bored is up to you. The machine shop that I deal with charges $90 per hole for big bores. If you want me to do it, reckon on about $35 shipping each way. If you want your cylinders black powder-coated with exposed fin edges, add $75.

750 Piston Kits
  • JE 86mm 11:1 or 12:1 with Head Gaskets
  • $700.00 for a kit to fit one engine.
  • As Above, plus Ceramic Crowns and Teflon Skirts
  • $850 for a kit to fit one engine.
  • JE 86.5mm 12.5:1 with Head Gaskets
  • $750.00 for a kit to fit one engine.
  • As Above, plus Ceramic Crowns and Teflon Skirts
  • $900 for a kit to fit one engine.
  • CP-Carrillo 86mm 12:1 or 13:1 with Head Gaskets
  • $950.00 for a kit to fit one engine.
  • As Above, plus Ceramic Crowns and Teflon Skirts
  • $1100 for a kit to fit one engine.
  • Any size, either mfg, any compression, any features as above.
  • Same price as above plus a "risk" fee.
  • Gen One Complete Gasket Set 750
  • $75.00
  • 750 high compression head gasket
  • $25 per pair

Last Modified:   Sun => 07:21:45 PM PDT - 14 Apr 2019 America/Los_Angeles