1004cc Kits

Arias 96mm 11:1 piston sets.   A "bare" kit: two pistons with rings, pins, and clips.   For those who get cheap machine work, or have a TR1 or Virago 1000.   See below. The bare set will also fit the one thousand Virago: raising its displacement as much as a (no longer available) factory last-over bore; and increasing its compression to 11:1.   With this kit, you provide your own machine work and you must set (if necessary) the ring-end gaps.   Sometimes I have several sets in stock, both bare and as part of the kits described below.   Lately, I have not been able to keep them on hand: I open an incoming box of pistons, repackage them, and ship them out that same day or the next.   If you want (or need) these pistons, I urge you to order them now and just wait for the next available.   Recently, I had a whole batch sold a full month before they arrived here.

What you get: two pistons, two sets of rings, two pins, four clips, no gaskets.   This gives you a full-liter (1002cc) twin with a significant compression ratio -- use the highest octane fuel that the station carries.

I sell these domestically (for the 920 and 1000 Viragos), and in the Eastern Hemisphere (for the TR1 and its variants).   Keep in mind that these are forged -- they require greater clearance than cast.   They will be noisy until the engine reaches operating temperature.   Scary noisy - like metal being hammered.   As long as as they are allowed to warm up before you put them under load, you'll be fine.

$495 Arias 1004cc 11:1 Big Bore Kit.   International Sales Pay Expedited International Shipping.

Out of stock. One month turn-around from your order

Warning Warning Warning

The pictures above are of some 920 cylinders I had on hand. Note that the first two have no aluminum "dam" between the head gasket recess and that for the cam chain tunnel o-ring. These are blow-prone, and I recommend against even running an after-market cam with them, let alone a high-compression big bore. As near as I can determine, "good" cylinders (with barrier) were used in the XV920RH/RJ "Euro" and the XV920MK Midnight Virago. It appears that the good cylinders had a 5H1 part number and the bad were 10L. All our complete kits utilise the early style barrels. When I buy cores, I ask for picures first, and when I do get fooled, I pitch the eroors on the scrap alumium pile.

1004cc With Nine Twenty Cylinders

A volatile, but complete option is available.   I have some early style nine twenty barrels that have been bored to the 96mm pistons.   As these cylinders have grooved decks, they use recessed head gaskets.   Due to this, the cylinder and head surfaces are in contact for more rapid heat dissipation.   The compression ratio is a torque producing 11.7:1

$825 Arias 1004cc 11:1 Big Bore Kit with 920 Cylinders and Athena Gasket Sets.   International Buyers Will be Charged Expedited International Rates.


Currently made to order: piston kits out of stock (one month), cylinders in stock. Upon your order, boring will take place - it takes about a week.

1004cc With Thousand Cylinders - Not normally Available.

A somewhat more durable option is available.   I sometimes get Virago one thousand barrels that have had the lower part of their sleeves turned down so as to press into the 920 case spigot.   They are bored to the 96mm pistons.   As these cylinders have flat decks, they use more conventional, less leak-prone gaskets.   Due to the thickness of the head gasket, the aluminum part of the cylinder is shorter -- resulting in the same compression ratio.

These may come in 1100 cylinders, which are essentially identical to 1000s. It depends on what I can get.

$1095 Arias 1004cc 11:1 Big Bore Kit with Thousand Cylinders and Gaskets.   International Buyers Will be Charged International Expedited Shipping.

Piston kits, gasket sets, and cylinders sporatically in stock. Upon your order, I shall acquire all the component parts and have the machine work done. Reckon on a two week or so turn-around. You may get 1100 cylinders; these were identical to 1000s except for the numbers cast into the aluminum. Correction: all my "big" cylinders are accounted for. This option not available at this time, or for the foreseeable future. Special order only.

981cc for the 920

A less expensive alternative is a kit as follows: Clean and painted 920 cylinders bored to standard Virago 1000 pistons. Includes after-market automotive rings, a gasket set, and those rascally dowels that always get buggered up. The decks have been polished, the dowel bores dressed to a nice slip-fit, the threaded holes chased. Due to the greater swept volume into the same size combustion chamber, the compression ratio is bumped from 8.3:1 to 8.8:1 -- enough to feel.   But not enough to warrant fiddling with the carbs -- unless you take the opportunity to change something else. This would be an excellent opportunity to add performance springs so that swapping out to healthier cams becomes a "driveway" operation when you have the loot.

$450 Poor Man's Big Bore

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As I collect cylinders and wait for pistons to arrive, I prep the barrels: They are degreased, fins straightened or built up, gasket surfaces cleaned and dressed. Some are stripped and blasted. Then all are painted high temp black, allowed to cure for a week, I play a MAPP gas torch over them for a few minutes so that they don't smoke after assembly. Then the fin edges are exposed: filed and polished. They are then shot clear, allowed to sit, then subjected to the torch again, Then they are ready for the machine shop. If you do NOT want black cylinders, tell me what you do want. I can strip, blast and shoot silver or clear, but expect to wait an extra week.

I clean the decks and dowel bores, and re-tap threaded holes. Don't sweat cured high temp on the insides -- it's pretty inert. Yamaha painted its engine parts for the Midnight series by dipping them; they were black inside and out. Over the years, the outside paint pealed off and the inside dissolved.