First some ; lifts are gross valve lift off of the seat. Rocker ratios were 1.347:1 for XV700s to 1100s; durations are taken from the point that the valve exceeds .040" (1mm) lift off of its seat until the point at which it falls below that. The cams whose names start with a C are those we offer. There was a 10L cam pair used on the '82 - '83 920 Virago. These sometimes show up on eBay still in their Yamaha wrappers. They are never cheap. I believe that these were identical to the 42H that they supercede to, except that they were a degree or so retarded - giving them a trifle more top-end.

Before I forget: engineering at Megacycle Cams states that rocker arm motors (like XVs) should (they said "must") run an engine oil containing zinc. It bonds to the lobes and ensures that there is always some lubrication between them and the shoe of the rockers. If a motor oil contains zinc it will state so on the label. Currently there are only two air-cooled motorcycle-specific oils fitting the bill: Motul and Redline. Neither is cheap and as the air-cooled and/or rocker arm motor is becoming rather rare, either or both may reformulate to save expenses in a market where zinc is unneeded. I counsel googling both and read as much of their sites as you can stomach. You may want to go to an auto parts house and read the labels on all the automotive oils. Meanwhile, I will see if I can scare up an oil additive that contains zinc to sell here. Read This page.

Cam Specs

C01; These cams have .492" lift and 270 degrees duration.   They have 292 degrees duration at .020".   Note: if you use Yamaha factory service manuals to find cam specs, you will find truly astonishing road-race-sounding durations; reputable after-market cam vendors quote duration beginning and ending when the valve is .050" off of its seat; Yamaha appears to count duration as including any time the valves experience any lift at all, including the longish "acceleration" ramps.   The stock springs coil-bind at .440" lift and float at 8000rpm.   I've run a similar combination up to 8900: where the rev limiter closed things down.

These are not a drop-in.   You must at least notch the pistons for valve clearance, unless you are running after-market pistons like our 1004cc kits.   These are road race cams (although I had no problem running a set on the street).   They are made to rev.   To fully benefit from these cams, you should run 11:1 pistons, a free-flowing exhaust, and carbs with accelerator pumps.   It wouldn't hurt to open the ports a little.   A multi-angle valve job would help.   Keep in mind that raising compression means more stress on your starter and related parts; you should stake the ring (sun) gear inside the starter motor to the housing so it does not just spin without turning the engine.

Note well: although the C01 will fit in 700s and 750s, I don't recommend them for the smaller engines.   If you don't run rather high compression pistons (12:1?), you will have essentially NO low-end power and will find yourself down-shifting a lot more.

C05: some cams that don't require spring kits.   At last: more power without having to pull the engine. These cams can be swapped-in in your driveway in under an hour. They have .432" lift and 272 degrees duration. A real punch in the mid-range (think passing power) and finally the ability to rev a little.

These cams are meant to be used in an otherwise stock engine -- although they would benefit from pipes and carbs (and compression). They push the stock springs pretty hard, so try to stay under eight grand. Nothing NEEDS to be changed, but you may want to put some washers under your jet needles. These work in ALL adult-sized Viragos: 700, 750, 920, 1000, 1100, the 920R, the TR1, and the SE. A good cam for the smaller bikes (700, 750) if you're looking to make them into café racers. Pipes a must, carbs recommended. For the bigger bikes, look for a greater willingness to rev -- you'll think your twin has "gone Italian." As with any longish duration cam, a little of the bottom goes away, but gobs of power are to be found from thirty five hundred on up past red line. These cams have over a quarter inch more lift than any stock Virago. See my listing for rockers. If you have the hole-in-the-pad unhardened rockers keep plenty of fresh oil in your motor. Change it frequently. Run an oil that contains zinc. Your beast will finally take the deep breaths that a big twin with big valves should.

C06: These are too much cam for any stock displacement XV. are our cam of choice for the TR1 with the 1065cc kit. These are based on flat-track profiles. They spin up faster than the C01. Running them with stock pistons would require notching the reliefs all the way through the piston crown. The lift is enormous and the duration long in the extreme. They don't idle well with constant velocity carbs. Please don't try running these with stock carbs; or Bings or Dellortos. You'll Be leaving a lot of power "on the table". Even with flat-slides, a stable idle will be between 1500 and 1800RPM. The lift helps give back some of the low-end that the duration takes away. NOT recommended for commuter bikes. They are meant to run with a minimum max rev of 10,000RPM. It is not recommended to exceed ten five, as I believe that the tensioners are designed (not by intention) to grenade between eleven and eleven five.

Also note well, cam prices are exchange.   We urge you to send your cams to start with.   The days of $15 cams on eBay are gone The C01 and C06 cams require spring kits, which requires pulling the heads -- on a Gen I, this means dropping the engine.   This would be a good time to install a big bore kit.

The combination of pistons and cams will have you looking for ways around the rev limiter cut-off.   Look at Ignitech (we'll add these, but not soon), or exercise some patience while we sort out our cam-driven single spark ignition.   There are some mighty gimmicky ("three sparks per ignition event") alternatives out there.   They are pretty tidy, but to buy everything needed for full tunability could easily run you a thousand - three times as much as the Ignitech.   Also, keep in mind that the cams have very little "flywheel" effect - they tend to move in-and-out and they self-retard under load - but not on a dyno!   Check out this

Note the prices below now obtain. I am often out of cores and there are suddenly few to be gotten. When cores can be found, they are asking a buck and a quarter or more each. Titanium jumped very high. Use the contact button on the front page to tell me what you want and I'll send you an invoice. Right now, if you want cams outright, I'll have to buy good cams and weld and grind them. If you sent me your cams first and I found them useable, you'd get the exchange price. I realize that this is not often practical. I have had customers buy cam cores off eBay and had the seller send them to me. Titanium topped spring kits are now $350. Queries from the contact button often proceed to dialogues that end in steep package discounts.

Note this: as of now all cam sets come with a pair of high quality, high speed SKF 6205 bearings to replace the drive-side bushes.

Cam Prices
  • Cam Set:
  • C01
  • C05
  • C06

Some thoughts on .

If you opt for cams outright, you spend an extra $150 each per cam - remember that there are two. If you send in your old cams after the receivng the new,   I will reimburse you $100 - less than the cores cost you, as I must srtip complete heads - a lot of work when one considers the rockers and valves. I am very small. I can't always afford to keep cams in stock; I try to keep C01 and C05 kits on hand. When I order from my usual vendor, it takes up to a month for them to grind my cores. If you are in a hurry, or want to explore other profiles, the cams on this are a hundred dollars more per set, but only have a maximum two week turn-around.

By the way -- how are your rockers and valves?

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Last Modified:   Tue => 09:17:56 AM PDT - 19 Oct 2021 America/Los_Angeles