Removing Carbs From A Virago With “Standard Tools”
A step-by-step way to simplify Virago carburetor removal and installation
- Remove seat These bolts are 5mm allen head bolts. They are located under the front of the seat. Beware, there is a spacer on the left side and it may fall when the bolt is removed.
- Remove 12mm tank bolt The XV-750 tank comes off easily. Leave the petcock on “run”. Disconnect fuel, vacuum, vapor lines, and wire to the fuel sender. Lift the tank off. On the XV-1100’s I lift the back of the tank by wedging a 2×4 under the tank. This should be high enough to get the tank clear from the carbs. Be sure to have less than a 3/4 tank of gas to avoid fuel leakage at the filler cap. If you have too much fuel in the tank, then drain some at the fuel pump.
- Remove air cleaner Bolts are 5mm.
- Disconnect throttle cable Later models have dual cables.
- Remove emissions stuff Bolts are 5mm. Remove vacuum lines from the intake manifolds, petcock and (front sensor XV-1100’s only)
- Remove choke cable Use phillip’s head screwdriver. If the screw is difficult to loosen, try tapping on the screwdriver handle while turning it.
- Remove left / right side down tubes These are usually referred to as “intake hoses”
- Remove fuel lines from carbs Place a rag under the carbs to catch any fuel that may leak out. Be sure you are working in a well-ventillated area and that there is no danger of spark. Very little fuel, if any, will leak.
Now for the tricky stuff!
- Loosen the “Front Inside” intake stub bolt From the left side of the bike, use a 10mm open end wrench and loosen the intake stub bolt. Do not remove yet, just loosen the bolt. (The intake stubs connect the carbs to the engine.)
- Loosen the “Intake stub” clamp screw Use a phillip’s head screwdriver and remove the screws from both clamps (one on each side of the engine). Gently open the clamps to allow access to the 10mm bolts on the intake stubs.
- Remove carbs from intake stubs This one’s tough, especially if they have never been removed on an older bike. Facing forward grab both carbs and twist them in a clockwise rotation. They will probably need coaxing but…
DO NOT USE TOOLS SUCH AS PRY BARS TO REMOVE THE CARBS!!
This may crack the cooling fins or bend the oil feed lines to the heads.
- Remove front outside intake stub bolt. Use 10mm open end wrench and remove bolt.
- Remove front intake stub The intake stubs are slotted on the inside to allow for removal. Hold the carbs out of the way and gently remove the intake stub. Be careful, there is an “O” ring on the back side of each intake stub. The stubs may need some coaxing so, if necessary, tap them gently with a hammer to loosen.
- Remove rear inside stub bolt Slide carbs forward and from the right side of the bike, using a 10mm open end wrench.
- Remove rear outside stub bolt This was the first stub bolt you loosened.
- Remove rear intake stub Move the carbs out of the way and remove the stub. Don’t forget the “O” ring.
- Finally, remove the carbs. Now that everything is out of the way, you can manuever the carbs out from between the cylinders. Remove them from the right side of the bike.
Let’s face it. You took those carbs out for a reason so while they’re out
check the items listed below.
- Take this opportunity to remove the pilot plugs. This is tricky, so be very careful not to damage the pilot screws. The plugs are thin brass and can be punctured easily.
- Inspect the “O” rings for cracks or tears. This is a critical seal, so when in doubt, throw it out (Replace it).
- Check the intake stubs for cracks, holes etc.
- Check the condition of the diaphrams while the slides are out. Check for cracks or
- If you’re handy, check the float levels and needle condition. Also, preset your pilot
screws to 1-1/2 turns out.
Now that we fixed the problem, it’s time to re-intall the carbs.
- Install the two inner 10mm bolts and keep them backed-off for ease of stub installation.
- Connect gas lines starting at the carb inlets, and then position the lines in their retaining brackets on top of the carbs.
- Position the carbs between the cylinders.
- Install the rear intake stub and tighten the 10mm bolts.
- Push the rear carb into the rear stub and make sure it is properly seated. (Spray some WD-40 into the stub to facilitate installation.)
- Position the front stub. It will go into place easily but must be worked past the carb outlet a little. Finagle it gently, and watch that the ear doesn’t get caught in the cyclinder head.
- Once generally positioned, ease the stub down until it aligns with the carburetor outlet. Push the carbs into the stubs and make sure it is seated properly. You will find that the outside bolt in the intake stub will not line up with the threaded hole in the cylinder head. Here’s what you do:
- Coax up the stub by using minimal force, so the 10mm bolt hole lines up with the stub.
- Start the 10mm bolt in the cylinder head.
- If you have trouble coaxing the holes to line up, try using a big screwdriver and using the short cooling fins on the cylinder head, right by the lower ear of the stub. Pry the stub till you can start the 10mm bolt.
- Tighten the front inner 10mm bolt.
- Finally, tighten the front outer 10mm bolt.
- Replace the screws in the intake stub clamps, and tighten them. (Snug is good)
- Install the rubber intake hoses (This is always fun). Push them up onto the frame outlets first, then swivel them around and work them onto the carbs.
- Coax up the stub by using minimal force, so the 10mm bolt hole lines up with the stub.Reconnect throttle and choke cables. Check throttle freeplay and actuation to be sure there are no restrictions in throttle movement.
- If you have the equipment, now would be the best time to tune the carbs. This will include
- Set the pilot circuits (CO levels)
- Synchronize the carbs (balancing)
- Set the idle (the easy part)
- If you are not equipped for the above adjustments, I suggest that you reinstall the tank, seat, air cleaner, smog pod and take it to your local Yamaha dealer for final carb adjustments.
‘Removing Carbs’ Submitted by Walt Trock, Mac McCurdy and A.J.(BUG)Mei