Virago Airfilter Conversion
The following tech tip is the Virago Airfilter Conversion which holds no warranty to the VOC or it's members. This modification is compliments of A.J.(BUG)Mei..........Enjoy!!
The honeycomb filter mentioned in this text is no longer available but here is one you get from Custom Chrome.
Notice: This modification will change the performance or handling of your Virago. Read and understand all the information enclosed before attempting to modify your bike. Consider all safety aspects along with performance conditions before making these changes. This is a voluntary change being performed by the bike owner with the understanding that the writer nor the VOC are responsible for safety or performance errors or problems. This project should be done only on bikes with aftermarket exhaust systems.
Additional Note: Although your bugeye removal-air filter conversion can be considered by some, it is a fair amount of work and leaves the Virago with a somewhat unbalanced look with only one bugeye on the left side. There is now an alternate solution to the bugeye replacement for better breathability for the Virago. K&N now offers a direct replacement air filter element for the stock OEM element. The K&N part number is YA-1186 for the 1000/1100 late model Viragos. I'm not sure if K&N has one available yet for the 750, as the bugeye may be smaller and the part number should be checked with the K&N website for compatibility at K&Nfilter.com . I have installed one in my 97 XV1100 SE and what a difference in power! The bike comes alive on acceleration and starts much better cold. The K&N element fits right inside the bugeye, but offers about 50% more filter surface area. The pre-charged filter according to their claims, offers better airflow over standard filters and should probably be included in any aftermarket exhaust conversion and rejetting.
Ok, let's get started!
Some people have a hard time understanding my procedures. If you should have any questions about this modification, don't hesitate to contact BUG.
Air Cleaner Conversion Instructions XV-700 or 750
Here's what you need :
- A Honey Comb air filter which you can buy from any Harley dealer or anyone who sells Custom Chrome or Drag Specialties aftermarket parts. This filter is round and has large holes in the outside cover. It comes with a mounting bracket and foam element. Discard the hose clamp and hose adapter. This filter costs about $25.00. If you decide to use another style filter you may have to make a mounting bracket.
- You need a piece of radiator hose with a diameter that will fit snuggly into the largest hole in the rear of the filter housing. Minimum length should be about 8". (Hint: A Big Block Chevy or Volvo hose should work) Also, TRAK or SUPER TRAK auto parts stores (I'm not sure if they are nationwide), their radiator hose P/N 71387 provides and excellent fit for this application. There is a bend that fits the Virago manifold and the fit is nice and tight in both the honeycomb back and manifold giving a good mechanical seal prior to using the weather strip adhesive. The bend of this hose allows the use of the existing mounting hole on the bracket.
- A tube of weather strip adhesive.
- All the extra holes in the back of the filter need to be taped off with a durable tape such as foil tape or body repair tape.
- Remove the factory air filter assembly by loosening the phillips head screw on hose the clamp, at the air box/frame. Remove two mounting bolts which hold the filter assembly to the frame. One bolt is located under the gas tank by the intake boot for the front carb. The other is part of the horn bracket (top bolt). See illustration on page 33 - Air filter case #1. * The illustrations I refer to are located in the shop manual. If you don't have one, you should get one!
- Remove the rubber boot from the filter assembly by separating the seal (tar like sealer inside, under the filter) from the whole assembly. The easiest way to do this is to just pull around the edges of the seal area to separate from sealer. Then pull the rubber boot from the back of the filter. The boot has radial ribs on it.
- Remove the "Bug Eye" from the left side (emissions stuff). Remove the 10mm bolt under the "Bug Eye". Take out two mounting bolts - one on the horn bracket and the other inside the Mixture Control case. See page 33 - Mixture Control case #1 and page 4-6 - petcock info. Also reference page 7-44 - petcock.
- Disconnect the vacuum line which goes from the petcock to the "Bug Eye". Separate from the "Bug Eye" and re-route this hose to the rear cylinder intake manifold (remove the line plug held in place with a hose clamp). Leave the spring on the vacuum line O.D. and route the line so it does not kink or restrict the normal amount of required vacuum. Disconnect the main vacuum line which leads from the mixture control case. Be sure to disconnect it from the front cylinder intake manifold vacuum source. Then plug the vacuum source with the plug from the rear cylinder intake manifold which was removed to accommodate the petcock vacuum line.
- Get out the bracket supplied with the new filter. Place it against the mounting holes on the frame. You will notice that you'll have to tweak the bracket so that it fits comfortably when the bolts are in place. Mount the bracket temporarily.
- Place an eight inch piece of radiator hose ( basically this hose becomes an adapter or reducer) into the factory air cleaner boot removed in step #3. Use a yellow pencil and mark off material inside boot to cut out. Remove the radiator hose and cut to the yellow line. Reassemble the radiator hose into the boot and install (temporarily) on the box/frame. Align to the bracket with as little interference as possible from the carb. There will be some bend to the assembly which you cannot eliminate. Where the center of the hose aligns to the bracket place a mark on the bracket for a mounting hole, for the air filter housing. While still in position allow one inch of the rad. hose to protrude past the bracket and mark a cut off line. Be sure to draw the line parallel to the bracket. Remove the hose assembly from the air box. Trim the rad. hose to the yellow line. Drill a mounting hole for the filter housing into the bracket. Cut the factory intake boot back to the inner most rubber flange (there are three).
- Drill a hole near the outside edge above the factory drilled hole. Place foil tape on the back of filter and be sure it adheres well. You don't want any air entering the filter anywhere but at the element. Apply a generous amount of weather strip adhesive to the rad. hose end which goes inside the intake boot. Assemble the hose and boot so that the trimmed area aligns to the boot contour inside. Set this assembly aside to set up.
- Once the weather strip adhesive is semi cured you can mount the air filter housing onto the hose using ample adhesive to seal imperfections in the hose and housing assembly.
- Mount the assembly to the bike. Be sure to install the mounting bolt on the bracket for the air filter housing.
- Trim the rad. hose about 1/2" to 3/4" from the bottom of the air filter housing. Use a fresh razor blade for this operation. Avoid having any loose pieces of rad. hose which could be sucked up inside the engine.
- Check the following items before starting your engine.
- Be sure all sealed areas are sealed properly.
- Check all mounting bolts for tightness.
- Check both intake manifolds for cracks and make sure all unused vacuum sources are plugged properly.
- Make sure your vacuum lines are not kinked.
- Place plastic ring, foam element, and steel screen into the air filter housing.Make sure the element is outside the steel screen. Put the chrome honey comb cover on the assembly.
- Start your motor. You will need less choke from now on and there will be better response. Your best bet is to install an aftermarket exhaust system to reduce engine back pressure and to get full benefit of power.
Take the bike to your local Yamaha dealer and have the carbs adjusted. They may have to block off some of the filter with duct tape. You will be out of spec with the CO's so don't be surprised if your dealer tells you it needs to be around 4%. *This procedure has many similarities between the XV-700 / 750 and the XV- 1000 / 1100. Refer to the additional information pertaining to the big bikes below . Additional Air Cleaner Conversion Instructions for the XV-1000 or 1100
- If you want to do a conversion on an XV-1000 or 1100 then we must first look at the Air Induction Pipes (chrome). There are two of them. They go from each cylinder head to the left "Bug Eye". Here you need a hacksaw or a pipe cutter to cut the rear cylinder induction pipe. Cut it about two inches before (front) the mounting bracket. You will need the bracket to hold the pipe in place. Next, you will need to cut the front induction pipe, which crosses between the cylinders. Cut it directly under the rear cylinder carburetor. Deburr both pipes and install them the way they were originally. Connect the two pipe ends with a piece of the large hose left over from the conversion. You may want to cover the hose with the chrome spring, just for looks. That wasn't so hard? Was it?
- Next thing we need to do is run a vacuum line to the pressure sensor switch located above your coils. Run the line from the front manifold. Block all other vacuum sources on the intake manifolds.
Happy Wrenching! **This project takes about two hours if done by someone who's familiar with Viragoes. Give yourself three hours. Pay close attention to the instructions and you'll be fine. I've done (65) of these conversions and every one of them were a success. There will be a noticeable increase in performance!
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Note: This Tech Article was created from the VOC site data.(Virago Owners Club)