Honda Shadow Aero Performance Modifications

The Honda Shadow line of motorcycles is very popular with beginning riders, it’s low seat height and unintimidating power delivery make it especially appealing for women, and, in many cases it’s their first bike.  That’s the way it was with my friend Rhonda, her Honda Aero was her first motorcycle, and over the past few years she has ridden the wheels off it.  There is a point you reach with your first bike,  you get the itch for something different, maybe a new bike, or modify the old one, no matter which way you go, something has to change, and Rhonda was ready.  A new bike was not an option for her, so the next best thing was to make some upgrades to the Honda.  Honda makes a stone reliable motorcycle, and Rhonda’s had given her years of good service, well over 40,000 miles, so no fault there, but the one thing that had appealed to her in the beginning, the unintimidating power, was now boring her to tears, she wanted more get-up-and-go!

The easiest way to more make power is to improve the breathing of the engine, you modify the air cleaner to flow more air, or buy an after market unit.  Since you are putting more air in, that makes the gas to air ratio too lean, so you re-jet the carburetor to balance the mixture.  Then, because you have more fuel and air going in, you have to get it out, that means opening up your stock system by drilling holes, (not recommended) or, purchasing an after market exhaust system.  Rhonda decided to take the after market exhaust route, modify her existing air cleaner, and re-jet the carb.

When Rhonda first approached me about the project, I said I would help on two conditions, that she would do the background research and select the after market parts, and it was to be hands-on for her, she was doing the mods herself.  She had never worked on her Honda much, others had always done the work for her, so she was a bit nervous about it, I told her I would pitch in when she got stuck, but, for the most part, it would be all her turning the wrenches.  To her credit, she jumped right in and did the research, checking out the part numbers and best prices on what was needed. She ended up going with a Dynojet jet kit and K&N replacement for her stock filter, the folks at Dynojet were very helpful, they said the best set up was their Stage Two, a K&N filter, and the snorkel removed from the stock air cleaner housing.  The big decision was selecting the right pipes, after browsing several manufactures sites, and watching what seemed like endless You Tube videos to listen to how the pipes sounded, she settled on Vance & Hines Cruzers pipes.

This is Rhonda at the start of the project in The Biker’s Garage, just a bit nervous to be doing the work, and, doing it all in front of a camera!

Rhonda and her new Vance and Hines pipes.

I always recommend that before you start your project that you throughly research everything you can, and that includes how things come apart, that’s why I suggest you buy a shop manual for your bike, or do a search online for one you can download.  Rhonda had found a Honda Aero service manual online, so we were ready to go.  We started out by lining up our parts on a padded surface.

Honda with the “goods” lined up.

 

Those pipes shine!

The first step was to remove the seat, saddle bags, and gas tank.

Removing the bags

The seat on the Honda Aero is held on with a bolt in the rear, two allen head bolts right above the top shock mount, and, a slip-in hold down at the front.

Getting at the seat bolt.

Once it’s all unbolted, the seat can be lifted off.

And we have lift-off!

The gas tank is held down at the rear with one bolt, the front slips over two rubber bumpers on the frame.

Removing the rear bolt.

Before the tank can be taken off, the dashboard must be removed, there are two allen head screws holding it down.  Those funny looking things that look like and extra set of mirrors on her handle bars were speakers for an “entertainment” system that stopped working, they got canned along with some other junk.  Want to listen to some really sweet music on the road?  Get a nice set of pipes!

Dashboard

You will have to disconnect the speedometer before removing the dash, there is one screw that secures the loom, and the wiring connection latches to the speedometer at the base.  Take your time, all of these parts are plastic, after the dash is off, lightly replace the screw to keep from losing it.

Take your time.

After you have disconnected the fuel line and vacuum line, the tank can be slipped back to clear the bumpers and lifted off.  Helpful Tip #1:  This is SO much easier with an almost empty tank, a full gas tank weighs a ton!  Helpful Tip #2:  Make sure your gas petcock is in the “off” position before removing the fuel line, gas everywhere is not a good thing!  Do I need to mention you should not be smoking during this procedure?  The gas line came off easy, the vacuum was a different story for us, we ended up cutting it off, not to worry, a replacement was easily purchased at our local Advance Auto Parts store.  Most of the time an auto supply house will have just what you need, just take your part with you and match it up.

Slide back, then lift off.

There is a vent line on the right rear of the tank, make sure it is disconnected. (red arrow)  The other wires you see that look like they are going into the tank are part of a nonfunctioning LED lighting system, which also got canned along with the speakers.  All of this stuff that didn’t work was installed by Rhonda’s ex-boyfriend, the “Zip-tie King,” we cut about thirty useless zip-ties off her bike, girls, just because he’s a man, don’t assume he knows how to wrench!  And the “King?”  He got canned too!

Vent line detail, and useless wiring.

The next step is to remove the air cleaner housing to gain access to the carb, there are a bunch of bolts and some hoses to disconnect.  Helpful Tip #3:  It’s a good idea to use a clean margarine tub for the nuts and bolts you remove, that way you won’t lose them.

Removing the air cleaner cover.

 

Cover removed.

 

Disconnecting the crank case vent line.

 

Loosening the clamp to the carburetor.

And, it’s off!  Just set it aside for later modification.  Why Honda thought putting an air intake snorkel under a hot gas tank is beyond me, engines run so much better with cool air!

Snorkel on the housing, the little white thing is more broken LED lighting.

While we were at it, we decided to replace the spark plugs, if your answer to the question of “when was the last time ____ was done?” and you don’t know, it’s time!  Rhonda had no idea the last time her plugs were replaced, so we figured this was a good time as any to do it.  Make sure you gap your plugs to the specifications in your shop manual.  We also removed the chrome head covers for cleaning and polishing, having the tank off made it convenient

Removing valve covers for cleaning.

 

Removing spark plugs.

 

Installing spark plugs, four total, two each side.

The next step was making the modifications to the carb, replacing the metering needle, and main jet.  The Dyno Jet kit is very complete with detailed instructions on Dynojet Stage One, or Stage Two installation, since we were installing the Vance and Hines pipes and removing the snorkel, we used the stage two instructions.  First remove the carb slide to replace the needle and stock Honda slide spring.

Remove the diaphragm cover screws.

 

Removing the slide spring, keep a hand on the cover.

 

Note the diaphragm index point.

To remove the metering needle, use a phillips head screwdriver, push down, and turn, it will come out, it goes back in the same way.

Removing the needle.

After the stock needle was removed we replaced it with the Dynojet needle, there is a tiny, tiny, tiny, washer that sets between the needle and a little spring, it is a BEAR to put in place!  We ended up coating both sides of the washer with a small amount of high temperature grease so the spring would stick to it, then placed both with tweezers, be sure to keep the slide vertical during reassembly so it all stays in place.  After that’s done, put the slide back with the Dynojet supplied spring, make sure you index the diaphragm.

Carb detail index point circled in red.

 

Installing the Dynojet spring.

Installing the replacement jet was our next step, unfortunately, there was some difficulty getting the float bowl off, and I had to put the camera down to help.  Many times motorcycle manufacturers use phillips head screws where they should not, and, they had used them on this carburetor.  The moment Rhonda realized she was having a problem getting them out, she asked for help.  Helpful Tip #4:  Anytime you get stuck, ask for help.  Even I could not get the screw to budge with the short screwdriver we were using, they were in tight!  There was no way to press up to keep the bit seated, and turn at the same time.  We ended up going to Sears and buying a Craftsman seven piece socket set with screwdriver bits, I can always use more tools, right?  I had to press up hard on the ratchet when I turned, but, they broke loose, and actually popped when they did, talk about tight!  After that things went smoothly, we installed the new main jet, adjusted the mixture screw with the provided tool per the Dynojet instructions, and buttoned it back up, pipes next!  But first, the old ones have to come off, first step, take off the right foot peg.

Removing the right foot peg.

Then remove the header nuts from the front and rear exhaust pipes.

Removing header nut.

Then unbolt the back muffler bracket, and lift the whole assembly off, it’s a good idea for two people to do this, it weighs a ton!  (camera down again)

Removing the rear bolts.

Once it’s off, it’s time for the new parts!  The Vance and Hines pipes come with very good instructions, first on, the rear pipe hanger.

Installing the Vance and Hines exhaust bracket.

The heat shields must be installed first before the pipes are put on, careful with those hose clamps, you don’t want to scratch the chrome!

Heat shield hose clamps.

Before the new pipes go on, remove your old exhaust gasket and install new ones, it helps prevent exhaust leaks.

Removing the exhaust gasket.

Now the pipes go on, front first, then the back.

Installing front pipe, leave the mounting nuts loose.

 

Installing rear of front pipe to bracket.

Install the rear pipe same as the front, have all fasteners slightly snug so you can move the pipes around so they look even, then tighten everything up.

Tightening up rear exhaust pipe.

 

Tightening the front exhaust pipe nut.

And, with the last nut tight, the Vance and Hines pipes are done!

Bling!

The last of the modifications to do was removing the snorkel, easy breezy, just two screws.

Removing the snorkel.

 

Snorkel removed.

Once it’s off we start putting parts back, air cleaner first, sans snorkel.

Installing modified air cleaner housing.

Every step of the way we (Rhonda) were doing some polishing, I just love having things shiny!

Polishing the air cleaner.

And start buttoning things up, reassembly is just the reverse of removal.

Air cleaner installation.

Helpful Tip #5:  Make sure all of the lines to the gas tank are connected, vent, vacuum, and fuel, check for fuel leaks before and after you fire the bike up for the first time.

Helpful Tip #6:  Before you connect the speedometer, place a small amount of dielectric grease on the male part of the connection, it prevents moisture buildup and corrosion.

Helpful Tip #7:  Clean the fingerprints off of your new pipes before starting your engine, if you don’t, they might burn into the chrome and be there forever!

And here is the finished project, sitting in the driveway at TBG, nice!  You may notice the saddlebags and windshield are missing, we discovered the bags did not clear the new pipes and might possibly rub.  A broken bracket was also found when we removed the windshield to polish the headlight, the bracket was replaced later, and the windshield reinstalled.

Beautiful!

 

A happy owner of a hot Honda Aero

Rhonda later removed the saddlebag brackets and the backrest, we estimate a weight savings of about fifty pounds overall, the biggest loss came from the replacement of the stock pipes.  This was a great project, the Honda looks and sounds fantastic.  Getting the right sound was important to Rhonda, and the Vance and Hines Cruzer pipes did not disappoint!  Congratulations Rhonda, job well done!

Words By: Terry Cavender

Images By: Terry Cavender