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!

vance and hines cruzers exhaust for honda shadow
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 shadow aero with k and n filter, dyno jet, vance and hines exhaust
Honda with the “goods” lined up.

 

close up honda shadow aero with k and n filter, dyno jet, vance and hines exhaust
Those pipes shine!

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

removing river road saddle bags from honda areo
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.

removing the rear seat bolt honda areo
Getting at the seat bolt.

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

lifting the seat off honda shadow
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 rear mounting bolt honda shadow
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!

removing dashboard screws honda aero
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.

removing the wiring connection
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.

removing the gas tank honda aero
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 honda aero
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 aircleaner cover honda shadow
Removing the air cleaner cover.

 

cover removed
Cover removed.

 

disconnecting the crank case vent line
Disconnecting the crank case vent line.

 

loosening the clamp to the carburetor
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!

air cleaner snorkel detail honda aero
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 valve covers for cleaning.

 

removing spark plugs honda shadow
Removing spark plugs.

 

installing spark plugs honda aero
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.

removing the carburetor slide cover honda aero
Remove the diaphragm cover screws.

 

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

 

diaphragm detail
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 metering needle
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
Carb detail index point circled in red.

 

installing the dyno jet spring
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
Removing the right foot peg.

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

removing header nut honda aero
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 rear bolts exhaust honda aero
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 vance and hines exhaust honda aero
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!

installing heat shield vance and hines
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 exhaust gasket honda aero
Removing the exhaust gasket.

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

installing front exhaust pipe honda aero
Installing front pipe, leave the mounting nuts loose.

 

installing rear of front pipe to bracket
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.

installing rear exhaust pipe
Tightening up rear exhaust pipe.

 

tightening front exhaust pipe nut
Tightening the front exhaust pipe nut.

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

installed vance and hines cruzers pipes honda aero
Bling!

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

removing the snorkel
Removing the snorkel.

 

snorkel removed
Snorkel removed.

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

installing modified air cleaner housing
Installing modified air cleaner housing.

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

polishing honda aero air cleaner
Polishing the air cleaner.

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

air cleaner installation honda aero
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.

finished project honda aero vance and hines exhaust dynojet k and n filter
Beautiful!

 

a happy owner honda aero
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

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41 thoughts on “Honda Shadow Aero Performance Modifications

  1. Great article Terry! It turned out really nice, so did the pictures. I learned so much from you O’ wise one doing this project. How to wrench, lots of research, some new words, and if one way doesn’t work, try another! I love my new pipes, the sound and the power, it was all worth it!! Shorty

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  2. Love the combination of photographs with descriptions. It makes it all come to life. And Rhonda makes it look easy. Great project.

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    1. Thanks Amy, it was a great “how to” article, I don’t know how easy it was for Rhonda, she was certainly under some stress from being in front of the camera! LOL!

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  3. Great “How-to”. I am doing the same project to my Aero. Only thing is I am doing one thing at a time due to my budget. I was debating on if I should do the DynoJet re-jet myself or have the dealership do it ($135). After reading your article and the instructions from DynoJet, I am more comfortable with doing this myself. Thank you and Rhonda for this. By the way, great looking bike and I bet it sounds just as great.

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    1. Thank you Ken, yes it does sound great! When Rhonda goes to bike nights she always gets complemented on how her bike sounds. We keep talking about doing a video of it running so that people can hear it, we should get on that, yes? Rhonda searched You Tube and found several examples of different Honda Shadow and pipe combinations, that’s how she selected her pipes. My recommendation is you do the same. Vance and Hines makes great pipes, we were pleased with the quality. You can do all of the work yourself, Rhonda had never touched a wrench before until this project, if she can do it, so can you.

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    1. We used the size jet recommended in the instructions Jason. The Dynojet kit has different levels of modifications called “stages.” Say stock is one stage, then adding an after market pipe would be the next stage up, the next would be the pipe plus a freer flowing air filter, and so on. It will all be clear to you once you have the kit and read the instructions. Enjoy your project, and let us know what you did, and how it went.

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      1. Thanks got my parts in today and the instruction are clearer than I expected. Did you notice a good gain on the performance side.

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      2. That’s great Jason! The Dynojet instructions are some of the best I have ever seen, always very complete and clear. I just finished installing a Dynojet Power Commander on my project “Little Red Riding Vic,” and the instructions were quite detailed. Yes, we did notice an improvement in power, smoothness in throttle response, and overall rideability. How much power you make is also dependent on your selection of pipes, and air box modification.

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    1. Thank you Jason, that’s what we were going for! LOL! Say, it would be great to see your bike, why don’t you make a few pictures and send them to me, you could be the first in our “Reader’s Rides” section. I have been wanting to start it, but nobody has submitted yet.

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      1. Mission complete, Vance and Hines shortshot exhaust, K&N filter no snokel and stage 2 jet kit with a 134 jet and mixture screw turned only 2 to 2 and quarter back out. I had acceleration problems couldn’t go over 55 so I tweaked a little and go faster than ever before alot quicker. Sounds great and thanks again for the article. I have a picture and video of sound just don’t know where to post.

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      2. That’s fantastic Jason! I am happy you are pleased with the result. It’s so satisfying when you make modifications and it’s everything you expected, isn’t it? The Vance&Hines pipes are a very good choice, they always have a great sound, and the performance to back it up. If you will email me the image, or images, I will post them here, and you will be our first in the “Reader’s Rides” section. I’ll post the video as well, but you will need to put it on You Tube first, then I can embed it into The Biker’s Garage.

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  4. Hi Terry, I just purchased a 2012 honda aero. I realize this blog spot was to highlight the instillation of the vance hines exhauste system but, I couldn’t help notice how nice the backrest are on this bike. Could you please share where I might be able purchase them. Thanks for your help. You have a very awesome ride!

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    1. Hello Robin,

      The back rest is a Cobra item, Rhonda purchased it from Dennis Kirk, I would suggest looking for it there. Just click on the DK banner and you will be taken to their site.

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  5. Hi Terry,

    Man what a great site–this is helping me out a lot. I am in the process of putting Cruzers on my 2009 Shadow spirit. I have two questions. First did you keep the stock exhaust collars on when you placed the new pipes, and second, did you use a torque wrench for precise torque in placing the new pipes or did you just tighten with a regular socket wrench?

    Thanks, Jay

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    1. Hello Jay,

      I am so glad the magazine has been useful to you. It makes my day when I get comments like that! The Vance and Hines pipes come with their own collars, what we did replace were the “O” ring exhaust gaskets. This will help prevent leaks, it’s good idea to not take a chance on the old still being good. As you can see from the pictures we did not use a torque wrench, we just tightened them until they “felt” right. Since it was Rhonda’s first time, I double checked her wrench work to make sure they were well snugged. I also rechecked them after bringing the bike back after the test ride. You can use a torque wrench if you want, and I am sure you will find the torque setting figures in the Honda service manual. Being honest, we should have used a torque wrench, but, we were trying to finish up. It was February 11, 2012, and below 50 degrees F in the garage, we were cold! Like I have mentioned before, this is my own garage, and it’s not heated, or cooled, so we suffer the effects of weather just like everyone else! LOL! Please let us know how the project turns out for you. You are welcome to submit some pics or a vid of the finished bike if you want, it would be great to see it!

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  6. Hi Terry,

    Many thanks Terry. My Cruzers didn’t come with collars. Would it be safe to assume I don’t need them? Or, should I re-use the stock ones? I am definitely going to replace the O rings.

    I will send pic when I am done for sure.

    Best, Jay

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    1. Ok, that one has got me stumped, unless these are different, they should be one piece pipes with the collars already mounted so you can bolt them to the heads. What do the instructions say? It came with instructions, yes? (Old axiom, when all else fails read the instructions.)

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    1. Thanks for the visual, it helps a bunch! I see it, Rhonda’s was not like that, it looks like Honda is doing with several pieces that V&H does with one. I would go by the instructions from Vance and Hines, if they don’t mention using the collars, then don’t. I pulled up what I could find on the V&H site, they mention checking the stock gasket, but mention nothing about the collars. (part #2) Put them on without the collars, if they feel solid, don’t rattle around in the port openings, and don’t leak after you tighten them up, it’s right. If they are loose, put the collars in. This is one of those times when you just have to try it one way to see if it works, if it don’t, try something else. This is what working on your own bike is all about, finding your way, learning what works, and what don’t.

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  7. Thanks for sharing your knowledge. I am a newbie, learning as I go. I will do and report back and let folks know how it went.

    Cheers, Jay

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    1. And we were all just like you in the beginning, that’s why I started the magazine. I have been riding for well over Forty years, still learning new things every day, it never stops.

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    1. Hello Cody,

      We removed it because the instructions told us to. It allowed in more air and it would be cooler too because the air would not be pulled from under the tank. Sans is a derivative of the Latin “sine,” meaning without. So, “sans snorkel” is with the snorkel removed.

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  8. Awesome ideas on upgrades and bike looks great. Any other sites you can think of would be very helpful. I’m always looking for more power and speed at low cost. Thanks for any info.

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  9. Your tutorial gave me the idea to upgrade my ’05 Aero. My parts include:
    Stage 2 Dyno kit
    Kuryakyn air intake (black)
    Cobra 2 into 1 pipe
    Iridium plugs

    I am hoping to buy a second bike and making a bobber out of my Aero. Blue collar bobbers has some nice examples.

    Any idea how much more power I would now have with these upgrades?

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    1. Hello Bass, I have no idea how much power you will make, but, I think you will find it will run better than stock. If you are curious, about the power numbers you could always take it to a dyno and run a few passes.

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  10. FWIW Japanese phillips head screws are cut differently than ours- JIS (Japanese Industry standard) vs S.A.E. (US)- AND different from metric at least German (DIN) metric for that matter..that’s a yet ANOTHER part of the reason they’re so damned hard to get out of aluminum castings..

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    1. This is the sort of comment I love, thank you David for your great informational comment! You are quite right, the Japanese phillips head screws are just a little “off” when it comes fit. When you combine that with a little dissimilar metal corrosion, you end up with a fastener that’s a bitch to get out! When I was a kid working on my bike, we always ended up with a few stripped phillips heads, no matter how many screwdrivers we tried, they never seemed to fit. Back in the day, we didn’t understand the “why” of it, we just crossed our fingers and hoped for the best. Had we only known back then what we know now! LOL! Thanks again for the great info!

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  11. Bought 05 spirit 750 (used) but has character. There was no filter with or on it the shop mechanic put a rag over hole an called it good (but it’s not) got a big sucker from Arlen ness to put on but nothing matches up, says to insert snorkel, I don’t have one and oem parts pictures don’t show what instructions show for snorkel…any ideas

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    1. Here’s my thoughts…… First, shoot the mechanic! Second, I think someone sold you the wrong parts, if nothing is “lining up,” this might be the case, send them back for a refund. If you still have the original Honda air cleaner housing you might want to consider just getting a new filter, putting it in, and calling it a day. You could go with a stock one, or a K&N, the K&N will flow just a tad more air, which could be a good, or bad thing. Like most modern bikes, your Honda left the factory running lean to meet the EPA emissions laws. Flowing more air, especially if you have aftermarket pipes, or modified stock ones, will make it run even leaner, not a good thing. If you have the stock pipes unmodified, you should be fine, no more air can flow in than can flow out. If you have aftermarket or modified pipes, you might want to get a Dynojet jet kit and install it. Just make sure before you start your work to have a service manual for your bike. I noticed in the exploded parts drawing you have two carbs, so I’m sure there will be some steps to take to keep your carbs in synch when you remove them to install the kit.

      Here’s some links to service manuals.
      Honda VT750 Shadow Chain Drive 1998-2006
      Honda Shadow VT600 & 750 1988 to ’09 Haynes Manual

      The Honda 750 Shadow is a nice bike, with the proper set up it runs and sounds (thanks Vance & Hines!) great. I hope things go well for you,let me know how it turns out.

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      1. No no factory airbox to it at all just a the rubber plenum that looks to be attached with gasket sealer to a small v shaped box, it doesn’t seem lean even with screaming eagle 2s on it. Just unsightly. Like my other cehicles it’s a running work in progress. I’ll try to upload some pics of current set up later tonight.

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      2. The “V” shaped box is your intake plenum, the air filter housing used to connect to it. If you can’t find a suitable aftermarket unit, you might be able to find a used one on eBay. I still think you might be lean, especially if you have aftermarket pipes. If you have any popping or backfiring during deceleration, you are lean. You will be running the risk of seizing, or burning a piston. It seems to me this bike has been hacked on a bit, you might just want to go through it and make sure all the maintenance has been done. And, I still think a service manual is a good idea, I have linked to two, both under forty bucks, well worth the investment.

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      3. I’m assuming you are saying “yes” to the popping? Pretty much any time you open up the intake and exhaust, especially these days with the EPA stuff, you will need to re-jet. By the way, if you use the links I provided and buy a manual, I’ll make about 67 cents, just being upfront about it. That said, you really do need a manual, I not just saying it to make 67 cents. First thing, when I get a bike, I buy a manual, can’t tell you how many times it’s saved me more than the cost of the manual.

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