Honda VT400 Problems: 3 Known Issues (Explained)

In 1997, Honda Motorcycle Japan launched the VT400, a replica of the full-sized Shadow ACE, but with a smaller displacement, 400cc motor. 

By 2000, the VT400 had been upgraded and rebranded as the VT400 Shadow Slasher, and by 2009 Honda Australia began producing and exporting VT400s as a Learner Approved Motorcycle.

IT might be approved for learning, but what are the common problems with a VT400 expressed by long-term owners? 

We crawled through the forums to bring you the moto-deets on the VT400!

1. Bike Won’t Start—Poor Previous Ownership

Unfortunately, the most common problem with the VT400 has directly related to poor ownership by the person the current owners bought it from. 

Most grievances we encountered about the VT400s were from frustrated used Shadow Slasher owners due to negligence by the person they bought the bike from. Not only is the VT400 old enough to be considered vintage by today’s standards, but it was also marketed to first-time riders, making it a popular choice for inexperienced motorcycle owners. 

There are various reasons a Shadow Slasher’s engine won’t slash—let’s get into the basics.  

What Do I Check When My Honda VT400 Won’t Start?

A VT400 engine requires three things to ignite: Battery, Fuel, and Ignition. If any of these three are missing or off ratio, your Shadow Slasher is going nowhere.

If you’re uncomfortable with dirty hands, find you a Honda literate mechanic to wrench her up for you—they’ll be familiar with this mini-Shadow motor. 

That said, just in case it’s something simple, inspect the following basics, and you might be able to solve your no-start problem faster than you think.

  • Is the fuel petcock on?
  • Is there fuel in the tank?
  • Is the ignition key in the On/Run position?
  • Is the Kill Switch in the Run position?
  • Is the side stand up?
  • Is the transmission in Neutral?

If you’ve answered yes to all the previous questions and your VT400 still doesn’t start, read on. 

Inspect Your VT400’s Battery

You must charge the Shadow Slasher’s battery to fire her up. 

You’ll hear some riders complaining that they know for a fact the battery is good because they just bought it.

That new battery needs to be fully charged to work, and it’s not uncommon for new batteries to come half-cocked. 

Most battery manufacturers suggest you slow charge the battery overnight; a trickle charger or Battery Tender works best.

You can test your new battery’s voltage with a voltmeter. 

  1. With the engine off, the battery should read in the vicinity of 12.5 volts.
  2.  When the engine is running, it must be rotating at roughly 1,500 rpm or faster before charging the battery. 
  3. With the voltmeter still attached, rev the engine, and you should see a reading of approximately 13.5 volts. 
  4. If it does, then the charging system is operating correctly. 
  5. When idling, the motorcycle is running off the battery, and if you let it idle too long, it could exhaust the charge in the battery, and the engine may die.

If you press the starter button and the engine turns over, but your VT400 doesn’t start, the fault is probably not the battery. 

However, if you press the starter button, and nothing happens, and you’re sure the issue isn’t one of the basics mentioned earlier, your Shadow Slasher’s brand new battery might be dead.

Check Your VT400’s Fuel System

We already said this once, but you’d be surprised how relevant it often is; check to be sure your tank not only has fuel in it, make sure the fuel in your Shadow Slasher is fresh. 

Too many new riders pull their bike out of storage and run last season’s leftovers through their fuel lines. 

Before winter storage, drain your VT400’s tank by looking up proper winterization techniques and applying them; at least make sure you flush some Sea Foam or a similar fuel stabilizer through your lines and carbs before you fire your bike back up.

  • If your 400cc Shadow sat for a season, it might be a clogged carb that’s stopping her from firing up. 
  • If the appropriate amount of Gumout or Sea Foam doesn’t do the trick, it’s time to detach and disassemble your carbs and clean the gunk out of them.
  • If it still doesn’t turn over after you’ve cleaned your carbs, you may have flooded your Spirit Slasher’s engine. 
  • Can smell a strong odor of fuel by the carburetors? If so, you may have flooded it.
  • If you smell fuel and think she might be flooded, op-out one of your VT400’s spark plugs and inspect its electrodes to see if they’re wet. 

If you smell gas or the spark plug electrodes are wet, it could be you flooded the engine. If so, make sure the choke is Off, and the bike sits for a bit. When you crank it again, stay off the throttle. 

If you don’t smell gas and the spark plugs look dry, you may not be getting any fuel. 

I don’t know off the top of my head if the Shadow Slasher’s fuel line filter changed location from year-model to year model; it could be in the tank or the petcock unit, or maybe even in the fuel line itself. Regardless, a clogged fuel filter will stop her from cranking over.

While you’re poking around the fuel system, see if (one of) your VT400’s fuel vent lines is plugged or pinched. If the fuel filter or vent line is obstructed, you’re not giving your Slasher enough fuel to start. 

  • To diagnose a pinched fuel vent line, pop the cap off your fuel tank to listen for a hissing sound of rushing air being sucked into the tank, then the vent may be the problem. Try starting the VT400 again. 
  • If it turns over, it could be the vent. Shut it off right away and resolve the vent problem. 
  • If everything looks healthy, spray some carburetor cleaner into your air intake, then start her up. If it fires up but then dies right away, then you are probably getting spark to the plugs but not getting fuel to the carburetors,’ and you may have to tear them down and clean them.
  •  Note: Do NOT keep spraying cleaner into the air intake, or you may damage the engine.

Now you’ve checked your no-start VT400’s battery and fuel. If it’s all good, time to move on to your ignition. 

Check Your VT400’s Ignition.

There are two simple ways to check if your spark plugs are firing. 

  1. Leave the spark plug installed, pull the rubber boot off the plug, stick a screwdriver into the rubber boot, making sure the end touches the connector inside. Hold the screwdriver’s shaft about 1/8 of an inch away from the engine block and crank the engine. If the ignition is sending juice, sparks will jump the gap between the screwdriver and the machine, and your coil is delivering spark to the plugs, but it won’t tell you if the plugs themselves are bad or not.
  2. Yank out a plug and look-see if the gap is within the Honda VT400’s owner manual spec. Plugin the boot and hold the electrode against the engine (with rubber-handled pliers), then shove the starter switch and see if you can see spark jumping the plug gap. 

If you don’t see a spark, you may have ignition coil problems—time to make sure all wires are connected correctly.

Now you’ve got fresh gas, new spark plugs, unpinched vents, unclogged filters, a charged battery, clean coils, and connected wires. Make sure your VT400’s choke is turned off and try starting the engine. If it still won’t start, time for a visit to that mechanic we mentioned earlier.

Related: How Long Do Honda VT 750s Last? 5 Examples

2. Handlebar Control-Button Failure

Honda Shadow owners often report issues with the buttons on their handlebar controls.

Based on owner-forum reports, the most problematic handlebar buttons seem to be the pesky starter switch.

Most hand-control button failures occur on VT400 Shadow Slashers after long periods without use, namely when the bike is stored outdoors or near corrosive chemicals. 

Over time, moisture and debris can gather under the buttons, causing corrosion or striking the button in a depressed position.

If you experience a stuck control button on a Honda VT400, disassemble the button. Inspect your wires for corrosion and clean out any debris.

If the buttons are still sticking, you might need to replace your Slasher’s new handlebar control assembly. 

Related: How Long Do Honda VT250s Last? 3 Examples

3. Seat Uncomfortable—Replacement Required

Another common complaint VT400 riders share is a consensus among owners of Shadows of all sizes; the seat is stiff and narrow.

Not only does an uncomfortable seat lead to unpleasant spine sensations, for some, it means stopping more often on long rides. 

Not to mention the cupcake experience; riding two-up on a Shadow isn’t ideal for long trips, but then again, neither is hammering miles on a 400cc motor all day long for two weeks straight. 

In short, the VT400 is intended to be an entry-level motorcycle, not a long-distance cruiser. 

The seat is excellent for learning, but if you intend to ride it long term, we suggest exploring some of the aftermarket options for Shadow seats of your year model; even the Shadow ACE 750 seats should fit. 

Related: 4 Most-Common Problems With Honda VT250

General Pros and Cons of the Honda VT400 ACE

Here are the merits and downsides of the Honda VT400:

Pros

  • Low Center of Gravity
  • Affordable Price
  • Efficient Fuel Mileage
  • Reliable 
  • Long-Lasting

Cons

  • Uncomfortable Seat
  • Handlebar Control-Button Failure
  • Bike Won’t Start—Poor Previous Ownership

What Do the Reviews Say?

BEST PURCHASE I EVER MADE!

When the bike arrived I was apprehensive at it’s size but after getting on and doing a few laps around the city I didn’t want to get off. As a complete learner who has just started out on a first time bike I highly recommend it as your starter bike. It’s had great reviews and everyone I have spoken to has told me I have made the right choice. It is easy to reverse and take into corners and the bike does all the work. A clean piece of machinery that I am now completely in love with and hope to get many, many years out of it.
Easy to handle

https://www.productreview.com.au/listings/honda-vt400

What’s the Resale Value of a Honda VT400?

Year Mileage Price
2009 1,079 $6,400
2012 12,476 $6,800
2012 13,580 $5,925
2014 12,745 $6,500
2014 15,803 $6,900
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