The Honda VFR800 is the evolved and most advanced version of the legendary VFR750. The VFR800 is a luxurious all-rounder, handling nimble enough to cruise downtown and aggressive, baggy, and comfortable enough for long-distance highway riding. In this post we bring you the most common failures of the Honda VFR800.
Despite being a luxurious motorcycle, it does not mean that it is perfect and like any vehicle, with the passage of time, some problems develop and that is why here we will talk about the failures that the VFR800 has developed.
Common failures of the Honda VFR800
The Honda VFR800 is an excellent off-road motorcycle and its cultured fans say it can compete with any other bike, but what are the most common problems with the Honda VFR800? Keep reading this article and find out what they are and how you can fix it.
1. The regulator/rectifier wears out prematurely
The regulator or rectifier on any motorcycle is bound to be replaced, eventually. That being said, in this investigation, we found that the most common complaint about the VFR800 concerns early failure of its regulator/rectifier.
The Regulator/Rectifier is vital to the operation of the VFR800 charging procedure. Now let’s see how the component works and cover some troubleshooting data from the VFR800 R/R.
How does a regulator/rectifier work on a Honda VFR800?
Any battery powered motorcycle, including the Honda VFR800, employs a charging system to charge the battery during operation. A fundamental element of the charging system is the Regulator/Rectifier.
As its name suggests, the Regulator or Rectifier of a Honda VFR800 rectifies the AC energy produced by the stator coil transforming it into DC energy, using it to recharge the battery.
The Regulator also manages, or regulates, the power output; the R/R also prevents the battery from being damaged or burst by keeping the power surge within the 14.5 volt range needed by the battery.
Causes of Regulator/Rectifier Failure on a Honda VFR800
There are many potential contributors to Regulator/Rectifier failure, the most common being heat:
- Honda’s regulator/rectifiers haven’t always been the best equipped to handle the heat produced by the VFR800’s four-valve engine.
- Some condemn the virtue of the component itself. At the same time, others take note of the positioning of Honda’s R/R on the VFR800, theorizing that the placement puts the part in a hot zone without abundant airflow.
Over time, a regulator that frequently overheats is bound to wear out.
- Another possible cause of R/R deterioration is battery malfunction.
- Sometimes a battery can malfunction due to temperamental connections.
- Other times, the R/R may fail simply because the battery is old and weak, and the interaction is detrimental.
Symptoms of a faulty regulator/rectifier on a Honda VFR800
There are two general patterns that a Regulator/Rectifier exhibits when it fails on a VFR800.
If the diode burns out, your VFR800’s battery will be drained, forcing all the usual symptoms of a bad battery to manifest:
- dimmer headlights
- fluctuating readings
- hard start
- VFR800 will not start
The first thing to do is check the charging system with a voltmeter, starting with the battery. Then, move on to R/R itself.
How to test the regulator/rectifier of your Honda VFR800?
Follow these steps to test the regulator or rectifier on your Honda VFR800:
- Separate the wires on your Honda VFR800.
- Set the multimeter to the diode setting.
- To test the rectifier, connect the positive lead to the positive diode of your VFR800 and connect the negative lead of the multimeter to the stator inputs of the VFR800. There should be no readings.
- Connect the positive diode of the VFR800 to the negative lead of your multimeter and the positive lead to the stator of the VFR800. The meter should give a reading; the number is not relevant yet. Repeat the operation for the negative diode connecting the positive lead of the meter to the negative diode of the VFR800 and the negative lead to the input of the VFR800 stator. Again, the meter should not reveal any numbers when you connect the positive lead and the stator inputs.
- Now, inspect the VFR800 regulator by connecting the meter leads to the battery of your Honda VFR800 while idling. Look for numbers less than 14.5 volts, but greater than 13.5 volts. If the reading is higher, your VFR’s battery has been overcharged. If it is less, the battery is not receiving a sufficient charge. In either case, it is probably time to replace the regulator/rectifier.
Fortunately, replacing the rectifier with a new, stronger one is a concise job for any trusted home mechanic. If not, Honda technicians are more than familiar with the infamous R/R problems and fixes on many models, including the VFR800 unfortunately.
2. Failure of the cam chain tensioner
The next most frequent failure among Honda VFR800 owners is the rapid wear of the cruiser-bagger’s automatic cam chain tensioner.
Instead of employing an iteration of the manually adjustable tensioners used on other makes and models, several early Honda models, including the VFR800, equipped an automatic cam chain tensioner.
Honda developed the VFR800’s Cam Chain Tensioner (CCT) to automatically acclimatise to fluctuating cam chains, adjusting the chain in real time.
To understand how an automatic cam chain tensioner fails, let’s start with how the cam chain tensioner works on a Honda VFR800:
The timing chain in your Honda VFR800 connects the engine’s crankshaft and camshafts so that they rotate in unison with each other, compensating for the timing between the pistons and valves, so the engine works as one.
- As its name suggests, the cam chain tensioner is designed to keep the timing chain at its specification tension.
- As we’ve noted above, while some bikes use a manually changeable TCC, the VFR800 uses a mechanical tensioner.
- A properly functioning mechanical tensioner is desirable unless it fails to automatically tension the chain as intended.
- If you can’t get the floating cam chain tensioned to spec, an automatic cam chain tensioner is not only useless, many of them can’t be adjusted by hand.
When loose, the chain wobbles, potentially wearing down nearby parts. Wear is uncomfortable, but a banging cam chain creates a horrible rattling noise on the trail.
Fixes for a Broken Automatic Cam Chain Tensioner on a Honda VFR800
There are several aftermarket cam chain tensioners, each intended to replace the factory part on a specific make and model of Honda, including many options for the VFR800. Here are the ways to fix a failing TAC on a Honda VFR800:
- Your VFR800 comes equipped with an automatic mechanical adjustment CCT. You can eradicate any potential problems by connecting your VFR with a manual adjuster.
- Installing a manually modifiable CCT allows you to eradicate any slack by adjusting the timing chain tension to a typical specification throughout the entire RPM range.
- More than a handful of Honda home technicians I’ve come across believe that a manual CCT is safer, more reliable, and more responsive, since valve timing will always be true.
It is vital to explore numerous options to ensure you purchase a tensioner that will suit your VFR800 and ensure it is built from a quality alloy. This way, you won’t have to worry about stripping the threads during installation.
A quality aftermarket cam chain tensioner tends to weigh less than Honda adjusters, lightening your load a bit. A well-made manual CCT should arrive with clear installation instructions.
That said, there’s no shame in using a trained Honda technician to find out which cam chain tensioner is right for your VFR800. It’s a common problem on multiple Honda models, an experienced Honda Technician has dealt with CCT replacements for years; we are sure they will be happy to suggest some choice options for quick and easy installation, either by yourself or by them.
The result will be a safer cam chain experience.
3. Thermostat stuck
Another common problem voiced by Honda VFR800 users on the forums and in some consumer studies is a malfunctioning thermostat; that is to say, that the thermostat is stuck when opening.
This is a real life example of a Honda VFR800 owner who had his bike’s thermostat stuck:
“On one of my last rides last season, I noticed my engine temp wouldn’t rise above 150°F or so at idle and would drop to 120-140° when cruising. Granted, the ambient temperature at the time was about 35°F, but just idling it should have gotten much higher. Normal operating temperature for my bike running was ~170-190°F. A dead giveaway that the thermostat is stuck.”
- When the thermostat is working properly, it should close when the engine temperature is 0° to 170°F. At this temperature, the thermostat closes to prevent coolant flow to the radiators and allow the engine to warm up.
- At 170°F, the thermostat begins to open, allowing coolant from the VFR800’s radiators to begin cooling the engine by dispersing coolant into the engine.
- The system then flows the hot coolant back to the radiators, where it re-cools the coolant to continue the process.
If the thermostat gets stuck in the open position, cold coolant is constantly circulating, not allowing the bike’s engine to come up to temperature.
Honda goes into more detail on this process in the VFR’800 service manual, around pages 6-8.
Note: Always refer to the service manual, available online or through Honda, during repairs. In this case, the VFR800 service manual provides detailed operating and repair data with pictures and diagrams so that the thermostat repair task can be accomplished with minimal stress.
In addition, there are different online guides scattered around the forums with better photos and, in some cases, with videos. Google quick and easy descriptions of how your thermostat works and what to do when it’s stuck open.
Between the VFR800 Service Manual and various online media outlets, fixing a stuck thermostat is an effortless procedure for anyone who can turn a key, including novice home mechanics like you.
Don’t rush. Keep tools and hardware organized, label detachable electrical connectors, and keep careful track of parts and screws.
At worst, it’s a quick and easy job for any decent motorcycle mechanic with knowledge of Honda; It won’t take more than the parts and an hour or an hour and a half or so of work if it’s a quick thermostat replacement.
The good and the bad of the Honda VFR800
Now that you know the common failures of the Honda VFR800 and how to fix the problems, here are some good points about this motorcycle. We start with the pros:
- The V-4 cylinder engine delivers silky power across the entire gear spectrum.
- The VFR800 is a bike that works well for commuting, leisure riding, or long, precise rides.
- Comfortable seat and driving position.
- The VFR800 can feel heavy when you’re sitting down; once you hit the pavement, the ride becomes smooth, and the low center of gravity evaporates apparent weight.
- The VFR800’s legendary handling, suspension and engine performance make it fun to drive.
- Cam chain tensioner failure
- Regulator/rectifier wears out early
- Thermostat stays open
What do the reviews say?
The VTEC model is even more reliable. Three problems each affected 5% of the owners; problems with the thermostat, burning alternator and failure of the cam chain tensioner. They’re all pretty rare, but you have to watch out for the cam chain problem: One owner paid big bucks to repair the resulting damage on his 2003 VTEC A3 model, with 32,500 miles on it. There were five other specific problems, all minor.
Overall, the VFR800 is one of the most reliable bikes we’ve studied, especially considering that many are getting older. You can buy and drive one with confidence.