Jump to content

My (new to me) 1998 VFR800 5th Gen is giving me running/idle Issues. Any advice will be greatly appreciated.


VicSev93

Recommended Posts

Hello all! My name is Victor, I'm new to the VFR world, and new to fuel injection bike world (coming from a carbureted GS500). I just bought a 1 owner, 15k mile VFR800, (It has not been used, and just stood around for over a year) the thing is absolutely gorgeous, and I think about it everyday. The issue is, it has a idling/running problem. I wanted to ask here for some of the expert opinions before I go throwing money and parts at it. Here is the issue, 

 

1)Bike will take a while to start. The starter will go off, and I have to rev the throttle for it to run. (sometimes even that doesn't help) Once its running, it will only run when I rev the engine, when I let go of the throttle the bike dies.

2(The bike also seems to die when its warmed up, as it seems to not want to start on a warmer engine vs a cold engine. 

3) Once I got it to run, I rode it for maybe 5 minutes and then it died on me on a red light. 

 

I bought a new battery to see if that would change anything, it did not. (the old battery was 5 years old) My friend who is a bike mechanic told me that the bike sounds like its running lean, (he said it even sounds like one of the cylinders is dropping) and that the fuel injectors may be dirty and need a good cleaning or be replaced so the bike can get the fuel it needs to function. Another mechanic has told me the fuel pump is bad, although we can clearly hear it prime when the bike turns on. What I think it may be from searching other forums and videos, is the R/R or the stator which I know nothing about, nor how to test it, but it seems to be a common problem on these bikes. My only question is that, I have not found much of the symptoms on the issue. 

 

We removed the gas tank and took a look at the air filter (its a K&N and is dirty) removed the air box (had to be drilled out, the bolts were all rusted) and saw that there is in fact a lot of grime and dirt (and I think even a plant growing?) under the throttle bodies (below the injectors) and all the wiring LOL. My plan of action is to take off the throttle body assembly and clean it, aswell as taking out the injectors and checking them, maybe sending them off for a clean/flush test. What do you guys thing? My only concern is I dont know what else these symptoms could mean, and it can be something electrical, like the R/R stuff I mentioned before. If you have any advice, I would greatly appreciate it, thank you very much, and have a great night! 

 

Link to comment
Share on other sites

Congrats on your VFR and welcome to the forum!  🙂

 

One obvious thing you probably already addressed but which I didn't see mentioned above, did you drain the old fuel from the tank and replace it with new gas?  Also, did you check inside the tank for rust?  I wouldn't think the tank would rust in just a year, but it's worth looking.  One other question is what is the idle speed set to?  Again, it's probably fine, but if it's set too low for some reason that could be a factor.

 

Sounds like you need to clean up the injectors, etc.  You could also try a fuel system cleaner in your next tank of fuel, though not everyone probably agrees about whether using those fluids is effective or even a good idea.  (I usually do mine every oil change.)

 

I'm not an electrical expert, so I don't know if this could be an electrical gremlin.  Are you able to ask the previous owner if there were problems when the bike was parked?  You already bought it, so hopefully the seller is willing to be perfectly honest about it at this point, if he/she hasn't been already.

 

Good luck getting it sorted out.  I promise it will be worth the time and effort, as these are fantastic machines with bulletproof engines that will last forever.

Link to comment
Share on other sites

  • Member Contributer

I would replace the spark plugs, and run a heavy dose of fuel system cleaner. 

I second the question of "what is the idle speed set to?" It may just be idling too low.

 

Are you using the fast idle (looks like a choke) lever when starting?

Link to comment
Share on other sites

  • Member Contributer

Yeah, bike sitting around can get gummed-up fuel-passages that cause variable fuel delivery. Use fuel-system cleaner with healthy dose of PEA.


- Red Line SI-1
- Techron Concentrate Plus 
- Gumout All-in-One
- 3M Max Strength Fuel System Cleaner #08814
- Royal Purple Max Atomizer 18000

 

Not sure if there's way to test fuel-filter. Maybe just replace it?
 

Also may be vacuum-leak somewhere. Use carb-cleaner spray to test all junctions on intake side. Anywhere there’s hose-clamp between parts that may be leaking.

 

Use vacuum gauge to test for vacuum leaks.

Multimeter to test output of MAP sensor.

 

Link to comment
Share on other sites

11 hours ago, VicSev93 said:

Hello all! My name is Victor, I'm new to the VFR world, and new to fuel injection bike world (coming from a carbureted GS500). I just bought a 1 owner, 15k mile VFR800, (It has not been used, and just stood around for over a year) the thing is absolutely gorgeous, and I think about it everyday. The issue is, it has a idling/running problem. I wanted to ask here for some of the expert opinions before I go throwing money and parts at it. Here is the issue, 

 

1)Bike will take a while to start. The starter will go off, and I have to rev the throttle for it to run. (sometimes even that doesn't help) Once its running, it will only run when I rev the engine, when I let go of the throttle the bike dies.

2(The bike also seems to die when its warmed up, as it seems to not want to start on a warmer engine vs a cold engine. 

3) Once I got it to run, I rode it for maybe 5 minutes and then it died on me on a red light. 

 

I bought a new battery to see if that would change anything, it did not. (the old battery was 5 years old) My friend who is a bike mechanic told me that the bike sounds like its running lean, (he said it even sounds like one of the cylinders is dropping) and that the fuel injectors may be dirty and need a good cleaning or be replaced so the bike can get the fuel it needs to function. Another mechanic has told me the fuel pump is bad, although we can clearly hear it prime when the bike turns on. What I think it may be from searching other forums and videos, is the R/R or the stator which I know nothing about, nor how to test it, but it seems to be a common problem on these bikes. My only question is that, I have not found much of the symptoms on the issue. 

 

We removed the gas tank and took a look at the air filter (its a K&N and is dirty) removed the air box (had to be drilled out, the bolts were all rusted) and saw that there is in fact a lot of grime and dirt (and I think even a plant growing?) under the throttle bodies (below the injectors) and all the wiring LOL. My plan of action is to take off the throttle body assembly and clean it, aswell as taking out the injectors and checking them, maybe sending them off for a clean/flush test. What do you guys thing? My only concern is I dont know what else these symptoms could mean, and it can be something electrical, like the R/R stuff I mentioned before. If you have any advice, I would greatly appreciate it, thank you very much, and have a great night! 

 

 

Sounds like you made a good purchase, 1 owner and only 15,000 miles, that's the way to start out.  And the VFR engine is very well-built and durable but the truth is that the rest of the VFR, its electrical system, its fuel delivery system and all are just standard Honda gear.  

 

By purchasing a 22 year old motorcycle you've put yourself in the position of having to do "old motorcycle" maintenance and refurbishment.  If you're not into old motorcycle maintenance you may have made a mistake.  If you've been a motorcycle guy long enough you've met "that guy" who loves motorcycles, loves to ride, but somehow knows absolutely nothing about maintaining them.  With a 22 year old motorcycle you can't be that guy. 

 

My personal standards always lead me to give "new-to-me" old motorcycles a thorough going over.  Here's where I went with my '99 after I purchased it in 2016.

 

IMG_20171020_095658.jpg

Link to comment
Share on other sites

  • Member Contributer

First off, we need pics of your new ride so we can all be jealous of your good fortune!   :wink:  

If you're going to remove the throttle body (to remove the plant?), then sending the injectors off to be cleaned  (about $100) would be a great idea.  Think of gas sitting for years - it degrades in to a varnish like substance that can clog the tiny holes in the injectors. Another item would be the fuel pressure regulator.  You can pull the vacuum hose and see if there is odor of gas, in that event it should be replaced.  How does the inside of the tank look?   Does the gas smell odd or is there crud / rust in the tank?  All that would need to be remedied if so.

When you get it running, place a voltmeter on the 20v DC scale on the battery terminals and see if you're getting around 14 to 14.5 volts (at 1,200 + rpm) - if the volts are low or drop as rpm rises,your R/R is on its way out and should be replaced - a very common failure on 5th gens.

.

 

Link to comment
Share on other sites

  • Member Contributer

We are in the age of the Electronic Bike... fuel delivery and spark
timing and instruments and everything else operate within millionths
of a volt (milli-volts) and for some reason a component doesn't
receive its allotted share of volts the system starts to prioritized
which components are powered and which components are cut so you can
ultimately return home...


Trouble Shooting begins with the battery for it's the weakest link in the whole

system... To determine the condition of an Maintenance Free battery give it a
refreshing charge... wait 30 minutes... measure terminal voltage...

12.8 or higher is a good battery...
12.0 to 12.8 is a insufficient charge... recharge...
12.0 or lower... battery unserviceable...

 

Hard to start problems is mostly a problem of not enough fuel is being sucked into the combustion chamber...

Generic things to check for that would effect cold starting are:

1) enriching cable adjustment if you have one... too loose or too tight effects range...

2) unobstructed idle air tubes... pinched rubber tubes from the air box restrict
idle air... the result is a lean mixture that doesn't support 100% combustion...

3) throttle body butterflies are 100% closed... any air that bleeds past the
butterflies kills vacuum needed to draw in the correct rate of fuel... the result
is a lean mixture that doesn't support combustion...

 

Download a PDF file of an offical VFR Honda shop manual...

 

Link to comment
Share on other sites

Guys! Thank you all so much for the replies, I finally am able to go to the garage tomorrow and sort out all these issues, I will send pics for sure! I should have also properly introduced myself in the intro forum, which I will do, along with the pics. You are all super friendly here! This is awesome, cause I'm part of some other forums (BMW car related stuff) and its def not the same. haha. 

Link to comment
Share on other sites

On 9/23/2020 at 10:22 AM, paulmeisterpk said:

I would replace the spark plugs, and run a heavy dose of fuel system cleaner. 

I second the question of "what is the idle speed set to?" It may just be idling too low.

 

Are you using the fast idle (looks like a choke) lever when starting?

Hello! I am in fact using a fast idle. Which threw me off at first, since that's something carbureted bikes also have, so I was confused on why its on a fuel injected on. haha

Link to comment
Share on other sites

  • Member Contributer

On early 5th gens the fast idle function was not yet automated.  2000 and newer models have the "wax unit" that reacts to the temperature of the coolant circulated through it for that function,  eliminating the lever.  But they can and do fail and are a PITA to replace.  Full electronic control has since replaced those. Personally I like the idle control lever - gives me choice and is fail safe vs later wax units.

 

Link to comment
Share on other sites

  • Member Contributer

Read this..... makes a big difference in how the bike idles, it certainly changed my 5th Gen.

 

 

If it were mine, I'd check the tank and if no rust/bad fuel (I would drain/siphon out and put in fresh.  I'd definitely run Seafoam or one of the fuel conditioners previously mentioned, and for the next couple of tankfuls once you get it running.  New spark plugs.  Not sure I'd go with injector cleaning just yet anyway, it should run.  Idle speed 1200 with starter valves closed ("choke" off) when warmed up.

Not sure how you're going to get the plant out from under the TB's but best of luck.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy.