Over fueling, over heating and overwhelming!

[JamesW]

Hi everyone, 

 

New to VFR ownership, looked like the perfect bike to meet my needs when I upgraded from my 650 Ninja. Sadly after 3 weeks she's doing my head in, I've been going through the forum (which is great stuff) but haven't been able to find anyone experiencing the same problem.

 

So far I've run 2 tanks of fuel through it getting 150 miles (country) and 110 miles (city) from 20 litre fills, that's about 25 miles per gallon if I've done the maths right. This is about 30% below what seems reasonable from extensive reading. The exhaust does smell a bit rich And idles a little rough but there's no odd back firing or anything.

 

Yesterday was the first time I took her out in town at temperatures above 7°C and when traffic slowed to a crawl in a tunnel the temp quickly rose to 120°C. Temp had been in the high 90s during my cold (4°C) morning, low traffic commutes and one country ride which after reading the posts here and the Hayes manual is much to high. 

 

Have checked the air filter (clean) coolant level (ok) and there are no error lights showing. I'm double checking the thermo-fan today but even if there's a fault there it doesn't explain the over fueling. 

 

Before I start hunting for a faulty sensor is there something really obvious I'm missing that I should check? 

 

Cheers

 

James

 

 

 

 

 

 

 

[Egg on Leggs]

Wax Stat could be sticking. 

 

https://www.bike-parts-honda.com/pieces-honda-detail-4848-13MCW2E1-VFR8003-2003-E__1700-VFR+800.html

[JamesW]

11 minutes ago, Egg on Leggs said:

Wax Stat could be sticking. 

 

https://www.bike-parts-honda.com/pieces-honda-detail-4848-13MCW2E1-VFR8003-2003-E__1700-VFR+800.html

Thanks mate! 

 

Good place to find all the parts from the looks of it.

 

Double checked the thermo-fan and that's not working so guess that narrows down the culprit a bit. Will pull the fairings this week and hunt for blown fuses, was stat and loose connections. 

 

Starting to think it may be 2 separate problems and the over fueling is due to something else.

 

 

 

[Egg on Leggs]

12 minutes ago, JamesW said:

Thanks mate! 

 

Good place to find all the parts from the looks of it.

 

Double checked the thermo-fan and that's not working so guess that narrows down the culprit a bit. Will pull the fairings this week and hunt for blown fuses, was stat and loose connections. 

 

Starting to think it may be 2 separate problems and the over fueling is due to something else.

 

 

 

 

The Wax Stat is effectively the choke, take the airbox off and you will find it under the top left corner of the Fuel Injector frame. The rod that connects it to the linkage can corrode. Some WD40 or ACF 50 should free it up if that is the problem.

[Auspanglish]

That rod is also prone to bending and deforming if you're doing other stuff in the general area, like syncing the starter valves. Pretty hard to get it perfectly straight and true again without a bit of know how or trial and error.

 

As to causes for overheating, could be thermostat stuck closed. Could be faulty reading (sensor fail or air trapped around sensor).

 

If fan not coming on there are several possible causes.

 

1. Fuse

 

2. Most common is air trapped around thermoswitch (top leading edge of left radiator).

 

3. Fan motor kaput, just ground the wire coming from thermoswitch and if not spinning, swap fan.

 

4. Broken hardened wires losing continuity

 

Etc

 

[GreginDenver]

Another possible cause of over-fueling is a failed fuel pressure regulator.

 

If you don't have an FI light but you have an over-fueling situation it means the problem is not one of the sensors that the bike's ECU uses to make up its fueling computation.  No FI light + over-fueling means that the fuel injector pulse width (the fuel squirt) being commanded by a perfectly healthy ECU is somehow being messed up somewhere down the line inside the fuel system.

 

If your Fuel Pressure Regulator goes bad here's what happens: 

 

The bike's fuel pump is designed to produce pressure well in excess of the system's needs and the fuel pressure regulator takes care of the necessary reduction.  All FI systems (both car and motorcycle) are designed this way because it means there's "overhead" available in the system for when the fuel pump gets older and weaker as its factory tolerances slowly get exceeded by long term wear. 

If the fuel pressure regulator fails it will allow the full pressure provided by the fuel pump to reach the fuel rail and injectors.  This causes over-fueling because the ECU will still be commanding a fuel pulse-width that is (by design) perfectly matched with the proper fuel pressure (usually about 43psi, or 3 bar).  So in the failed fuel pressure regulator scenario the higher fuel pressure (as high as 50+ psi) will push more fuel out of the injectors each time the ECU commands what would have been the proper fuel pulse width (for a properly regulated fuel system).

 

Injector Pulse Width = a pre-determined base time period of Injector "open" command (part of the ECU's firmware load from the manufacturer) + dead time (the time it takes for the 12 volt electrical power to drive the injector to reach full open) + or - various fuel "trim" corrections (for things like altitude, rapid throttle movement, coolant temperature, intake air temperature, and etc.)

[Grum]

Agree with GreginDenver regarding the Fuel Pressure Regulator.

 

Another issue the FPR can have is a ruptured diaphragm. This will cause terrible running as the FPR will be dumping excess fuel into cyclinders 3 & 4 via Vaccum hoses. The number three exhaust could also appear cold. Also there will be no FI error codes with this fault.

 

Verify your cooling fan operation - wiring, fuses, thermatic switch and the fan itself.

Cheers.

[JamesW]

Thanks guys, 

 

Now I've got somewhere to start!

 

I've got a lot to work through and will post the results here.

 

 

[Urbanengineer]

On 2/18/2018 at 7:01 PM, Grum said:

Agree with GreginDenver regarding the Fuel Pressure Regulator.

 

Another issue the FPR can have is a ruptured diaphragm. This will cause terrible running as the FPR will be dumping excess fuel into cyclinders 3 & 4 via Vaccum hoses. The number three exhaust could also appear cold. Also there will be no FI error codes with this fault.

 

Verify your cooling fan operation - wiring, fuses, thermatic switch and the fan itself.

Cheers.

I'm having an overheating issue also while riding at high RPM's. I am also having an idling issue that people have said seem like a lean condition. How does one test the exhaust temperature? I have no codes.

 

As the day heated up and I kept getting faster (track) on the VFR it kept going north of 220* to up to 260*! I recently flushed coolant and believe this should self bleed... unless I am missing something. I'll check into the FPR diaphragm. @Grum when you say terrible running you mean at all RPMs not just idle?

[Grum]

5 hours ago, Urbanengineer said:

I'm having an overheating issue also while riding at high RPM's. I am also having an idling issue that people have said seem like a lean condition. How does one test the exhaust temperature? I have no codes.

 

As the day heated up and I kept getting faster (track) on the VFR it kept going north of 220* to up to 260*! I recently flushed coolant and believe this should self bleed... unless I am missing something. I'll check into the FPR diaphragm. @Grum when you say terrible running you mean at all RPMs not just idle?

 

If you were able to do a track day, then I would doubt you have a ruptured diaphragm in your FPR, performance would have been shocking.

You can purchase a digital, optical thermometer fairly cheaply these days if you wanted to monitor your exhaust pipe temps.

 

Ringing the bikes neck on a hot track day is certainly going to raise the engine temp, 220degF doesn't seem too bad but 260degF = 126.7degC seems way too high, at 122degC or 252degF this should have turned ON your Red Overheat Light!. At 203degF the thermostat is Fully Open.

 

Is your cooling fan kicking in?

 

Did you go through the process of burping the cooling system after replacement to clear the air from the system? Is the reservoir tank coolant full to the upper level? 

[Urbanengineer]

5 hours ago, Grum said:

 

If you were able to do a track day, then I would doubt you have a ruptured diaphragm in your FPR, performance would have been shocking.

You can purchase a digital, optical thermometer fairly cheaply these days if you wanted to monitor your exhaust pipe temps.

 

Ringing the bikes neck on a hot track day is certainly going to raise the engine temp, 220degF doesn't seem too bad but 260degF = 126.7degC seems way too high, at 122degC or 252degF this should have turned ON your Red Overheat Light!. At 203degF the thermostat is Fully Open.

 

Is your cooling fan kicking in?

 

Did you go through the process of burping the cooling system after replacement to clear the air from the system? Is the reservoir tank coolant full to the upper level? 

Okay not the FPR. Brand new vacuum line to it. 

 

>Suppose I need to “burp the air” but I thought this was an automatic feature of the closed system. It’s currently at the max line. < I’ve been running this coolant for about a month in a bike with the bike never going about 225* until the track day. 

 

Cooling fan comes on at 220*F. 

 

Overheat light comes on at 250*. It only happened twice yesterday at the end of the day. Running Engine Ice Coolant. Brand new OEM thermostat just went in. 

 

I’ll go purchase an optical thermometer at the end of this week and test the temps then. 

[Auspanglish]

No automatic burping.

 

Firstly the cooling system of the VFR800s with side mounted radiators, in a word: sucks!!

 

There are several spots air tends to get trapped: one is around the thermoswitch which turns the fan on and off; the second is in and around the tubing that runs through the automatic choke mechanism for enriching the fuel:air mix when it's cold. Both of these sites are just perfect spots for stuffing up your enjoyment of the 5th and 6th gens until you get it sorted.

 

There is a procedure explained in the workshop manual you can obtain in PDF format from the download section. There might be some how tos in the tutorial section.

 

Just do it.

 

Secondly, unfortunately, if your bike's fan was coming on, at typical race track speeds on hot days, this will actually have been making things worse. The air flow the fan produces is in the opposite direction to that of the natural air flowing into the bike as it moves forward. Above about 40 Km/h the fan is rendered useless but the naturally inflowing air can't flow in either so the net cooling effect at speed on a hot day is nil and when you stop the fan is now incapable of doing much as even the chassis is too hot to touch and the air in close proximity on a hot day is even hotter... So you're trying to fight fire with fire.

 

For serious track days in hot climes you'd be better off swapping the fan blades out with the ones off an SP1. They blow air from the inside, through the radiator to the outside, which, you will realize if you give it a second's thought, is the same direction as the natural incoming air as the bike moves forward.

 

No, this set up is not as effective when at a standstill, which is why it's not very useful for street use. If you are not dedicating the bike exclusively to the track, all you may need is to install a manual override circuit to the wire "downstream" of the thermoswitch and while blitzing the track override the fan to not come on. Just don't forget to switch it back to regular function.

 

If you're handy with tools and tinkering it's not hard to swap the blades over. If you're good with soldering and wiring schematics then it's even easier to install a manual override.

 

No. Not worth trying to make the OEM fan spin backwards, the blades are curved. That would be about as useful as installing an ashtray.

 

This has been discussed to saturation point on this forum already many a time. Use the search feature. People have gone to quite some extremes trying to improve the cooling system on this all-rounder (does everything reasonably well but don't expect special performance in any one field).

 

Finally, when the 6th gen reaches 120°C the temp display on the dash starts to blink on and off... there's a rhyme to the reason and you should stop and let the bike cool down. Some have said at 125°C their bike turned itself off. This on a track or anywhere really, could be catastrophic!

[Urbanengineer]

Exactly. Heat and lack of lubrication is what kills engines. I appreciate your thorough reply I’ll start with a full air bleed.

 

Has anyone successfully wired an SP1 fan on the right hand (sitting on) mounted radiator? That way I could turn one on for track use while disabling the other, and vice versa?

[Urbanengineer]

I do realize it isn’t a track bike, but it’s cooling system should function in many conditions witthout question. I can’t believe the fan flows the wrong way, but it’s hilarious now that it’s mentioned. 

 

I bumped this topic because basic searches of “overheating” and such came up with nothing. I’ll adjust my search terms. 

[Auspanglish]

Exactly. Heat and lack of lubrication is what kills engines. I appreciate your thorough reply I’ll start with a full air bleed.
 
Has anyone successfully wired an SP1 fan on the right hand (sitting on) mounted radiator? That way I could turn one on for track use while disabling the other, and vice versa?

Looked at that but no space for a "proper" fan, i.e. SP1 ... Someone may have found an aftermarket model withstanding temps and general climactic conditions and thin enough, plus having sufficiently reduced diameter to fit the small area I think I recall is available on the inside lower forward corner of the right radiator, yet having considerable pull/push... I'm not sure.

I remember giving up taking it to the track as I exceeded it's other limitations and needed something more... and just made sure she was well burped, swapped out any dodgey hoses and spent the extra on good quality coolant and for hot summer sport-touring use on public roads this was enough to keep me out of the hot seat.

A guy I knew had two high-flow PC fans pulling air from the outside face of the rhs rad he would turn on at his discretion ... ugly, but at every red light his bike was always several degrees cooler.

I had swapped the blades out for a while on my 5th and 6th gens but on the street overall it was worse whenever doing urban duties. With my tendency to prefer two wheels for city use (as you can lane split and park no dramas where I live in Spain and most other areas I've lived), it's more convenient than a car unless carrying larger items, so I'd end up using the VFR for what it's not designed for (at least the models with side mounted rads); city scratching, and with the hawk blades it ran a lot hotter overall and the fan and the heat would overwhelm the electrics and on the 5th gen the R/R fries and on the 6th gen the stator fries.

It's a bit like Bart Simpson would say if he were older: fu#%ed if you do and fu#%ed if you don't.

[Dutchy]

I added a simple on/off toggle switch to my SP2, running the ground wire on the left fan (the SP2 has to, they operate in unison) to ground with the on/off switch in between.  It is ground that triggers the fans.

This allows me to switch them on manually while riding around town as there is not enough airflow at lower speeds.

Will do the same on my VF500F2 tomorrow.

Cost is a few bucks at the most.

[Dutchy]

Ignition on and...

 

 

[Urbanengineer]

Nice, I’m riding a 2002 800 but I’d imagine the installation is very similar. Also - you only have 10.5 volts when sitting without the bike on?

[Auspanglish]

The problem is, Dutchito, that the fans in the 5th and 6th gen VFRs blow against the natural airflow so turning the fan on manually while getting around town will just make things worse. You could turn it on while stopped at traffic lights BEFORE the bike heats up over 100°C to try and prevent overheating but should turn it back to automatic operation or manually override to off if you're reaching 104°C but truth is this just takes all the fun out of riding the bike. (Some people swap the fan's thermoswitch for an aftermarket one with a lower temp threshold).

 

It is possible and an engineer friend of mine even designed a set up to automatically override either on or off with a timer, depending on a number of criteria being present or not and option just to leave everything according to OEM operation, but we never bothered building it. I just did as I said earlier; stopped taking it to the track and used quality coolant with regular (at least annual) renewal and burped that baby good and proper and swapped out suspicious hoses and new rad cap. Proper maintenance. As well as just using the bike for what it was designed for.

 

Then I sold it soon after. :]

 

 

[Urbanengineer]

I’m trying to keep this one lol, not trying to sell anytime soon haha. But I have some work cut out for me. 

[Dutchy]

3 hours ago, Urbanengineer said:

Also - you only have 10.5 volts when sitting without the bike on?

 

Well spotted!

 

I tap the current from the cockpit lights, that's why. 

With the engine running it shows a tad under 14.

 

Putting my multimeter to the battery I get healthy readings.

 

I will notice if the reading is "different" and thus suspect something is up

[Urbanengineer]

Okay! Had the rad cap tested today and unfortunately it’s not the rad cap or the hoses or leaky radiators that seem to be the problem. 

 

I leaned the bike all the way over until the center stand touched on the left side, and the right foot peg on the right. 

 

I removed the cap (cold) and the fluid was at the top. Started it and “blipped” to circulate some fluid and still, at the top. Leaned the bike side to side again, removed cap at top... still max fluid. 

 

Checked the reservoir and it’s as full as it was before this attempt. 

 

70*F overcast ambient temps. 

 

Went out to similate track speeds (aka constant VTEC) anytime the RPM’s were above 5500 the bike’s temperature rose. Below 5000 and the temp would drop. Makes sense - more RPM = more energy = more heat.

 

Problem is it would get up to 225*.... and then keep climbing while in VTEC. This is unacceptable for the kind of riding I regularly planned to do on this bike. It hit a peak today of 240*F before I dropped back down to 4000 or less RPM’s to cool the bike.

 

Engine ice coolant freshly replaced before winter storage. Running in spec valves and recently serviced bike. TB’s synced. Idle is low, but runs fine above 4000 RPM, hangs at 4000 RPM of idle too high. All

vacuum lines replaced with new vacuum hoses. Stainless Tunes exhaust with factory header.  

 

The bike can’t sustain VTEC operation!?! Is this an issue with my bike or is this a VFR problem as a whole?

 

What steps are next?

[Urbanengineer]

I should add VTEC drastically rose the temperature, quickly. 

[Terry]

Have your ruled out a stuck thermostat?

 

My simple test is to rest a hand on the right radiator when you start the engine from cold. If the radiator stays cold until you see around 176F/78C, then quickly gets too hot to touch , the thermostat is opening correctly. If the radiator gently warms along with the engine, then the thermostat is stuck. 

[VARIABLE9]

1 hour ago, Urbanengineer said:

Okay! Had the rad cap tested today and unfortunately it’s not the rad cap or the hoses or leaky radiators that seem to be the problem. 

 

I leaned the bike all the way over until the center stand touched on the left side, and the right foot peg on the right. 

 

I removed the cap (cold) and the fluid was at the top. Started it and “blipped” to circulate some fluid and still, at the top. Leaned the bike side to side again, removed cap at top... still max fluid. 

 

Checked the reservoir and it’s as full as it was before this attempt. 

 

70*F overcast ambient temps. 

 

Went out to similate track speeds (aka constant VTEC) anytime the RPM’s were above 5500 the bike’s temperature rose. Below 5000 and the temp would drop. Makes sense - more RPM = more energy = more heat.

 

Problem is it would get up to 225*.... and then keep climbing while in VTEC. This is unacceptable for the kind of riding I regularly planned to do on this bike. It hit a peak today of 240*F before I dropped back down to 4000 or less RPM’s to cool the bike.

 

Engine ice coolant freshly replaced before winter storage. Running in spec valves and recently serviced bike. TB’s synced. Idle is low, but runs fine above 4000 RPM, hangs at 4000 RPM of idle too high. All

vacuum lines replaced with new vacuum hoses. Stainless Tunes exhaust with factory header.  

 

The bike can’t sustain VTEC operation!?! Is this an issue with my bike or is this a VFR problem as a whole?

 

What steps are next?

I don’t know the service manual procedure, so pardon me iif this is off base for your purposes/VFR’s.  Urban did you have the radiator cap open in order for the ‘burp’ to escape?  You can loosely cover with a rag to prevent splashies.