engine running too cold

Hey,
I ride a '99 vfr and temp outside is dipping into 60 degree f and the bike runs too cold.
The optimum heat range is between 180 and 200 f.
Shouldn't the thermostat keep the water hotter?
It drops to 160 on the freeway when the temp drops.
Oil and EFI needs to be at least 180 for proper fuel mixture.

 

Don't know if the 05 is the same as the 99 in this regard but your temperatures are similar. In colder weather the operating temp is very similar to yours. The thermostat activates at 79 Deg C which is 174 Deg F and if it is below about 40 F air temp the coolant temp is in the 175 to 180 range on the highway.

 

sometimes thermostats can stick in open position.
check that system is full, not low on coolant.
or slide a bit of thin cardboard about size of #10 envelope in front of radiator in cool weather.




VTR 250, baby brother of VFR:

 

Operating temp for a 99VFR is 170-175 on the temp range.. In cold weather my VFR will run between 170 and 178f and I ride if there is no ice or snow on the roads .

Check your coolant level/ antifreeze and water mix ratio..

 

Your t-stat is stuck open. You will only notice this in cool weather. If it was stuck closed it would easily overheat. If the engine temp stays too low, the EFI map can go into cold start mode and fuel mileage will plummet and also possibly foul the plugs.

My 4gen now has a digital temp guage and recently on a trip it still pulled 180's in high 30/low 40f morning air after warmup.

 

For a semi quick fix, duct tape the radiator air vents shut on the fairings. This should be done with some discression, tape it shut a few widths of tape at a time. Tune in to any NASCAR race, this method is often used to adjust engine temps and also to adjust car downforce. But lets not confuse anything by talking about downforce. eddie

 

I was also under the impression that optimum temperature should be 180-190*F. It has been getting cool up here in the northeast and my '02 will hover around ~160*F when ambient is ~50-55*F. This is when i'm moving. I assumed this to be abnormal like the OP. It will warm up if i just let it sit for a while, but seems slow to climb temp.

Not sure about VFR, but other bikes will not run normal FI map until 170-180*. Below that it will use an idle map that is richer.

Some bike models have used poor locations in coolant system to read temp (temp would not be accurate). Folks would move the sensor. Don't know design of VFR system.

Stuck open will not have overheating symptoms; it will take longer to reach proper operating temp (if at all).

Stuck closed will have overheating problems.

I think there are some models of thermostats which are designed to default to the Open position if they fail because that scenario is generally safer than Closed (overheating).

 

On the Gen 6 bikes the t-stat should begin to open 176-183F (80-84C) and should be fully open at 203F (95C). If you radiators are getting hot at a much lower temp, say 150F, then your t-stat is stuck open. I know from experience the VTEC bikes don't run as well with the t-stat stuck open. I'm in the middle of replacing mine now, see the "how to" form.

Action

 

The temperature guage needle on my 97' VFR only gets slightly past the "C" mark while driving.. When idling or driving in the city it may be a little more.. Is this normal?? According to the manual the normal operating temperature is beetween C and H.. I live in Norway so the air temperatures here are not that high (about 60-77 deg F in the summer, sometimes less)

 

You need to take a look at the cooling system flow chart.

A thermostat has no way to read the temp in the rads. It simply reacts to the coolant temp coming out of the motor. Once the coolant is above whatever the t-stat is rated for (say 185f) it will open and stay open as long as the coolant remains above thus allowing 100% flow at all times.

Once the coolant gets above a pre-determined higher value (say 220f) another thermo switch on the radiator tells the fan(s) to come on. If those fans and the airlfow from a moving bike don't reduce the temps, then it overheats.

 

Maybe I'm not following you. Say you have a t-stat that is stuck permently open. If I understand what you're saying, the water pump is moving the fluid through the radiators too quickly for maximum heat dissipation to occur.

This is not the case on VFR's. With the t-stat open you are getting maximum efficiency (with in your systems limitations) for fluid to air heat transfer based on flow. The electric fan helps when the air flow is low. If you example was correct the t-stat would have to close again at high temps, restricting flow, to allow more time in the radiators.

Yes - you can over heat in traffic with an open t-stat (or no t-stat) because you have exceeded your cooling limits, but it will not happen faster with a stuck open thermostat.

 

No prob D, if you were closer I'd say come on over and help me put mine back in. I got the new t-stat via Fed EX today and Service Honda sent the wrong one GRRRRRR. Now I have to wait another 5 to 7 days for the right one. Hopefully I'll remember where all that stuff goes.

Action

 

Sure do. In fact, I was worried because when I pulled mine out it was closed. The bike had been running cold and I though it would have been stuck open. Luckily I checked and sure enough it opened right at 180 and never closed back up as it cooled off. Sooooo soon as I get my new one I'll check it, install it, and hopefully be back on the road.

Action

 

Nope, coolant is always flowing to radiator. T-stat just dictates whether it flows via 1 of 2 modes (normal or max flow). Max flow will still capture heat perfectly fine from motor; the add'l coolant rate more than offsets loss of contact time from a temperature transfer point of view (probably oversimplified, but hopefully makes sense). Overheating won't occur if stat is stuck open assuming everything else operating normally.

No need to stick your head in the sand. :wave:

 

postmortums on several stuck-open thermostats have seemed to suggest that a calcified, hardened substance builds up on central post, jamming block off plate from moving.
possibly using only distilled water in coolant might eliminate the problem in some cases.

there are crossover #s which list the same VFR thermostat as fitted in several Japanese cars and can be purchased for about $8-10 at your autoparts store, not from Honda stealer for, what, $40???!!!!!!


I may try to locate this info and post up #s soon............

VTR 250, baby brother to VFR: