Normal Operating Temperature?

My VFR750 passed safety check yesterday, and is now plated, and back on the road after 5+ years sitting in the previous owner's garage. I put on about 30 miles last night in a couple trips, stopping a couple times to do a visual check, and all appears fine. One question though, as this is my first VFR. What is the normal operating temperature for this bike? Ambient temperature was about 70F, (20C) last night, and the temperature needle barely moved off the cold mark. After about 15 minutes of riding it settled into the position shown by the red line on the pic below, and never went higher. Is this normal, or should I be planning to swap thermostat? Now I did replace the coolant during the maintenance blitz last week. Could there be an air pocket causing improper reading?

 

I think something is wrong with that as these bikes run on the hot side of the spectrum. Granted, 30 miles is not enough to make a solid assessment, but i think the needle should be more in the middle of the gauge.

 

My 6th gen typically sits around 75-90*C while on the highway.

In traffic, it can easily reach 110-115*C on a hot day ... on average though, it seems to settle right around 104-106*C stopped in traffic.

Burp the coolant lines (squeeze them with the bike running) several times and check coolant levels. If that doesn't work, then you will want to check that your thermostat isn't stuck open. After that ... it could be the temperature gauge itself or the attached wiring / sensor.

 

That's normal for 4th gens. People have swapped thermostats and seen no change. It's not right, but that's the way it is. As long as the fan kicks in when it supposed to. you'll be fine.

If you do spend a lot of time in traffic, with the fan running, make sure that your idle is set high enough to be in charging mode. Many a poor sole has had the fan run the battery down, due to the charging system being inadequate.

 

Thanks for the responses, everyone. The manual says something vague about anything between the C and H being OK, but that seems like a pretty wide range. I know in my Volvo, the temp gauge moves quickly to the exact mid-position, and stays there no matter how cold or warm the day is. I was kind of expecting something similar here. karazy - thanks for the 4th gen-specific info. I'll leave things as-is, and certainly keep an eye on the idle speed if I'm stuck in traffic for an extended period. Fortunately, I live in a fairly rural area, and doubt I'll spend much time in heavy traffic, for the first while anyways. I've been out of the motorcycle scene for over 20 yrs, just re-entering now that the kids are grown. My last bike was a Nighthawk S (750cc I4, shaft drive), sold back in around '92!

 

Watch that volvo thermo, if it ever goes high on you, shut her down quick, ditto on the VFR, otherwise you've cooked it.

 

Unless you're working the engine hard, it's normal for the temp to sit at about 1/4 to 1/3 of the range............especially in Canada.

 

I was out for about 250 km's (160 miles) on my wife's 96 VFR on the weekend and the temperature gauge barely made it a few needle widths past where you are showing. A lot of time was spent in the 50-70 mph range and higher revs as most of the ride was in the twisties (around 7000-8000 rpm) and the ambient temperature was 38*C (about 100*F) but on shorter trips, that's not far away from where I've seen temps on the gauge. I'm sure someone will correct me if I'm wrong but I would think that if there was still some air in the system you would see higher temps and a bit sporadic temp readings. My guess would be that everything is running close to normal.

 

I wish all VFRs run "lower than hot" normal temps...
Karazy, what's the idle RPM for a 2000 VFR to be in the charging mode? I have mine at the recommended setting and do more town ridding than highway. I occasionally put my battery (quiet new) on tender charge when the bike is sitting still for more than a week.

 

Well, I don't know the specific RPM for this ... but the best way to do this is to hook up a digital multi-meter to your battery and take note of the battery's resting voltage, then start the bike and see where the voltage is at idle and adjust the idle accordingly.

 

Are you sure it has a thermostat in it? Get an infrared heat gun/meter and let bike idle for 10 to 15 minutes. Then take a temp reading of the rad. It should be at least 180 degrees. If not take it around the block come back and take another reading and see what it is after riding. Should be 190+.

 

Sorry, but you shouldn't have to raise your idle for fear of battery drain. If sitting in traffic is killing your battery with the rad fan cycling on and off you've got something wrong. Either your charging system is toast or you're running way too many accessories.

Even though the stator isn't anywhere near max output at normal idle. It's still charging the bike to a degree. Your bike doesn't just magically run off battery under 1200 rpm. A properly maintained VFR should be able to idle all day long with normal factory electrical stuff, including a cycling rad fan until the gas tank empties

If you're truly just parked in traffic, not inching forward at all. There's a better option. Turn off the bike.

 

z-z, your comments seem to match those of karazy, so I'm hoping all is well. I hope to get out for some more riding tomorrow, and will watch that temp gauge again. I can probably borrow an infrared temp gun from work and check the rad temp to get a number. And no, I can't say for certain that the bike has a thermostat installed, as I didn't pull the thermostat housing during coolant change.

 

You'll be able to tell if the thermostat is present/working by noting the radiator temp (by hand) when you start the bike from cold. The rad should stay cold for a few minutes, then have a rapid increase to uncomfortably hot. If you have a slow, steady rise in temp, the thermostat is either stuck open or not installed.

The thermostat should remain closed (so the coolant just circulates through the block) until that coolant is hot (70-80C) then the stat opens and allows coolant through the radiator.

 

As everyone probably knows, the higher the rpms, the higher the output of the charging system. Until the windings of the generator become saturated and max out. The same principal dictates that the lower the rpms, the lower the output will be. Because not all systems are perfectly identical, the rpms at which each system will begin to start effectively charging will be slightly different. When Honda designed this system, they decided to sacrifice the lower rpm capabilities in lieu of the normal cruising ones. In most riding situations, there will be no problems with this logic.

If someone was to adjust the idle, relying solely on the smoothness of the engine, most would find that the charging system would not be charging. This is why, as Jeff stated, you should use a volt meter and adjust the idle up to the point where the charging system begins to increase. This is usually between 100-300 rpm greater. Relying on your riding conditions, to decide how high you want it set at. I set mine at around 13V, as I don't usually spend a lot of time in traffic. If I did, I would probably increase it a little. The fan has a high current draw, which can put a lot of stress on a battery, that is not being charged.

Simply turning your bike off is not always an option and can create other problems. Depending on the traffic flow, it can sometimes be making matters worse. The constant use of the starter will not only be bad for the starter, but will also drain the battery faster. In the earlier gens it also cuts power to the fan, which can make over heating more of a concern. If I know that I'm not going anywhere soon, I will shut it down, of course.

As for the stat, yes it seems to act like it's stuck open, but several members have installed new ones and saw no changes. They have been running this way for 20 years and with any luck, the next 20 will be just as great.

Cheers

 

I suggest you check out your bike's service manual. Under setting idle. I can tell you using a multimeter is not part of the process. Honda gives you a value plus or minus 100 rpm. That's it. There's no caveat about "well if you're sitting in traffic...." You'll also notice voltage specs for numerous coils etc are given at idle.

My 99 idles right around 1100 - 1200 which is factory spec. I've sat in plenty of summer gridlock, never had the battery die. Setting your bike to idle at like 1500 for fear of a rad fan is an old wive's tale. You're just wasting gas

 

While true (6th gen is 1200rpm +/- 100 I believe -- and I'm not suggesting / condoning setting the RPM any higher than what the manual suggests) ... you can test using a meter to see what the voltage is coming out of R/R at idle vs. resting. If it's too low, you may have other issues ...

You'll learn if your charging system is working as it should at the "appropriate" OEM suggested idle RPM with a digital multi-meter.

 

its fine, I have had twelve of the 4th gen and only one ever reached halfway up the gauge when the fan kicked in, most ran were yours is

 

Just a small note of caution: if the coolant level is too low, you can't depend upon the temp gauge's reading to be correct. :confused-new:

 

Hello all. I have got the MOT test done and now fully legal. Never had a vfr so I was surprised at how hot the frame members got by my knees. The coolant level is ok the gauge goes about half way then the fan cuts in ok. The mot tester was a Honda technician and said all is well the 90 to 93 models all behave the same according to him. Cheers