cooling sys question

this bike is new too me,after riding for about 35 minutes cause thats the longest i have riden it so far,the temp gauge barley moves off the bottom mark,coolant hoses don't seem that hot either,outside temp is about 20 deg c .just wondering if they should run at a certain temp or if it veries

I dont like to diagnose by forum, but sounds like a stuck thermostat........

Thermostat is either stuck open or non-existent.

My VFR700 runs pretty cool too, the temp gauge barely moves until I sit in traffic. The fan finally came on in traffic this week, for the first time ever. But I did test it out the easy way when I first got the bike, by idling it in the driveway and standing beside it, till the temp gauge finally went up, and then till the fan came on.

That's the easy test.
But another way you can test it is to remove the thermostat, suspend it from a wire wrapped around a wooden spoon or something, and let it hang in a pot of hot water with a candy thermometer in it. Bring the water to boiling and watch the thermostat. Note the temp at which it opens, and the temp at which it is fully open. Most thermostats have a temp stamped in them, that is the number at which it should begin to open.

That said, thermostats do go bad with time. They do wear out, and they generally don't cost that much, especially if you can find an automotive one that fits with the right temp range and avoid buying one from Honda. Also remember the o-rings at the thermostat housing are 25 years old and you may as well replace them.

Since my VFR did cycle coolant as I watched through the filler cap (per the manual's checklist), and since the fan came on at the appropriate time, I'm still running my 25-year old thermostat for now.

These carbureted bikes run pretty cool. My Magna never went over 170 degrees.

running rich would make it reasonably cooler aswell

ok thanks everyone i'm just trying to get a feel for this bike,gunna try letting it idle for a while but for now i am stuck waiting for a new reg/rec and from what i hear this is a pretty common failure,diddent have to really do any testing there was a giant crack in it so i assume that is my charging problem,the old girl has 82000k on it,but still looks great,runs good and never misses a gear so i figure its worth paying some much needed attention to.Thanks again ya'll

[image: View Post]corpsy, on 12 May 2011 - 06:56 PM, said:

ok thanks everyone i'm just trying to get a feel for this bike,gunna try letting it idle for a while but for now i am stuck waiting for a new reg/rec and from what i hear this is a pretty common failure,diddent have to really do any testing there was a giant crack in it so i assume that is my charging problem,the old girl has 82000k on it,but still looks great,runs good and never misses a gear so i figure its worth paying some much needed attention to.Thanks again ya'll



I would still put a new t-stat and gasket in it, along with new coolant.

[image: View Post]coffeebrake, on 12 May 2011 - 08:53 AM, said:

My VFR700 runs pretty cool too, the temp gauge barely moves until I sit in traffic. The fan finally came on in traffic this week, for the first time ever. But I did test it out the easy way when I first got the bike, by idling it in the driveway and standing beside it, till the temp gauge finally went up, and then till the fan came on.

That's the easy test.
But another way you can test it is to remove the thermostat, suspend it from a wire wrapped around a wooden spoon or something, and let it hang in a pot of hot water with a candy thermometer in it. Bring the water to boiling and watch the thermostat. Note the temp at which it opens, and the temp at which it is fully open. Most thermostats have a temp stamped in them, that is the number at which it should begin to open.

An even easier test (considering we are not likely to see a stuck-closed thermostat on a bike that is slow to heat up) is just to look at the thermostat: if it's stuck open, that's your problem right there...

Ciao,