Running cold... Thermostat?

[nosaint7]

Weather finally cooled down...  (to below 80's!).  Had a chance to get on the highway for more than 2 miles.  Engine had been fully warmed up (temp gauge smack in the middle) before I got on the highway.  Got off the highway 45 miles later and the engine stalled as I came to the stop sign at the bottom of the ramp.  Noticed temp gauge read just above "ice cold".  Gave it some choke and she started right up.  Noticed on the way home that temp gauge showed temp dropping fast after about 2 miles at 65mph.  Has the thermostat croked?  Or, is there something else I should check?   

[F-106]

I rode this morning and the temp was mid 50's. The bike never got into the normal range at 55MPH and above. I would say start the bike and let it dun in the driveway and see what happens. If the guage rises and the fan come on then you know. I would also check the coolant level just to be on the safe side.

[nosaint7]

Fan comes on just fine when the bike warms up enough.  I'm wondering if the dang thermostat has stuck "open" - causing an open loop thru the radiator.  Any way to tell? 

[SteveJ.]

Get the bike back on the highway, doing a steady speed around 55-65. Watch your temp gauge for about five miles, to get an idea of what's happening. Showing just above ice cold(the "C" mark?) is normally a bit too cold, but after coming off the highway, the stat probably didn't close in time to reflect the less heat the engine was creating. Doing the above test will give a better indication of thermostat action. What most do in the cold is kinda cycle up and down within the lower side of the range.


Now, all that being said, your bike is 8-9 years old. If it's not been done, this winter may be a real good time to go through the entire cooling system, replacing all hoses, clamps, O-rings, thermostat, radiator cap, and of course, the coolant. Then you will know where you stand on this stuff. Having to disassemble a good chunk of the bike away from home over a $3 hose would/does really suck. BTW, I installed a 195* stat('83 Honda Accord), I like the way it keeps the temp up in cooler weather and it still works fine in the Floriduh summer heat.

[nosaint7]

As the bike currently only has 4400 original miles on it, I'm sure none of those parts have been replaced.  Previous owner did a coolant replace, air filter replace and oil/filter change just before he put it up for sale.  This was one of those hardly ever ridden "garage queens" - PO's new wife forced sale of multiple bikes after her 1st ride scared the stuffing out of her.  New tires, brake line flush and rear hub grease are already on my "winter" list - will add cooling system to list.  Any other "components" I should be suspicious of just due to age?

[Daytona_Mike]

Your bike sounds like it is running normal. Warmed up is 1/4. My temp gauge is low all the time. I added a manual switch so that when I sit at red lights  in hot weather I can turn it on long  before I get anywhere near halfway. At halfway that is when the fan comes on.  So far your normal.
If your halfway and you drive and it drops to say 1/4 to or  1/3 at the most, that is what it is supposed to do. ( just  barely off the first notch)
 These bikes do not act anything like a car temp gauge where it goes to the middle and stays.
What is your idle set to? It should be 1100rpm.
Oh , and what ever SteveJ said. He is correct.

[Mettler1]

  I very seldom look at the temp gage. The colder the it gets the lower the temp gage reads. The only time I ever had a problem was when it puked a little coolant on a hot day. The fan switch had quit working. Replaced it and fine since.

[goatmar]

Wish mine ran cool     a few minutes at a light and its hot....... that's when its 40 out......    good on cold days though.... like 10/20.......

[Mettler1]

Wish mine ran cool     a few minutes at a light and its hot....... that's when its 40 out......    good on cold days though.... like 10/20.......

   Basicly any reading between cold and  up to the red zone is fine as long as the fan turns on. If it pukes a little antifreeze make sure the fan switch is working.

[T Cro ®]

Wish mine ran cool     a few minutes at a light and its hot....... that's when its 40 out......    good on cold days though.... like 10/20.......

(1) Does your fan kick on while your sitting there waiting on the light?
(2) Is your Anti Freeze mixture higher than 50/50 mix? A/F is thick and does cause poor circulation if the mix is wrong.
(3) Has the cooling system been vented at the highest point (T-Stat Housing) to rid it of trapped air? Trapped air will keep the T-Stat from working properly.
(4) Is your Rad or Oil Cooler obstructed with road debris or caked on bugs?
(5) Has the Cowling or Inner Cowling pieces around the engine been altered or removed? Proper cooling requires proper air flow.
(6) Check the coolant tank and it's hose and routing. If the engine can't retrieve coolant as it cools down it will become lower on coolant each time it heat cycles.
(7) As long your not puking coolant at the lights while waiting and not running in the HOT zone of the gauge you've little to worry over as these engines do cycle widely between cool and fairly warm on the gauge.

[Karl]

Weather finally cooled down...  (to below 80's!).  Had a chance to get on the highway for more than 2 miles.  Engine had been fully warmed up (temp gauge smack in the middle) before I got on the highway.  Got off the highway 45 miles later and the engine stalled as I came to the stop sign at the bottom of the ramp.  Noticed temp gauge read just above "ice cold".  Gave it some choke and she started right up.  Noticed on the way home that temp gauge showed temp dropping fast after about 2 miles at 65mph.  Has the thermostat croked?  Or, is there something else I should check?

As the other guys said, normal for these bikes to vary temp a lot.  This is because it has a non-bypass cooling system.  If you have occasion to have the stock t-stat out, take a look at the small hole in it.  Very little flow when the t-stat is closed, not real effective system.   The KLR system is the same way.

 It can be converted over pretty easily to a true automotive style bypass system.   This will improve the temp stability a lot.

[T Cro ®]

It can be converted over pretty easily to a true automotive style bypass system.   This will improve the temp stability a lot.

Please do tell....

[cc_ryder]

I believe you are correct. The thermostat is remaining in the open position. Most of the problems listed so far deal with overheating with exception of the dilution ratio. Your cooling system is not malfunctioning as we normally see, it is working too well. Removing the thermostat and a visual inspection will confirm your idea. If it is an intermittent problem you can test it in a pot of water on the range. The manual gives the temperature and valve travel range for normal operation.

I have heard of some who increase the size of the bypass hole in the thermostat, or use one with a larger hole to reduce those high temperature spikes.
All of this is relative except testing the thermostat as our "temperature Gage" has no numeral indicators on it. I guess the only temperature indicator we truly have is when the temperature sensor is supposed to turn the fan on.

[Connie Mark]

Here is a true bypass system that an inmate made for the KLR. I believe that it can be jiggered to fit any bike.

http://members.cox.net/watt-man/TB%20order1.htm

Here is the study he has performed comparing it to the stock system.

http://members.cox.net/watt-man/TB%20Testing1.htm

[Motor Head]

Fan comes on just fine when the bike warms up enough.  I'm wondering if the dang thermostat has stuck "open" - causing an open loop thru the radiator.  Any way to tell?

 Harbor Freight sells a Infer Red temp gun, pretty cheap. You can take the surface temp all over your system, including individual tubes of the radiator core. Take temp readings during the warm up cycle, on the outlet hose on the filler neck, up at the radiator, etc. If the temp starts going up at the radiator, right after starting, bad T-Stat.

[AZBiker]

Here is a true bypass system that an inmate made for the KLR. I believe that it can be jiggered to fit any bike.

http://members.cox.net/watt-man/TB%20order1.htm

Here is the study he has performed comparing it to the stock system.

http://members.cox.net/watt-man/TB%20Testing1.htm

Thnaks for the info!