Thermostat

[b1rks]

Rescently Purchaced 98/Valk. Bikes great. Been doing maintanence per manual schedule. Some things previous owner neglected. Coolant being one. Changed The Coolant. I was at a Local Bike Shop rescently the mechanic tells me I should be replacing Thermostat every couple years. Bikes got 60,000 KM.  Does this guy know what he,s talking about?

[Bone]

Honda recommends changing the coolant every 2 years. I didn't see the thermostat mentioned.

[98valk]

Rescently Purchaced 98/Valk. Bikes great. Been doing maintanence per manual schedule. Some things previous owner neglected. Coolant being one. Changed The Coolant. I was at a Local Bike Shop rescently the mechanic tells me I should be replacing Thermostat every couple years. Bikes got 60,000 KM.  Does this guy know what he,s talking about?

not needed to be changed unless it stops working, when is that?, only it knows. not being smart but thermos rarely go bad and there is no set time frame when they would. Radiator pressure caps are more likely to lose their pressure rating before a thermo goes bad.
I use www.evanscooling.com  no worries about rad cap or corrosion, its a lifetime coolant.

[b1rks]

Thanks one less thing to be concerned about.

[Chrisj CMA]

Rescently Purchaced 98/Valk. Bikes great. Been doing maintanence per manual schedule. Some things previous owner neglected. Coolant being one. Changed The Coolant. I was at a Local Bike Shop rescently the mechanic tells me I should be replacing Thermostat every couple years. Bikes got 60,000 KM.  Does this guy know what he,s talking about?

not needed to be changed unless it stops working, when is that?, only it knows. not being smart but thermos rarely go bad and there is no set time frame when they would. Radiator pressure caps are more likely to lose their pressure rating before a thermo goes bad.
I use www.evanscooling.com  no worries about rad cap or corrosion, its a lifetime coolant.

I agree with CA........if you are not having temp issues then leave the thermostat alone.  Its not that big a deal (more work on the IS) to change one.  I have 106,000 and never a temp issue and original thermostat.  I do change the coolant every couple years and it always looks as new coming out as the fresh going in

[b1rks]

yea I agree with that. I got same feeling when I changed coolant as changing oil. Why am I doing this ,this stuff looks like new. I had older bike before allways needed stuff done. I,m regonizing the absolute reliability of the Valkyrie.And that allot of maintenance is easy and easy to get at. Kind of like my 95/GM pickup.

[alph]

I felt my cycle was over heating this summer so I changed my fluid, hoses, and thermostat.  I guess I would rather be safe then sorry when it comes to keeping an engine cool, less trouble with a cooler engine right?

Here’s what went wrong!! 

While checking the thermostat two of the three bolts broke!  I was able to drill out one of the bolts, the other was so badly rusted in the housing that I stripped the threads out completely!  I ended up welding in the threads, drilling it out and re-tapping the hole.  Actually pretty fun since I have access to an aluminum welder, and mill at work.

I put in a 160-degree thermostat instead of the 180-degree that was from the factory with 58K miles on it.  Sure, it was still good, it opened up right when it was suppose to, I just figured I was this far into everything why not change it anyway.  Well, my mileage dropped from 33mpg to 25mpg.  I’ve since bought a new thermostat and will be reinstalling a 180-degree to see if my mileage comes back.  I’ll let you know later……

So, if you do check your thermostat, don’t be too surprised if you bust off a few bolts like I did!!  Good luck!  BTW, if you do decide to change your thermostat, ask your local auto parts store for a thermostat that is 180-degree and is 52mm in diameter, don’t forget the gasket!!  Honda wants $34 for their brand of thermostat when you can get one for about $7 from the auto store!!!!

[98valk]

I felt my....I put in a 160-degree thermostat instead of the 180-degree that was from the factory with 58K miles on it.  Sure, it was still good, it opened up right when it was suppose to, I just figured I was this far into everything why not change it anyway.  Well, my mileage dropped from 33mpg to 25mpg.  I’ve since bought a new thermostat and will be reinstalling a 180-degree to see if my mileage comes back.  I’ll let you know later…… Honda wants $34 for their brand of thermostat when you can get one for about $7 from the auto store!!!!

why did u feel the temp was a problem? what calibrated temp gage did u use?
OEM thermo starts to open at 176-183 and is fully opened at 203. So the factory engineers require a high flow 203 thermo. a 180 thermo and lower, which is only causing excessive engine wear, less performance and lower mpg. IT IS AN ALUMINUM ENGINE AND HEADS which means it disapiates heat must faster than cast iron and the reason for the oem 203 thermo. It also is not sitting in an engine compartment increasing the surrounding temps.
oem fan switch on at 208-216 and off at 199-207 for all models
temp idiot light on at 234-244 and off at 226 for all models.
So the factory considers 234 to be overheating.
My autometer gage sits at 195 when  ambient temps are 80-90 degrees going down the hwy.
From an engineering stand point u do not have a problem based on the specs from the tech manual.
have u looked into www.evanscooling.com  this is what i use.

[Chrisj CMA]

I felt my cycle was over heating this summer so I changed my fluid, hoses, and thermostat.  I guess I would rather be safe then sorry when it comes to keeping an engine cool, less trouble with a cooler engine right?

Here’s what went wrong!! 

While checking the thermostat two of the three bolts broke!  I was able to drill out one of the bolts, the other was so badly rusted in the housing that I stripped the threads out completely!  I ended up welding in the threads, drilling it out and re-tapping the hole.  Actually pretty fun since I have access to an aluminum welder, and mill at work.

I put in a 160-degree thermostat instead of the 180-degree that was from the factory with 58K miles on it.  Sure, it was still good, it opened up right when it was suppose to, I just figured I was this far into everything why not change it anyway.  Well, my mileage dropped from 33mpg to 25mpg.  I’ve since bought a new thermostat and will be reinstalling a 180-degree to see if my mileage comes back.  I’ll let you know later……

So, if you do check your thermostat, don’t be too surprised if you bust off a few bolts like I did!!  Good luck!  BTW, if you do decide to change your thermostat, ask your local auto parts store for a thermostat that is 180-degree and is 52mm in diameter, don’t forget the gasket!!  Honda wants $34 for their brand of thermostat when you can get one for about $7 from the auto store!!!!

Not sure if this would have helped.  But, when I take off the timing belt cover I go for a short ride, loosen them bolts while they are warm.....I have heard the same technique works to help get the waterpump out........would thermostat removal be easier on a warm engine as well? 

just thinking out loud

[KCvalk]

"a 180 thermo and lower, which is only causing excessive engine wear, less performance and lower mpg. IT IS AN ALUMINUM ENGINE AND HEADS which means it disapiates heat must faster than cast iron and the reason for the oem 203 thermo. It also is not sitting in an engine compartment increasing the surrounding temps"

Question:  how does running the valk at a cooler temp cause excessive engine wear,and less performance i have never heard of this before.  I have always thought the whole idea of machinery is to keep it as cool as possible or at least within the lower boarders of factory temp.  I mean this as a ligit question not a smart@ss reply.

[Bone]

Let me post a guess while we are waiting for a qualified response. The specs of an engine are based on an operating temperature. Running an engine at a cooler temp never allows it to reach it's peak performance. Horsepower, operating cost, longevity and reliability could be altered.

[KCvalk]

So then a bike running at 180-205 with the addition of water wetter, 180 degree thermostat, proper operating fan is going to have less reliability and longevity than one that daily tips the scales at 216-225?  Maybe I'm not reading up on things but its my thought that, especially with an aluminum engine that expands with heat,  you want to keep it as cool as possible.  The temp gauge on my valk has never gotten above 205 even in 90 degree sitting at stoplights,  the fan comes on around 185 and a blast furnace of heat comes off the radiator and its levels out in about 4-5 minutes.

With any car engine there is a wide line of proper operating temps I would think that since were talking 20 degrees here their cant be that large a difference to cause reliability and longevity issues?   
I can somewhat understand performance in gas milage but  how does horsepower factor into the temp of the oil or cooling fluid?  Is the viscosity of the oil that different between 190 and 210?

plz educate me here if im wrong......

[98valk]

a 180 thermo and lower, which is only causing excessive engine wear,

this is based on testing that was done in the 60s and 70s for cast iron engines. 180 was the mid point.
operating temp of oil should be at least 200 so that moisture and acid are burned off, some writtings state that some additives in the oil function best around 200. The oil is also part of the complete engine cooling system.
an engine is designed to operate at a certain temp range so that all of the internal clearances expand to as design. this helps the engine to maintain proper hydrodynamic lubrication oil film in the bearings.
the valkyrie engine was designed as a compromise, since honda doesn't know how and where the bike will be ridden.
if always in 95 to 105 or more ambient temp and hwy speed 70 to 100 mph, a 180 thermo is probally right.
When I ride 50 degrees or lower I know the stock thermo is too cold and I have to partially block the radiator to maintain a warmer engine esp in the 30 to 40 range.
A warmer engine gives better mpg.
web searches will bring most of this info up. books by David Vizard are also excellent

[KCvalk]

wow guess i have some research to do.....  cause this is totally coming out of left field to me.

thanks for the info and will start reading up on this stuff.