Hmm... I'm definitely considering in in the small list of upgrades I have coming. I still need to do a little more research on how it works compared to the stock system. Correct me if I'm wrong, but the stock system appears very simple:
Coolant flows in engine, out tube to radiator, tube out of radiator, to the thermostat, and back into the engine block. So almost a complete circle, with the exception of the coolant overflow tank. The issue, I take it, is that the thermostat can't regulate the temperature very effectively?
So the Thermo-Bob is just a secondary thermostat? But where does that other tubing come into play. I'm very familiar with my car's cooling system, but this has me baffled a bit.
Stock thermostat is removed from its housing when installing Thermo-Bob's bypass thermostat system... I recommend replacing the original thermostat cover O-ring with a new one. I had mine matched at local hydraulics supply shop.
Thermostat cover O-ring (45mm OD x 2.50mm thick) # 92055-1279 Retail $4.82, $3.02 from:
Kawasaki's claim of the Versys' "simplified cooling system" is in fact not to be bragged about, if only for its reduced external plumbing favored over a proper bypass:
Kawasaki (about the Versys engine): "Coolant is routed through the engine cases to the cylinder and head via a simplified cooling system, which reduces external plumbing. A large radiator and under-engine muffler contribute to easier heat dissipation..."
Some of us have the background and knowledge to understand the benefits of a quick warmup and consistent running temperature. Others do not.
For those who understand, no explanation is necessary.
For those who don't or won't understand, no explanation will ever be sufficient.
The literature is out there. Study it if you want.
I have no intention of getting into a shouting match with people who obviously have no knowledge of proper cooling system design.
Originally Posted by twowheeladdict
I do understand the benefits on the KLR. Single cylinder large thumper.
The part in your response I don't understand is your statement about proper cooling system design. Are you implying that the engineers at Kawasaki don't know about proper cooling system design?
Oh, they probly know, but it's a cost control thing. Sometimes the bean counters win. If you can save a nickel a unit by getting along without a bypass, they'll do it. Saw it happen a lot over my 35 years at Ford Engineering
I wanted to step in with some actual test data from my '08 Versys. What I found interesting was that the bleed hole in the Versys stock thermostat is quite large (3mm diameter), and even though the bike has a 180 stat, the bike doesn't simply warm up to 180 and sit there. Even on a 50 degree day it was always running below that 180 reading, and bouncing around every time the 'stat opened and closed. See plots below.
As for the 'stat slamming shut' vs. looking at it on a stove, the bottom line of course is what the temperatures are actually doing in the engine as a result of its motion, no matter how 'slow' it might look. Note the swings in the temperature of the coolant entering the engine (blue lines in the plot above). That data was taken every 3 seconds. I took the data from those two tests and plotted how much the inlet temperature changed in six seconds. Blue is stock, majenta is with the Thermo-Bob. For instance, at minute 13 into the ride, the inlet temperature went from 94.3 to 126.3 F in six seconds - this is when the 'stat opened (quickly, in my opinion anyway) and a hot gulp of coolant ran through the radiator into the water pump. If you don't think the coolant moves quickly on these bikes, I've tested the KLR and the coolant makes seventeen trips through the engine and radiator in one minute at 4000 rpm.
As for what this does for longevity, agreed - I don't have data other than my testing - measuring temps. The KLR, at least, has a problem with the cylinder going oval at the bottom - right where the cold water comes in. I don't know what issues the Versys has, if any. But I built one for my KLR back in 2005 because I didn't like the 160 'stat, didn't like the cold oil, didn't like the lack of a bypass. The lack of bypass was probably my biggest concern. The Versys also has no bypass, which is why we see the swings in the 'stock' temp lines.
I was quite surprised to see that the Versys didn't do what most people would think that it does, which is warm to 180F in 3 miles and sit there all winter.
... and to address the supposed "overheating" issues - the temp in the heat of summer, based on actual testing, is only 2 or 3 degrees hotter than a stock bike. Here's why:
See post #215
Keep in mind that in that post when I say my "yellow line in my plots" that's actually a black line today at the website.
Again, this is based on testing, not opinion.
If a thermostat fails closed, no matter if it's stock or with a T-bob, the engine will get hot, and the high temp light will come on. There's no difference there.