I want one of these!

 

I have the Thermo-Bob on both my KLR650 and my KLX250. I believe Watt-man, and if you believe Watt-man and are concerned about longevity, you'll get a T-Bob, too!

 

I like the Thermo-bob coolant temperature plots. "After" looks much nicer than "before".

But what is the measurable or quantifiable benefit from more accurate coolant temp control? Or is this a "for your peace of mind" modification?

--
Mikko

 

I think that's a fair question. Here are five thoughts on that.

1) For anyone who knew KLRCary, the guy who invented the 685 and 705 kits for the KLR650, he was a big backer for the T-bob making the jetting more consistent.

2) I like boiling the water out of the oil, and after monitoring oil temps on these singles in the winter (I ride daily) I'm a fan of warmer oil in the winter. Less water in the oil has to be a good thing. How to quantify it? I can't - other than showing the oil is waaaay below 212F on a stock bike.

3) I've seen enough stuff about cylinder wear at cold temps (fuel falls out of suspension in the boundary layer up against the cylinder wall and washes away the oil on the cylinder, and tends to find its way into the oil easier) that more modern temps seemed to be a move in the right direction.

4) Being involved with machinists who are always fighting oval cylinder bores and the efforts they go through to generate a round bore during operating temp, it would seem that directing a cold stream of coolant at one point of the liner (instead of the full circle) is bound to end with a slightly oval cylinder, which piston rings will not follow. The KLR seems to have a reputation for oval cylinders, particularly at the bottom where the water comes in (who would have guessed?!). I don't know if the KLX has this issue to the extent of the KLR, because maybe we don't see a lot of guys with 40,000 plus miles on KLX250s to notice.

5) Being a mileage weenie, I've noticed mpg improvements in my cars when replacing a 160 stat with a 195. Instead of sucking heat out of the cylinder with the cold water, more of the energy (heat) of combustion pushes on the piston.

Since production cars have had bypasses for decades and decades and hotter stats, it seemed like this would be the natural progression for these bikes as well. Seeing those temp swings with thermocouples really freaked me out. And agreed, how much of their elimination is peace of mind? That's a great question. But the way I see it - even your engine doesn't like a cold shower!

 

Nice presentation Watt-man, just as persuasive as the one which lead to my buying a ThermoBob for my KLR.