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Thermo-Bob 3

17K views 37 replies 8 participants last post by  DPelletier 
#1 · (Edited)
Here's a picture of my Thermo Bob Original in the usual place:


It works great and always has. It's perfectly positioned and doesn't shake, rattle, or roll. The problem is that it tends to get in the way when I need to get the valve cover off. Since I'm constantly fiddling with stuff, that's a nuisance.

What I wanted to do was put the new Thermo Bob 2 on, but I wasn't sure it was going to fit underneath the IMS tank. I contacted Watt-man and asked.

Sure enough, it won't. Underneath the IMS 10 tank there is about 3/4" of clearance between the thermostat housing and the tank. Bill told me the Thermo Bob 2 housing is one inch thick.

He suggested that I might try a Thermo Bob 3, which he originally designed for the Ninja 250 and which is used on snow machines and such like that.

He very kindly set me up with this kit:


The only thing special about this kit is that he didn't install the bypass hose fitting and added a 90° and 45° fitting so that I could fine tune the bypass hose placement.

I'm going to try placing the TB3 where the current bypass fitting is...


...and put the bypass fitting where the original Thermo Bob was.

Since this will be regulating the cooler coolant coming out of the bottom of the radiator Bill has installed a 185° thermostat.

The TB3 has a port in it for a coolant temperature sensor. I've ordered the proper sensor from Trail Tech and will install it. It will be interesting to see the comparison of the temperature at the TB3 vs the temperature at the head and the timing of those temperatures. The sensor should be here tomorrow.

Working at the Speed of Tom™, I should be playing with this next week.

Tom
 
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#3 ·
Dave,

Mine is a Gen 2 with the IMS 10.

If you have at least an 1 1/4" clearance between the housing and the tank you should be goo to go with the TB2

Let me see if I can get a picture of the area I'm talking about.

Tom
 
#6 · (Edited)
Cute little jeeter, innit?



(loosely installed, crush washer not shown)

I'll be wiring this in parallel with my oil temperature sensor with a switch to select between the two.

Tom
 
#7 ·
Installing the TB3 into the lower hose, with the 185 'stat is basically what Watt-man does for the Versys 650.
My friend Mike is very pleased with his Versys 650 Thermo-Bob.
Mike may give us a Versys/Kawa. oil sample to compare to KLR's, yet this year.
 
#8 ·
That'll be good info. Tell him to hurry up! Ride more! Faster!

Tom
 
#10 · (Edited)
I've got it mocked up.

The bypass T is located much lower than where the Thermo Bob original was:


While the Thermo Bob 3 is located where the bypass T was:


Another peek at the Thermo Bob:


I am awaiting delivery of a new pair of hoses. I swear I had an extra pair around here, but danged if I can find them.

Need to work on lighting for the final pictures...

Tom
 
#12 ·
It is downstream, as is the sensor port.

I'll double check it on final assembly, in case I'm suffering from recto-cranial insertion and my clear plastic navel cover is foggy.

Tom
 
#13 · (Edited)
Here re the differences in size and construction:



And the bypass flow path:


Tom
 
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#18 · (Edited)
Tom,
Can you please 'add' direction of FLOW arrows to the 'yellow-wire' pics and 'upper' hose, 'lower' hose NOTATIONS!

I would also like to Thank, Normk!
For finding the Chinese source for Thermostats to make this Modification possible!

ps,
 
#15 ·
Yes. Coolant will flow out of the head through the upper radiator hose. The bypass fitting is in that hose. The bypass hose will run down to the TB3 and around the T-stat, which is a 185°F unit.

When that bypassed coolant reaches the 185°F range the t-stat will open, allowing full flow of coolant from the bottom of the radiator to the pump.

Schematically, it will look like this:


Tom
 
#16 ·
I was asking for the benefit of those following your path. It would be easy to in inadvertently pipe it using the "standard" inlet/outlet arrangement.

Your arrangement is a clever one for those of us using the IMS 10.7 gallon tank. In my case I had already install a bypass line from a fitting tapped into the head. So, when Watt-man came out with the 195 deg. t-stat that fit the stock housing, I just popped one in and my big tank fits fine. With the advent of the t-bob3, I recommend your approach over mine.
 
#17 · (Edited)
If I had more confidence in my ability to drill and tap where there is no room for error I might have gone your route. My work area is called the Shop of Horrors for a good reason.

I cannot claim cleverness for this; it was Watt-man's suggestion. The sketch above is his.

New hoses (to replace the spares that are lost somewhere in the Shed of Horrors) are supposed to be here tomorrow.

Tom
 
#20 · (Edited)
Kind of.

So, Watt-man did/does offer a 185 thermostat for the Original T-Bob. It is used in the Versys kit, which uses the backward flow pattern. T-Bob in the lower hose.

So with a 185 stat in an original housing, couldn't one just trade locations of parts?
 
#21 · (Edited)
I had the original T-Bob totally bassackwards.

Fixed it.

The original T-Bob won't fit at the lower location because it has to go in backwards. That puts the fat, flat end on the down side where it won't fit between the hose at the front of the engine and the headtube.

Tom
 
#22 · (Edited)
While I'm doing this because it's fun, interesting, and keeps me out of the bars, the real intent of this is for someone who has an IMS 10 and no T-Bob.

This is an option for such a person, as the T-Bob 2 won't fit. Installing the T-Bob 3 in the lower hose fits better, overall, than the original does in the upper hose.

Using the original T-Bob backwards in the lower hose is not a part of the equation.

Tom
 
#23 · (Edited)
The new hoses arrived, there was a round tuit on the counter, and the planets were aligned.

First thing, clear the front of the engine:



There were a lot of fits and starts, trying to find the perfect position and the perfect hose cuts, but I finally wound up with a good mock-up and pulled it out and built this, working on getting all the hose clamps correctly positioned for easy access and non-interference:


Installed:


Functionally it works identically to the original Thermo Bob.

It fits really nicely and doesn't touch anything. Should be good to go.

Tom
 
#24 ·
It took a while, but I finally got a 1000 miles on the 195° thermostat.

I have ridden in 25°-30° with snow, mid 30°s clear and dry, 40°-60° with rain, and 55°-70° clear and dry.

The temperature at the T-Bob is always ~188° and the head temperature is rock steady at what looks like between 215° and 220°. Never varies.

Tom
 
#26 ·
It depends.

The oil takes forever to heat up.

In 70° ambient with the Poor Man's "Block Off The Engine" the temp will be up towards 195°-205° after 20 miles and it will finish off at 215° after about 30.

In 50° ambient in might only be up to 180° after 20 miles.

Without the BOTE mod it takes a lot longer, of course.

I tried to judge how long it took to get up to a stable temperature on the last trip. It seems that a half hour of 65-70 mph will do it, and the final temperature depends on the ambient conditions.

Running up the Grapevine at 30-40mph (max for conditions) I watched the oil temperature drop from about 185° (about 50° ambient in the rain at the bottom of the hill, 65mph) to 150° (25°-30° and snowing as I went up the grade). That drop occurred in about 5 miles.

These are rough numbers from recollection, as I didn't specifically look into this. I remember being surprised that it took as long as it did.

I need to find a way to elevate and stabilize oil temp, keeping it over 200°.

Tom
 
#27 ·
This is Half of the reason that I do not ride my KLR the 1.1 miles to and from work every day! My pick-up has a proper Positive Crankcase Ventilation system on it. No Milky OIL. Normk is working on this issue!

The $400 exhaust system is the other Half of the reason! vs $70-$100.00 for the pick-up.
 
#28 · (Edited)
I am enjoying reading how you guys really get stuck into your bikes!

This is Half of the reason that I do not ride my KLR the 1.1 miles to and from work every day! My pick-up has a proper Positive Crankcase Ventilation system on it. No Milky OIL. Normk is working on this issue!



The $400 exhaust system is the other Half of the reason! vs $70-$100.00 for the pick-up.

(British humour warning - following comments made 'tongue in cheek')

You not tempted to walk the 1.1 miles? Lots of benefits:
- engine at full working temp within 2 blocks
- exhaust system good for life of 'vehicle'
- exhaust gases able to flow freely (and colleagues appreciate these being burned off prior to arrival)
-daily operation positively extends 'vehicle' lifespan
- $30 annual budget for 'tyres' needed
- opportunity for walk through coffee on route
 
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