2005 S4R thermostat question

[DucHead]

Gee-whiz - it's been a while since I posted.  I'm still riding my Monster and a bevy of Suzukis. 

I read through a few thermostat threads on the board, but didn't see exactly what I was searching for... dMy Monster coolant temp gets quite high (up to 200°F while riding), and I thought perhaps the thermostat shit the bed. So I drained the coolant and removed the thermostat and it opens at ~165°F. I cycled it a few times and it seems to be working although the opening temp seems a little high. I'm going to flush the system with 1:1 vinegar:DI water once the new silicone hose kit arrives and I re-assemble everything.

I believe that the two sensors that connect to the unions are to trigger the radiator fans, so I don't think that could be a problem.

Any thoughts?

[Duck-Stew]

IIRC, one is the fan switch (on/off through a relay) and the other sends the temp (variable voltage signal) to the ecu.

[ducpainter]

I might not have a ton of relevant information to add, but my track bike, that has no fan, runs at 180 while moving. No clue about the thermostat condition.

[DucHead]

Thanks, gents!

[koko64]

It's worth investigating thermostats for both coolant and relays for fan operation that cut in earlier. I've had to do this with both Triumphs and MV Agustas that don't like our climate down under. In the case of MVs bikeboy altered the ECUs fan programme to engage earlier and stay on longer. There are also high flow fan blades around the market. On both a 955 Daytona and F4, I have modified the coolant thermostat to work at a better flow rate. Too fast and the coolant doesn't loiter in the radiator long enough to exchange enough heat and too slow it doesn't keep up with motor speed and corresponding increases in heat. The ID of a coolant thermostat helps regulate flow so you would need to live in a very high temp climate to remove it altogether. There is a risk of the coolant moving through the heads too quickly as too high a flow rate may also not grab enough heat from the heads.

There are also manual fan switches available.

[greenmonster]

I have modified the coolant thermostat to work at a better flow rate.

Very interesting, how did you do that?

[koko64]

I removed the thermostats inner sprung section but left the body so that the inner diameter could govern the flow rate. I experimented with  stock, modified and no thermostats and recorded engine temps at various rpm during the same weather temps.  Sometimes you can find a thermostat which activates at 70-75 deg C rather than 80-85 C.

I can't recommend the same mods across the board for bikes because it relies on various factors like radiator capacity, water pump rate, impeller design, and radiator fan design. I used "cored" thermostats on two bikes, uprated fan blades on another and one bike had an uprated water pump. Another bike had a cored thermostat, uprated fan blades and the ECU fan programme was altered as a factory option. A summer season race bike (NC30) had the thermostat completely removed but it had no fan. A Brutale had an altered ECU fan programme by bikeboy and high flow water pump. A Daytona 955 had a cored thermostat. There were different combinations of cooling mods. It required testing for each type of bike on a case by case basis. You can imagine the wrong modification may not let the bike warm up properly in cool weather or run too hot at certain rpm.

[Howie]

200^oF is not overheated, just damn uncomfortable for the rider.  For your comfort, a lower temperature fan sensor or manual switch.  Do check your CO level.  Lean = heat.

[DucHead]

200^oF is not overheated, just damn uncomfortable for the rider.  For your comfort, a lower temperature fan sensor or manual switch.  Do check your CO level.  Lean = heat.

Thanks, Howie!

[greenmonster]

Thx f info, Tony!

You can imagine the wrong modification may not let the bike warm up properly in cool weather or run too hot at certain rpm.

That`s why I haven`t dared change thermostat on my MTS although it runs too cold most of the time in Nordic climate.
Covering the cooler year round is a pretty good compromise IME.

What would you do to raise engine temp 10-15 degrees on a 1100DS, Tony?
Coolercovering a bit too much McYverish... (Pardon thread jacking)

[koko64]

I had my seat upholsterer make up some oil cooler covers for M900's that experienced carb icing during our humid winters. I also have used neoprene fork protectors or exhaust wrap on the carb manifolds to prevent icing in the CV carbs.