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Hotter Thermostat Available?

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uspspro

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Nov 7, 2011
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First, a few notes:

- It looks like the stock Gen II thermostat is 160 deg F.
- On cooler days, it seems like a I am barely at 160.
- On the other end of the spectrum, the fans definitely come on a little to late (more reactive, than proactive).
- In general the range of operating temps is pretty wide.
- The bike runs richer at temps up to 160 deg F

Some things worth considering:

- Hotter engines are more efficient
- Keeping the temp over 160 well help power and efficiency
- Turning the fans on sooner will help out with controlling excess heat in stop-and-go
- Keeping the range tighter, and closer to optimal, is always a good thing.


I've read about the fan controller mod on this forum, and think that its a great idea for the high end of temps.

But what about the low end? I've read about some riders using block offs (cardboard) on the radiator. Which can definitely work, but a more elegant solution would be to get a 170 or 175 degree thermostat. This would allow for quicker warmup, higher temps on cold rides and not take away from the efficiency of the cooling system at temps over 180 or so since the thermostat would be fully open at that point (with no blockage on the radiator).

Does anyone know of any hotter thermostats that will work in our Gen IIs?

I bet this could give us a couple MPGs without sacrificing power or smoothness.
 
Why not just trust the Yamaha engineers? Haven't heard of any engine failures due to operating temps being too high/too low. Seems that Yamaha has the engine temperature management dialed in to good results.
 
Things are not always designed perfectly from the factory. Hence the need for revisions on newer model years, or people getting good results from tuning/mods, etc..

Yamaha engineers have budgets, design constraints and compromises.

It's common in the automotive world to run thermostats +/- 10 degrees.

I think that there a few MINOR teaks that might improve the efficiency of this engine. (1) A little more timing advance, (2) proper operating temps, (3) running the appropriate octane fuel for the timing map being used, (4) some slight aero tweaks [better windscreen, etc]

I don't see the harm in running a higher temp t-stat and closely observing the temps, it's easy enough to change back. If it works well, then you don't have to think about whether or not to run with a block off or not. It would just work. Sure, possible outcomes are speculation now, but results are unknown until their tested.

Loosenut, I will probably try that if no replacement thermostat is discovered.

Thanks.
 
Yeah, we are not faced with the same problems here on 45 degree nights and mornings. The stock cooling system does it's job really well actually. Tonight was pretty cold, and the temp was solid 160 with barely any fluctuation.

This tells me that it the thermostat were 165, that it would do a pretty good job of keeping it there.

I am actually thinking something like 165 would be perfect, just a few degrees warmer to keep temps away from the enrichment threshold on cooler rides.

Blocking off the radiator (at least in our climate) would result in the thermostat closing more, and fighting that effort, until you covered it enough to regulate the temp. Whereas changing the thermostat makes the system work around a different target temperature.

It's not a huge deal anyway.. I mean the bike rides great. I just posed the question, to find out if someone knew of any other thermostats that fit (for example if we shared the same design as another bike or a car). If someone does, that would be something cool to test out. If not, then no big deal. I will ... :rmwl:
 
Evitzee said:
Why not just trust the Yamaha engineers? Haven't heard of any engine failures due to operating temps being too high/too low. Seems that Yamaha has the engine temperature management dialed in to good results.
Click to expand...

I agree.....and in addition, f--ing about with them generally makes them unreliable.
 
uspspro said:
Blocking off the radiator (at least in our climate) would result in the thermostat closing more, and fighting that effort, until you covered it enough to regulate the temp. Whereas changing the thermostat makes the system work around a different target temperature.

... :rmwl:
Click to expand...

Blocking the radiator changes the cooling capacity of the cooling system- it reduces capacity - it doesn't regulate temperature. This can be risky. If the engine needs more cooling under some conditions- weather, idling in hot traffic, high speed, ... - the cooling system capacity has been lessened. This could result in trouble - overheating and damage.
The engineers planned well for the engine's health. To try to re-engineer things is not always wise.
 
uspspro said:
It's not a huge deal anyway.. I mean the bike rides great. I just posed the question, to find out if someone knew of any other thermostats that fit (for example if we shared the same design as another bike or a car). If someone does, that would be something cool to test out. If not, then no big deal. I will ... :rmwl:
Click to expand...

I thought it was a good question. Adjusting the operating temperature is why they sell differently rated thermostats. I'm guessing by the responses that no one knows, because if it was just that it was wrong to change anything on our carefully designed bikes they would all be stock.

Dave
 
I found, by running a wideband all of the time now, that the bike runs real fat till the water temp goes above 163-165. I now run a radiator block on about 40% of the surface area when outside temps get below about 65.

Beast
 
Looks like our housing is external. There are tons of universal external thermostat housings out there that accept more common (GM, etc) automotive thermostats that have many different temps available.

Best case would be that there are other thermostats that fit our housing, otherwise the housing could just be replaced with a universal.

I came across this online --> Thermo-Bob™ Remote Thermostats with Radiator Bypass - No more KLR running cold
(Not saying I want this whole kit, but it is interesting, and tons of ADV riders are getting good results) He offers it with a 180 or 195 degree thermostat.

TBFig08.jpg
 
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