Dan M

That is what the clarification was about 5 or so posts up. I knew you wouldn't get it. I meant not out in the wind. I felt the need to clarify because you, in your wisdom think the factory sensor reads temp from the exposed hexagon which is the only brass part that is out in the wind. You and Dave have a great deal of time to split hairs.

Right Dave I'm talking about the SENSOR. not the holder. The holder is not vented, all of the holders are closed. The factory designed the set up with a small AIR gap so the sensor is actually measuring air temp just a few millimeters off of the cylinder head surface. (man has this been gone over) As designed, the brass sensor is reading AIR temp inside the holder. And for those who don't know the function of one of these, the brass hex on the outside of the holder does not read the temp. It is the probe that resides down inside the holder. The plastic sensor has holes in the bottom. You can see the thermistor in there. So, if you are reading air temp just off of the head surface as it is designed and mapped, the plastic sensor with the holes is better. You are reading air temp with an air temp sensor. Just to clarify, the air temp that is being sensed is not the surrounding atmosphere. It is the air inside the holder in very close proximity to the head surface.

Yes Dave it is. The bottom of the sensor is open to air so the thermistor is exposed. Makes for more accurate measurement of surrounding air. Get it? Funny how you have a strong opinion about a device you don't know much about.

Hey Greg can do math! How impressive.

There are statements and contradictions in your last post that illustrate your lack of knowledge about how these sensors work and how flawed the MG system is. You should reread it and compare it to your previous writings. I don't have the time, energy or interest to respond to this at the moment. Maybe later....

You are assuming none of the players have side bets on how long it will last....

This is the crux of it. It is enclosed in plastic, blocking the air flow. It's thermistor is encased in brass which is designed to be submersed in moving coolant which would change the temp of the brass quickly. As designed the sensor is sitting in a small air pocket that is attached to the head. It will lag in response time because the head heats the air which heats the brass which heats the thermistor. The reverse is true when cooling. An open to the atmosphere thermistor can read the surrounding air immediately without having to heat and cool the brass encasement. All major manufacturers use a plastic body, open thermistor when reading air temp. All RH is doing is the same thing. He is simply reading the air temp right off the surface of the head with an air temp sensor rather than a coolant temp sensor. It is simply a better way to read air temp. Is it a requirement? Of course not, it is up to the individual. Mine developed one on very hot days only after adding goo to the factory sensor. This tells me something and it is not too hard to figure out. This is true enough.

Remember the head is being cooled by air flow when moving and the temp rises when stopped. The sensor is not up in the wind. It is enclosed in a holder. Some are even enclosed in a holder and packed with grease. They lag behind. They get heated all right but not cooled as fast. If the coolant sensor was submersed in moving coolant that would be a different story. My point is a temp sensor that allows air to flow around it, (plastic and vented as what RH has settled to) it will be quicker to react to head temp. As the head heats and cools it also has to heat and cool the sensor. Without coolant flowing around a probe that was designed to be submerged in liquid, the response will be slow. If you use an air temp sensor that will change quickly with the air around it, lag will be less. But I am repeating myself, again. Perhaps taking a different path to this whole temp sensing thing rather than following what was put out as gospel is bruising someone's ego.

There is clearly a problem. The root cause is a poor design. The whole "add goo, switch to brass" temp sensor bandwagon initiated by others than RH suggested that the bikes ran too rich. Others complain that the bikes have issues when extremely hot (too lean) so evidently there is a temp sensing problem. If most people's factory set up works well as you suggest, why all the sensor tampering? Why all the PC3s? Why all the tune boys? The system is flawed. The system needs an amount of tuning. You like to call it hacking but any altering from factory is a manner of tuning be it better or worse. A proper map on with a PC3 will not compensate for temp. If the temp sensor is faulty or does not react quickly enough the "proper map" will still be flawed. If any modification of any motor in any way causes it to run better or eliminate a particular problem that you are trying to get around then why not? Why not do anything if it solves the problem you are trying to solve or makes the improvement you are trying to make? Seems like personal choice to me. Oh yea, that last time I checked, points are awarded around here for "bodges". Perhaps you are on a higher level and should not rub elbows with the rest of us.

Is this the right place for an argument? On this topic I agree with R. What he's done makes perfect sense and parallels what I've experienced on my own machine. I don't see how someone can constantly argue the idea of the sensor's mass. Do you really think that a sensor that is made of plastic with the thermistor exposed to air does not have less thermo mass than one that has the thermistor encased in brass? Do you really think that the brass will change temp as fast as the surrounding air? Do you really think it is a good idea to use a coolant sensor on an air cooled head? I mean do you? Really? Or is it just an argument. This thread reminds me of this: http://www.youtube.com/watch?v=k3HaRFBSq9k...=PL&index=1

* Without the side effect of horsepower

Is that what is referred to as a lady's aid?

Quite easy, go for it. Do a search or if needed, a quick walk through is available for the asking.

Good one Raz

I was under the impression we were discussing non feed back Moto Guzzis here. Like yours, mine, and Ratchet's. I don't understand why you or I or Ratchet would argue about a system we are not using. (feedback) My BMW uses a O2 sensor and a MAP. It is a feedback system as are newer MGs. My friends Ducati uses a O2 and a MAP. The newest Ducatis use 2 O2s. BTW, BMWs especially R1100 and R1150 (pre twin spark) models have a lean surge. Go to any BMW forum and search "surge" Ducati's air cooled feedback motor also is prone to surge. Enough so that Jason Borders of Boulevard Performance has developed a manipulator to fool the ECU into adding fuel by manipulating the O2 signal. His product is called "Fatduc" appropriately enough and is marketed to Ducati owners. He let me try one on my Aprilia (because guess what, it has a lean surge about 3000RPM and, it is liquid cooled) Unfortunately the Ape's ECU recognized that too much fuel trim correction was needed and it would trip a lean code illuminating the MIL. Ran great with it though. BMW's air/oil cooled motors keep a very steady temp for a mostly air cooled motor. Mine comes up to mid gauge (oil temp) and stays there, pretty much no matter what the weather is. I have no idea what HD or Buell does.

My point is, comparing a feedback system that uses multiple inputs to our non feedback system is like comparing apples & oranges. So far as engines are engines are engines. Comparing the MG 2 valve to say for example, Yamaha's new R1 motor is well, like comparing apples to um oranges. I didn't realize Yamaha went to FI on their air cooled cruisers. I don't follow the cruisers much. Looks to be a feedback system with more modern injectors to boot. Again more sophisticated than what we have. Funny, the Japanese didn't even try to use a non feedback system. Please realize when I refer to the MM unit on our machines as "antique" or "WW2 era" There is a bit of tongue in cheek there. (hint - there were no MM ecu's for M/C FI during WW2) Ducati's 900s had their fueling issues, they surged as well. We all know temp is important. There is about 50 pages here about it. I fully agree that a proper map will solve running issues. However, with a system such as this you really will have a hard time having both good running and emission compliance. It is precisely what limits manufacturers maps. The reason everything is lean and runs poorly out of the box is emission compliance. More modern systems can deal with both. Hell, most carb'd bikes didn't run at their best as delivered because they were too lean. I don't want to speak for Ratchet but I believe his exercise is aimed at getting better economy while retaining good running. While his bike ran good before he's taken the time to try to improve it. (more accurate fueling)

What air cooled Yamaha and Suzukis are fuel injected? Yes, quite silly.

You are comparing apples and oranges. I don't think any of the three you listed use the antique M/M ecu the pre feedback V11 uses. Ducati uses Siemens, BMW actually senses oil temp. They are both feedback systems with map sensors. I gladly know nothing about Harleys. That said, other bikes have fueling issues as well. Most early and some modern fuel injected bikes have issues out of the box. Mostly it is because of emission regulations and they are too lean. Most every other system uses more sensor inputs. If you add an O2 and a MAF or a MAP into the mix the temp is not as important to the big picture. The Guzzi makes do (sort of) without that stuff. As we've gone over 600 times, more heat sensed means leaner. Leaner generally means more fueling glitches. again:

I'll assume that you will use a silver stud and drill a hole through the center to make it hollow, eh?

Track down the hissing. Possible vacuum leak. Look for cracked T-body boot, loose fit from boot to t-body, broken hose or missing cap. Dribble some carburetor cleaner around the noise and listen for hissing to change and rpm change. Careful with flammable spray around ignition wire and hot stuff. (that's why I said dribble)

Tough to prove. The regular beer consumption while riding offsets any brainpower gain.

GM has a pig-tail readily available

Really, I think Ratchet has hit on the best temp sensor set up for this non feed back system on an air cooled engine. An air temp sensor actually sensing air temp (yes, I know the air is not moving). Beyond that, the difference between aluminum and copper and brass for a stud is just splitting hairs. The system is not that particular. Getting past the enormous lag of the factory set up and having an air gap at the same time pretty much covers it. Not that anybody ever splits hairs here...