THUMPS
Junior Member
THUMPS, ridden by Dave
Posts: 92
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Post by THUMPS on Nov 26, 2008 10:51:13 GMT -5
I am installing a Trail Tech computer with an engine temperature sensor (sparkplug washer mounted). The unit is programable and has lights that light up if you get too hot.
Does anyone have any information on what might be considered too hot for our air cooled singles.
If there are no answers forthcoming I plan on monitoring mine. By next summer I should know what the bike runs at.
Thanks
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Post by cafekid on Nov 26, 2008 21:25:18 GMT -5
from what my sr crazy mechanic says, you can ride a sr all day long flat out and if all is well you will be hard pressed to get to 200/210. now if it is true i am not sure but i have heard such a thing from a few people.
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jeffz
Full Member
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Post by jeffz on Nov 27, 2008 4:40:10 GMT -5
According to a guy I work with, the oil in his Harley runs at 400-500F.  I almost believed him. |
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pcnsd
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Posts: 113
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Post by pcnsd on Nov 28, 2008 23:04:49 GMT -5
When my SR was on the road, it ran between 150F and 200F depending on ambient temperature (60F-105F) without an oil cooler and would come to temperature in about 10 minutes. With an oil cooler, it never went above 175F, but would take 30 minutes to come to temperature. I tested my oil temperature gauge in boiling water to confirm accuracy.
PC
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Post by solo2racr on Nov 29, 2008 0:50:29 GMT -5
Temp readings are totally meaningless unless they are of the same thing (oil, CHT, EGT, etc) and taken from the same location.
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pcnsd
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Post by pcnsd on Nov 29, 2008 17:46:09 GMT -5
Temp readings are totally meaningless unless they are of the same thing (oil, CHT, EGT, etc) and taken from the same location. Well... since the original post was regarding what appears to be a cylinder head temp unit, I guess will I have to agree and recognize I got off thread. So to address the original question. CHT's are load dependent and readings will vary. I do not have SR specific data, but I think some generalities may apply to air-cooled four strike engines that most can agree with, given an engine in proper tune. 300F-375F is OK. 400F + is not OK. First range would cover idle through medium duration full throttle loads. Second is "Too much load for too long a time." There are others here with deeper aviation backgrounds that may be able to add to or refine the above. CHT's and air-cooled engines are common in general aviation. PC |
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Post by solo2racr on Nov 29, 2008 18:19:51 GMT -5
Wasn't meaning to bust your balls there, pcnsd. It just looked like all the answers were either incomplete or a bit off base. I was just trying to make a general statement.
The only data I can offer up is my oil temp runs 150 +/- degrees. That is with a Lockhart cooler and taken from a dipstick temp gauge.
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THUMPS
Junior Member
THUMPS, ridden by Dave
Posts: 92
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Post by THUMPS on Nov 29, 2008 20:18:14 GMT -5
I went to an aviation site and they mentioned that the cht should be about about 435-465F depending on the make of engine. I have read that the oil should be lower something around 2ooF or so. I imagine that the EGT might be higher than either one. My unit should read cht as it is a copper ring around the spark plug.
My project today was to make a new headlight bracket from tubular and flat stock. I plan on mounting my instrument unit bolted to the top of the headlight nacelle. It may weigh half what the stock unit is. I used mild steel for this one. I am going to rid myself of the key and use the compression release as the kill switch. Wiring harness is going to be emasculated. Going to put a fuse between the regulator output and the lights. In case of shorts.
We have snow in the forecast. My welder laughs at snow.
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pcnsd
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Posts: 113
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Post by pcnsd on Nov 29, 2008 20:50:52 GMT -5
Solo2racr - No worries.  Thumps - 435F-465F? I can't believe that is correct. Those temperatures are well within the thermal breakdown range for lubricating oils including most synthetics. Worst yet, a CHT reading is buffered by the available cooling. This means internal engine surface temperatures are higher still. PC |
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Post by solo2racr on Nov 29, 2008 21:50:02 GMT -5
435F-465F? I can't believe that is correct. Those temperatures are well within the thermal breakdown range for lubricating oils including most synthetics. I agree that temp will destroy oils, petro or synth. But, for CHT that would be about right. Remember, that is at the base of the spark plug, which is were CHT should be taken. Barring that, under a cylinder head nut. |
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THUMPS
Junior Member
THUMPS, ridden by Dave
Posts: 92
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Post by THUMPS on Nov 29, 2008 22:36:36 GMT -5
Perhaps aircraft motors are much tougher than the SR motor. If our motor dies we just coast to the side of the road. I did a google search and got that number, I just redid it and got this link: www.littleflyers.com/engcool.htm Look in the middle of the page. I didn't know either so when I programed the warning lights I set the orange light to come on at 300 and the red light to come on at 380. I was just taking a guess so I decide to ask others. Thanks to all who are posting replies. |
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pcnsd
Full Member
Posts: 113
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Post by pcnsd on Nov 30, 2008 16:09:45 GMT -5
What I read is, these temps represent the factory maximums (do not exceed or engine damage, etc.) and should not be taken as a operating target. I will offer a AV website with its CHT commentary also. I think you are probably safe into 425F for short durations. www.avweb.com/news/pelican/pelicans_perch_84_mixture_cht_194816-1.htmlUltimately this is all just conjecture for an SR. I believe you will know within a day or two what represents "Normal" for an SR after installation, then please clue me in too. PC |
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THUMPS
Junior Member
THUMPS, ridden by Dave
Posts: 92
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Post by THUMPS on Nov 30, 2008 18:12:59 GMT -5
PC
Thanks for the info. Very good article. Thanks.
I was reading where CHT wasn't good for checking mixture as response was too slow. They said that EGT would be better which makes sense.
No chance to test anything with 3" of snow since yesterday. I spent today in the garage making some new parts.
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Post by chew652 on Nov 30, 2008 19:23:02 GMT -5
I saw an aircooled VW thread where a guy said he was running 325 to 350 CHT on long Summertime runs.
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Post by aero on Dec 1, 2008 5:09:30 GMT -5
The simple fact here is that you have no information as to what is normal.
Yamaha never published any CHT info, if they ever had any in the first place. Even if they did, you'd have to use the same sort of probe and position it in exactly the same place to get anything like meaningful readings.
What you can do is fit this sensor and keep a note on what's normal, when it goes away from this you can investigate why.
Piston aircraft engines are very under stressed, basically they are 1940's designs where you rely on large capacity to give you power rather then RPM, the smallest engines I worked on were 4 litre. CHT is only ever used as an indicator that something was wrong, even then it wasn't very accurate and never used to set up anything. Adjustments were made after assessing the mag drop test to check the timing and how the engine reacted to being shut down to set the mixture, IE did it die straight away, did the engine speed up before stopping etc.
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I almost believed him.
