EGT (Exhaust Gas Temperature)

[Rick]

Has anyone ever used a IR gun to check exhaust gas temperature of the headpipe / exhaust port?

If so what would be an acceptable temperature for a properly jetted 2 stroke motor?

Has anyone ever seen a table with temps? Lean? Rich?

Just thinking out loud...................

Thanks

[Jakobi]

You can get those stickers that indicate temp too. You'd probably have some luck finding out what temps are acceptable through researching that a bit. I think most run them on the rads though.

Be interested in seeing what you work out. Going to do some testing yourself?

[(F5)]

An IR gun? You'd be a bit lucky. There's no way it would give you sensible readings trying to measure some metal with a vastly changing stream of gas flowing through it on the other side.

Best way is of course with a decent exposed probe (enclosed ones are too slow to react) welded to the pipe 4-6" away from the piston. Then you work out how hot it is getting, but guessed figure measurement is only ballpark, - best thing is to dyno it changing jets to find the best power & record the temp it achieved. Then you can alter jetting for changing conditions to achieve that same temp.

Sounds like too much work for an enduro/trail bike. Just a dyno session with an old road spooned on would give you main jet size close enough for most use if you wanted to be that sure.

[pierce]

http://twostrokemotocross.com/2009/1...ry-and-tuning/ every engine is different coolent temp should be close to 200deg

[(F5)]

Originally Posted by pierce

http://twostrokemotocross.com/2009/1...ry-and-tuning/ every engine is different coolent temp should be close to 200deg

um, you what?

Careful when giving advice when you don't really know.

For a start, most of the world uses Celcius so best to specify degrees F or C.

2ndly if we are talking F because 200C would be seized long ago, that is 93 dec C & that's crazy hot too. Maybe you're thinking Cars,. that still seems hot but I don't know much about cars so I won't comment.

A dirtbike should ideally run above 50 & below 70. That's a wide range but good enough for the small amount of cooling provided.

[Gasgasogeros]

hi i have test my bike with egt because i have elot oil out of exhaust and find this on needle section can see about 200-350 c and in wot about 650-700 c with pilot 42 , needl dj blue on 3 off the top ,and main 182 on 300 ec 2004 end thermostat on bike

[lindsey97]

i agree with the previous post. i carry a IR scan laser gun with me at all times to check my engines temps on my bikes and 140-160 deg. F is all i ever see. this is on my banshee, 02 rm125, 04 ec300 gasgas and the the wr250f. if a bike gets over 200 deg F then you have problems, or will have shortly.

[pierce]

my yz 250 always ran its best between 180-200f and not one time did it ever overheat. with the stock jetting it ran 120f and would foul plugs. running at these temps burns the oil completly and runs much cleaner no spooog. the bikes that boil over are usually over 240-260f. i have been riden and tuning these 2 strokes for 30 years.

[(F5)]

Oil coming out the exhaust has nothing to do with running temp, it has to do with how complete the combustion was. If the bike was too rich at a certain throttle position then it will not burn all the mixture so it will spit the rest out. That 'rest' contains oil. We mixed it with the petrol before.

Obviously combustion works best when the engine is in its tuned range (on the pipe if you will) so when you aren't running it at its optimum tuned frequency you will lose more charge than otherwise, but you can't ride dirtbikes in technical dirt areas like that always, unless you are being paid to perhaps.

water boils at 100c of course but pressure raises that somewhat.

But either way it is common practice to run 2 strokes in that range I suggested. In road racing some people advocate cooler & these people are at the top of the tree, but there are other factors at work with small cc roadrace bikes.

[Jakobi]

Where is everyone taking their readings from? I'd have no idea what temp my bike gets up to. Its never boiled over or spat coolant but its jetted on the line.

I get a bit of spooge build up on the bashplate from the PV drain line, but never any out the exhaust. Just an oily ring at the tip of the silencer. It smokes a bit after lugging around on the bottom end, but clears out as soon as you open it up.