What do you know about EGT fact?

[Wayne Miller]

Anybody use them?
What can you tell me about them?

[coaster]

A handy tool but the readings can be confusing and you will need to learn to 'interoperate' the readings especially if you have a variable ignition.

[soulsurfer]

It's all here, and a very interesting read...
http://www.iwt.com.au/EGT_CHT.htm

[Wayne Miller]

It's all here, and a very interesting read...
http://www.iwt.com.au/EGT_CHT.htm

Cheers for that mate

Has anyone set one of these things up and used one sucessfully?

[soulsurfer]

Yeah, loads of us use them.

[Wayne Miller]

Any info on which ones are best to buy? How to install? How to set up? How to use one? What to look out for? What temperatures people are running at? Any issues people have had? Are thy useful? Why are they useful? Are they realy any good at helping set up your carb? Do you have to dial your carb in a lot due to weather conditions? Do wether conditions actualy make a difference? Or indeed any other Facts regarding EGT

[coaster]

The best type are the digital ones as small increases are quite hard to spot with the analogue ones. That said, I have a very cheap analogue one on my Jet and I find it accurate enough for my purposes. As for normal temps, it is no use using someone else's readings as anything other than a guide, there are too many variables such as how far the probe is mounted from the piston skirt and how far the probe is inserted. Then there will be variations between probes (mine's on it's 3rd one). You really need to set the engine up on a rolling road or by plug chops and THEN note the readings on the EGT and use them to tell you when things are going wrong. I also have a CHT and use both together.

[Wayne Miller]

Yeah Ive heard having a CHT and an EGT can have benifits when detonation is on the horizon. CHT goes up, EGT goes down, Piston goes BOOM!

I understand that at first you have to find your own ideal temp and that if the temp goes up your running lean and if the temp goes down your running rich. Ive read that things like weather conditions can affect the running temp. What I want to know is does anybody use them to this extent, is there a massive difference in temp lets say one a cold day than what there is on a hot day or a rainy day or an overcast day. And if you rejet to bring back up/down to temp then what affect does this actually have on the motors performance. Is it a noticable difference.

I have a digital one on order and I'll install it soon and find out for myself I just wandered if any body else that used them could offer any feedback etc. Things to look out for and such like.

Thanks for the input coaster

[nelson pk]

EGT's are a great, fast, real time indicator of what is going on inside your engine.
You are absolutely right in that you need to know the temp range which is safe or where your scoot is happy at and you are right that lean indications generally cause higher temp and rich indications are generally lower temps however if I was riding and my temps were normal and then they dramatically went down, that could be an indicator of impending doom also.

You will find if you advance the timing the EGT temp will more than likely go down because you are retaining more heat in the head (firing earlier in the cycle)rather than going out of the pipe therefore when you retard the timing (firing later in the cycle) your EGT temp will go up as the charge is burning hotter as it goes into the pipe.

So you find out your safe temp range when your scoot is running nicely and if it dramatically changes in an abnormal way stop and figure out what the problem is.
For example as you accelerate your EGT temp should follow by going up as the revs rise, same as it should go down when decelerating to come to a sharp corner etc. As you cruise along your EGT should gradually climb and plateau at a safe temp however as you roll off from full throttle to mid throttle to cruise at 60 say your EGT temps are more likely to rise at mid throttle. This is the danger area on most scoots and an EGT can be hugely beneficial in setting up jetting in this area (needle/atomiser).

[Wayne Miller]

Cheers mate, so let's say I do a dyno session and lots of plug chops and I get my engine dialed in nicely what should I expect to see on an over cast day and on a hot day. Would there be a massive EGT reading change in my nicely dialled in motor and If I rejectted acordingly to get EGT back to where it previously was would be a massive difference to the performance of the motor before and after jetting. And would the change in weather dramitacally richen or lean off my mixture?