Scooterotica

Sorry if this has been asked many times , i have no idea what my egt should be, can someone explain these , at tickover , mid range and balls out, when is it too hot and going to go bang etc, i have a sip speedo with the egt on the plug if that helps, its a cast cylinder also, temp is set to centigrade , thanks .

Do you mean CHT (cylinder head temp) rather than EGT (exhaust gas temp). If it's on a SIP speedo It will be CHT I think. It's very dependent on where you mount the sensor, on mine (mounted under the head cowling bolt, not the spark plug) I see anywhere between mid 50 to high 60 and if I stop at the lights it climbs to 70+.
I think you have to get used to whats normal for your setup and take it from there.

Search CHT and you'll fing the temp range.

I seem to remember that you want to stay below 450f. That's mounted under the plug.

sorry cht temps, thanks for the replys , ill stiil ride with my hand on the clutch

gerryjunior wrote:sorry cht temps, thanks for the replys , ill stiil ride with my hand on the clutch

Don't we all...

Every engine is different so what might be right for one engine might not be right for yours.

A cht gauge should be used for reference, use the gauge and see what results you get. After a while you will know what your engine runs at in different riding styles. If it starts showing results that are different from the usual then you know something is wrong and the possibility of something expensive is about to happen.

Head temp does not give much guide to tuning, but will warn of the engine being "too hot". I've used them on karts (air cooled two-stroke) as the full throttle mixture could be varied on the run. So one can set up the mixture during practice.

I'm just getting back into Lambrettas and I live in a hot country (39C last Saturday) so i am concerned about engine temperatures, magneto fins and cowling outlet sizes.

I see anywhere between mid 50 to high 60 and if I stop at the lights it climbs to 70+.

I assume this if Fahrenheit and we need to add 300?

You have to compare temp to plug colour.

Given the above numbers would suggest 360-370F which is 180+C Karts run 220-240C

As Lambrettas are fan cooled engine RPM and thus airflow when cruising is important.

The biggest concern is slowing down from a full speed run. NEVER snap the throttle shut and slow down on overrun. No throttle = no oil. Ease off the throttle , pull the clutch in and keep the engine rpm about mid range by blipping the throttle until desired speed is reached.

From direct (no pun intended) experience karts always seize at the end of the straight when the driver lets off for the corner. Which is why kart racers don't.

onthelam wrote:Head temp does not give much guide to tuning, but will warn of the engine being "too hot". I've used them on karts (air cooled two-stroke) as the full throttle mixture could be varied on the run. So one can set up the mixture during practice.

I'm just getting back into Lambrettas and I live in a hot country (39C last Saturday) so i am concerned about engine temperatures, magneto fins and cowling outlet sizes.

I see anywhere between mid 50 to high 60 and if I stop at the lights it climbs to 70+.

I assume this if Fahrenheit and we need to add 300?

You have to compare temp to plug colour.

Given the above numbers would suggest 360-370F which is 180+C Karts run 220-240C

As Lambrettas are fan cooled engine RPM and thus airflow when cruising is important.

The biggest concern is slowing down from a full speed run. NEVER snap the throttle shut and slow down on overrun. No throttle = no oil. Ease off the throttle , pull the clutch in and keep the engine rpm about mid range by blipping the throttle until desired speed is reached.

From direct (no pun intended) experience karts always seize at the end of the straight when the driver lets off for the corner. Which is why kart racers don't.

Nope, thats degrees C, think it's that low because of the mounting and why I said you have to get used to whats normal for your set up.

Minority wrote: why I said you have to get used to whats normal for your set up.

Which I suppose is OK but given that Head temp does not give much guide to tuning, but will warn of the engine being "too hot". Then the point of a temp guage would be to alert the rider to something out of the ordinary which is of no use if one doesn't know what normal or ordinary actually is.

I'll get my hat...

onthelam wrote:

Minority wrote: why I said you have to get used to whats normal for your set up.

Which I suppose is OK but given that Head temp does not give much guide to tuning, but will warn of the engine being "too hot". Then the point of a temp guage would be to alert the rider to something out of the ordinary which is of no use if one doesn't know what normal or ordinary actually is.

I'll get my hat...

Both are important. As the CHT goes up the EGT will go down with in a certain range. I know on my RT I used the CHT (SIP speedo) to tune the carb and could easily see the temp diff with each jetting change. Read up on Jennings, there is some great information regarding temperature ranges. Just because it's "normal" for someones set up does not mean it's correct.