EGT temp and powerjet........

[alanscottj]

I have been running my scoot without the power jet on since I had it dyno'd a couple of months ago and with the 108 main the temp was always around the 400 degrees Celsius mark, the scoot was set up to be very safe (rich) and has been nice to ride but a little boggy in the lower rev range. Anyhoo, I decided today to bring the power jet (from CamLam) back in to play and dropped my main down to a 100 and opened the jet three quarters of a turn, was a little boggy at WOT so I closed it to half a turn. The result, this really cleaned up the lower rev range as I thought it would and the scoot is a pleasure to ride. Had a little spin on the local dual carriage way and she sat lovely at 65 and had a fair bit left if I wanted or needed.

The EGT rarely went over 300 the whole time I was out and about - Am I right in thinking that I am in a fairly safe place with this temp? Does it seem a little on the low side?

Engine spec:

Mugello 198
Delly 30mm phbh
JL3
CamLam PowerJet

Any thought appreciated as always

[ForemanBob]

I always think that the EGT is an indicator and not a guarantee of "safe".... Plug chop at WOT is the only way to check that your carb is delivering the correct fuel levels....

EGT values vary with timing, position, sensor type etc so I dont think there is one stock answer...

[coaster]

Foremanbob is right but in your case you DO have the same egt on the same engine so it is perfectly fine to use it to gauge engine conditions. That said, ask yourself if EVERYTHING is the same as before, including air temp and weather conditions which could both affect the running temps. As Bob said, a plug chop would confirm

[alanscottj]

Foremanbob is right but in your case you DO have the same egt on the same engine so it is perfectly fine to use it to gauge engine conditions. That said, ask yourself if EVERYTHING is the same as before, including air temp and weather conditions which could both affect the running temps. As Bob said, a plug chop would confirm

Cheers fellas, yeah I appreciate these are only good to give an idea of what is going on in the engine. I have had a few spins today and the max temp I got was about 380 (when tootling around town) and the cylinder head tempt is keeping low , as well (90 Fahrenheit rising to 120 when sitting in traffic) so I think I am doing ok with the jetting I have. When it was set up by ReadSpeed the temps never went over 400 (egt), I figure if I am getting similar or lower temps to what they were when dyno'd then I am in the right ballpark. Gonna try and do some plug chops over the next couple of days weather permitting to see what the plugs looking like at WOT.

[nelson pk]

I always think that the EGT is an indicator and not a guarantee of "safe".... Plug chop at WOT is the only way to check that your carb is delivering the correct fuel levels....

EGT values vary with timing, position, sensor type etc so I dont think there is one stock answer...

Absolutely!

However if your EGT never read 400 after being dyno'd and its not reading over 400 now you should be ok.

Rather than pootling around town you should measure it on a fair distance when you are on the power cruising along and compare that with how your EGT's were before when you were at cruising speed etc before.

[alanscottj]

Absolutely!

However if your EGT never read 400 after being dyno'd and its not reading over 400 now you should be ok.

Rather than pootling around town you should measure it on a fair distance when you are on the power cruising along and compare that with how your EGT's were before when you were at cruising speed etc before.[/quote]

Managed to have a blast on the dual carriageway for a couple of miles. The temp on the EGT stayed below 300 when cruising at 60/65, if I am understanding this correct, the reason for the lower temp is that there is more petrol going through and cooling it. My powerjet is open half a turn so I have space to tweak it a little come the summer and the higher weather temps. Finally looks like I'm getting some where in setting this engine up to how I want it....Happy Days! (I shouldn't say that, tempting fate and all that!)

[nelson pk]

I would do plug chops and choke tests to be 100% sure or take it back to be dynod and have the power jet set up.
Your EGT seems to read very low generally but that can be down to the sensor or where its mounted but the key is knowing your safe temps on your EGT set up.

[alanscottj]

I would do plug chops and choke tests to be 100% sure or take it back to be dynod and have the power jet set up.
Your EGT seems to read very low generally but that can be down to the sensor or where its mounted but the key is knowing your safe temps on your EGT set up.

I think it is reading low because the probe isn't in as far as it should be, the guy that welded the probe holder didn't fit it flush so I don't think the tip is at half way, more like quarter the way in. Gonna do some plug chops but please forgive my ignorance, what's a 'choke test'???

[eden]

what does it read when your ridding at say 65mph on very little throttle?

[alanscottj]

what does it read when your ridding at say 65mph on very little throttle?

Around 300 / 350