LCGB Forums

hi peeps
i've just built a new motor with an RT 225 kit and for the first time ever i'll be able to monitor cylinder head temp while on the move.
can anyone give me some idea of ideal working temps while in town and on the motorway.

appreciate any info

Hi peejay. I presume you're using a CHT rather than an EHT sensor, the latter I have researched to be more responsive and the former lagging too much, other opinions may differ of course..

Anyway I believe the CHT runs anywhere between 250-400, EGT temperature aslo varies depending on throttle setting and the often quoted 1250 - 1350 F is the full throttle heat range.

I bought an EHT last week & welded it to my U bend last night ready for my rebuild.

Hope this helps.

thanks mainstand for the info.

i'm using this bracket:









connected to my RT 1000



probe checked with a boiling kettle and was reading slightly over, i've ammended the base setting on Centigrade scale as i'm an old git

1250 F appears to be the melting point of aluminium so i'll try and keep the temp a bit below that

Not ran one on a lambretta yet, but ran a cht on a std vespa t5 and it ran between 220c and 260c.
260 would only be up long hills or into headwinds. Would be about 240 at full throtle and about 220 cruising.
Cheers hope this helps

Thanks Mike for info

peejay wrote:1250 F appears to be the melting point of aluminium so i'll try and keep the temp a bit below that

Farenheit yeah.

had the engine running for 15 mins today, on tickover mainly and revved to 2500 a few times.
max head temp was 59C. once switched off temp rose to 61C.

Peejay , ive been running a cht gauge on the trailtech for a while now ,the sensor is situated under one of the cylinder head nuts .ive set the warning light to come at 170c and very rarely have i got to this temp ,it would probably be ok well beyond this point but thats the point i give the old girl a rest , hope this helps .

Pejay forgot to add this is on a ts1 .

thanks for the info amb, hope to get some set up miles on it very soon

under 300 in town 350- 400 on motorway....choke it up before 400.

hi peeps
done 100 miles now mainly at 35-40mph and peaked at 45.
max revs 4.500.
head temp is 104-110 and peaked at 115 C

Difficult to say Peejay, Depends on so many things especially when bolted to the fin of the cyl head. Always best I think when you bolt one to an engine that you know is solid and set up well, you just benchmark it at different revs and away you go, using your known safe reading as a gauge. More difficult on a completely new engine with unknown set up as the position you bolt it on could vary reading by 15 degree, so you cannot use others settings as safe. I've bolted them to cyl head on a number of different TS set ups. flat knacker on the motorway at 7000 - 7500 rpm plus for an hour running at 170 degrees c is not untypical on my motors. in traffic at 60 mph it drops to less than 130, and around town not normally over 115. I've holed piston at 180 deg. I would generally think something untoward is happening if over 170 or so

They will always rise slightly as you cut the engine, basically the head is a heat sink and the lack of air and lubrication makes it rise for short while

thanks for that berniek
this is all new to me so i'm learning as i go along.
at least i'll have some warning while setting it up if temp suddenly rises, i've seen the difference riding on a wet road compared to dry

You need to ride it to find that out pete

bamrattle wrote:You need to ride it to find that out pete

i have been riding it Trev, just thought it would be nice to have some idea what to expect

peejay wrote:

bamrattle wrote:You need to ride it to find that out pete

i have been riding it Trev, just thought it would be nice to have some idea what to expect

Your just adding more things to look at, and worry about..
If you got time to worry about all that you aint going fast enough..

Edens spot on the money but pejay always be aware a drop in normal cht means the heats going to piston mesns running weak xxx

thanks eden and piskie for your replies