Athena sport 70cc maximum temp,rpm

[bt94]

I have a 93 yamaha jog. Athena sport 70cc bbk stock crank malossi mhr overrange variator malossi delta clutch dellorto phbg 19mm carb vforce3 reeds yasuni z exhaust. It runs great but it idles at about 140 degrees Fahrenheit and when I get into it it's around 115 degrees. I'm just trying to find a max operating temp and what is the max rpm I can take this setup too

[90GTVert]

Idle seems in the realm or normal to me. WOT is cold. Are you sure your temp sensor is working correctly? We are talking CHT (cylinder head temperature) here, correct? A max CHT could be about 3X or more what you're seeing getting on it and it's unusual to see temps drop from idle to WOT. If it's CHT on an air cooled engine, is the sensor somewhere that ambient air could be cooling it a lot at speed?

[bt94]

I believe the jet I have is too big.

[bt94]

I also am using a trailtech vapor to read the temp rpm speed

[90GTVert]

It would have to be a huge jet to run at 115 degrees being hard on it, and really it should be running very poorly if it were that rich. Again, assuming this is CHT and not coolant temp on an LC scoot.

[ThaiGyro]

Unless modified to a liquid cooled cylinder...a '93 Jog has a horizontal Minarelli. My only guesses are: Wrong CHT sensor location, somehow or the bi-metallic sensor ring is loose. "The answer, my friend, is blowing in the wind."

Kidding aside...not much to the temp. sensor on a Trail Tech. I did the above on a Yamaha XS650 a few years ago. It too had a Trail Tech Vapor dash. I had just re-installed the engine and forgot the sensor. During warm-up it was hanging on the bottom of the cylinder fins...reading a bit low. When I ran up the highway, it was reading about 55 degrees F. because it was flapping in the air.

I have not seen a defective dash unit yet, but anything is possible. You can check your sensor easily. Make sure your wiring is not cracked or frayed to the sensor. Remove the sensor from the cylinder bolt. (It is best to loosen them all equally) put some cold water in an insulated can or coffee mug...turn on your Trail Tech and ensure it displays temperature, then dip the sensor in and see what the reading is. Now do the same with hot water. Boil if you want or simply add hot tap water.

Also worth checking: TT makes three sizes of sensor. (10mm, 12mm and 14mm) Best to have the right size for your head stud diameter. They also make oil temp probes...and cylinder fin sensors. If you have a fin sensor, they are highly unreliable in my experience. Replace it with a CHT sensor.

If the sensor is OK...worth a call to Trail Tech customer support. I have had good luck with their knowledge of older bikes. They are still in Washington State.

['O'Verse]

If your cylinder is air cooled and your trail tech vapor is somehow measuring in Celsius. Than technically you are operating around the right temperature. I like to keep my cast iron air cooled cylinders under 340F myself if I can help it. Aluminum cylinders are a different story..... If I were you I'd double check your cylinder temps with either another gauge or infrared thermometer before making any drastic changes to your main jet. If your idling at 145. I would definetley expect temps to rise higher than 145 with higher rpms period. Then drop at WOT due to main jet size.

[bt94]

It is reading in farenheight. I have the correct 14mm cht sensor. I am running a 100 jet. I was going to lower the jet size to see if it helps

[pinkscoot]

I always check mine before I start the engine to see that its reading around the ambient temperature. I also reminds me to add or remove a layer of clothing.