when i ride my trx 250ex is seems to get awful hot quickly...it has a full hmf and dyno jet i know my exhaust will be extremely hot but is it common for my engine to be real hot to? i do ride it hard but even when im babying it, it still gets hot...any suggestions??

 

This engine is air/oil cooled, so we at least don't have a water cooling system to deal with. A couple things come to mind:

Is it possible the oil cooler is clogged? Do you change oil at a reasonable interval, and what weight of oil are you using (Thicker summer weight oils (like 20W50) are slower to pump, so they don't make the circuit through the engine as quickly, so they don't get to the oil cooler as often.)? Have you ever cleaned the screen in your oil line or the centrifugal oil cleaner?

Are you properly jetted, because a lean engine will run hot (and cause engine damage!)? You said you have a Dynojet kit installed, but did you just throw the "recommended" jets in and go, or was it done by a competent professional who actually rode the quad to eveluate the jetting (jettin is more art than science!)?

Are your valves properly adjusted? (Tight valves will transfer more heat to the engine block). Are you running a spark plug that is in the proper heat range for your temperatures? (To "hot" a plug will not transfer heat out to the engine block as efficiently.) Are you keeping your air filter cleaned? (Air coming in the carb has a great cooling effect!)

 

Quite possible that with hot weather you are just now noticing how hot your engine actually runs.

The only way to know for sure if it is actually running hot (and not just your imagination!), is to check the temperature of the oil. Find yourself an "immersion" thermometer and go for a ride on a hot day, then immediately take off the oil filler cap and immerse the thermometer (immerse to the immersion line only!), and take your oil temperature.


Get yourself a SERVICE MANUAL, and it will tell you what normal operating temp should be, along with tons of other usefull info!!!

 

yep, i had the jet kit installed at honda of houston and they said it is at the right position and everything was ok, and im using the gn4 10w-40 oil 1.7 quarts and yes my air filter is good i just cleaned it today so ill see how it performs today...but ya i ride hard at spring creek which is pretty much a beach with alot of sand and i ride it hard, so maybe thats why, but i will def have to check my spark plug and the oil temp. thanks