Hi Folks,
I was riding yesterday in 95+F heat. Riding like a jackass, multiple full throttle trips to the redline, etc. My temperature was staying between 225-233. That seems excessive to me, but I was thinking maybe that's just what it does in extreme temperatures. What do you think? Problem or expected temperatures under extreme conditions?
Thanks,
That on the high end for sure. Was the fan running? Lots of time under 35MPH, and/or idling?
46 minutes ago, MBraneThat on the high end for sure. Was the fan running? Lots of time under 35MPH, and/or idling?
Fan was running. More high speed/high rpm/full throttle than slow/idling.
Possibly a stuck thermostat. The bike should stay closer to 180F even when being thrashed as higher speeds = more airflow. Next time the bike is cold started keep a hand on the radiator. It should stay cold until around 176F when the thermostat should begin to open, then get too hot to touch quickly. If it warms slowly from engine start, you need a new thermostat.
I keep a log (doesn't everyone) at average and high temps that goes with every tank fillup.
My 1998 #s are 185F/220F
My 2000 #s are 185F/229F
Following
bmart, 8/15/2025 at 9:58 PMI keep a log (doesn't everyone) at average and high temps that goes with every tank fillup.
My 1998 #s are 185F/220F
My 2000 #s are 185F/229F
My numbers exactly on my 2001.
Follow-up to this thread. It's cooled off a little bit and the bike is running much cooler. I'm now convinced it was the absurd OATs + jackassery that were causing the high temperatures.
If you see *continuous* temps higher than 220ºF or below 180ºF then
trouble shooting is in order:
Continuous engine temps above 220ºF or 104ºC is also a problem and the proper
order of items to trouble shoot are:
1)Faulty radiator cap... system should hold 1.1 pressure ratio...
2)Insufficient coolant...
3)Passages blocked in the radiator, hose or water jacket...
4)Air in the system...
5)Thermostat stuck closed...
6)Faulty temp meter or thermo sensor...
7)Faulty fan...
8)Faulty fan switch...
Engine temps below 180ºF or 82ºC is an problem... it means that the
moisture produced during combustion is not getting hot enough to
evaporate out the pipe as steam... instead that moisture will migrate
to the oil and produce a milky white contamination...
Note normal by products of combustion is water... . Every gallon of gas
creates roughly 8 pounds of water vapor... we all have witnessed water
escaping out of tail pipes on cold mornings...
The sequence of events to trouble shoot are:
1)Faulty temp meter...
2)Thermostat stuck open...
3)Faulty fan switch... (stuck on)
Leaky Head Gasket Check...
You can visual inspect for a leaking head gasket by pulling the spark
plugs and peering down each hole... if the top of the piston is black
then no leak that cylinder... if the top of the piston is a bright
shiny aluminum then leak detected... because a leaky head gasket
allows coolant in and that produces steam under the heat of
combustion... the net effect is a super clean piston dome and no nasty
black...
On bike Thermostat Check
To check if the thermostat is opening start the engine at its lowest
temp... open the rad cap... observe at what temp the coolant begins to
flow... if the temp rises above 180F and the coolant does not flow
then your thermostat is suspect
To trouble shoot an oil leak start by tracing the wet trail back to
its the highest point to determine the origin... if the origin is mid
cylinder then investigate a possible blow head gasket... take a
compression test to verify the effective cylinder..
data point of one and not at all the same bike, but the stock fan on my sv650 was just downright not up to task for texas summers; if i was standing still, the temp would climb even if the fan was on. swapping it out for a 5" spal fan fixed that problem. (at first i had a pair of them but that turned out to be way overkill.) the vfr fan looks to be similarly constructed, so i wouldn't be surprised at all if the root cause of everyone's overheating issues is just a wimpy fan. i still have that second fan laying around somewhere, so before my bike's finished i plan to slap it on so i can see how it performs.
Popular swap for those of us who ride 5th gens in warmer climates is to swap to a VTR1000 fan blade so it blows out instead of in. That, and stay above 35MPH.
11 hours ago, MBranePopular swap for those of us who ride 5th gens in warmer climates is to swap to a VTR1000 fan blade so it blows out instead of in. That, and stay above 35MPH.
Hi.
Any known fan assembly that'll fit the right side rad without major mods?