Sportbike Forums on WristTwisters banner

1 - 12 of 12 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter · #1 ·
Hi all,

I've purchased my 919 (second owner) about 6 years ago from an older gentleman who takes great care of his (many) bikes.

While I did ride ATV's and dirt bikes in my teenage years, this is my first and only street legal bike (so far).

For as long as I can remember, the bike seemed to be running a bit hot at every stop. When I first rode it, I remember stopping and seeing the gauge slowly rising up from the middle of C and H, up to about 3/4 of the way up.

It's never been in the red, and I have done coolant flushes/changes. The fan also works.

This happens whenever I'm at a stoplight, and as soon as I pull away and ride normally, it'll go back down to about half way.

This may be a silly question, but I figured if ask the community. Thanks!
 

·
Registered
Joined
·
4 Posts
Thermostat maybe? Check with an infrared temp sensor or by feeling the temperature on both sides of the unit. By the time the gauge gets to 180 to may as high as 220 the thermostat should one and the temperature on both sides should be equal, before that point there is a noticeable difference between one side and the other of the device.
 

·
Registered
Joined
·
4 Posts
Hi all,

I've purchased my 919 (second owner) about 6 years ago from an older gentleman who takes great care of his (many) bikes.

While I did ride ATV's and dirt bikes in my teenage years, this is my first and only street legal bike (so far).

For as long as I can remember, the bike seemed to be running a bit hot at every stop. When I first rode it, I remember stopping and seeing the gauge slowly rising up from the middle of C and H, up to about 3/4 of the way up.

It's never been in the red, and I have done coolant flushes/changes. The fan also works.

This happens whenever I'm at a stoplight, and as soon as I pull away and ride normally, it'll go back down to about half way.

This may be a silly question, but I figured if ask the community. Thanks!
If you have had this 919 for 6 years, you have flushed the radiator 3 times already, right? just routine maintenance we always do. At what point did the temp start to rise? My guess is perhaps/maybe poor maintenance and the radiator is partially blocked. Consider a change over radiator but prior, do several 50/50 white vinegar flushes of the whole system, plenty of youtube vids advising the procedure, good luck. I flush my 919 as part of my regular service procedures.
 

·
Left of Centre
Joined
·
3,921 Posts
Hi all,

I've purchased my 919 (second owner) about 6 years ago from an older gentleman who takes great care of his (many) bikes.

While I did ride ATV's and dirt bikes in my teenage years, this is my first and only street legal bike (so far).

For as long as I can remember, the bike seemed to be running a bit hot at every stop. When I first rode it, I remember stopping and seeing the gauge slowly rising up from the middle of C and H, up to about 3/4 of the way up.

It's never been in the red, and I have done coolant flushes/changes. The fan also works.

This happens whenever I'm at a stoplight, and as soon as I pull away and ride normally, it'll go back down to about half way.

This may be a silly question, but I figured if ask the community. Thanks!
It's certainly unusual - these bikes are more known for being cold-blooded. Thermostat is easy to get to - I'd inclined to start there, too.
 

·
McTavish
Joined
·
6,309 Posts
First off, once a 919 is fully heated up, and I mean heated up - not just warmed up,
meaning hot metal, hot oil, and coolant fully up to temperature, my experience has been they stay hot in slow traffic on hot days and the fan cycles on and off with a fair amount of frequency.
But now with as high a needle as you are experiencing.
Assuming the rad is not screwed up inside with gunk, the cooling system is full, the hoses are OK, and the fan cycles on and off while managing the temp range reasonably, then I'd guess at the gauge and/or the 'stat.
Suggest you pull the 'stat and check it per the FSM method, and go from there.
 

·
Pokemon Master
Joined
·
74 Posts
The thermostat in my 07 still technically worked, but when I had to change my water pump at 56,000 miles, I went ahead and changed the thermostat too. I put the old thermostat and the new one in a pot of water with my meat thermometer and the new one snapped almost fully open at 180F. Maybe 10 seconds and less than 5 degrees of water temperature between fully closed and fully open. The old one was just barely starting to open, and never got beyond half of its range of motion, all the way up to a full boil. It never opened all the way up.

My gauge still rises if I'm stopped for more than one traffic light cycle. It goes from the little notch just above C, up to about halfway through the gauge. I've never heard the fan come on unless it's over 100F and I'm stuck at multiple consecutive lights for more than one cycle. I think it's just the tiny radiator volume that makes these bikes warm up at stoplights.
 

·
Wanna free cat?
Joined
·
700 Posts
I'm in Texas. It gets hot round here. Recommended coolant changes, along with new thermostats, haven't stopped the fan from cycling, nor have they kept the gauge from climbing into the upper zone in traffic
Ride it like you stole it
 

·
McTavish
Joined
·
6,309 Posts
The thermostat in my 07 still technically worked, but when I had to change my water pump at 56,000 miles, I went ahead and changed the thermostat too. I put the old thermostat and the new one in a pot of water with my meat thermometer and the new one snapped almost fully open at 180F. Maybe 10 seconds and less than 5 degrees of water temperature between fully closed and fully open. The old one was just barely starting to open, and never got beyond half of its range of motion, all the way up to a full boil. It never opened all the way up.

My gauge still rises if I'm stopped for more than one traffic light cycle. It goes from the little notch just above C, up to about halfway through the gauge. I've never heard the fan come on unless it's over 100F and I'm stuck at multiple consecutive lights for more than one cycle. I think it's just the tiny radiator volume that makes these bikes warm up at stoplights.
Your gauge needle movements sound normal to me based on what mine does.

Yes, the 919 has a small rad, so has limited heat rejection area. If one looks at the 919 cooling system, it's a relatively high volume X small heat exchanger design combination.

Very interesting observations about your old vs new 'stat behaviours!
 

·
Pokemon Master
Joined
·
74 Posts
Your gauge needle movements sound normal to me based on what mine does.

Yes, the 919 has a small rad, so has limited heat rejection area. If one looks at the 919 cooling system, it's a relatively high volume X small heat exchanger design combination.

Very interesting observations about your old vs new 'stat behaviours!
If you look at the radiator size on all of the CBR900RR variants and compare it to the first year of the CBR1000RR, it's night and day how much more surface area the newer radiators have.
 

·
McTavish
Joined
·
6,309 Posts
If you look at the radiator size on all of the CBR900RR variants and compare it to the first year of the CBR1000RR, it's night and day how much more surface area the newer radiators have.
Perhaps also less volume, that said based on the rad x volume combination on the 07 GSX'R 600 & 750 in the family.
 
1 - 12 of 12 Posts
Top