Coolant Temp - How hot is TOO hot

Hey gents. I remember seeing a thread about this a year or two ago but I can't find it. Scenario: I didn't run the bike for a while after a lowside and small flip. Replace a few parts, start the bike. (Now for the BONEHEAD move) I start the bike and walk away to drop something at the next door neighbors. Come back and bike is REALLY HOT! 256 degrees. Red warning lights flashing. Apparently, the flip had shoved the radiator back into the left fan so it could not turn. Only right fan was running and the bike temp shot up. Question: How dangerous was 256 and how likely is it that I did damage to my baby's engine. Thanks for the schoolin' guys.

turn off the motor and let cool. when rad's f1xed go start and see. don't th1nc 250's are bad...

I shut the bike off after it happened and then restarted after the radiator cooled. That then brought the temp down more. It seemed to run ok after that but it doesn't mean I didn't lose some compression etc...

probably not. only real way too see are to do some dyno runs and compare or run comp. tests

I shut the bike off after it happened and then restarted after the radiator cooled. That then brought the temp down more. It seemed to run ok after that but it doesn't mean I didn't lose some compression etc... Question: How would this cause an engine to lose compression?

I'd say since it was just idleing you probobly did minimal damage. the biggest problem at those temps is your oil breaking down and it stops doing its job. since you werent putting it under a bunch of stress you may be fine. I'd change your oil just to be safe, and take it easy for a day or two, just to make sure all the bad oil, and any damage you may have done, gets "washed" out.

Question: How would this cause an engine to lose compression? One of the most common problems from overheating an engine is blown head gaskets. Then you lose compression and/or start mixing oil and water. That's a really bad thing. Like it was said though, I don't think short exposure to 250s will do anything permanent. Fix the apparent damage and do a compression check then take it from there.

If it were my bike, once I got every thing with the radiator fixed, I'd drain the stock coolant, and replace it with Redline's Water Wetter. I would probably mix it a little on the rich side. I've found my bike runs on average 25 degress cooler with Water Wetter. As far as your question goes I don't think you have done any damage to the motor or the gaskets for that fact. I had mine get up to 248 last year at Barber during an endurance race. I changed the coolant, and the oil that night and raced it the following weekend with no problems.

Maybe the R1 is differant, but my R6 actually said HIGH on the temp gauge when temps were dangerously high......

Maybe the R1 is differant, but my R6 actually said HIGH on the temp gauge when temps were dangerously high...... Ours do that too. When the temps go over like 245 or 250 then hi shows. When that happens, you need to stop the bike and let it cool asap... :fact

I've found my bike runs on average 25 degress cooler with Water Wetter. Are you serious????

I've heard the same, I.m trying it once we thaw ot here, we get 100+ deg temps all the time..

Are you serious???? Try it sometime, and you can be the judge.

Thanks guys! I have started the bike a few times since my 256 degrees and it seems not to be damaged.

Yes I am serious