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Hey guys, unfortunately my first post is not one of good news. Well, in a way...I bought an RC51 today, so that's good I guess.

Anyway, I bought this bike off of a guy who said he took good care of it, and I trust him on that. He said he just had the bike looked over and fluids changed for me to ride it back home. The bike seems to be in very good shape, except for the fact that it's running intensely hot. I rode it back ~250 miles today in Texas heat, it was around 97 today, and on the highway I looked down and saw the light flashing. The temperature gauge was reading 270 degrees...now I know 51s run hot, but that's kind of abnormal yes? 270 was the peak that I saw, but it was regularly between 235-250 degrees and rising to 255-260 when stuck behind trucks (an indication of decreased airflow I imagine). Has anyone else had any issues like this and if so is there a solution? Could this be an indication of a failing radiator or is there something a little less dramatic I should check on first? Try to break it down for me in layman's terms, as I'm not ridiculously savvy. Thanks!
 

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The max temp on my best guest according internetz is 230 then you have to stop. While moving the temp should go down. Check cooling fan and coolant. I have water wetter on mine and in really summer days i use 20-50w oil.
 

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Hey guys, unfortunately my first post is not one of good news. Well, in a way...I bought an RC51 today, so that's good I guess.

Anyway, I bought this bike off of a guy who said he took good care of it, and I trust him on that. He said he just had the bike looked over and fluids changed for me to ride it back home. The bike seems to be in very good shape, except for the fact that it's running intensely hot. I rode it back ~250 miles today in Texas heat, it was around 97 today, and on the highway I looked down and saw the light flashing. The temperature gauge was reading 270 degrees...now I know 51s run hot, but that's kind of abnormal yes? 270 was the peak that I saw, but it was regularly between 235-250 degrees and rising to 255-260 when stuck behind trucks (an indication of decreased airflow I imagine). Has anyone else had any issues like this and if so is there a solution? Could this be an indication of a failing radiator or is there something a little less dramatic I should check on first? Try to break it down for me in layman's terms, as I'm not ridiculously savvy. Thanks!

My bike, essentially stock with cans, was hitting 235 in normal city traffic @ 90 deg, stop and go between lights, and about 35mph when moving, I went to two "Spal" pusher fans from ebay, and have not seen above 225deg since. I think it starts flashing at about 250deg... at witch point you need to stop or... maybe do 80mph to cool down. they're s a trick to mounting the fans but an easy task and about $80-90 to do both...
 

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yeah, 270 is extremely hot for the RC. I'm would first talk with the previous owner about who looked the bike over and changed the fluids. Could be anything from air in the system from the coolant changed, to a bad fan motor or thermostat. The RC temp should never reach more then 250 after that you should shut the bike off. Mine run up to 222 before the thermostat opens up and cools it back down to 212 -209 in city traffic. Also after a long ride if the fans are still running I let the fans cool the motor off before I remove the key from the switch and sometime I turn my electric leaf blower on a cool her. But that's just me
 

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^ I'm willing to bet whoever changed the fluids for him (dealership?) forgot to burp the air out of the system - those temps are VERY hot !
 

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Is there coolant left in the overflow tank?
Do you hear the fan turn on around 210-220 degrees?

I would start by pulling off both side and upper fairings and burping all air from the system by warming it up to temp then reving it up while keeping the radiator topped off. Any air bubbles? Make sure there is coolant in the overflow.
Still overheats?...It also could be the thermostat.

A warped head would suck- but not the end of the world. I would definitely have a nice little face to face chat with the seller.

I have carbon louvers on mine to aid in cooling- and did all the above. She never gets above 220. Usually she's at 175-185 when in motion. But louvers, water wetter, or engine ice coolant won't solve your problem. You're too hot.
 

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It's in the past tense, but you should not run your engine with temps over 251 deg F.
That's the critical temp with the temp indicator blinking and the temp light lit.
It's trying to get your attention for a good reason. Pull over and let it cool down!

Be sure and check:
1) Fan operation (SP1 have one fan, SP2 have two).
2) Coolant level and if presence of air in the system.
3) Thermostat operation (if fans work, and coolant ok with air purged from system).
4) Check that your hose clamps are snug and no leaks near them.
5) Check for coolant leaks around the radiators (cracks, pinhole leaks, etc.)
6) Radiator cap holding proper pressure.
 

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This is my first summer with the RC and these are very hot running bikes. I rode around in the AM this weekend before it got over 100F and it was hard for the bike to get below 200F when moving (lots of stoplights). My dual Span fans kick on @ 219-220F and shut off around 209-210F. I'm running distilled water with water wetter, but I guess it's just the radiator design that keeps these things so hot.
 

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I'm running Engine Ice, Thorsten radiator fins, and Spal fans. My RC constantly hits 230-235 on the track. I'm in the process of converting to a front mount radiator setup. One other point of failure on the RC is the water pump. Make sure yours is actually working properly. To do so requires the replacement of a couple seals which have to be pressed onto the impeller but its worth it to have them replaced for insurance purposes alone. You can almost bet its never been done on your bike. Mine actually went this year and cost me a full track day.
 

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270 degrees? really? That's the hottest I've heard of.
What did you find out with that?
 

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Discussion Starter #13
Hmm, sorry for the late response...for some reason it stopped notifying me via email when new replies were posted.

At any rate...I did all the checks as prescribed and couldn't really find anything wrong. No holes, clamps seem fine, replaced coolant and burped the system as well as changed the oil while I was at it. Both fans kick on at the prescribed temperature. It's still running warm, but it's not nearly as bad as it was. The max I've seen since changing the coolant is like 252 on one occasion, and the minimum temp once it's warmed up I've seen was 201 today, got caught in a light rain shower earlier on the highway...like I said still warm but a noticeable improvement for sure.

Should I try the pusher fans and rad fins next, or is there something else you guys recommend that I check first? If the fans are a good option which are recommended, as in size/voltage, I'm unsure which ones I would need.

Thanks for the replies and suggestions, and again I apologize for the late response. Cheers!
 

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You didn't mention if you replaced the thermostat. Although I've not heard of them sticking closed before, usually if they fail, they stay open and that wouldn't be your problem. Still...

I think your bike is still running way to hot. 220 - 230 should be the max you see most of the time. This is just a shot in the dark, but I would let the bike cool completely. Then I would open the rad cap, hang a thermometer in the coolant, and start the bike. When you see the coolant moving in you rad - should start at 167F degrees and be pretty active at 172 - the thermostat has opened and you'll have circulation now. compare your gauge reading to your thermometer reading to see if the gauge is accurate. At about 195 or 200, the coolant will begin to rise and spill out, so be ready for that. Shut the bike off and put the cap on.

From there -- well, I don't know. :confused:
I'd definatly test or replace the radiator cap too.
 

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I'll have to check the manual on how to replace the thermostat...I've never done something like that before.

I like your recommendation on the thermometer idea though, I'll have to give that a try and see. If the situation goes how you outlined it above, would that eliminate the thermostat as a potential problem?
 

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I'm running Engine Ice, Thorsten radiator fins, and Spal fans. My RC constantly hits 230-235 on the track. I'm in the process of converting to a front mount radiator setup. One other point of failure on the RC is the water pump. Make sure yours is actually working properly. To do so requires the replacement of a couple seals which have to be pressed onto the impeller but its worth it to have them replaced for insurance purposes alone. You can almost bet its never been done on your bike. Mine actually went this year and cost me a full track day.

You are also in the desert too where its hotter than balz!!:eek::D

 

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This is my first summer with the RC and these are very hot running bikes. I rode around in the AM this weekend before it got over 100F and it was hard for the bike to get below 200F when moving (lots of stoplights). My dual Span fans kick on @ 219-220F and shut off around 209-210F. I'm running distilled water with water wetter, but I guess it's just the radiator design that keeps these things so hot.
That all sounds normal to me. That's pretty much how my bike acted too with the stock temp sensor.

My bike, essentially stock with cans, was hitting 235 in normal city traffic @ 90 deg, stop and go between lights, and about 35mph when moving, I went to two "Spal" pusher fans from ebay, and have not seen above 225deg since. I think it starts flashing at about 250deg... at witch point you need to stop or... maybe do 80mph to cool down. they're s a trick to mounting the fans but an easy task and about $80-90 to do both...
Glad that worked good for you.
I've heard enough people say that so, next project for me too for sure.
 
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