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Discussion Starter #1
So I finally have managed to find the bike I have wanted for 10 years! A clean 2005 with low miles.
The previous owner has done some work. Supposedly stahl fans, the fan switch mod and other cosmetics.

so I took the bike out for my first ride, on the highway, it got up to 230 while doing atleast 70 miles an hour?!?!?!

When I got off the highways and encountered street traffic... damn thing shot up to 250?!?!?!?!?!?

So I pulled over and turned it off.. waited about 20 mins and returned home?

Did I buy a brick? did I do harm to the engine? (it seemed to run fine when restarted).

Any thoughts.. any feedback would be greatly appreciated. I love the bike.. don't know what to do here. Thanks in advance.
 

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Welcome to the RC51 community.

I'm not an expert in this area, but there are a few things you should check. Firstly, the RC should not reach 230 at 70 mph. It will be around 190ish on a not so hot day. What did the previous owner say?

-test/change engine/water temperature sensor! It may be that simple; if the sensor is faulty.
-Check radiator fluid level
-Flush system
-Change radiator fluid
-Burp the system to get the air out
-check to make sure the cap closes properly. It needs to prevent air from getting in.
-test the fans (were they on when you pulled over?)(should not need fans at high speed)
-test direction of fan flow (OEM fans blow air from the inside out, which can cancel air flow around 30mph. More powerful fans may cancel air flow at higher speeds. Aftermarket fans are commonly used to reverse the flow of OEM for this reason, so the work well at all speeds)
-remove fans to make sure the rad fins under the fans are okay (common damage with Stahl fans)

At the heart of the issue; something is preventing cool rad fluid from reaching the engine, and with some diligence you will figure it out.
-
 

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Discussion Starter #3
gws.. thanks so much. Im not very handy. but I think I can check some of these things.

Did I do harm to it. by getting up to to250 in traffic?
 

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Welcome.

250 F = 121 Deg C - which should still be fine I'd expect, but you're getting close to damaging a head gasket at this temp, probably. I'd avoid letting it get so hot.
Your oil is also probably hotter & quite thin at that temp too...So I'd do an oil change as well as coolant check, etc.

Fans should come on at 100 Deg C, which is around 210 - 215 F. If it doesn't come on, then you need to figure out why...

Keep an eye on the coolant and if it drops, find out why...A pressure test is one way to do so.

I've never tried to connect the two terminals of my temp sensor together for the fan on the SP2 (not sure if there are even any, someone will confirm soon, I expect - but that's a classic way to check for car fans and if they're working or not - rather than letting it get to temp first...
 

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Discussion Starter #6
The guy i bought it from had the fan switch mod on it. Im beginning to suspect, he had the fan switch mod on, because the fan was not coming on automatically. I did not know this, and rode the bike with the fan in the off position.

in any case, im dropping it off at the shop.. and dealer is going to take me to the cleaners. rrrrrr

but i do love this bike!
keep you all posted.
 

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The guy i bought it from had the fan switch mod on it. Im beginning to suspect, he had the fan switch mod on, because the fan was not coming on automatically. I did not know this, and rode the bike with the fan in the off position.

in any case, im dropping it off at the shop.. and dealer is going to take me to the cleaners. rrrrrr

but i do love this bike!
keep you all posted.
Change the oil straight away after getting that hot, especially if you run dino oil.

Did you just change the coolant recently? I'd check to see if it is low or has air in it, just to be safe too.
 

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Discussion Starter #8
just rode the bike the way I received it.is currently at the shop they're doing an oil change and coolant flush and diagnostics with the temperature will keep you posted
 

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I'm from Texas and I see 230 often. In Austin traffic I seen 254 and pulled off. Some have said the temp light doesn't come on until 260 idk but I have yet to see mine. I would still pull off at 240 and over and let cool. To help I use engine ice and it helps some but not great. Haven't tried fins or scoops yet. Hope that helps


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According to the service manual, your temp light should come on at 251F and the temp display will start blinking.
I've read from the folks here who would know these things, that at 250F, engine damage (namely head gasket) is likely to occur. Does it take 5 seconds or a couple minutes - that I don't know.

I'd be shutting the bike down if I saw 240F or above. But that's me trying to be safe rather than sorry.
 

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Discussion Starter #13
OK. just wanted to keep everyone posted and chimed in. Just got the bike back from the shop. Faulty Thermostat. faulty temperatgure sensor. Coollant replaced. Now it runs, rises up to 219, fan kicks on automatically. Temperature drops back down to 215.. All working perfectly. Turns out the reason the bike had a "fan switch mod".. was to address the fact it was over heating.
 

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OK. just wanted to keep everyone posted and chimed in. Just got the bike back from the shop. Faulty Thermostat. faulty temperatgure sensor. Coollant replaced. Now it runs, rises up to 219, fan kicks on automatically. Temperature drops back down to 215.. All working perfectly. Turns out the reason the bike had a "fan switch mod".. was to address the fact it was over heating.
Good to hear you got it figured out!

I had low milage on my bike when I bought it, about 15,000. One of the first things I did after getting her roadworthy, was remove the rads and hoses, clean and flush, wire brush all the hose nipples, clean the overflow bottle and lines, and I did 2 flushes before removing the rads one last time to clear out the water. I even put a little belt dressing on the hoses to help keep them fresh. Replaced rad cap and thermostat, and ran DexCool. (That's what I had at the time and it's silicate free). I also tried engine ice and noticed a couple degrees drop on average. I'm back to DexCool now, it's about a third of the price and has been very reliable and consistent.
The point here is I think it's a good idea to completely go through the cooling system and restore it to as good as condition as possible, then enjoy many, many more miles of normal, reliable cooling.
 

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Discussion Starter #17
Final Status. So I finally got a dry day in NY and was able to ride for about 4 hours, mixed environment. Some highway.. some stop and go, city traffic. Hers the final numbers:

highway riding, went down to 160's
Slow, but flowing traffic 190-220, fan cycles on temp drops below 220 again
STOP and GO traffic, BUMPER TO BUMPER.. walking bikes for 30 minutes: Bike climbed to 220, and over the course of 30-35 minutes in bumbper to bumper traffic, very slowly creeped up... one degree at a time up to a high of 234.. Then fluctuated between 233-234-233. Keep in mind.. im literally stopped, roll one car.. then sit in traffic. this was for atleast 35 mins.

Would you guys consider the above, normal?
 

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How did the frame and tank treat your legs? Get's effing hot, huh?
You didn't mention what the ambient temperature was.
Sounds ok, although I've never seen my bike go over 225F in 95 to 100 degree weather and stop and go traffic. (I just don't ride the RC51 if it's hotter than 105 outside.) But I can lane-share, so I don't have to sit in traffic. Maybe that's the difference. The hottest I've seen my bike go was 230 at Thunderhill track on a hot-ass summer day and really pushing the rpm's.
I'd be looking to replace the factory fan(s) with SPAL pusher fans. There's a lot of posts and threads where guys swear by them and see real results.
 

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Discussion Starter #20
Wow. That's when the fans click on, 220. So so it never gets above that? oK you've got my attention what are twin pushers how much are they
 
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