Running a little hot, I think I know what's wrong, now what?

[hppants]

2005, 62K miles, well maintained.

Bike was running a little hotter than normal on Friday. Ambient temp is in the mid-80's mid-day. Temp display goes to 3 bars in traffic slower than 60 mph and even 70-ish mph on the slab tucked behind a truck or large vehicle. Fan kicks on a 4 bars in stop/go traffic, runs a little longer than it normally does, brings temp down to 3 bars, and then kicks off.

In short, the bike is running like it normally would in 95-100 degree temps, not 85-ish.

Coolant has been flushed more often than necessary. The system is clean - there is no doubt. Coolant used is Honda-pre mix. Coolant level is normal - 1/2 way between low and high when bike is cold. 1/8" above high when stopped hot (IOW - I've got the maximum coolant it can hold in it).

Here's what I think is the problem.

Approximately 25% of the radiator fins are smashed down pretty good. If you could look straight at the radiator from behind the forks, it's the lower left part that is smashed (should get more wind than the upper part).

I did this myself. About a year ago, I got a wild hair and tried to blow the fins with compressed air to clean them out. Lesson learned - just use the garden hose for this. I think the air was too strong and folded the fins down.

I've got the "radiator brush", but can't grab the fins to straighten them. I tried a very small screwdriver, but it just tears the fins when i try to pry them.

So here's the dilemma - do I replace the $400.00 radiator or not?

Seems like a pretty straight forward job - pull the tupperware, disconnect the hoses and the fan, remove the radiator, swap the fan, reinstall in reverse order.

I'm hoping to replace this bike this year.

Your thoughts?

 

[want2ride]

I would recommend doing nothing unless it actually overheats. Running 3-4 bars is not a big deal to me. Not sure of how others will feel about this issue....

 

[Geezer]

My '05 does the same thing, and I don't see bent fins on mine. I do rinse out the bugs once in a while with the garden hose. I don't sweat it.

If you do feel the need to do something about it, take the radiator out and work in a comfortable place to straighten the fins and clean out the dead bugs. I wouldn't replace the radiator unless it is leaking or crushed.

 

[Ignacio]

Bike was running a little hotter than normal on Friday. Ambient temp is in the mid-80's mid-day. Temp display goes to 3 bars in traffic slower than 60 mph and even 70-ish mph on the slab tucked behind a truck or large vehicle. Fan kicks on a 4 bars in stop/go traffic, runs a little longer than it normally does, brings temp down to 3 bars, and then kicks off.

Sounds totally fine to me. If it's not overheating (think 7 bars or more) then no problem.

 

[infrared]

My '05 does the same thing, and I don't see bent fins on mine. I do rinse out the bugs once in a while with the garden hose. I don't sweat it. If you do feel the need to do something about it, take the radiator out and work in a comfortable place to straighten the fins and clean out the dead bugs. I wouldn't replace the radiator unless it is leaking or crushed.

hppants,

If you take this option, you will not need to get every fin perfectly straight, or even close. As long as more air flows than before, you are doing well enough. A slightly bent fin probably tranfers heat better, due to the turbulence in the air flow.

Cheers,

Infrared

 

[ionbeam]

^^^^^^ Ya gotta respect details on heat when the author is named infrared

 

[Brodie]

Take the bike to a reputable radiator shop and get a quote from them for the repair. That's what they do.

 

[ionbeam]

Just to pile on other ideas, perhaps the thermostat isn't fully opening (unlikely) or the temperature sensor is drifting with age.

 

[Enn]

I did the same trick to my radiator, with the power washer. Was also worried about overheating, bought the fin brush, but could not use it on this radiator. To my luck, even if I have been riding in really hot conditions like >+35 C in Italy in slow traffic and the kind, the bike never came even close to overheating. So I am positive you do not need to be worried at all.

 

[audiowize]

I would classify this as paranoia. If you want to spend money on parts and mess with it, more power to you, but you might end up with other issues that aren't there now.

 

[infrared]

^^^^^^ Ya gotta respect details on heat when the author is named infrared

Ionbeam,

Thanks. That handle does come with some good stories.

Anything done to cause a little turbulence in the flow will make cooling tubes more efficient.

Canted radiator core tubes:

Twisted tubing:

Hppants will probably get some extra cooling efficiency, from slightly bent radiator fins.

Cheers,

Infrared

 

[MrZappo]

You will likely be OK.

But, I'm going to go out on a limb and say that they are the "best" exactly as the engineers designed them from the factory.

I'm very familiar with evapco products and guarantee that everything they do is done with purpose and to fulfill specific design specifications as part of an integrated system.

Yamaha did make significant cooling system requirements for the Gen II and later. I realize that your 2005 is Gen 1 though.

In any event, we don't know the design specifics Yamaha used or if bent fins would restrict airflow enough to cause problems elsewhere. Or if they would improve things.

Maybe neither, maybe a little of both.

There are way to many variables to know without testing.

In any event, there is likely significant excess capacity of heat rejection in the first place. Probably 20 percent more than the worst temp they expect the bike to experience.

So weather or not you get a little more or a little less capacity, you will still likely be in an acceptable range.

I wouldn't be so sure about it being a benefit though.

My 2 useless cents.

 

[PhilJet09]

So this winter I had my radiator off again and was looking at the fins. At least 25% of the radiator was plugged with tiny pebbles, just large enough to fit between the fins. Not sure where I'm picking all of them up. Anyway, I tried air and water and didn't get many of them out. I resorted to cutting down one of my feeler gauges to fit between the fins and then spent about an hour using it to clean those spaces out. I ended up with a pretty sizeable pile of what I call large grain sand. Pushing the feeler gauge through the fins straightened the bent ones back out as well. I like to think my bike runs a bit cooler, but that could all be in my head.

 

[majicmaker]

Of course it's in your head, Phil. But, that doesn't mean that your bike isn't running cooler.... [Harry Potter - Deathly Hollows Part 2]

 

[wheatonFJR]

So this winter I had my radiator off again and was looking at the fins. At least 25% of the radiator was plugged with tiny pebbles, just large enough to fit between the fins. Not sure where I'm picking all of them up. Anyway, I tried air and water and didn't get many of them out. I resorted to cutting down one of my feeler gauges to fit between the fins and then spent about an hour using it to clean those spaces out. I ended up with a pretty sizeable pile of what I call large grain sand. Pushing the feeler gauge through the fins straightened the bent ones back out as well. I like to think my bike runs a bit cooler, but that could all be in my head.

Cooler heads prevail.

 

[Redfish Hunter]

Just to pile on other ideas, perhaps the thermostat isn't fully opening (unlikely) or the temperature sensor is drifting with age.

How DARE you to suggest the temp sensor might drift over time! Everyone knows that once it is built it never moves and never breaks.

I would argue with you some more but I have to go replace a thermocouple. Then I have to re-calibrate some temperature and pressure transmitters...

'Pants I suspect that you have nothing to worry about with regards to the radiator. It would take a lot of plugged fins to seriously degrade the heat transfer. You might think about changing the T-Stat or...

You could just trade the thing in to my favorite motorcycle salesman. I am sure G squared is around here somewhere and would love to take your money.

 

[LKLD]

Of course it's in your head, Phil. But, that doesn't mean that your bike isn't running cooler.... [Harry Potter - Deathly Hollows Part 2]

Way to go Dumbledore.

 

[wfooshee]

Having had to remove the radiator last summer as part of my other repair (you remember that, right, 'pants?) I can tell you right now that pulling that thing is NOT a job you want to take casually. All KINDS of **** is crammed up around those top mounts, and that thing has way more hoses that a simple upper and lower, too!

But as long as it brings it down with the fans running, you're getting enough cooling. You might not wanna plan any Death Valley rides for the moment......

 

[Mudslide Miller]

Coolant used is Honda-pre mix.

You answered your own question, your bike now thinks it's a Honda.

Ride it till you're ready to trade it 'Pants.