Hot weather riding, engine temp

[Gearhead]

Hi. This is a question mainly for those of you who live in hot areas, like 90 plus, regarding engine temp. Now I know the gage catches alot of flak for inaccuracy, but what I've noticed is consistent. If I'm riding at any kind of steady speed in cool weather, my 87's temp runs at about 1/3, where there's a little gap in the green line on the gage. I'm assuming this gap indicates "normal" which I think is 180, right? As the weather warms, it doesn't hold there. When the weather gets over 90 or 95 temp tends to run more like 2/3 or 3/4, right about where the fan kicks on. At mellow speeds, like 55, it might go a little lower like 1/2 plus, but on the Interstate the increased wind drag loading causes the temp to go up. In fact, it may be kicking the fan on and off, but it's hard to tell at those speeds. It does generally hold at that temp, not continuing to climb into the red. One time, in extended riding at 107 deg and 90 mph (we wanted to get it over with) the temp was getting close enough to the red to make me a little nervous. I know there's limits to everything, but if the cooling system and thermostat are effective, it really should be more steady regardless of the weather, methinks.

 

Furthermore, I'm pretty sure I see a correllation between hotter temps and reduced gas mileage, by maybe 2 or 3 mpg. The one trip mentioned above was horrible, 26 mpg or so. I also notice a little ping here and there in hot temps, so I run higher octane gas in those times.

 

Is my bike just like everyone else's, or should I look for trouble? I've flushed the cooling system but never replaced the t-stat or anything else cooling, for that matter.

 

Jeremy

[GigaWhiskey]

Sounds like mine. That is even after all new hoses and thermostat. if it goes over 100 degrees and I am running 70 to 80 for about an hour+, throw some BBQ sauce over me cause i am done.

 

My calves get so hot they hurt. The heat comes right through the seat and starts to work on my own parts perty bad.

 

Ran from Nacogdoches to McKinney and it was about 107 degrees out. About 20 minutes left to the house, the gauge was pegged.

 

I really do not want to ride when it is over 100 degrees, takes all the fun out of it for me.

[Squeeze]

Maybe it's time to flush and descale the Radiator ?

[Gearhead]

GW, I know whatcha mean, but yours sounds worse. What did you do when the gage pegged?

 

Your 85 has open triangular areas in the side panels beside your calves, right? My 87 has the adjustable louvers, and closing them makes a HUGE difference on my legs. In fact, in the summer I tape a piece of auto underhood insulation over the inside to help prevent leakage. I also glued this stuff to the entire inside surface of both side panels. Passenger still gets a fair bit of heat leaking from below the panels, though. But if you could get louvers or fabricate a decent-looking plate to fill the hole, you'd love it in the summer. And the sheepskin I have on the seat helps insulate the boys and their house from heat leakage from under the "hood". Baker Air Wings help alot too.

 

I gotta say, though, that my Virago is a nicer ride when it's hot. Knees in the breeze, and the air-cooling transfers the heat directly from the cylinders which then blows behind me. Contrast this with the Venture's radiator being out front, so all the heat comes right back to me. And no temp gage means no overheating worries, right? :-)

 

Jeremy

[Gearhead]

Maybe the radiator needs rodding or something. I did do a chemical flush on the system. Maybe the t-stat is not opening all the way. I'd like to hear from other hot weather riders, though, if this is normal, typical behavior for these bikes. Maybe the cooling system just isn't up to the task.

 

A couple more observations:

My daily commute involves 25 miles, about half of it Interstate with a few miles of 2-lane on each end, and a mile of dirt to my house. Yesterday I rode home in 95 degree weather. Once going on the Interstate, it stayed at that 2/3 level and I suspect the fan was going most of the time. By the time I got home after the slow dirt road, it was still right about the same on the gage, fan running, coolant overflow tank chock full. By morning the tank was normal level, between the marks, so the recovery system is working properly.

 

This morning I came in with 85 degree weather. After riding the dirt and 2-lane, the bike was fully warm, gage camped at 1/3 on the gap in the green line. Once on Interstate, temp went to 1/2 and stayed. Then, on 2-lane afterward going 55, temp crept back down, almost to the gap. This confirms that it runs hotter at higher speed, and that the t-stat set temp is at the "gage gap".

 

I know there's more load at higher speed, but there's also more airflow. But...once a Yammy factory-trained service manager told me that on the Virago's air-cooled v-twin, the rear cylinder actually runs cooler than the front, which is counterintuitive. This, he learned in class, is because the front wheel splits the airflow around the front cylinder and it converges on the rear. Maybe something like this happens to the Venture's radiator at higher speeds. They must have put those little side "scoops" on the grill for a reason.

 

I have some ideas, which I'll post separately.

 

Jeremy

[Gearhead]

OK, one more, this one for cooling improvement ideas. If my system needs repair, that's a different story, but suppose this is as good as it gets for a stock system.

 

1. Extend the grill's "side scoops" out wider to "grab" more fresh air to the radiator. The front wheel has got to block a bunch of flow to the middle.
   
2. Expand the capacity of the radiator. Perhaps a rad shop could get a thicker core with more rows and mount the factory tanks and trim brackets to it.
   
3. I also thought about a bigger core, but this could be a problem. Wider would fit on the bike, but the existing tanks wouldn't work. Taller would work for the tanks, but there's limited vertical space on the bike. There is a little bit, maybe an inch or so, however this might also cause problems for the side trim and mounting brackets. The trim could be redone somehow to accomodate this.
   
4. Add an extra radiator in series. I had a friend back in the day with an 84 Interceptor 1000. It had a radiator like ours, and a smaller one up near the headlight in the fairing. I was looking at the lower scoop, and a radiator from a small bike or an auto heater core might fit in there, and that way the heat from it would be down low and hopefully not blow back on me too much, except maybe for my feet. At a glance, it looks like something 4" x 8" would fit.
   

What about Water Wetter? I admit I'm skeptical. Have you guys that use it really seen a difference in the indicated temp? Where do you get it and what's it cost?

 

Any comments?

 

Jeremy

[SilvrT]

Jeremy... what you've explained seems fairly normal. Mine is pretty much the same and my '85 was too. In fact, my '85 seemed to run closer to the red most of the time.

 

On this bike, I installed an auto thermostat. Can't recall part number but it's an exact fit and a lot cheaper than the Yamaha one, not to mention that it supposedly works better. Somewhere buried in this site is a post with the info for it.

[GigaWhiskey]

GW, I know whatcha mean, but yours sounds worse. What did you do when the gage pegged?

 

Stopped for a few minutes and rode it the rest of the way home. Yes it pegged again.

 

Your 85 has open triangular areas in the side panels beside your calves, right? My 87 has the adjustable louvers, and closing them makes a HUGE difference on my legs. In fact, in the summer I tape a piece of auto underhood insulation over the inside to help prevent leakage. I also glued this stuff to the entire inside surface of both side panels. Passenger still gets a fair bit of heat leaking from below the panels, though. But if you could get louvers or fabricate a decent-looking plate to fill the hole, you'd love it in the summer. And the sheepskin I have on the seat helps insulate the boys and their house from heat leakage from under the "hood". Baker Air Wings help alot too.

 

I have the vents and they were closed. Even with my feet on the back pegs, they were cooking.

 

I gotta say, though, that my Virago is a nicer ride when it's hot. Knees in the breeze, and the air-cooling transfers the heat directly from the cylinders which then blows behind me. Contrast this with the Venture's radiator being out front, so all the heat comes right back to me. And no temp gage means no overheating worries, right? :-)

 

Well, I have read that the best thing to do is put a piece of tape over the gauge and forget about it.

 

Jeremy

 

On regular days, it is acceptable. Stand still traffic gits me worried when that guage starts to climb. Yea, I hear the fan kick on.

[SilvrT]

here it is... NAPA # 156 thermostat

[Squeeze]

Jeremy, i'm a bit confused.

 

Over the Time i came to the Conclusion, you're thinking and analyzing Issues like this as an Engineer. Also, you're argumenting like a Pro.

 

But why is it, that you rely on this Temperature Theme on a Guesstimator Guage ?

 

Any Contact Resistance at the Sensor will in influence the Readings. If you want to know what's really going on, you need to measure the Temps. There no need for a Super High Tech Equipment, nearly anything is better than the Guage in the Dash.

 

Probably, there is something wrong with the Cooling System, and there's no Room for Guessing. Check it, measure it and you can judge by Facts and not by Guesses.

 

 

just my 0.02 USD

 

 

 

P.S.

 

Water wetter works and helps, but with a proper working Cooling System, you won't need it.

[Gearhead]

SilvrT, thanks for the lead.

 

I know there's other hot weather riders - does your bike behave like mine does?

 

Squeeze, you're on to me, I am in fact an engineer, I have the analyzing disease. Are you confused that I'm putting all this thought into the issue based on data from the dash gage? Well, I have two reasons for that:

1. It's all I have! I don't have another gage on the bike and haven't looked into what it would take to mount one.
   
2. I don't think it's all that unreliable. Granted, I don't have temp numbers which would be very helpful. But as far as its consistency of operation over different ambient temps, its reading when the fan kicks on, and other observations, the stock gage really reads quite consistently. I know that in cool weather it always runs at the gap at 1/3, and I know the t-stat starts opening at 180, so I assume the gap is 180 F. I know the fan comes on around 2/3 and according to the manual that happens at 221 deg F. The fan turns off when the needle gets a little above 1/2, which should be 208 F. It's consistency over 2 years leads me to trust it to some extent.
   

Anyway, I'm not itchin' to mount another radiator or whatever just yet, just thinkin'. I think I'm gonna replace the t-stat for good measure, and try reducing the percentage of Ethylene Glycol to about 25% and adding Water Wetter. I do live in a pretty extreme climate, hot-wise.

 

I looked over my fuel mileage figures from the last year and I am now sure that my mileage drops in warm to hot weather. When I'm riding in temps predominantly over about 80 or 85F, my mileage drops by 2 or 3 mpg compared to cooler ambient temps.

 

By the way, Squeeze, I always appreciate your 2 cents, whether in US, Euros, Francs or whatever!

 

Jeremy

[Squeeze]

Jeremy,

 

i'm sure not on to you. If you feel so, i sincerely apologise. But your last Posting shows exactly what i've meant...

 

I assume, i think, i guess, according to the Manual it should be ... Those are Words and Terms which have no Place in analyzing a Situation. Your Argument about not having another Gauge brought me a chuckle, it's true, but who said there can't be another Gauge, temporarily mounted, for picking up real Numbers instead of a Needle in an Area Type Gauge.

 

Even if you buy a cheap infrared Device or a Chinese produced DMM with Temp Option, you can check the Device against boiling Water and know the Readings or even adjust the Device.

 

I'm not saying that the Dash Gauge is unreliable, but it has no Numbers and therefore you have no real Reference to judge your Findings. The Consistency of the Gauge is fine and it works like Yammi designed it, but it's nothing more than a better Guess-o-meter.

 

All that said, i think your Radiator needs another cleaning from inside and from the Outside with an Airgun and a good Load of pressurized Air, or even a Bath in an ultrasonic Cleaner, fresh Coolant with reduced Antifreeze Ratio and probably Water Wetter or you go to a local Shop and ask them about making a new Radiator with a 'tropical Net', i don't know the correct Term in English.

[GigaWhiskey]

I hear if the water pump is seeping from the seep hole, that it may be coming due for a rebuild. Also, I understand that they came with a plastic impeller and the replacement is metal. Could you have a plastic impeller that mwy be wearing, i dunno.

 

I am seeping a little from the seep hole but have not gone in for a rebuild to even see what impeller type I have. I am sure there are posts on this topic - even for the overheating issues and what people have gone through.

 

I have seen this spoken of often here and at another site.

[SilvrT]

I am seeping a little from the seep hole

 

 

That tends to happen as one get older......

[GigaWhiskey]

I didn't realize what I said so I had it coming!

[Gearhead]

i'm sure not on to you. If you feel so, i sincerely apologise. ...

 

... or you go to a local Shop and ask them about making a new Radiator with a 'tropical Net', i don't know the correct Term in English.

 

 

Hey Squeeze, "you're on to me" is just a phrase that means you figured me out. It's has no negativity to it, and indicates no offense. I am in fact an engineer.

 

And I am in fact going on some assumptions that would be better not to make. I haven't had the gumption to rig up something else. Would an IR thermometer pointed at the upper rad tank be a valid way to measure temp (I'd have to pull over, of course)?

 

As for the "tropical net", are you referring to a thicker core radiator, or one that's heavier duty in some fashion? That might be good...

 

Jeremy

[GigaWhiskey]

As for the "tropical net", are you referring to a thicker core radiator, or one that's heavier duty in some fashion? That might be good...

 

Jeremy

 

 

This would be an interesting option for many 1st gens!

[Gearhead]

Per the manual, the radiator is only 5/8" thick. The tanks appear to be 1.5" wide at least, so I'd think a rad shop could fit a thicker core. I may make a couple calls to see.

 

Jeremy

[SilvrT]

Per the manual, the radiator is only 5/8" thick. The tanks appear to be 1.5" wide at least, so I'd think a rad shop could fit a thicker core. I may make a couple calls to see.

 

Jeremy

 

Wouldn't a thicker core just make the rad require more coolant to be cooled? Seems to me it's the amount of exposed fins that would provide more (or less) cooling effect...???

[Squeeze]

Hey Squeeze, "you're on to me" is just a phrase that means you figured me out. It's has no negativity to it, and indicates no offense. I am in fact an engineer.

 

And I am in fact going on some assumptions that would be better not to make. I haven't had the gumption to rig up something else. Would an IR thermometer pointed at the upper rad tank be a valid way to measure temp (I'd have to pull over, of course)?

 

As for the "tropical net", are you referring to a thicker core radiator, or one that's heavier duty in some fashion? That might be good...

 

Jeremy

 

Sorry, i translated this wrong. Your Descriptions is axectly what i've meant to say.

 

 

I'd mount a IR Device facing towards the Alumium Collector on the right Side of the Carbs, just there the Sensor and the Fan Switch is placed. This Way, you measure the hottest Coolant from front and rear Cylinders and also at the Place where the Bike's Devices mount and operate. You can check the Trigger Temperature Hysteresis of the Fan Switch as a Side Effect.

 

The 'tropical Net' is not only a thicker Core, but also a Core which has smaller but a Lot more Ducts inside the Core. I had let a local Company make three of them for 1500cc Maxxes. This worked out very good. The Price was not cheap, but cheaper than a new Stock Radiator from Yammi. If you'd make the Calls, make sure that you get an black painted Radiator. Black has more cooling Capacity than any light Color.

[Gearhead]

Wouldn't a thicker core just make the rad require more coolant to be cooled? Seems to me it's the amount of exposed fins that would provide more (or less) cooling effect...???

 

A thicker core gives the air passing thru the radiator more time in contact with the hot coolant (indirectly thru the aluminum or copper). More time means more heat extracted. It would be kinda like mounting two stock radiators back-to-back. Fin count is also very important. I'm sure that in expanding a radiator it's theoretically better to go wider and taller (like two radiators side-by-side) than thicker, because that would expose the radiator to more fresh air rather than longer exposure to the already hot air. But wider and taller are not easy without bike mods.

 

Squeeze, black radiates better, but I would think the dominant mechanism of heat transfer is not radiation but rather convection which is color-independent. No?

 

Jeremy

[SilvrT]

The 'tropical Net' is not only a thicker Core, but also a Core which has smaller but a Lot more Ducts inside the Core.

 

Hence...more "fin count" ... which translates to better cooling.

[Squeeze]

I totally agree on Convection being the prime Factor on Heat Transfer.

 

I've read three industrial Studies over the last Years. Two of them were Automotive. All stated even when Paint (any Color) is an Isolator and prevents a Portion of Heat Transfer, a black Paint lifts the Efficiency of the Radiator.

 

The Engines ran cooler, in their test Arrangements up to 8K. In Cars on road Tests, they have had a 5K lower Coolant Temperature.

 

The third Study was from the Hydraulics Industry, with basically the same Results, of Course with Hydraulic Fluids as Medium not water based Coolant.

[GeorgeS]

Double check that stupid little Valve, in front of the radiator, make sure its in the correct position.

 

Also, a question: Has anybody ever Washed this bike with a High Pressure Spray Washer ??

I found this out the hard way, that if you water blast the front of the radiator, that the Horizontal cross fins of the radiator, will all get flattened down. This will cut down on the Air Flow thru the radiator.

I did this a couple times, and next time I pulled the radiator I spent about an hour straightening out the fins with a small tool. ( my mistake )

 

I have been useing the Prestone " Dex Cool" radiator fluid. The Orange colored stuff, GM approved. They claim it carries, and dissapates more heat then the green stuff. ??? Who knows, Anyway I use it in both cars, and both bikes, no problems in all 4 units.

[Squeeze]

Any Updates ? Inquiring Minds want to know ...