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GT engine heat issue

9K views 41 replies 21 participants last post by  Lighning 
#1 ·
I had an earlier 2013/ 14 F800 GT model and found - as very many others did - that the heat emanating from the lhs of the engine/ fairing was almost unbearable, especially as I ride mainly in a sub-tropical clime most of the year.

I'm now looking at a new 2018 GT model after having had my fill of larger boxer twins and others - getting old and frail!

Has there been any improvement in this excessive heat issue since the bike was first launched - any inputs gladly received? TIA.
 
#3 ·
I am new to the bike and have only been riding it for a few months, and riding temps have gone up into the 80's - but no 90's yet.

The only time I noticed a lot of heat was when I fitted a larger windscreen - it caused a big increase in the amount of hot air coming out of the vents by my thighs. I imagine the extra flow is a result of the larger low pressure area behind the larger windscreen.

I am currently using a cut down windscreen and I don't even notice the hot air from the engine - but I ride in a rural area and spend very little time in traffic.
 
#4 ·
This is a 'new' contribution to what seems a problem for many of us, but not for others, I wonder if you've found at least one of the reasons. Personally when it gets too hot a just stick a bit of gaffer tape over the vent - one day I'll do it more professionally, but at least in the winter I keep a little warmer....[:)]
 
#5 ·
Few years back, when my particular F model was sorta new, I sat in a seminar with the big honcho of BMW Motorrad (don't recall his name but it was German) where someone in the audience asked a similar question: "Does BMW have a solution for the excessive heat put off by the new F engine?" The answer was something like this: "There is no real problem with our engine heat management; perhaps you should wear proper riding pants?"

I learned a lot that day about German engineering.
 
#6 ·
I live and ride in Tucson and the surrounding area. Regularly in the 90's and 100's (30-40C) this time of year. I don't have any particular issues unless I am in the city in stop and go traffic when the fan kicks on and hot air is blown onto my thighs. That's hot.. The rest of the time it's a non-issue, and I even wear jeans a lot of the time, which are not optimum.. In fact I much prefer the F800GT for local riding than my RT with that big fairing. I get plenty of airflow..

However one thing that was mentioned in previous threads was heat from contact with the frame rails. Hmmm.. I have checked my riding position while riding a couple of times. My legs do not come in contact or even close to the frame rails, they are an inch or two away. Yet I can see from minor scuff marks on the rubber frame insulators that the prior owner apparently did. Based on the fact that some find it intolerable and others barely notice it, I suspect it is a fit issue, and this has something to do with it. The frame gets pretty warm, even hot, and if your legs touch the frame rails or tank with your legs, then you will need insulated pants. Just my 2 centavos..
 
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#8 ·
I notice some heat coming from the engine. But only every so often. I was riding across Eastern Washington last Thursday and the temperature reached 100F. I didn't notice it then.

When I do notice heat coming off the engine, it seems to be more when the wind is coming hard across the bike from one side or the other. Then it seems like the heat off the engine exits only on the leeward side. Then I notice it. But...I've never found it unbearable or anything more than a passing thought.

Fit is perhaps a reason why some people notice it more than others...besides the type of riding pants we wear. If you use an infrared thermometer on various parts of the bike after stopping, you'll see some definite hot areas on the frame. It's really to be expected, since the engine is mounted directly to the frame.

Heat from an engine sitting between your legs is not unusual. I find the heat to be no different in amount than I had on my Honda NT700V. I belong to other forums for different makes and heat is a very common comment on a faired bike.

Chris
 
#9 ·
Well I wear 'proper' kit, often with winter quilt lining and a pair of trousers! I still feel the heat - which is OK in winter, but come summer when I reduce the layers (good textile kit) it can become unbearable. My take is that my knees cover the vent rather than the 'tank' - yes I'm vertically challenged with 30" inside leg and I've always ridden gripping the tank of my bikes over the last 60+ years - but none ever got as 'hot' as my GT - but I'll persevere!
 
#15 ·
I'm 6'4", have ridden my former F800GT many days in hot weather, and never noticed the issue, and attributed this to these Olympia X Moto 2 pants I use. Maybe my longer legs changed the issue I'm not sure, but as I say, never had an issue with heat:
View attachment 343523
Now you have me wondering...

I don't have any fancy-pants and not exactly height challenged, 6' and 33". My riding style is, 'grip the tank with your knees like it has your rent money in it.' (Old YouTube video.) The heat is noticeable, but not unbearable. When stopped in traffic I do relax the legs away from the frame to vent a bit. But while riding, even at a fairly slow pace, the heat is not a bother at all. I am running factory-size windscreen.

My wonder is whether taller riders are not blocking some airflow as much? Perhaps a shorter leg is covering, just enough, to increase the heat retention.

Have actually come to embrace it a bit, knowing the engine is up to proper temp and running well. Have also noticed when the bike is at proper temp, my fuel consumption goes down appreciably. I.e. short runs without heat-soaking the frame averaging 50mpg. But longer rides with proper miles and everything up to full temp I am getting 60+mpg.
 
#16 ·
Short rides in town have the penalty of stop signs and stop lights. It takes a lot of miles to make up for that.

When I owned a Suzuki Burgman 400 scooter, it had an average MPG readout. Coming back from the Costco gas station a few miles away, I'd be up to 73 mpg on the readout...especially when I coasted down the hill to my driveway. The next morning going back up the same hill, it would drop a lot. My commute was 37 miles each way. On the way to I-5, I had to pass through two stop signs and about 4 traffic lights. By the time I hit the freeway on-ramp, my MPG readout was down to about 55 mpg. It took about 15 miles for the readout to start climbing from just those few stops. By the time I got to work, it would be up to about 63 mpg.

I notice the heat coming out of the vents and off the frame...I just wish it would be a lot warmer on days like today when the temp is 55F. :)

Chris
 
#18 ·
Just returned from a 12 day 4,00 mile trip to western Nebraska on my 2016. Rode in temperatures from 50's to 93 (F). The heat was not an issue as long as the temperatures were below the upper 80's. Once into the 90's it got hot. I always wear long cotton pants and over pants. In the 50's the heat is nice but not that much. Most of the trip was in temperatures of 80 or less and was very pleasant. Heat is mostly an issue when at high speed in temperatures over 90 and when in stop and go traffic.

A part of the problem is that the engine runs very lean which tends to generate more heat. A very nice side benefit is the ability to get great gas mileage. When going long distances with unknown gas stations it is very comforting to know that by slowing to between 50 and 60 it is possible to squeeze 70 or 80 mpg out of the bike. I did notice that the mileage computed by the bike tends to be less than what it really gets - not a new observation.
 
#19 ·
. . . I did notice that the mileage computed by the bike tends to be less than what it really gets - not a new observation.
I've been thinking, and talking to riding buddies, a bit about this topic. Some claim that computing fuel mileage manually (you know, dividing the distance between fill ups by the number of gallons put back into tank) is the most accurate way to determine a vehicle's fuel mileage. The questionable factor here is always filling up the tank to the precisely same level each time; pretty hard to do. Others claim that letting the vehicle's onboard computer calculate the mileage is the most accurate way because it knows how much fuel was actually used by the engine, not how much was put into the tank.

My personal experience over decades of being anally retentive enough to write down every fill up and save those little notebooks in my closet, is that the difference between manual math and computer calculation varies from slight to not even measurable. A couple years ago I quit writing down the fill ups and now just go with the computer mileage. The slightest twisting of my right wrist, or a few RPM difference in my shift point is probably more important to the fuel mileage the bike gets.
 
#20 ·
I'm one of those anal retentive people on my gas mileage. I started on my first car...and 50 some odd years later, I'm still doing it. (Gosh, that makes me sound old...)

Here's a snapshot of the spreadsheet I use. I also keep it on Fuelly.

Font Parallel Screenshot Number Pattern


One column is the calculated MPG. The other is what the bike's readout showed. I try to figure out under which conditions the mileage is off. On the last circled figure of -7.64, that's a big difference that can affect what you do on a trip. FWIW, all of which you see there were hard fast riding up and down hills and hitting turns hard. That's pretty good mileage, IMHO. But on that one readout on line 320, that's the difference between a range of 188 miles and 218.

What seems to be my best indicator of range, is when I hit the half tank mark. At 50 mpg, it'll be at 120 miles. At 45 mpg, it'll be much lower.

Chris
 
#21 ·
OK Chris, you win. In all my years of keeping these kinds of data my delta was NEVER as great as some of yours. You are apparently a harder rider than I. So maybe for you it is better to keep both manual and machine-calculated data.

For the life of your 800, what is the machine's overall fuel consumption rate? Mine is 55+mpg overall with a "high" tank of 92+mpg and a "low" tank of 49+mpg.
 
#22 ·
56 mpg is my average. 71 mpg is my highest. My lowest is in the mid 40's.

I live in an area that is known for traffic congestion. So I've given up worrying about maximizing my gas mileage in local riding. The only mileage I pay attention to, is when I'm traveling outside the area, and that only to make sure I don't run out of gas. I set 180 miles as my range for planning purposes. If I'm riding into a stiff headwind at high speeds, I may only get 48 mpg, so that gives me a little buffer. And if I'm getting 55 mpg, I have a much larger buffer...but my rear still needs a break.

I did notice something interesting on my Northwest Concours Rally trip. I was in 2nd, 3rd and 4th gear a lot to keep up with these guys. Yet my gas mileage as you can see was still consistently at 50 mpg or better. I think the reason is that when in the lower gears (not 5th or 6th), when I twisted the throttle the response was immediate. When you are in the higher gears, you twist the throttle and get a delayed reaction. You're probably delivering more gas to the engine, just not seeing the result.

Chris
 
#23 ·
WOW that is detailed record keeping. I just put gas in and get back on a ride, generally do a quick mental calc to see if mileage is where I expect it to be. I do fill to almost the exact same spot every time - tank iOS small so try to get as much as possible in every time. My mileage was pretty consistently 5 to 7 MPG difference between the bike and the calculate mileage. At higher speeds with the side cases on I have several times gotten mileage of 39 to 40. When local I almost neve have ethanol free gas. When in Nebraska and Wyoming i was able to find ethanol free gas which gave me better mileage. I did notice from the instant mileage displayed that it seems to give the same milage regardless of wether in 4th, 5th or 6th gear - note this is just a casual observation and not a careful study. Didn't seem totally logical.
 
#24 ·
F800gt heat issue revisited

Hi fellow GT riders, last spring I traded in a 2009 ST for a 2013 GT. I live in Northern California and last summer we had many days where the temps were above 100 degrees. That is uncomfortable for riding any bike, but the GT was really showing the engine heating problem. After reading all the previous posts here is a solution that I found purely by chance.

One day I was buying something at our local hardware store. As I was checking out I noticed a cheap pair of knee pads for gardening. They are made of hard foam and you attach them via velcro bands. I immediately thought - hmm wonder if these would help with the engine heat. I purchased them and they work like a charm. They do two things, provide insulation against the heat and they also force your knee a couple of inches away from the bike so there is better air flow. On longer rides I wear them inside my riding pants. On short trips around town, I just strap them on the outside of my trousers. For $15 the heat issue was solved.

Relating to engine, or body modifications for the heat issue, I just had my spring service done at Ozzie's BMW in Chico, CA. I talked to them about the heat issue and they advised two things. First, do not do any modifications. He said that BMW obviously spends a lot of time designing and testing the engine and fairing design and he thinks trying to change things is counter productive. Their recommended solution is wear better riding gear with more padding.

By the way, if you live in N Cal, plz check out Ozzie's. It is a fantastic shop, great guys reasonable prices and it was the best service experience I have ever had!

Hope this helps.

Synthetic rubber Wood Belt Automotive tire Cylinder
 
#32 ·
Good one Phil! My last long warm weather ride was over 18 months ago but I can recall I had plenty of time to ponder the GTbarbecue issue. Like Daboo (who?) I noticed that the problem was greatest when the apparent wind direction was somewhere around 40-odd deg. from dead ahead. Fairing aerodynamics providing negative pressure around the side vents at thigh level, perhaps?
My GT is one of the last built, 2019, so I am pretty sure there has been no OEM activity on the issue over the model run. I am loath to block off or redirect the vent, there is a lot of electronics up under the "tank" area, that I think would not benefit from slow cooking.
Still hoping for a solution apart from firefighter wear, we are hoping to resurrect our LongRide program towards the end of this year.
 
#33 ·
Seriously, I was thinking of sewing some insulation material into the inside of the upper leg of my summer jeans for hot days. The stuff they put in oven gloves and teapot cosies. I'll let you know how it goes.
Several days of my trip to the South of France last year were pretty interminable.
 
#34 ·
I only found heat to be difficult with temps 93 and above. Gripping the tank made a difference. Running 85mph on I80 (80mph speed limit) in 95F temps would get it nice and toasty! Any faster and it would really be putting off a lot of heat. I rode in temps up to 103F but combination of stiff headwind and high ambient was the worst. I could slow down 5 mph and it would make a difference. I’d splay my legs out from time to time to cool off a bit.
 
#35 ·
I can't be the only fool riding in this heat lately..

I can't be the only fool riding in this heat... or maybe I am. Pro tip: the ambient temp sensor reads spot on at 113F, and increments down satisfyingly in 0.9 steps from there...

Left side oval port was a heat gun at any speed above 50, but the engine thermostat readout never budged from the lower tick mark. Evaporative cooling vest allowed me to make it home to share. Would have done it again tomorrow but hey, surprise federal holiday.

Plant Motor vehicle Vehicle Gauge Automotive tire


Sidebar: oddly enough, my instrument cover got death rayed a month ago at 75F, and through a tree... always park her facing the sun.
 
#36 ·
I can't be the only fool riding in this heat... or maybe I am. ...

Sidebar: oddly enough, my instrument cover got death rayed a month ago at 75F, and through a tree... always park her facing the sun.
I leave for South Dakota Saturday morning. I'm sure I'll be joining you in 100+F temps. :D As for the death ray...buy a Madstad next time.

Chris
 
#37 ·
I can't be the only fool riding in this heat... or maybe I am. ...

Sidebar: oddly enough, my instrument cover got death rayed a month ago at 75F, and through a tree... always park her facing the sun.
I leave for South Dakota Saturday morning. I'm sure I'll be joining you in 100+F temps.
As for the death ray...buy a Madstad next time.

Chris
Chris- Your Madstad- is it tinted? I'm still playing around with the oem and Puig screens mine came with, but I think a Madstad is next. I went to order one the other day and second guessed myself on the size. What size screen is yours? I think somewhere in a previous post I saw we may be similar heights. I'm 5'8" and shrinking, I think.
 
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