For the doubters and sceptics, an Engineer's view.... The bike is designed to work and run ok in a wide range of different climates. So that's why bikes run cooler in the UK. It's not a bad design, in fact you could argue that it's actually quite impressive that the bike will work across a wide range of climates. It's just that here in the UK it's cooler, so the bike runs cooler. So it could very conceivably be made to run warmer with little or no risk to the engine or cooling system. Whether that would impact fuel economy, mixture, performance, rideability etc. would all need to be tested and verified.
Just to be clear, I have not started this thread because I am stating that it is a bad design. But what I am saying is that in 30years of riding motorcycles and cars, small to large, slow and fast, always the coolant temperature has been around 90C in the climate I live in. Sometimes warmer is stop and go traffic or high ambient temperatures. So with the Multi running at 65C it is out of the (my) ordinary.
The engine's temperature is controlled by the thermostat, not the weather, not the amount of radiator you cover.
If the temperature gauge is as accurate as the fuel gauge then who knows what temperature the bike is running at!
The engineers should indeed have designed the cooling system to be able to cope with all ambient temperatures that the bike may encounter (except for maybe some really extreme climates). But to be able to do this, the radiator surface needs to be available, so you cannot just cover a large part. If too much is covered the is not enough heat-exchange surface to allow the system to cool the engine to the specified operating range.
May I ask how you draw that conclusion? I ride my bike all year round, all round the UK, so I'd consider myself well-versed in the British climate.
OK Stupid question time What is the temperature showing? Oil Temp or Water Temp? Reason for asking is that on the Ducati I don't know but on my car it definitely shows the Oil Temperature not the water temp, obviously they are linked but just wondering.
Thanks, In that case my 4 previous VTwin Multis all ran cool water in the UK without any issues at all. The V4 should make a good cuppa tea in traffic as it runs noticeably hotter
Agree the bike works OK, it will no doubt run for 100k miles at UK temps and we'd likely not notice any issues (related to low temp at any rate). This doesn't mean the bike isn't spending a lot of that time with suboptimal engine temperatures (be that for efficiency, power and longevity). IIRC the thing that killed off the old air cooled R1200GS engine wasn't unreliability caused by an inability to tightly control engine temp, it was the result it had on emissions. Many cars have gadgets to limit air flow around the engine to get them to heat up quicker to aid emissions (BMWs close the grill for example). If the only thing that controlled engine temp was the water thermostat why would BMW go to the bother. The old BMW 530d car engines were notorious for suffering thermostat problems (failure mode was not closing properly). There was no indication on the dash (the e60 5 series didn't have a temp gauge and it didn't throw a check engine light). The first thing you'd notice was significantly reduced fuel consumption. Another example of something being OK (no alert to driver), but far from optimal. I know, a deisel engine, but the principles still apply. These are primarily emissions related examples as that is the factor that drove the industry to change designs that were otherwise OK. For me this is an interesting theoretical debate rather than anything else. Very few bikes will ever cover enough miles to wear out the engine, even if it is running at a suboptimal temp. I'm curious how much contribution these 2 factors have; Its a v twin with all 4 sides of each barrel exposed (not insulted by adjacent cylinders as is the case on an inline engine or even a v4 or parallel twin). Oil flow through the cooler isnt regulated, e.g with an oil stat. I notice the engine temp plumet (into the 60s) when riding at speed on main roads early in the morning or on cool summer days, e.g. when the flow of cool air around the engine and through the rads (even when you'd expect the water thermostat to be closed) is greatest. I cant say I notice the cool running temp, even in cool weather, whilst riding at urban speeds or stationary. Will this stop me riding in those conditions, no. Does it get me wondering, yes. Is it s bad design? No. Is it a clever design, yes I think it is. Is it a compromise, most definately.
I recognise the temperature problem with the BMW (E61 in my case). The EGR thermostat was stuck open resulting in an engine that most of the time did not reach normal operating temperatures. Because of this the fuel consumption increased. As you said no temp guage on the dash so I had to find out through the OBD port. Replaced the EGR thermostat the the consumption instantly dropped.
I concede the Dynamic flaps are for aerodynamics, I hadn't realised. I meant clever in as much as they get 150bhp out of an engine that even with its faults its relatively reliable. Not clever as in innovative. I've chimed in on and off on here for years sharing my view that the running temp is too low. I put some theories on the table, I don't think I said the oil stat was the solution. Having now read the rest of the other thread it does look like the chap has pinpointed the issue as the coolant thermostat. I'll invest in the Aprillia thermostat or machine up a housing for a standard thermostat (as I'm also lucky enough to have a lathe and a mill etc.)
