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Commuting in summer on a big bore air cooled bike

Discussion in 'Bike Reviews, Questions and Suggestions' at netrider.net.au started by Eddo, Oct 18, 2010.

  1. Gidday

    I was wondering if anyone has had any experience commuting over summer on a big bore air/oil cooled bike such as an Xjr 1300 and if there is a tendancy to experience engine over heating problems on for example 35' plus days? My daily commute is approx 20k of freeway and a slow occasional filter crawl for the rest. The yam and the gsx 1400 are on my list. No other bikes are being considered as I've pretty much decided either of these is what I want. I know these bikes not an ideal commuter proposition but I just want one.



    Regards
     
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  2. I used to commute on an air/oil gsxr1100. they never overheat as such, but you do get a worried about the stress applied wen you are completely stuck. They cool down pretty quickly with a bit a movement.

    In fact I'd say the Triumph suffers more in the traffic. Once it get to the point where the thermo fan comes on it wont cool again unless I get a fair bit of open space and speed. The whole time roasting my legs and groin.

    I used to run heavier weight oil in summer. I have seen the light stuff boil on a DR650.

    The modern xjr and gsx are in a lower state of tune.

    So overall they shouldn't be a problem commuting. Look at it this way; if you are only using 25hp it doesn't matter what the engine configuration or capacity is you've still got to dissipate the same amount of heat.
     
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  3. I never had any trouble with my Bandit 1200S but both of my Moto Guzzi twins really didn't like hot days and stop/start peak hour traffic.

    I suspect some air cooled bikes handle it better than others, the Bandit for example is oil and air cooled, not just air cooled.
     
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  4. All my bike does when it's over 35 in peak hour crawl is ping under load, it does feel hot but cools very very quickly when you are moving.
    Fresh heavier weight oil works wonders. This is a bmw r1100s
     
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  5. It'll be fine. If you're super paranoid just change the oil twice as frequently (no need to do the filter as well) for cheap peace of mind.
     
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  6. Your BMW is air/oil cooled as well though Smee. There aren't a lot of pure air cooled bikes left on the market these days.
     
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  7. The difference is more academic than real. All aircooled engines that I'm aware of rely on their oil to carry at least some of the heat away from the hottest area of the heads (adjacent to the exhaust ports, generally) to somewhere that it can be dealt with more effectively. Whether that is a sump/crankcase where it can be transferred to passing airflow via finned ally walls or whether it goes to a dedicated oil cooler, the principle remains the same. The only real difference between oil/air cooled bikes and air cooled bikes that I can see is in the presence and size of the cooler. Detail differences in internal circulation routes are just that. Detail.
     
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  8. Those details add up to significant differences in real, measured heat transfer ability though.

    The Bandit motor (for example) has approximately 3 times the oil pump oil circulation rate compared to the earlier GSX1100 4 valve motor and a greatly increased ability to disperse heat.

    That extra heat transfer ability was used to obtain power outputs in the later air/oil cooled GSXR1100 motors that were about 30% higher than those that were attained in the earlier GSX1100 4 valve motors at almost identical operating temperatures. Sure you can get that same amount of power out of a GSX1100... but it runs HOTTER.
     
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  9. Eddo,
    you'd be very unlucky to have a problem at all mate,....... this very question has been brought up on the GSX1400 forum and to be honest.......regardless of the day, the guys basically dont think it gets hot enough for the fan to even come on so.........
    Theres your answer (wink)......... get a 14 !!\\:D/

    The fan on mine has never come on to my knowledge

    Cheers, Rogues
     
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  10. Sure, and if you can find a workable method of putting 3 times the volume flow of oil through a GSX1100 head, it'll run a whole lot cooler too.

    My point is not that engines such as the old GSXR, the BMW twins, my own DR650 do not cool better than their earlier counterparts. Obviously they do. But, marketing hype aside, they're still basically aircooled lumps without (in most cases) much extra oil capacity to act as a heatsink and without radiator fans to create artificial airflow when the bike is stationary. Indeed, at idle in slow traffic, I doubt if their ability to shed heat is that much better than an older engine design, the improvements becoming more significant at high outputs (ie big throttle openings).
     
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  11. The buell is air-cooled I find that if I can stand the heat in atgatt then the bike can hack it.
     
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  12. Riding both a GSX-1100EF and an XR600R. Both air-cooled, both running well. Only really notice the warmth from them when moving slowly through traffic, and it isn't really an issue as I filter every opportunity I get. Part and parcel of having a motorcycle.

    The GSX does give off a bit extra warmth when you're gunning it, but again its not an issue and would be expected on most aircooled bikes. Hell, they had 40'C days when they made the bikes back then, too, you know.

    - boingk
     
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  13. Thinking about it, the blast of heat from my old (watercooled) K100 when the fan cut in was pretty spectacular too.

    Bottom line is that all bikes will run a bit warm if sitting in traffic. Unless something is very wrong, though, it will do no harm and temperatures will recover to normal very quickly on getting a bit of airflow going.
     
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  14. In fact I'd say the GSX would be better. The R has the radiator without a fan stuffed up under the fairing, and short engine fins. The GSX has much more pronounced fins and they tend to be much more exposed to air. So in still or near still conditions I'd say the gsx would be superior.

    Of course the modern gsx is even better because it is air/oil and the engine is nice and exposed to air.
     
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  15. I tend to agree. My DR ( a bike that might reasonably be expected to see m uch more slow speed work than a sports bike) has, allegedly, the same SACS(?) oil cooling system as the GSXR. However, it has fins that would not disgrace a pure air-cooler and a small, fanless oil-cooler . My speculative theory is that, on this particular engine, the oil cooling is basically used to get the heat out of the top of the head where four valves, an OHC and limited clearance to the frame make it difficult to get adequate finning in. Most of the rest of the cooling then depends on the fins, just like air-cooled engines since the year dot. If I'm right, it suggests to me that, with no airflow, fins give better cooling than radiators.

    Where oil or water radiators score, of course, is that it is much easier to duct them and provide a fan so that they get some airflow at a standstill. Generally, though, this will still only provide enough cooling to cope with idle or a bit more. Ask full output from an engine with no forward motion, as happens on a dyno, and even a watercooled lump will cook its little bollocks off if held wide open for more than a few seconds.
     
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  16. SACS is 'Secondary Air Cooling System'. It was implemented after designers looking for more power from their engines, without sacrificing reliability, looked back at the powerhouse engines of WWII fighter planes. Most of the advanced designs featured oil cooling as an integral part of the design. SACS took this to the motorcycle world, integrating numerous seperate passageways throughout the head to take away heat where it was the biggest threat to making power. It was quite an involved system, but flawed - the bikes would still lose power under sustained high load due to the inability of the cooling system to cope with such high output for prolonged periods of time.

    The real answer was water cooling, but in the meantime they'd developed one of the most powerful engines around, and put it in a good chassis to boot. The 1100 upped the ante on the 750, and both took out numerous world titles.. as you well know. One challenge is that with a watercooling system you need to abandon the traditional layout completely - the cylinder no longer sits in a mass of finned alloy, but more or less by itself in a sleeve of coolant. This presented engineers with a packaging problem, and a weight problem - size and weight are enemies of performance motorcycles.

    I have no idea if the DR's head is actually kept cool by oil. I would assume that the cooling system is simplified and only drawing on the success of the original GSX-R series. Its oil cooler more likely draws hot oil out of the sump and cools it before delivering it directly to the head in a more or less normal fashion.

    Meanwhile, how good a motorcycle is when at a standstill is of little importance to me - its how good the thing is when running that I care about. Both my XR600R (without oil cooler) and GSX-1100EF (with oil cooler) tolerate open roads and town trips very well. As for traffic lights, filtering is the way to go. If I can do it on a 260kg hyper-sports tourer from yesteryear, then you can do it on pretty much anything.

    Cheers - boingk
     
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  17. Suzuki usually at least incorporate oil spray on the underside of the piston on all air/oil bikes and often include oil reservoirs in the heads around the valve seats. I'm not sure if the DR incorporates these, but I would be genuinely suprise if it didn't include the oil sprays.
     
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  18. DR has the oil sprays. As for where the cooler comes into it, there's a scematic of the oil circulation in the manual, but I can't remember what it looks like right now.

    OP's question was about commuting in traffic, hence my speculation about cooling performance in low airflow situations. Bottom line, no modern bike should have a problem in any traffic situations encountered in Australia.

    I agree that no bike should ever spend much time sitting stationary though :D.
     
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  19. I'd say that if you're concerned, simply run a grade colder plug than the manual specifies. Also doesn't hurt to do that if you really give your bike some stick on occasion.

    - boingk
     
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  20. I wish I could help on this question as I had a GSX 1400 that I rode on 30+ degree days but, alas, eight days isn't really long enough to gauge these things when you're too concerned with just getting on it and riding. From what memory I do have I can't say I noticed any issues and I faced some serious congestion on the initial stage of my ride home, perhaps the fact that the 14 is an open naked allowing more of the heat to bleed off is a benefit.
     
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