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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => Project Classic Motobricks => Topic started by: beemerphile on January 10, 2018, 06:54:35 AM
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I see on FleaBay that there are quite a few older 3 row K radiators out there for not much money (along with some expensive new ChinaFab items. Will any of the 3-row radiators fit in the place of the newer 2-row units and is it a change worth the effort? During my current resto I am wanting as much as possible to make it not a hot bitch. This will include fuel cooler, johnny blanket, etc. but I was left wondering whether basic cooling capability needs a boost. I thought I saw discussion on here on the topic of 2 and 3 row radiator swapping, but I cannot find it now.
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I don't know about the different radiators, but my K100RS4V ran at the temperature redline nearly all the time. Just stopping for a red light on a hot day would be enough to start the fan.
Turned out the cooling system was coated inside with a layer of minerals, probably from hard well water. After soaking the inside of the radiator a couple of times with white vinegar and doing a couple cooling system flushes the engine runs where it is supposed to be. Not saying this is your problem, but it's worth looking at to make the bike run a bit cooler.
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Yeah, my radiator needs a good cleaning, but I was wondering if I was going to put the work into one whether it would be better to start with a 3-row radiator.
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A few years ago I did fit a 3-row in my '95 K11LT. There is some fabrication needed to fit it on an 1100.
The first issue I did have was with the stock fan motor would hit on the air box. I cut the portion of the motor cover that was hitting and sealed it with some gorilla tape.
The other issue I had was the left side mounting ear would hit on the coolant riser pipe, so I cut the ear off.
Since then I seen the aftermarket low profile fans being fitted by some users... I think one of these fans would be much better in this situation.
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I'm uncertain whether the overheating problem is with you or your bike, Lee. :giggles
If the bike is manifesting overheating symptoms like Gryph's example—and even if it isn't—flushing the radiator, cleaning its fins, changing the fan type, checking the thermostat then replacing it if necessary, and replacing the radiator cap gasket are good remedies or maintenance strategies.
If you are overheating, the fan will still be pulling heat from the radiator and sending it back to you regardless of the radiator's size or whether you can get the engine coolant to be x degrees cooler—even if it needs that. I don't believe that an xº decrease in coolant temperature is likely to result in your being x degrees cooler; maybe Gryph or Scott_ can affirm that.
From what I read here, heat radiating from the tank is a significant discomfort. If it were my bike I'd be committed to cooling the fuel to lessen heat radiating from the tank and routing engine-heated air coming from beneath the fairing away from me somehow. On my naked bike I rarely experience significant discomfort from engine or tank heat. Installing a fuel cooler is a compelling idea with some good reviews for frequent and extended hot weather riding and I might do that, but it's a motorcycle after all. Discomfort is part of its cachet. :giggles
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Thanks for all of the replies. I don't have much seat time on this bike. My SOP when I buy an older lightly used BMW is to strip it to the frame and do a baseline maintenance checking the condition of everything. With bikes I have experience with, this is pretty much rote. But since, I am a brick virgin, I have been trying to better understand the "normal" watch and trouble points in order to hit as many as possible on this renewal so as to hopefully get the best result without going back in because I didn't know to do A or B.
With what time I have ridden the bike, I do get uncomfortably hot. When I am drafting a vehicle the temp goes up significantly but it does not show an overheat light. The right side heat deflectors under the fairing are missing, so I will fab some of those. For the cooling related part of the renewal, I plan to do the Johnny Blanket (c); replace all hoses; insulate the fuel lines; replace the fan with an aftermarket SPAL fan; install a fuel cooler; check the thermostat and water temp sensors; change all gaskets and o-rings; and clean/purge the entire system a couple of times with several rinses afterwards; refill with new 60/40. I have a new water pump and thermostat if they are needed after inspection.
So, with all that, I was just wondering whether there was any benefit to starting with a 3-row radiator since it would be cheap to do and the system would be opened up anyway. Concerned that I might be solving an imaginary problem or that it was even possible the newer 2-row rads are somehow more efficient than the older 3-row rads, I decided to consult the brain trust.
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I have a 1991 K100RS 16v and live in a country where it is pretty much always hot. The engine does not overheat if I am moving, though it does get up to maybe 3/4 of the way up the dial if I am stopped in traffic for any length of time, I have a manual fan switch which handles that issue just fine. I however do overheat quite a lot. I was missing the heat shields on both sides of the bike and got serious burns on my left leg after a six hour ride one day. As a result I found and installed the LHS heat shield and also installed a fuel cooler. The overall result has been a much more comfortable ride for me with a slight increase in engine running temp, because of the heat shield I imagine. So if I were you I would fit the Johnny blanket and fuel cooler first and then see how things stand before installing a new radiator.
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So if I were you I would fit the Johnny blanket and fuel cooler first and then see how things stand before installing a new radiator.
That seems to be the way to go. thx - Lee
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Lee be with the careful if you are going with a non OEM thermostat. The Corolla one apparently needs a modification in order to work correctly. there are posts on the subject.
Regards Martin.
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Lee be with the careful if you are going with a non OEM thermostat. The Corolla one apparently needs a modification in order to work correctly. there are posts on the subject.
Regards Martin.
Yeah, thanks. I wussed out and bought the BMW item. Capital Cycle had a new OEM on EvilBay for nearly half price, which is only twice what it should cost instead of four times. Also, I haven't checked my current one yet which may be fine making the new one a spare.