| Author | Message | ||
     Firstbatch |
Installed the first version of a duct for the cooling fan. It is made of a double layer of Thermotec stuck together and then folded and shaped to fit. Have a 5" x 1/4" tube spacer molded in the top section to provide for a 1/8" rigid steel rod that spans between the bolt holes that attach the side seat rails. Looks like it will work very well in directing the air down and back, exiting out by the inside plastic fender. Wanted to test the fan operation while the bike is all torn apart and see how the air flow works but simply cannot get the fan to power on when I connect a 12V source to the two fan leads. Fan worked fine before the current project. Checking the Service Manual schematic and it is just a simple DC circuit. Any ideas, or have I just simply discovered a bad fan?     | ||
| Hughlysses |
Firstbatch- No idea why your fan won't work. I like the idea of re-directing the exhaust air from the fan but I think your design is going to restrict the airflow too much. You're taking the exhaust flow from a ~4" diameter fan (about 12.5 square inches) and forcing it through a duct that's only about 6" wide x 1" tall (about 6 square inches of cross sectional area). That's going to cut the exhaust airflow way down, especially when the fan's not running. It's certainly worth trying the way you've got it, but if you find it results in almost continuous fan operation, I'd try making a duct with more of a "U" cross sectional shape, that sort of wraps around the shock. That would increase the duct area, allow more airflow, but still direct the hot air where you want it to go. Good luck. | ||
| Firstbatch |
You may be absolutely correct on the effects of the duct on flow.....while it is all apart it was going to be a simple experiment to observe but as usual some little gremlin jumps in and makes the things complicated. Guess I will have to buy a fan. | ||
| Froggy |
You can use ECMspy to force the fan to turn on. | ||
| Firstbatch |
Frog, right now the ECM and most everything is off the bike. I thought it would be a simple exercise to connect a 12V to the fan right at the connector and make it run, but no dice. At that connection point the ECM is out of the control loop. | ||
| Tsorl76 |
I would have to agree with Hughlysses on the airflow issue though it would be hard to assume static air pressure of velocity pressure across the engine without the use of a magnehelic. I think the idea is very clever but remember that many fans of this design are not built to produce the static pressure needed to force air into a small duct and still carry the necessary BTU load. Notice in duct systems axial fans are used while free flowing exhaust can be accomplished with a standard design fan. | ||
| Tsorl76 |
Also on the fan bench test? I see on the schematic that there are two wires? The fan is two speed isn't it? That might mean that the frame is grounded to complete the circuit. You might try grounding the frame (neg) and applying the positive lead to one of the wires. | ||
| Hoon |
Firstbatch, I shall watch this with interest. Keep us posted on your R&D project please,thanks. | ||
| Treadmarks |
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| Firstbatch |
This in-ability to make the fan run with 12V power applied is really a mystery. Tried hooking up the frame ground to the battery and then completing the circuit.....even have a test light in the circuit to verify the connection. Still no fan. Left with no choice but to buy a fan, no big deal....but something tells me it is not the fan. Not sure why the two speed nature of the fan would prevent the fan from powering on when you apply 12V. Is that possible? Any Buell mechanics on board? | ||
| Hoon |
Have you re-fitted everything back to normal and it still doesn't work? You gotta try that before shelling out for a new one | ||
| Tsorl76 |
Firstbatch, tell you what. Monday night I have class at the community college. I'm taking a course on Auto electrical systems, and I can ask the Prof to take a look at the schematic and see what he thinks. It seems strange that there are two terminals on the ECM that both feed into the same wire leading to the fan (Black/Orange) the other lead goes to a fuse. I wonder if the ECM is sending different voltages to the fan?? Anyway, the Prof is an ASE Master Mech and might be able to clear it up. so if you can wait a bit before you shell out the money we might be able to figure it out. | ||
| Firstbatch |
Excellent Tsor176....that would be very helpful! Can't put my finger on it why 12V applied to the fan won't power it up. I did find out the fan frame is not a ground as there is no continuity shown when I tested it. AS you can see Hoon the Uly is far from "back to normal" and at this time connecting the ECM back up to test the fan in that mode may not be possible as there are other ECM cirucits, namely the ignition timing, that are completely off the bike right now. But I just don't see why those components would prevent a "bench test" of the fan. A couple of extra pics showing some of the Thermotec that has been installed on the Fuel tank/frame......have it on virtually all surfaces inside the frame, especially right above the front cylinder head and the area around the fan that is directly adjacent to the rear exhaust header. Add in the Jet Hot headers and Odie's blanket and this should be less heat going to rider and frame. Can't wait to get it all put back together. Parts are all at the powder coater so hopefully in about 2 weeks she will be back on the road         | ||
| Tsorl76 |
Okay Firstbatch, I showed the schematic from the service manual to the prof and he said there was no reason the fan shouldn't run if you connected it directly to the battery. Yellow positive, black negative. He mentioned that your ohm reading would be small and that the fan is grounded through the ECM probably one terminal has increased resistance to ground to get a volt drop, facilitating the two speeds. How are you connecting the power to the molex connector? Did you have to insert a pin into the female connector and then clamp on the pin from the battery? Just wondering, hate to see you have to spend money if you don't have to. | ||
| Firstbatch |
Thanks much Tsor176 for taking the time to ask the experts. Looks like a random bad fan. For the test connection I was using an alligator clip connected to the male pin of the connector that had the yellow wire and connecting that to the (+) battery and then using a test light tool connecting the black wire to the (-) battery. The in-line test light lights-up showing a completed circuit but the fan does not run. The picture does not show the connector pins well but the fan side of the plug has two male pins and the ECM side of the plug has the female and of course the extra wire. Thanks again, time to get some experience pulling the fan. Bummer is right now I have the engine rotated and supported by a scissor jack and the front and rear of the bike on Trex stands. I'm pretty sure you have to have the all pressure off the rear swing are to disconnect the rear shock and then access the fan. I'll have to wait until I get the cam cover and Primary cover back on and the engine bolted up to tackle the shock removal. | ||
| Teeps |
It will be interesting to know if the ducting has an effect on the swing arm oil temperature. | ||
| Hughlysses |
Firstbatch- Where'd you find the Thermotec and what'd it cost? I applied adhesive-backed aluminum foil HVAC tape to several of the same rear frame areas on my Uly and noticed a marked reduction in heat from the frame; I imagine the Thermotec would work even better. I'd like to try your "double layer" method to construct a rigid "baffle" below the seat to replace my trimmed Odie heat blanket. I shortened mine and tucked it in front of the ECM to keep the hot air off the battery and ECM and force the air out of the side vents and below the seat tray. I think I could do a much neater job using a double layer of Thermotec. | ||
| Firstbatch |
It will be interesting to be able to measure the temperature of the cooling fan exhaust once I can give this option on a test run. I don't anticipate much of a measurable increase in oil/swing arm temp....but who knows I expect a good drop in fuel temperature if the Thermotec does it's job as advertised. I know Tread has said he can feel a marked difference from his left fuel rail from the right due to one having the Thermotec and the other not. I purchased the Thermotec adhesive back material in both 12" x 24" sheets and the the 2" wide rolls. Seems their products are readily available across the internet/google and I think the last place I bought it was through Amazon and there was some free shipping. I was thinking that to create the potential for more airflow as Hugh has suggested there may be a way to cut a round hole, say 2" diameter, in the prototype and then fit in a flexible hose and route that down and back. Seems as though there are a number of ways to reduce over-all heat for the frame and rider which would be a nice improvement over stock, especially when summer starts to cook these parts of Virginia. | ||
| Tsorl76 |
I would definitely trust the Thermotec much more than HVAC foil tape, even the UL181 rated tape. I'm a Mechanical Contractor and the tape is meant to seal the joints of air ducts and isn't heat resistant. I have seen it fall off of vent joints on single wall and double wall vent because the adhesive dries out and becomes useless when there is too much heat. | ||
| Hughlysses |
Tsorl76- thanks for the info on the HVAC foil tape. If it falls off it's no biggie; no doubt Thermotec will be a much better product. I am amazed at how well the HVAC foil tape reflects heat though. | ||
| Firstbatch |
Hughlysses, I think I paid about $17 for a 12" x 24" sheet | ||
| Firstbatch |
Just to update this thread for those that may have interest. Bought a new fan and proceeded to bench test it per the Service Manual by simply applying a 12V source. Once again, no dice. What a mystery. Anyways, installed it on the bike with the duct prototype and took the bike for a 30 mile test ride on a very hot day last weekend. Fan finally came on late in the ride and the sound was much reduced. My riding partner at a stop light who had heard the fan before commented on how much quieter the fan was and none of the higher pitched wailing. Pulled into a parking lot and inspected the air flow coming out the rear....very strong and substantial air flow....and very warm/hot. Seems as though the flow is enough in to get the job done, but this is just a simple observation....I'm not at all scientific about the CFM before and after...just seems to be a fan pushing a strong current of air. Went back to riding and all is fine, noticed that most of the fan heat is coming out at about the right ankle area and some to the the left. Will be testing a longer ride this weekend to see how much relief from nut roasting this mod provides. That was my main complaint before. When I shut the bike down the fan ran at the high speed for about 30 seconds then went to the slower speed for a short time and then cut off. Certainly no indicators of high temps requiring the fan to fun longer at engine shut off. For the time being I like the mod, time will tell if it will work long term and if it causes excessive heat build-up on the fan itself, etc. From a simple perspective I like the hot air being directed out the back and not pushing straight up through the shock and in to the seat area. | ||
| Packdog |
Thanks for the update. I'm happy to hear that the initial results seem promising... I think it's promising enough that I will go ahead and order some Thermotec and get started! | ||
| Firstbatch |
Yep Pack, I think this mod will be a keeper...I think if Buell molded something out of plastic much like the seat pan they could fashion a very functional duct arrangement | ||
| Bertotti |
I have been wanting to do this but haven't found the time. I am still curious if the bike was designed so the frame would work as a heat sink to remove some heat from the engine area. | ||
| Lousirider |
Firstbatch, whats the status on the duct work? Is it working out for you? Also, how much to build one for me?  | ||
| Firstbatch |
This duct arrangement continues to work fine and has eliminated nut roasting. Fan seems happy and I cannot detect any downside issues. Louis, I had not thought much about making these though I do believe I kept a template. I will PM you. |
