I wish I would have paid more attention to this thread a while back.
Now that it is getting warmer out in the desert, 90-100F, I am starting to have some issues with boil overs in the tight stuff only. I have read through the entire thread and wanted to add my two cents worth:
In regards to the amp draw relationship when compared to volts. Fans such as computer fans are rated at 12V @ .2amps. Computers have a very, and I mean very close tolerance on voltage. And so the fans are rated with their amp draw in relationship to this voltage. WATTS is a measure of true power or work performed and is derived at by VOLTAGE X AMPS. The amount of watts does not change. So, if our Husaberg's are running at 13.5VDC or 14VDC the amount of amps is going to DECREASE. So, if we are running computer fans at 12VDC @ .2 amps, the true power is 2.4watts. So, in theory if we are running 14VDC the amp draw is going to be .17 amps. That's three one hundreths of an amp difference. Either way, I don't see this being an issue for either one of the 70 watt stator coils. Remember this is straight DC theory, AC theory is somewhat different, but it still doesn't matter as computers actually run on DC current from the power supply which turns your 120VAC house voltage into DC. KTM definitely has the right idea here with their available thermostatically activated cooling fans. I wonder what the Husaberg World enduro team uses on their bikes?
Berger: Be sure that the spot radiometer that you are using is set with the right constant for the material that you are measuring the heat on. We use these spot radiometers, or heat guns as we call them at work, and after reading the instructions I found that it is pretty importatnt to have the right constant or surface co-effiecient set on the gun to get a true measurement of heat. Still, the fact that you were able to discern a 10 -15 degree drop in heat shows that there was some effect.
Piggd: I know that you are riding really tight woods, and or trails. What I have found on my bike is to make sure that I don't lug the motor too much, as the coolant flow is entirely dependent on the impeller speed as I believe Taffy has suggested. So might I suggest that if you are rarely if ever using your sixth gear perhaps lowering the gearing on your bike might also benefit your problem as your riding conditions sound pretty extreme. I know I have thought about lowering my gearing, but, there are enough times during my desert races that I find sixth gear to be necessity with the stock gearing. As far as bleeding the system.... I didn't even know until now that there was a bleed screw between the headers, but, now that I know I can see it. What I have done in the past per the Husaberg manual to bleed the system on my 01 501 is to fill the rad, put the cap on, and lay the bike over on one side. You'll hear the coolant gurgling through the system. Stand the bike up and check the level, you will see that it is lower. Repeat the first step, except on the next time lay the bike over on it's other side as well. Do this a couple of times until you are satisfied that coolant level is not changing. As far as your valves ticking, I've been listening to the Husaberg sewing machine tick for a few years now
. Make sure you set the axial play of the rocker arms before you adjust the valves. This usually doesn't change over time like the valves do, but, since your bike is new I'd check them. It's really easy to do, so no worries. Sounds like you are headed in the right direction with the Evans, as the OTHER bikes around you were blowing chunks!!
REGARDING THE EVANS COOLANT: I spoke with one of their techs last week and he explained to me how critical it is to use their prep fluid, as well as the NPG-R fluid. (Note: this tech also explained to me that after recovering the prep fluid, set up a stove hot plate whatever outside, and heat the prep fluid to 220F and boil off the water in the prep fluid and put it back in the container to use again) The other fluids they sell are too viscous for our cooling systems. He went to explain how if there is any water in the system it can create a vapor barrier between really hot spots such as the cylinder head area and the coolant. This is also called film boiling. Kind of like when you heat water in a pan and go to pour it into a bowl and the water radically boils on the sides of the pan, this is what precipitates a boil over as the heat in these area's continues to climb and the amount of film boiling area increases. Whereas the Evans coolant, with it's much higher boiling point will stay in contact with said hot spots and not allow the temps in these areas to get out of control. Thus, the heat will be extracted fromt these area's and taken to the heat exchanger. And, I will be going to this cooling fluid very soon.
REGARDING ENGINE ICE: The only reason that I have run/run this product is b/c the national forest service, at least out here, requires that you run this as it is not nearly as toxic as the ethylene glycol. And I have come to the conclusion that at least with my bike, boil overs are way more prevelant. This after many rides with my partners who just run regular automotive coolant in their bikes.
I have also seen in this thread talk about the possibility of engine seizure due to heat. While this is a real possibility, I would think boiling out your coolant and continuing to ride would certainly lead to a seizure. Whereas at least with the Evans coolant, the coolant would remain and would perform it's function once a little air flow started to pass over the rad. Over memorial Day my friends and I were out riding in probably at least 100 degree temps, and went through the infamous Check Chase canyon section that was at the beginning of this infamous race. Bobzilla will know exactly what I'm talking about. My bike boiled out allot of fluid, I finally turned the motor off when I could coast through some of the sections. When I got to the bottom and was waiting for one of our older riding buddies, I got the cap off and used up quite a bit of my drinking water to refill the rad so I wouldn't hurt the motor on the way back. Hopefully the Evans will take care of this for me.
