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bluemotorcyclesam

PC Fan Mod

26 posts in this topic

I currently have a problem with overheating my 01 yz426f. From what I have been told by the awesome members of this site that this is normal of the 426 to do when idling or slow ridding. I have found a pc fan mod on here but wondered is there a way to run this off of the stock 426? If you are interested in looking at the mod here it is.

http://www.thumpertalk.com/forum/showthread.php?t=805094&highlight=cooling+fan

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I believe it is not possible unless you get an aftermarket stator or run it off batteries that can be recharged. Also I wouldn't use a PC fan as it is not purpose built for this application.

You need a high CFM fan with relatively low current draw that can handle a bit of weather/dust/rain.

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Evanscoolant.com and be done with it. No need for fans or overflow bottles.

This ranks right up there with installing an o-ring on the carb to get it to work properly.

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I have a yz426f so I dont have a charging system. Is there any way to tap into the ignition coil to power my fans? I hate the idea of having a battery to power the fans.

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AFAIK, your electrical system is ignition only. I meant charging by an external charger

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Try Zip Ty's coolant first...I had a few overheats before, none since...

And just be sure to shut the bike off when it's not moving...

No more sitting there letting it idle while your friends catch up...

I would think the fan would actually be a slight hindrance at higher speeds since it's blocking a bit of airflow...

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Remember too that you dont need your rad right full, covering the cores is sufficient and the excess will just get spat out anyway and no idling while sitting and waiting. Does it seem, by the number of post you see, that the 426s are more prone to overheating though?

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If you're going to do a lot of low speed stuff, one thing that will help is to use the larger radiators from a '01-'02 WR426. Possibly the later ones may also fit.

Still, you have a the same two basic problems: Radiators don't work without air flowing over them, and the water pump is built to be run at 10,000 rpm without significant cavitation, so it circulates rather poorly at 1500 rpm. Increasing the idle speed increases the heat generated at idle, so that isn't a solution. Sometimes the problem can be addressed by bouncing the revs up occasionally to move some water around, but the crux of the matter will be the same, nevertheless.

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Boyeson water pump impellor and cover will help a little also. Quite a few of those who run our bikes on the street in SM form have done this to help with overheating at red lights. There is no single perfect solution to this. Just several small things that overall will help, but not cure. Oversize radiators for sure, even oil coler setups and oversize clutch covers to hold more engine oil - anything to kep the motor cooler just a little longer. I run a 50-50 mix of Maxima 's Cool-aid and Coolanol, but Zip Ty's coolant is prob just as good if not beter. For a fan, go with the Spal fan as mentioned - it's waterproof, unlike a PC fan. Just use a small rechargable battery that you can mount in the airbox area, and a switch on your handlebars. Hook up a Trail Tech Vapor to your bike so you can monitor your water temp in real time, and switch on the fan only when you need to

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... oversize clutch covers to hold more engine oil ...
Please, let's not perpetuate that myth. The YZ450 is a dry sump system, and the engine oil is not carried in the clutch housing, trans, or the actual crankcase itself. Since the normal oil level in the sump is lower than the clutch, a cover the size of a quart can won't add anything but air space.

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Try Zip Ty's coolant first...I had a few overheats before, none since...

And just be sure to shut the bike off when it's not moving...

No more sitting there letting it idle while your friends catch up...

I would think the fan would actually be a slight hindrance at higher speeds since it's blocking a bit of airflow...

Zipty is Evans with a different label from what I was told.

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Let me try this one more time. My son in law recently went riding with friends that were on a 08 crf450 one on an 09 kx450 and an 08 yzf 450. He was on an 09 yzf450. All bikes had stock coolant except the 09 yzf450. We run Evan npgr coolant. They were on a very technical single track. Very slow and some parts they had to ghost ride rock faces to get up. All of them are very fast and experienced riders. At one point they had to stop because of boil over to all of the bikes except the one with Evans. After they got back to camp the yz with Evans had lost zero coolant. My advise is that there is no need to do any mods except replace your coolant with Evans.

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How many times per thread are you going to feel compelled to push Evans coolant? You said it already, a number of times, in fact, and if he wants to follow your advice, he will. Otherwise, you're going to have to learn to let go.

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Gray - I'm not saying it's gonna be a huge difference, but wouldn't keeping the engine oil cooler help keep the overall motor temp down? If only slightly? Wouldn't a slightly larger volume of oil take a little longer to heat up? Isn't this the desired effect of the aftermarket and factory team oil cooler setups? To keep the motor temps down by keeping the oil cooler? My reasoning is that if the motor is cooler overall, then the colant won't heat up as much either. even if it gives me an extra 15 seconds at a red light, that could be significant.

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Gray - I'm not saying it's gonna be a huge difference, but wouldn't keeping the engine oil cooler help keep the overall motor temp down? If only slightly? Wouldn't a slightly larger volume of oil take a little longer to heat up?
Absolutely. But again, because the crankcase is not where the oil is stored, expanding the space available in the crankcase by adding deeper clutch covers and such will not increase the oil supply. That was my whole and only point on that score.

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OK, now here's something else i'm confused on. I know that overfilling your bike with oil will cause problems - let's say filling your bike with 1.25 liters instead of 1 after an oil/filter change. (approximately)

In addition to blowing excess oil out the breather, isn't it bad for other things also? So now if i understand you correctly, even with an oversize clutch cover which the company that makes them says you can run an additional .2 liters of oil, the oil system will still be overwhelmed by this extra volume of oil since it's not being contained in the motor/clutch area?

how bout with an aftermarket oil cooler? I still haven't gotten around to installing mine, but was planning on running additional oil due to the oil lines and oil tank volume. Is this a bad idea also, and I should stick with stock oil volume?

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How many times per thread are you going to feel compelled to push Evans coolant? You said it already, a number of times, in fact, and if he wants to follow your advice, he will. Otherwise, you're going to have to learn to let go.

It's that good. You would feel the same if you used it.

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The reason your hypothetical .25 overfill causes problems on an '06 and later model is that there is no room in the oil reservoir for the excess. Remember that in a dry sump, oil is stored in a reservoir, or tank, if you will, and pumped from there to the important lube points. When it naturally drains to the sump, it is immediately picked up and returned to the tank by a second oil pump that moves oil 2-3 times faster than the feed pump does, so that all of the oil is sucked up and returned to the tank, leaving the sump "dry". When the tank is filled to its physical limit, any further oil returned is forced out through the pressure balance line that links the tank to the crankcase, which raises the oil level in the sump. In extreme cases, the crank splashes in it and it blows out the vent, and all that other uncool stuff.

In a steel framed YZ450, there was a considerable amount of extra room in the frame/tank beyond that taken up by the 1.1 quarts of oil stored there. On those, you could run up to 1.5 quarts or more and it would all fit in the tank, even if it was actually higher than the dip stick port. This didn't change the oil level inside the engine at all, because there was still a volume of air at the top of the tank for the returning oil to go to.

Not so the aluminum framed models. Now in your case, however much oil the cooler and associated plumbing holds when full can be added to the system without having a negative effect. But it's going to be difficult to determine at what point the tank overflows, since there's no way to see into it. Starting with a low oil level, adding small amounts and checking the dipstick as you go would be the best way.

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Ah OK I think I understand now - the potential oil volume space isn't really in the crankcase/motor itself per se, rather it's in the passageways and oil lines of the system when the bike is running, therefore those areas can only hold so much oil at a time. Therefore the oversize clutch cover, since it isn't part of that system, doesn't add to the overall capacity. The only time it would add to the capacity is when the motor is off which does us no good. Think I'm understanding this dry sump concept now.

But the oil cooler tank and lines would, since they are a part of the circulating system.

Maybe I could connect the hoses to the tank and see how many cc's of oil it takes to fill everything up with oil, then add that figure to my stock capacity to get a ballpark oil capacity with the cooler installed? Too bad the oil cooler setup doesn't tell me that in the instructions!

Now one other point - since i recirculate my "blown out" oil back into the crankcase with my oil recirculation system, am i actually risking failure of any components if I did have too much oil in the system?

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