Chinese oversized radiators?

[Ktmboy]

I don't understand why you would want to run an engine 25% cooler. (??) Car engines & larger bike engines have an optimum temperature at which they are designed to run all the time. The cooling system (including the fan) should provide more than enough cooling for any driving/riding condtions or you have a design problem. The thermostat is intended to continuously adjust the coolant flowrate so that engine temperature is always correctly maintained.

Are you saying that you need more cooling to meet the conditions under which you operate some engine?
(The old English cars pre-60s often suffered from this problem when operated in NZ.)
An over advanced ignition, operating in 40 deg C temps or blocked radiator fins can obviously cause heating problems too.

Ahh.. because when radiator coolant is shitting itself out through the radiator cap it means that the bike is getting rather hot.

Dirt bikes don't get air flow at 1\2 walking pace nor are they fitted with fans.

[oldskool]

http://www.ebay.com/itm/Universal-Mo...b47858&vxp=mtr

Hey that's interesting...DIY do-able for even me. Plenty of pix there to go by too. I could even flash up a micropic to give it some smarts and a visual display.

120mm x 120mm x 25mm (4 3/4"x 4 3/4"x 7/8") fan pulls 75cfm of cool air through your radiator powered by a 1800mAh Nickel-metal hydride (Ni-MH) battery pack. This battery will run the fan for an hour continuously. That's usually good for 4-6hrs of riding time on a hot day in technical terrain.

Is that all the fan cfm required? And such little coverage. Is this adequate to instantly drop the temp below blowing out the top?

[barty5]

I don't understand why you would want to run an engine 25% cooler. (??) Car engines & larger bike engines have an optimum temperature at which they are designed to run all the time. The cooling system (including the fan) should provide more than enough cooling for any driving/riding condtions or you have a design problem. The thermostat is intended to continuously adjust the coolant flowrate so that engine temperature is always correctly maintained.

Are you saying that you need more cooling to meet the conditions under which you operate some engine?
(The old English cars pre-60s often suffered from this problem when operated in NZ.)
An over advanced ignition, operating in 40 deg C temps or blocked radiator fins can obviously cause heating problems too.

There are no thermostats on these bikes and yet to see 40 deg c in auckland or NZ for that matter and radiator dont tend to block up riding in sand (and i know evan would be cleaning them every ride anyway)

[dafydd roberts]

Hey that's interesting...DIY do-able for even me. Plenty of pix there to go by too. I could even flash up a micropic to give it some smarts and a visual display.



Is that all the fan cfm required? And such little coverage. Is this adequate to instantly drop the temp below blowing out the top?

Yes not the best but unless you can pick up power from the bike the only option as far as a fan goes same as KTM boy said its the way to go.

All the after market fans KTM and Honda only cover a small space on the rad but this seems more than enough.

[bogan]

+1 to the fan plan, depending on the bikes electrics you might be able to hook up some pc fans just to test it. They're probably quite durable if you can squeeze em in behind the rads.

[sootie]

There are no thermostats on these bikes and yet to see 40 deg c in auckland or NZ for that matter and radiator dont tend to block up riding in sand (and i know evan would be cleaning them every ride anyway)

Hmmm - sounds a bit crude - is this a problem with all makes of bikes? Has anyone tried re-tuning & running these engines on an ethanol mix (Gull Hi Octane maybe)? I think that would keep the engine temperature down.
Agreed on the 40 deg C in NZ!

[oldskool]

Yes not the best but unless you can pick up power from the bike the only option as far as a fan goes same as KTM boy said its the way to go.

All the after market fans KTM and Honda only cover a small space on the rad but this seems more than enough.

I'll have a nosy at Tony's fan at the 2day'r ride. Excellent, this'll give me a project to work on over the next few weeks.

I could use one of these http://www.trademe.co.nz/motors/car-...-524956508.htm and a thermistor or simply attach the thermistor lug to the aux bolt on the secondary radiator.

Thanks for the inspiration Daffyd!

[oldskool]

+1 to the fan plan, depending on the bikes electrics you might be able to hook up some pc fans just to test it. They're probably quite durable if you can squeeze em in behind the rads.

They seem to fit and blow well. Being brushless I'm guessing they'll be fairly water resistant but time will tell. Haven't yet identified whether causing a partial vacuum to draw the heat out or blowing fresh air onto the cooling fins is more efficient. The way the fans are constructed it would be far easier to blow onto the radiator from behind, due to the flush fan case molding and also the protection of fan electricals by the fan itself. These fans aren't polarity reversible.
There is a fair bit of air circulating through the fins tho!!

[bogan]

I don't think the bearings will like the water/grit too much though. I would say have them draw the air through, that way they won't be fighting the airflow at low speeds.

[dafydd roberts]

They seem to fit and blow well. Being brushless I'm guessing they'll be fairly water resistant but time will tell. Haven't yet identified whether causing a partial vacuum to draw the heat out or blowing fresh air onto the cooling fins is more efficient. The way the fans are constructed it would be far easier to blow onto the radiator from behind, due to the flush fan case molding and also the protection of fan electricals by the fan itself. These fans aren't polarity reversible.
There is a fair bit of air circulating through the fins tho!!

Are these on your bike now?

[Jinxycat]

maybe you should talk to poggy about forced or induced air flow, it can affect the type of motor you use.

[barty5]

They seem to fit and blow well. Being brushless I'm guessing they'll be fairly water resistant but time will tell. Haven't yet identified whether causing a partial vacuum to draw the heat out or blowing fresh air onto the cooling fins is more efficient. The way the fans are constructed it would be far easier to blow onto the radiator from behind, due to the flush fan case molding and also the protection of fan electricals by the fan itself. These fans aren't polarity reversible.
There is a fair bit of air circulating through the fins tho!!

you will need to set the fans up so they pull the air through just as your car radiator fan dose

[ding322]

The main problem that you will face with PC fans is that they are NOT water tight. So the moisture and grit (as suggested above) will get into the bearings and wiring of them and kill them.

They will let you know if they don't like it with a horrible smell and some sort of smoke

I have seen these types of fans fail in mobile equipment due to corrosion caused by high moisture environments, but this would of taken a reasonable length of time.

One advantage is you just turn them around to reverse the direction of flow.

Looks like a good fit tho

[pete376403]

If your bike has a 12 volt system you could look at the fans installed on KLR650s, designed for off roadable bike so able to survive drownings and they move a good bit of air when running. About 120 mm diameter.

[oldskool]

I don't think the bearings will like the water/grit too much though. I would say have them draw the air through, that way they won't be fighting the airflow at low speeds.

Yes you're probably right about the bearings. With this in mind I'll regard the PC fans as temporary until they kark. Then I'll scour the internet for decent replacements. Shouldn't affect how I rig up the temperature sensor circuit tho. In regards to low speed turbulence caused by blowing back....I wonder if the induced turbulence may actually help dissipate the heat more effectively? ...just a random thought

dafydd roberts: Are these on your bike now?

They're just pinned there at the moment for sizing. 1x 120mm would be too large. 2 of these are 80mm.

Jinxycat: maybe you should talk to poggy about forced or induced air flow, it can affect the type of motor you use.

Pogs gave them a squiz last night but was more concerned about powering them up rather than airflow. Getting a modified stator is out of the question. A compact 12V 1.4a/h SLA were my thoughts.