250 air cooled max temperture cooling methods?
 

Zong 250 (223cc) what would be the normal operating temperature and max temperature for this motor on a dirt bike? I'm a little concerned about having enough air flow. How necessary is it to have a front fender with air flow cutouts like I see on a lot of China air cooled bikes?

Has anyone experimented with cooling fans? I realize it's air cooled but since I'll be doing mostly trail riding at higher RPM, slower speeds, I wonder if it's worth it? I can easily make something up with fans I have.

Does anyone know of a decent temp sensor and gauge that might work with this engine? Since it's a conversion of a 450x I'm considering a trail tek digital gauge setup designed for a 450x. Anyone use one before?

They make temp gauges for bikes that replace the oil fill cap.


Some quick examples.


https://www.ebay.com/sch/i.html?_fro...gauge&_sacat=0



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An oil cooler would be the way to go.

Chinese had 2 type:
http://item.taobao.com/item.htm?id=546435316215 (ie. the oil-cool system is NOT always ON)
http://item.taobao.com/item.htm?id=546033184506 (ie. the oil-cool system is ALWAYS on)

You are over thinking it....
As long as your spark plug dosn't show an overly lean condiction "white"
you won't have a issue...

I ride a air cooled Yamaha in some pretty gnarly hard enduro's at times i have seen
these bells & whistle water cooled bikes sitting on the track while the rider waits
for them to kool down while I ride passed them with the air cooled motor..
i don't have a oil cooler either but i do have one to put on it when ever i get
around to it...

if you are going to get it very hot run a full syn oil....


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Pete's right change oil when you know you are going to be beating it up. Provide it clean synthetic oil and it will give you no problems as it was designed to be run under the most brutal conditions of east Asia and the south American jungles with poor maintenance

More proof of synthetic oil . Notice the flow of even the dirty synthetic on the right.

https://hips.hearstapps.com/roa.h-cd...20230-oils.gif

Yeah I'm definitely over thinking it. Just a bit paranoid, fresh build and sticking an air cooled 223 into a frame designed for a liquid cooled 450 but the motor is still a bit shrouded compared to an open air designed bike.

So I'm running shell rotella t4 15w40, what would be better? T6 15w40 full synthetic or another brand of synthetic? I love the synthetics but not sure what is best for these air cooled bikes and the wet clutches etc etc.

oil
 

I've been running rotella T6 in my hawk for almost 5,000 miles with no problem.

I can only recommend what I have run...
one you can get the other you may not beable to... Austrailian made..

Motul 5100 semi syn or 7100 full syn.... not cheap at $100 for 4 liters..
I now use Penrite ST4 MC 10/40 full syn...

PS... Motul is also sold as Yamalube...


..

On my Zong 250 I have a spark plug base type thermocouple. During break-in I would occasionally see 450+ and it freaked me out a little.

I richened the main and fine tuned with moving the needle clip a bit richer. Now it seldom goes over 400. Usually runs about 365-380.

Where do you have your needle clip set at? (from the top going down)

Every motor will be a little different... plus I'm at 5000 ft above sea level.

My clip had to be moved down (which pulls the needle up) to get a little richer mixture. I believe it is in the 2nd slit from the bottom, moved from the center slit of 5.

I'm only 785ft above sea level. I have mine in the middle clip but it might be too rich actually. Holding the throttle about a quarter to half on sitting the motor hesitates and belches with lack of power. I think it's flooding itself out.

I've got the same 230cc in a crf250 clone chasis, you definitely over thinking it, i thrash the f# out of my zong in sandy dunes & bush gets pretty hot here in perth & power gets a bit vague when climbing soft sandy steep dunes, but that's aircooled for you,otherwise she's runs sweet, will definitely be trying full synth as the rimula still gives slight slip, how's the 230cc feel in the alloy 450 frame?

Well I finally worked some of the bugs out and have taken it for a couple rides. I still have a bit of carb tuning to do but I must say I'm ecstatic of how well it turned out.

Between porting the intake passage to the carb open size, re-jetting the carb, aftermarket CDI, larger 450x exhaust, 13T/53T gearing the thing is a torque monster! Both my buddies ride true 450cc bikes and so far I've been able to power my way out of any mud hole and situation they can't!

Only down side, I'm only 5'7" and a 450 frame / suspension is a bit tall for us short people. ;) Takes some getting used to with balance when stopped.

Unfortunately we are seeing the last of the 30 deg Celsius weather as fall is upon use here in Canada. :( If we are lucky we might be able to ride into October before rain and eventually snow hits. Then it's a full 7~8 months before spring riding...maybe.