why SO hot????

Moto

Moto

Member
first off, let me clarify that my engine is not running lean, in fact it is still rich and the plug is an oily black. It is a stock, 50cc china girl engine, with a gutted stock pipe, a bored out nt, and a billet intake. It runs great, pulls into very high rpms and is incredibly smooth. yet I have always had trouble with this engine heating up way too much. I have a temp gauge and it will easily break 450 degrees F. and keep climbing if I let it while going uphill. I am not experienced with what makes an engine run hot, but have had no problems like this with my other engines. I am thinking that maybe a more free flowing exhaust might help vent the engine better, but really have no idea. Any suggestions? -Moto

:-||

here is the most recent pic of the engine setup that I have, since that photo I have swapped the head for another stock 50cc one which has more surface area in hopes of cooling down the engine, but it make no noticeable difference:
IMG_1368_zps232e849f.jpg


IMG_1364_zps0a382e2a.jpg
 
What fuel mixture are you using?

I wouldn't advise you run your engine at that temperature, it shouldn't really be above 250. That temperature is almost red hot
 
TakeiT said:
What fuel mixture are you using?

I wouldn't advise you run your engine at that temperature, it shouldn't really be above 250. That temperature is almost red hot
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400+ is really the danger zone, according the Gordon Jennings 2 stroke tuning handbook, and the engine looks fine internally. I just really dont want it over 400 because thats the point at which aluminum starts to weaken.

I am running 32-1 redline synthetic oil, great stuff.
 
if it is only while going uphill, then float angle could be a problem

could also be heavy grease & oil coating engine between fins
 
crassius said:
if it is only while going uphill, then float angle could be a problem

could also be heavy grease & oil coating engine between fins
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its painted black. float is a possibility..... ill go check. but it does get hot on the flats too, what height should it be?
 
It could also be a build up of crap in the cylinder creating a lot of friction. Have you noticed a loss of power?
 
How about the accuracy of your temperature guage?
Where is the temperature probe taking its reading? Near the exhaust port?

Running an open pipe doesn't help matters. In spite of what your plug color is you might be lean with no baffles or back pressure in the muffler.

I'm curious about the carburetor. How did you go about "boring out" and NT carb?

What fuel to oil ratio are you using?
Tom
 
with bowl off, turn carb upside down and check that the main jet just peeks a bit above the float - that's about where it needs to be

be sure that sides of bowl are polished nice & smooth to keep float from getting stuck to some rough spot on the side of the bowl
 
Theon said:
May need more retard in the timing?
May need to lower comp ratio?
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this ^^

Sounds like detonation. What quality of gas are you running? Have you measured your exhaust temp too? if the head is significantly hotter than the exhaust pipe about 2 inches from the jug, it could be a sign of detonation. Both temperatures should be close to the same. Try a higher octane gas and see if it comes down.
 
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