How hot is to hot ??

[haggard 2hundie]

o.k. so ive done a thread search and i understand that my machine ( 86 200X ) is air cooled, but it just seems to get extra hot quick ! i took a nice hour or so ride on the gravels near my house , wearing shorts , i know i know tsk tsk anyway my leg was getting slightly burned from the excess heat coming from the head , almost like a sunburn and i could feel the heat all around me coming off this thing.
so i guess my question is how do i know if its too hot ? and what may cause extra heat , aside from a lean condition ? and what is the worst case scenario from running too hot ??

[Thorpe]

Worst case... BLOWN MOTOR....

[AutoXer]

when a air cooled motor gets too hot it starts to perform crappy the idel raises and ultimately will die .... best case cenerio you let it cool down enough and it will start back up and no damage. With shorts? yes it will "feal" hot

[RIDE-RED 250r]

along with the obvious things like low or incorrect oil, incorrect jetting, incorrect valve timing can contribute to overheating. check jetting first. if it has some aftermarket stuff like a better air filter and exhaust on it, it would need to be jetted a little fatter and would run hotter if it wasnt jetted accordingly. if the jetting is good, verify that the valve timing is correct. i have seen cases where the valve timing was off a tooth or 2 and the machine ran, but ran hot....

[haggard 2hundie]

thanks guys it has a uni filter and i think its a cobra pipe , i upped the main jet to a 115 from a 112 and it runs good , and i have checked the valve clearance and aligned the t mark with the index mark on the flywheel cover. do i need a tach. to check timing ?

[RIDE-RED 250r]

well, if you went from a 115 to a 112 main, you actually went leaner. i would put a 125 main jet in, and raise the needle one notch to richen the midrange a bit to compensate for the pipe. a 4-stroke motor can still run "good" even if the mixture is on the lean side. but it will run hot. they arent as quick to let you know you are lean as the 2-stroke motors are. as far as the timing, you are correct to check valve clearance when at top dead as you did, but to check valve timing, you need to remove the rocker housing. once removed, you will see to marks on the face of the cam gear that are positioned 180 degrees from one another. when the flywheel shows the "T" in the window, those 2 index marks on the cam gear should be parrallel with the top of the cylinder head. HOWEVER, i dont think this is your problem since you have a leaner than stock main jet in place while using an upgraded air filter, and especially the upgraded exhaust system. my friend (who goes by Chillian here on 3ww) had the exact same issue you are describing with his 250sx. he is running a stock motor, with a K@N filter and full Cobra exhaust. jetting it richer made all the difference.

[Thorpe]

Agreed with RR^^ that I would still jet the high end a bit fatter... But you are stillneeding more adjustments than what you have done to it... Have a read...

http://www.3wheelerworld.com/showthr...Jetting-Theory

[cbx1170]

Its June temps are hotter. Heat takes more time to scrub off. Need air flow across fins all the time. Its called Delta temp diferences. And in general cyl head temps rise a little. Spark plug heat range? Correct plug? Cyl head temp gauge with temp sensing ring in place of spark plug compression gasket will give you exactly how hot head is getting, if you really want to know. I've seen air cooled 4cyl bikes run fine in PHX AZ in July at stop signs and stop and go driving also. Heat to the legs YES.

[ailll1]

well, if you went from a 115 to a 112 main, you actually went leaner.

In fact he said that he went from 112 to 115 which is richer just in a different order.
Better go back on school bench

[RIDE-RED 250r]

In fact he said that he went from 112 to 115 which is richer just in a different order.
Better go back on school bench

your absolutely right! lol! i completely misread that.


but i still stand by my recommendation to start at 125.

[haggard 2hundie]

sorry for the confusion i think i have a 118 and maybe a 120 main still , ill try them ? but if i order any more parts this month i think my ( pregnant hormonal ) girlfriend will castorate me hahaha
should i still try raising the needle?/ by lowering the needle clip ?

[litebulblsc]

I ran a 200s wit open header and open carb with no need to change jetting. I was still at factory carb settings and the thing ran good.

[atctim]

Does your 200X have a heat shield on the head pipe? If not that is normal to feel that - I have actually gotten a pretty nasty burn from riding my Big Red with no heat shield and in shorts - no contact was made - just radiating heat. Seems normal if you ask me. A good heat shield will eliminate some of that heat on the leg feeling.

[haggard 2hundie]

no heat shield but i will look into one soon as soon as im off ebay , dennis kirk restriction i know i know el whipped o ! but hey there are certain things a woman can do that my 200X cannot ( without a terrible burn )

[TeamGeek6]

thats what weak ignition does.

Engine temperatures cannot be more than the max operating temp for the engine oil. Thats hard to measure. Cylinder head or engien parts shouldnt go over 180-200F as a SWAG, thats where water cooled units operate.