Yamaha Starbike Forum banner
1 - 4 of 4 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 ·
I have one of those remote laser thermometers, when I shoot the outside engine temperature after a decent run it tells me 640 degrees on the fins. If anyone have any ideas on that. The oil stays around 200, 220 Max I can't find any information on this anywhere so any help would be appreciated
 

·
Administrator
Joined
·
15,321 Posts
don't know much about operating temps on different bikes, but that sounds way off. i know on some bikes it's typically around 300 degrees right on the cylinders while idling.
 

·
Registered
2003 RS Warrior S*2-1-2(G2). -AIS. VBAK/K&N(RC1290). CobraCVT. Ivans. SR-2. DC2-1.
Joined
·
86 Posts
Are you shooting the fins on the exhaust side?

Exhaust headers are cooled while moving but get hot quickly when stationary. Depending on variables, when moving they can get ~300F but stationary depending on variables they can get 600F~1200F which explains why exhaust paint advertises its temperature rating.

Air cooled bikes like the vstar use the gasoline to cool the cylinders. That effect reaches into the headers too. So if your carbs are incorrectly jetted or if there are fuel delivery troubles of some other sort making it run lean then you don't get enough cylinder cooling. That radiates a ton of heat. On these motors ~650F is worth pulling spark plugs and reading them to diagnose. I use the NGK plug charts for this sort of maintenance but there are other good ones.

If you are getting ~650F on fins on both the left and right sides of the motor and your oil measures ~220F then your thermometer is messing with you lol.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #4 ·
Are you shooting the fins on the exhaust side?

Exhaust headers are cooled while moving but get hot quickly when stationary. Depending on variables, when moving they can get ~300F but stationary depending on variables they can get 600F~1200F which explains why exhaust paint advertises its temperature rating.

Air cooled bikes like the vstar use the gasoline to cool the cylinders. That effect reaches into the headers too. So if your carbs are incorrectly jetted or if there are fuel delivery troubles of some other sort making it run lean then you don't get enough cylinder cooling. That radiates a ton of heat. On these motors ~650F is worth pulling spark plugs and reading them to diagnose. I use the NGK plug charts for this sort of maintenance but there are other good ones.

If you are getting ~650F on fins on both the left and right sides of the motor and your oil measures ~220F then your thermometer is messing with you lol.
Thank you very much that Jesus my mind a little yes I am shooting the temperature on the exhaust side I'll make sure to check the other. I appreciate your help
 
1 - 4 of 4 Posts
Top