Gx 390 ?

They say around 400 +/- 20 but mine went to 510 once and it didn't bother a thing and ran the best it ever had and it didn't tear up a thing. Parsons racing builds good parts
 
400 seems to be a benchmark many shoot for. Not sure if that's based on actual testing or just someone's theory. I'm with metalmagic, a little more works a little better I think. 450 is safe I believe on a consistent basis. Getting to this on gas is not real hard to do. Alky on the other hand ,can be tough to get this warm on some builds. Fuel mixture and timing can get you there easier than by just simply taping it up. Lets say you have a real rich engine that runs OK but not great. It seems to run around 340 or 350 degrees or maybe less. If you tape it up and finally get it up to 420 or 440, it will run a lot better. Through combustion chamber temperature increase you have helped it burn just a little more of that rich fuel mixture. But, if you had simply leaned it out some and got the temp up by getting the fuel mixture right, it would be running better than the simple taped up engine. I guess I'm saying, use the temp to help tune the engine. Good luck.
 
Nobody will listen to me, but the CHT tells you very little of importance. The EGT on the other hand, tells you what is going on inside the engine. Take for example the guy who says his engine CHT is 510. And it runs fine. How do you rationalize that big difference from what most people run? I would like to see somebody put both on their engine, the EGT and the CHT, and tell us what they tell them.

Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory.(Al Nunley)
 
D&J Racing said:
alky and I'm not even getting to 300
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have you tried smaller Jets? Sounds to me like your real rich. One of the advantages with a two cycle was if you're rich you would see a lot white smoke.

Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory.(Al Nunley)
 
D&J Racing said:
super bn8 carb ...maybe some one can give me starting points on how far to run out low side and high side
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If you mean mikuni 38sbn.....its not about needle settings like a tillotson......its about jet sizes.......needles only do a small part in carb setting.......1 turn out on high and low is where you want to be when jets are correct.......
 
ok no heat and when I stomp pedal on starts or restarts it almost quits real sluggish off corners but from from mid straight to corner shoots out like rocket what you guys think?
 
OK guys I'm back and have jet problem evidently the guy that built my carb drilled original jet I ordered some going off of number on jet I had they are way to small I am at 2000 2500 feet above sea level ...looking at some large head jets I have I am thing maybe 155 160 some where in that area any help will be greatly appreciated
 
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