Track Tac

Predator RPM on and off stand

Yes sir, these little motors are extremely lean from the factory, it an attempt to keep emissions compliance for use in their intended purpose.. ;)
 
Cakalac said:
I ran 2 features on a new spark plug the other weekend. When I pulled it out if looked as if it came right out the box brand new. There was zero soot on it. I thought it would have at least shown some wear after 35 laps. Would this indicate lean?
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Did it run good, were you fast? What's the problem? If you had been "too lean", there would have been some detonation and that can slow you down a bunch. I told the story about a friend of mine; sitting in the pits with some friends of his (he was a guy who I had tutored, when they first started racing) his engine builder came by and wanted to look at the plug. His eyebrows went up, "this is way too lean!" he said. Even with oil in the gas, (two cycle) the plug was clean. That day, despite his engine builders advice, my friend had fast time and won all three heats. Doesn't sound lean to me! lol
If you had written down the air density that day, and knew what jetting you had, and wrote it down, you would know what jetting to run the next time you see that level of air density.
 
alvin l nunley said:
Did it run good, were you fast? What's the problem? If you had been "too lean", there would have been some detonation and that can slow you down a bunch. I told the story about a friend of mine; sitting in the pits with some friends of his (he was a guy who I had tutored, when they first started racing) his engine builder came by and wanted to look at the plug. His eyebrows went up, "this is way too lean!" he said. Even with oil in the gas, (two cycle) the plug was clean. That day, despite his engine builders advice, my friend had fast time and won all three heats. Doesn't sound lean to me! lol
If you had written down the air density that day, and knew what jetting you had, and wrote it down, you would know what jetting to run the next time you see that level of air density.
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It actually did slow down at end of run. Just was trying to decide if that was tires because kart never handled bad actually felt better or motor giving up at end of run.
 
Cakalac said:
It actually did slow down at end of run. Just was trying to decide if that was tires because kart never handled bad actually felt better or motor giving up at end of run.
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Always possible, what did your tack say? Were you losing RPM on the straights? What about lap times?
 
Cakalac said:
Yes and I assure you I've asked the same exact question and I am not a motor guy. Lol. I don't know another way to set the RPM though. I think the rule set at 5000 is silly. I think 5300 minimum and the other tracks around my place are 5500.
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How do you set the governor
 
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