So, I got the Xtreme back together with no problems and got all the oil injection crap pulled off of it. It has an occasional rattling sound down in the bottom end. It will only do it at certain rpm's, about 25% throttle not in gear, and sporadically at other times. If I turn the choke on, it won't do it and it seems to still run fine. So, that leads me to thinking maybe it's running lean on the pilot. This isn't a new sound. My daughter rides it so little I just leave the choke on. What puzzles me is that with the choke off, I can kill the motor by screwing in the air screw. The rpm's will pick back up at about 1 turn, so I've got is set at 1-1/4 turns. That would seem to me that the pilot circuit is close or the scew wouldn't be doing anything.
Anybody got anything for me?
Carb (Huh??? What's that?) tuning
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cannondale27
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I've heard that these mini's should be mixed at 40:1. Amsoil says they'll guarantee they're Dominator oil if mixed at 50:1 and actually says on the bottle "use in oil injection systems or as a 50:1 premix". So, I split the difference and went to 44:1.
As for the carb, I think it's a SunL. Yeah, they're real popular, arent' they?!!! I read once that 2 stroke carbs have an air modulating screw while 4 stroke carbs tweak the fuel. It was stated as if that's across the board, but I don't know that it's true.
As for the sound, if it didn't go away when the choke was on, I'd swear it was the piston rattling around in there. I pulled the pipe off and looked in the cylinder. I could see cross hatching on the other side and some carbon smearing below the bottom ring on the piston skirt. I'm not sure if taht's normal, but that's what I saw. The top of the piston was just heavily coated with rough black carbon build up. The plug that came out was pretty much black. I'd say it's a safe bet my girl almost never hits full throttle since we don't have any big open areas. So the plug is a pretty good read on probably 0-1/2 (maybe 3/4 throttle).
As a side note to plug reading, the other day I saw Jack Rousch and one of his engineers looking at some plugs they'd just pulled out of a Cup car with a magnifying glass. I had kind of lost faith in plug reads, but after seeing that, there must be something to it.
As for the carb, I think it's a SunL. Yeah, they're real popular, arent' they?!!! I read once that 2 stroke carbs have an air modulating screw while 4 stroke carbs tweak the fuel. It was stated as if that's across the board, but I don't know that it's true.
As for the sound, if it didn't go away when the choke was on, I'd swear it was the piston rattling around in there. I pulled the pipe off and looked in the cylinder. I could see cross hatching on the other side and some carbon smearing below the bottom ring on the piston skirt. I'm not sure if taht's normal, but that's what I saw. The top of the piston was just heavily coated with rough black carbon build up. The plug that came out was pretty much black. I'd say it's a safe bet my girl almost never hits full throttle since we don't have any big open areas. So the plug is a pretty good read on probably 0-1/2 (maybe 3/4 throttle).
As a side note to plug reading, the other day I saw Jack Rousch and one of his engineers looking at some plugs they'd just pulled out of a Cup car with a magnifying glass. I had kind of lost faith in plug reads, but after seeing that, there must be something to it.
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thedeatons
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You might try a hotter plug, or lowering the needle so the bike gets less fuel at lower throttle openings... My daughter's DRR ALWAYS has perfect plugs, the only thing I do is swap jets for altitude. You could also try a compression test, then go on the forums at www.exriders.com (mini forum for your brand) and speak with them about what the compression should be. The more information you have the better your results will be when trying to get answers.
You could also try a new plug, then get on it and full throttle it around for a while so you can do a plug chop and verify your main jet is right...
That thing should run and idle just fine with the choke off after warm up. My daughter's idles fine after about 1 minute on the choke.
You could also try a new plug, then get on it and full throttle it around for a while so you can do a plug chop and verify your main jet is right...
That thing should run and idle just fine with the choke off after warm up. My daughter's idles fine after about 1 minute on the choke.
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cannondale27
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I just had a huge reply written, then it logged me out for some reason and I lost it all. My computer is having issues, so when I get it taken care of, I will reply again.
Cliffs from it though:
C27 is right about checking the float level.
Amsoil sucks
You have a compression or compression loss issue (could be due to running rich).
Do you have an adjustable timing plate or pickup? Some bikes have adjustable from the factory and yours may be advanced.
Reading plugs are great if you know what you are looking for.
Cliffs from it though:
C27 is right about checking the float level.
Amsoil sucks
You have a compression or compression loss issue (could be due to running rich).
Do you have an adjustable timing plate or pickup? Some bikes have adjustable from the factory and yours may be advanced.
Reading plugs are great if you know what you are looking for.
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thedeatons
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- Joined: Wed Mar 10, 2021 10:41 pm
QUOTE (thedeatons @ Nov 7 2008, 12:53 PM) <{POST_SNAPBACK}>
By the way, I use Redline.... My friends told me my plug is the cleanest 2 stroke plug they have ever seen, and they owned fast Banshees for years....
Did you remember to block off the injection hole on the intake/carb? This could be the reason.
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thedeatons
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