The right Jet??

Karl Snarl

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Sep 20, 2019
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5,691
I personally have tried Amsoil synthetic at 100:1 in my fuel mix when I started and this is what my cylinder and piston looked like only after maybe 6 hours of total ride time or less. I was even running a 78 jet (very rich jet)
View attachment 161652 View attachment 161653
Very low piston wash and I can't say with 100% confidence that the low oil caused chipping of my cylinder but it couldn't help.

I'd run 40:1 with high quality synthetic oil like that or 32:1 with anything else. 100:1 with Amsoil is the minimum for an engine with low load like a weedeater.

Piston wash with same Amsoil
Walmart oil offers more than enough protection. No need to lie to oneself to justify the expensive oils. These bikes will last just as long on a good shot of Walmart oil as they will with a good shot of Amsoil ( @40_32:1). 100:1 is just way to little oil to help anything but oil emission.
 

DieselTech

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Sep 18, 2021
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Yep I run 32:1 with opti-2 synthetic
This oil discussion comes up every noob. 30-35:1 is perfect, 2 stroke drag bikes run 25:1 of quality dino oil, nuff said.
Everyone tells me I'm wasting my money, Phff! Oil is cheap insurance. 25:1 if I'm beating on it!!!
 

Backwoods

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Nov 21, 2021
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21
This is a 60 jet, it's way too rich IMO. The 58 is a little better, and the best all around as far as top speed, the 55 even cleaner, but cant flow enough to support higher rpms. This is the way its been with all oil types I have tried. Walmart ST, Echo, HEB GTC, and one or two other off the shelf gas station bottles. All ran at around 32:1, except the amsoil, at 95:1. This is after a 6 mile ride roughly. I'd really like to have a nice milk chocolate brown, but I've never seen it on this particular engine. The needle has nearly always been set at the 2nd notch, I couldn't ever get any decent adjustment to my satisfaction through the needle. I did try moving it around at first before I ordered a jet set.
 

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DAMIEN1307

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The needle has nearly always been set at the 2nd notch
In other words...2nd notch towards the bottom or 2nd notch towards the top of the needle???...Your at sea level altitude...on a 5 notch needle you should be starting in the center notch on a #70 jet...if still too rich, you go to the next notch going towards the top of the needle to lean it out a little more.

Im at a 4500 ft altitude with my needle valve at the very top notch for full lean on a #70 jet because of my altitude here in the high deserts of NM.

Ps...Also make sure if your using that Chinese plug Z4C or Z8C, chuck it out and get either an NGK-B6HS, BR6HS, or B6S to replace it and gap it at .025 thousandths...Like yourself, I also use Amsoil Dominator 2 stroke full synthetic racing oil, but at a 32:1 mix with 87 octane enthanol free gas myself on my bike and have that chocolate brown colour plug you speak of.

DSCN0177.JPG
 

Karl Snarl

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Sep 20, 2019
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This is a 60 jet, it's way too rich IMO. The 58 is a little better, and the best all around as far as top speed, the 55 even cleaner, but cant flow enough to support higher rpms. This is the way its been with all oil types I have tried. Walmart ST, Echo, HEB GTC, and one or two other off the shelf gas station bottles. All ran at around 32:1, except the amsoil, at 95:1. This is after a 6 mile ride roughly. I'd really like to have a nice milk chocolate brown, but I've never seen it on this particular engine. The needle has nearly always been set at the 2nd notch, I couldn't ever get any decent adjustment to my satisfaction through the needle. I did try moving it around at first before I ordered a jet set.
can I see a pic of your carb?

To me the plug says you are burning hot in one rpm range and 4 stroking in another. Sounds like an air leak.


Your bike, you can run as much or as little oil as you want. I just know from my years of experience, what happens when people follow fancy oil directions without taking into account their specific engine and it's requirements at whatever loading the user is putting it through.
 

Backwoods

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Nov 21, 2021
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In my quest to get a better burn, I further decked the head. Its about as close as I'm comfortable with. It measures out at around 3/4 of one mm. The engine did noticeably hit harder. I test drove it a few miles with zero signs of contact. I am running the JRL top bearing available from Amazon. At 4.99, it's a must have. It's a beefier bearing, slightly longer, sticks out both sides of rod so theres less play. The added protection of a better bearing is Definitely worth $5, IMO. My engine has less vibration for sure. The rollers are also thicker. The picture is from Amazon, but that's exactly what it is. Tightening the squish did in fact give me a slightly cleaner burn. The plug did look a tad cleaner.
 

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Street Ryderz

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Oct 14, 2016
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This is a 60 jet, it's way too rich IMO. The 58 is a little better, and the best all around as far as top speed, the 55 even cleaner, but cant flow enough to support higher rpms. This is the way its been with all oil types I have tried. Walmart ST, Echo, HEB GTC, and one or two other off the shelf gas station bottles. All ran at around 32:1, except the amsoil, at 95:1. This is after a 6 mile ride roughly. I'd really like to have a nice milk chocolate brown, but I've never seen it on this particular engine. The needle has nearly always been set at the 2nd notch, I couldn't ever get any decent adjustment to my satisfaction through the needle. I did try moving it around at first before I ordered a jet set.
You need to use a brand new plug for a main jet reading as this plug shows many things and alot of use! You say a 55 jet cant support higher rpms and your right it's way too lean, you also say top speed is 30 with a 40t and that is only 5800 rpm that's not high it's below the stock engines normal operating speed with nothing done to it! You definitely have other issue's at play here, many people can get 8-9k rpm from a stock setup some even over 10k when they know what they are doing or follow advise from those whom do, best of luck with this!
 
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