Power loss and bad idle

[604scoot]

Its called an air screw isnt it? Google and even the nibbi instruction sheet says that screwing it in richens it. Regardless, screwing it in or out doesnt gain low end power or fix idle. I tried a 30 and 32 pilot as well. And it ran fine with a 32 pilot without reed setup

 

[Gordy]

If it is turning it in makes it richer and it runs best all the way in that means it needs a richer pilot jet. Try a bigger pilot jet. 34 or 38.

 

[ImpulseRocket]

If it is turning it in makes it richer and it runs best all the way in that means it needs a richer pilot jet. Try a bigger pilot jet. 34 or 38.

Yes, the PZ20 carburetor has an air screw for the idle mixture screw, located on the left side of the inlet (when facing the inlet).

I'm not even going to dig into this potato salad too far. Way too many variables at play to even try to troubleshoot this without being there in person.

My 2 cents: Air leaks cause many tuning anomalies like this, where you chase your tail trying to solve multiple running issues. Those changes "fix" one spot, but make others worse.

G2 Reed valve setups are consistently 2 things.
1. Air leak disasters - The number of people that get G2 reed setups and have air leak issues is beyond measure. They are very hard to get to seal properly, and have a lot of places to leak from.
2. Too big in internal volume for these little engines. They create a very very low pressure zone between the carb and intake port, and this often hurts flow. This is why "stuffers" for them exist.

Also, in my own experience and along with the experience of others and a couple of dyno comparisons I have seen, putting a windowed piston and reed valve on these little 2 stroke bike engines doesn't actually increase power, and in some cases reduces it.

My 2 cents, go back to a non-reed piston port setup.

If anybody wants to question what I have to say, all I will respond with ahead of time is this - I'm not trying to sell anybody anything.

 

[Johnny_]

I know you said you checked for an air leak, but to me this sounds an awful lot like one.
Also what @Gordy was saying about the reed valves, is #1 they could be faulty from the factory, #2 a piece of junk could have gotten in there and be holding them open. And again, I know you said you checked them, but that's something that a very very small issue could be causing problems.

 

[Chainlube]

I assure you the carb is sealed and has no leaks. Like i said before it ran great with no reed setup. So how is the pilot too big now. Reeds need a richer setup? Dont they? As for the air screw? Turning is closes the air off, thus making it richer.

Bin the reed.

 

[604scoot]

Bin the reed?

 

[Gordy]

Bin the reed?

He means don't use it.

 

[604scoot]

I got the reed because i need to offset the carb and thought it would run better. And my piston is allready windowed now. Im aware they have those offset intakes but i heard they suck and it wont wven match up with my 48mm carb screw holes. If i ditch the reed i will have to get another piston, and find an intake that will work.

 

[604scoot]

On a side note ive slowly been playing with carb, trying diff needle settings and changing both jets. Im all the way rich on the needle, 32 pilot and 85 main jet. Ive tried 70,72,75,78,80 and 85 doesnt 4 stroke. But it does this weird thing if i am WOT it feels like its running out of fuel because it has less power, and drives faster on 3/4 throttle. 72 main jet runs really bad, like there isnt enough fuel. 85 seems big doesnt it? I do have a good size expansion, transfers match with case, good bearings, polished port, and had a good squish. Does an 85 main seem fine for that setup?

 

[WEEDHOPPER420]

I run a G2 setup and what I did was drill and tapped the bolt holes to 8mm with blue loctite.
I also made my own gaskets, and added a set of aluminum pedals slightly bent inwards over top of the carbon fiber ones( making them stiffer).
I never had a problem from my G2 (except when I had a piece of trash holding open my pedal - lol Gordy).