Weak, low power, and bog at full throttle

[bradmeehan]

I'm still having issues with my 85. I can barely get up the driveway.

I found the piston was in backwards, no expander ring, caulk for base gasket, the works.

So far I've:
replaced rings and gaskets.
decarbonized exhaust port
swapped in known clean muffler
new air filter
new plug
cleaned fuel filter
cleaned carb a few dozen times and have taken a carb off my Frankenspree and tried that
fresh gas in tank.

Starts easily, low speeds decent but weak take off. Around 15mph it loses it's balls. It doesn't stall but you can feel it bogging slightly.

Is this a reeds issue?
Two dirty carbs?
Petcock?

I'm stuck.

[Saved]

1. Are you using the stock air box?
2. Is it bogging down and then dying completely, as though it's getting flooded?
3. Is it bogging down or is it just losing power?
4. Have you adjusted the air mixture screw to stock and gone from there?

[bradmeehan]

Stock air box and new filter
Its more of a 'losing power' than a typical 'bog'

my air screw is at 1 7/8ths right now

[turtle13]

you sure it is running a proper jet for a stock setup? if they had all that wrong, the previous owner may have rejetted to compensate.
if its hard to start, check the reeds, i would suspect an air leak/exhaust leak/ or improper jetting.

[Clivester]

Brad:

What's the compression like? I know its less likely to be that since the bike starts easily, but finding the piston installed incorrectly does make me wonder.

Can you switch the coil/ignition wire and CDI from your other bike?

[bradmeehan]

Well, I just did a full top-end rebuild after finding that mess. My compression gauge sucks so I haven't checked it since the rebuild.

[joeweir1]

I was going crazy trying to figure out why my 85 Aero 50 was "bogging down", but idled fine.Checked everthing I could think of at the time at least twice.I then decided to replace the reeds and that fixed it.I thought I was wasting my money on them, but was wrong.I had a series of posts on this problem at the time and got tons of help and suggestions, but it was the reeds that did it.I did have another issue with hard starting when cold and we decided to put a big bore kit in it and now it starts fine.I believe the compression was just low enough to give it hard starts when cold.Now plenty of compression.Good luck

[bradmeehan]

It's getting better, but it's still not full power. I can get up the driveway but I'm barely hitting 25 on the flats. My OrangeJuice Spree is 35 easy.

Add to the list:
Inspected reeds. They looked good, but i flipped them over any way
Bought some carb dip. Soaked over night
Swapped out my plug wire. <- this may have been the best improvement.

[maddog]

Put your scoot on the center stand and full throttle the engine if it sounds normal that means you have 2 other problems which i yet to see anyone post on this forum which is in the trans, reed s are stainless steal and will never go bad in a stock engine, pm me for the the tricks of the trade

[Clivester]

pm me for the the tricks of the trade

Why not just enlighten everyone else? Sharing experience and help is the heart and soul of the forum.

[bradmeehan]

Thanks everyone. Here's the latest:

120lbs compression but still hard to start.

Swapped in (from other Sprees):
bystarter
petcock
float / needle

Reeds are the only thing left?

[bradmeehan]

Also...

After shutting down I was going to removed the carb (again) and when I removed the throttle I noticed exhaust smoke IN the carb. So gasses are leaking back in the carb? Huh?

[Bear45-70]

Sounds more and more like reeds and possibly a partially plugged exhaust.

[bradmeehan]

I'll try the reeds. I've swapped in another muffler earlier and it was the same effect. I have a spare I can put in.

[CharlotteSpreeRider]

Earlier you said you flipped the reeds over...I didn't think you could do that.