MOPED ARMY

When I had a vm20 I ended up buying a whole Shit ton of jets.

Dude, CARBS ARE NOT SETUP FROM THE FACTORY! Lol You need to tune your bike. buy a set of jets in the right range and get to work.

Sorry that wasn't meant to sound mean, I just don't understand how often people expect a universal part to be plug and play. It could be put on any bike!

Jetting is an art, you screw up and your engine seizes. So don't run it anymore until you get an idea of where you need to be jetting wise.

Running rich= four stroking, meaning it doesn't fire every revolution. No risk of seizing here as the engine is getting plenty of fuel/oil mix..

Running lean= bogging down.

You want to get the bike rideable rich, then slowly jet down until the four stroking stops and temps equalize...best you get a head temp sensor too, no-no zone starts at 400° be cautious....

There are thousands of threads on jetting here, prolly in the wiki too. Good luck. Someone will chime in with a range to start with (edited)

Idk if this is useful but here is a video of it running with the choke on:

Yeah if it's rich ur not gonna seize it. I still wouldn't tho. But whatever not my bike.lol

Idle is way high. Slow that downnnn. But yeah get some jets n you'll be golden. Seriously tho, get a temp sensor.

I used this one. Has a tach too.

https://www.amazon.com/dp/B078YRRR5R/

you probably have an air leak. a 22.5 pilot jet is pretty large, that's a high idle, and you just rebuilt your engine. i would pressure/vacuum test.

hey Aaron does that tach/temp gauge read in celcius or farenheit. it kick ass that it has both tach and temp and you can replace the battery. iam gonna get one thanks

A) Requiring choke to run indicates a lean state, which with a 180 you should be anything but. You have a leak somewhere that is pulling in air.

B) VM's are easy to get running fair, but less crisp until you find the sweet spot. Most bikes I slap a VM20 on can be tuned enough for a life of riding within an hour. This is versus the 2 hours I would spend dialing in a PHBG, but I would typically have a VERY tight tune after that.

C) Don't buy the Dial-a-Jet from Sudco. For the same price you can have a full range of hard jets and tune multiple bikes.

The biggest downsize is you have no frame of reference for what size jet you are running. The dial-a-jet is not indexed, so you have no way of knowing what orifice size you are actually getting.

That, and all it takes is someone or something rotating that screw on you, or vibrations turning it and you could fuck yourself. even if you don't seize, you have to go through the whole process of turning and tuning again. I would much rather have a hard jet that I can properly clean and replace without re-tuning every time.

Hi all and thanks for the responses,

Ill order a set of jets today so that I can experiment. And ill order a temp gauge.

As far as an air leak... I cant imagine where the leak would be i build the engine last week and everything is to torque specs and all the seals and gaskets are new. i guess the only real way to check for air leaks w/in the engine case is to use a compression tool?

Id like to verify im running a 180 because like Dirty30 said, running with choke on is a symptom of running lean right? so with a 180 i should be far from lean. Is there a way to check and be sure im running a 180? is it written on the jet?

Does the wrong size jet commonly cause the bike to run only when the choke is on? or is that uncommon?

when you google "wont run without choke" everyone says its a blocked pilot jet. since my carb is new that cant be but maybe i need to adjust the pilot jet? is that an option? like i said im new to the art of carbs and jets.

Thanks for all the help.

You've checked the idle passage to validate your statement , right ?

New isn't always better or even correct .

NEVER buy, let alone use , carb cleaner .

It eats rubber and rubber type materials . But , go ahead and shorten the life of your seals and such . The vendors love that and you really need the practice of tearing your motor apart .

If you want to clean a carb use brake cleaner . It cleans better , quicker , leaves no residue and doesn't destroy rubber .

If you need to find a cylinder leak , try a propane torch , opened on low and unlit .

If there's a leak , the motor will notify you , immediately , without any damage .

Yeah, I definitely never buy Carb/Choke cleaner, just good old Brake Cleaner.

I run the vm20 needle clip second notch from the bottom 17.5 idle jet and a 122 or 125 main jet. Temperatures play a big role in jetting so your bike could run great one hot day then when temperatures changes u have to rejet.