Trouble Tuning Apollo 125

[VA-DBX18]

Hello all,
I’ve been struggle for about a week now trying to get my DB-X18 bike to run properly. The bike starts and idles fine. Anything beyond a quarter throttle turn and it bogs. Will shut the motor down if I hold it.

I have the knock off Amazon VM22 carb and it came with a 38 pilot jet and 95 main jet. I have the needle currently set to the middle but I’ve tried moving that up and down with no change.

Today I replaced the main jet with a 105 and a 90 and there’s no change to how the bike runs. I start with the screw 1 turn out and adjust a little at a time but still no change.

Unfortunately the pilot jets that I ordered are not the correct space so I couldn’t try swapping them. I’m going to order more and hopefully get the right ones.

Any suggestions on what to try?

Link to video of what’s happening below
https://drive.google.com/file/d/1fWn...w?usp=drivesdk

[4T_Goblin]

We need access to that link. Try uploading to YouTube and share a link that way.
Are you hitting the throttle in neutral stopped or riding on street?

[4T_Goblin]

Is this what you experiencing?

[VA-DBX18]

I updated the link permissions so this should work now.

https://drive.google.com/file/d/1fWn...w?usp=drivesdk

I’ve tried both neutral and riding. I can’t go anywhere riding though because it bogs down as soon as I get it into gear and try to increase throttle.

My bike is doing similar to your video but not as bad as yours. I can give it some gas before it starts to bog. Yours seems to be anything off idle and it dies.

[4T_Goblin]

I'm just experimenting with my jetting. I have a genuine Mikuni vm22 and sounds like you have a clone mikuni.

If I feather it I can get it to go . So that's Lean I believe, but I can drive mine. It will run in gear

[VA-DBX18]

I did buy a knock off. That wasn’t my intension but I got lazy when reading through all the Amazon ads and stopped paying attention. I just ordered a genuine Mikuni from TBolt with some additional jets. I’ll see how that goes when I get it.

[4T_Goblin]

The genuine will show up with a 30 pilot and a 100 main. I got mine for like $80, from Niche Cycles but from a seller on Amazon.

I'm still testing mine but I have found a couple combos that work for me at 800ft above sea level.

Float bowl should come at about 26mm. I remember changing mine to 21mm because I read a tech sheet that said stock was 21. I thought it gave me a stalling at red light after long run WOT, but I'm not sure if it was from the float height or the idle being set too low. Anywaysit changed it back to roughly 24/25mm , seems good there.

I'm experimenting with lean pilots right now based on internet research and user testimony but I've had better luck from idle to 1/4 with pilot Jets in the 20 range.

I ride a 125cc Grom clone. Keep us updated

[VA-DBX18]

Thanks for the info. I’ve heard from some other Apollo owners and they had good results from the genuine Mikuni carbs. I am at 75 feet elevation so I have to imagine that I’ll have significantly different tuning from what works for you.

I’ll provide an update once I get the carb in the mail and can get it installed.

[VA-DBX18]

Ok. So quick update on things. I wanted to ride the other day so I put the stock carb back in and added a shim to the needle and it was running great. But then I got the genuine Mikuni in the mail today. I cracked it open and it came with a 95 main and a 15 pilot jet. I pulled the pilot and replaced it with a 20. Turned the mixture screw to 1 full turn out. I left the shim on the needle where it came which was one slot up from the bottom. The bike ran great.

I wish I could try to adjust the mixture screw while it was running but dammit my hand gets burnt up instantly. It’s like playing operation with hot parts instead of buzzer noises.

Any way all is running well at the moment so I’ll enjoy that.

[4T_Goblin]

You got a fake mikuni. Genuines come jetted 30/100. And the idle screw is an air screw on the rider's right side of the carb. Clone mikuni have the rubber pad on the choke, which is oriented different as well. Clone mikuni has AF mix screw in the bottom

Either way if it's running that's great!

[VA-DBX18]

This is what I ordered. It has Mikuni stamped on the carb.

https://tboltusa.com/store/mikuni-22...nis-p-107.html

I had a Carbhub VM22 previously and it came with completely different jets than this one did. But it did not have Mikuni stamped in it anywhere.

[dirtbkr188]

That carb is the infamous Mikuni-clone that's been around for years, it is made in Southeast Asia under the Mikuni name. It has a fuel screw that you turn OUT to richen the mixture and turn IN to lean it.


You might want to pick up one of these https://tboltusa.com/store/flex-jet-p-1063.html it helps prevent fried fingers...

[OffRoadToad]

That's definitely a knock off Mikuni. There's nothing wrong with that, though. Mine is a knock off as well but works great.
What's your elevation? only 1 turn out seems a little lean. Mines just under 1.75 turns out, and that's at sea level (FL.)

edit: forgot to mention I have the exact same bike. And a Z20 Max as well. and just noticed your at 75ft. Check that air/fuel setting again.

[VA-DBX18]

Are you running the same size jets as I am too? 95 main and 20 pilot? It came with a 15 and since I increased it that’s why i started out only 1 turn out.

Originally Posted by OffRoadToad

That's definitely a knock off Mikuni. There's nothing wrong with that, though. Mine is a knock off as well but works great.
What's your elevation? only 1 turn out seems a little lean. Mines just under 1.75 turns out, and that's at sea level (FL.)

edit: forgot to mention I have the exact same bike. And a Z20 Max as well. and just noticed your at 75ft. Check that air/fuel setting again.

[4T_Goblin]

You can order genuine Mikuni vm22-133 from Niche Cycles

Lots of people use the chikuni and have success