SAI Delete, Manifold vent popping, Staying Lean no matter what.

firstBike · 12-05-2020, 06:13 PM

Hello fellow China Riders.

So some background...

I put in a new Mikuni clone into my Apollo DB36. https://www.amazon.com/exec/obidos/A...im/refuge08-20

I removed the SAI crap, attached a oil catcher and breather filter for the crankcase, and plugged the motor with this
https://www.ebay.com/itm/NCY-EGR-BLOCK-OFF-PLATE-FOR-50cc-QMB139-150cc-GY6-MOTORS-/182189030236

I also plugged the manifold vent with some silicone cap I had.

The problem....

It was running amazing. Had the spark plug a nice caramel color. Came back in a week, and now no matter what i do, the spark plug is white.

I noticed the cap on the manifold is not there anymore, I am also hearing and seeing that the vent lets out a loud burst of air or spark? (it was blue). So the cap probably got blown off.

The spark plug is now white, no matter what i do. No matter how rich i turn the fuel screw, it stays white.

Question: Could this vent on the manifold be affecting the tuning process?
Question: Should i cap this vent on the manifold? Any suggestions on how?

Thanks everyone. I took a 5 second video where you can see the bursts coming out of the manifold vent, but i don't know how to upload videos here.

I spent like 6 hours trying to get the spark plug caramel again. Would appreciate any help.

**JerryHawk250** · 12-05-2020, 06:54 PM

Yes, plug the vent on the manifold. You're sucking in too much air. That's why is running so lean.

firstBike · 12-05-2020, 08:03 PM

Quote:

Originally Posted by JerryHawk250

Yes, plug the vent on the manifold. You're sucking in too much air. That's why is running so lean.

I was thinking of just cutting a piece of an old fuel hose, and filling the tip with silicone.

Should be ok? Or do you have any other suggestions?

old_airhead · 12-06-2020, 09:19 AM

A piece of fuel line plugged with silicone that fits tightly should work fine - I've done that in a pinch. You could also trot down to the auto parts store and buy what is called a vacuum plug.

franque · 12-06-2020, 11:42 AM

It probably backfired and blew the plug off, just put another plug on, but make sure that it's clamped on pretty good, too.

firstBike · 12-06-2020, 01:39 PM

Quote:

Originally Posted by old_airhead

A piece of fuel line plugged with silicone that fits tightly should work fine - I've done that in a pinch. You could also trot down to the auto parts store and buy what is called a vacuum plug.

Yup i think i'll go get a vacuum plug. Should be a safe fit.

Thank you

**JerryHawk250** · 12-07-2020, 12:46 PM

I just used a short piece of vacuum hose and stuck a bolt in it to plug it.

firstBike · 12-10-2020, 11:19 PM

Got the vacume caps, couple bucks at autozone for a set of different sizes. Worked fine. Now back to tuning the carb at below 20f lol

12-05-2020, 06:13 PM	#1
firstBike Join Date: Nov 2020 Posts: 21	SAI Delete, Manifold vent popping, Staying Lean no matter what. Hello fellow China Riders. So some background... I put in a new Mikuni clone into my Apollo DB36. https://www.amazon.com/exec/obidos/A...im/refuge08-20 I removed the SAI crap, attached a oil catcher and breather filter for the crankcase, and plugged the motor with this https://www.ebay.com/itm/NCY-EGR-BLOCK-OFF-PLATE-FOR-50cc-QMB139-150cc-GY6-MOTORS-/182189030236 I also plugged the manifold vent with some silicone cap I had. *The problem....* It was running amazing. Had the spark plug a nice caramel color. Came back in a week, and now no matter what i do, the spark plug is white. I noticed the cap on the manifold is not there anymore, I am also hearing and seeing that the vent lets out a loud burst of air or spark? (it was blue). So the cap probably got blown off. The spark plug is now white, no matter what i do. No matter how rich i turn the fuel screw, it stays white. Question: Could this vent on the manifold be affecting the tuning process? Question: Should i cap this vent on the manifold? Any suggestions on how? Thanks everyone. I took a 5 second video where you can see the bursts coming out of the manifold vent, but i don't know how to upload videos here. I spent like 6 hours trying to get the spark plug caramel again. Would appreciate any help.
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12-05-2020, 06:54 PM	#2
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,723	Yes, plug the vent on the manifold. You're sucking in too much air. That's why is running so lean. __________________ 2024 Linhai 300 ATV 4x4 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S (Sold) 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel
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12-07-2020, 12:46 PM	#7
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,723	I just used a short piece of vacuum hose and stuck a bolt in it to plug it. __________________ 2024 Linhai 300 ATV 4x4 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S (Sold) 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel
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12-06-2020, 09:19 AM	#4
old_airhead Join Date: Nov 2020 Location: Bloomington, IN Posts: 56	A piece of fuel line plugged with silicone that fits tightly should work fine - I've done that in a pinch. You could also trot down to the auto parts store and buy what is called a vacuum plug.
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12-06-2020, 11:42 AM	#5
franque Join Date: Nov 2017 Location: Marseille, France -> Conakry, Guinea Posts: 1,481	It probably backfired and blew the plug off, just put another plug on, but make sure that it's clamped on pretty good, too.
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12-10-2020, 11:19 PM	#8
firstBike Join Date: Nov 2020 Posts: 21	Got the vacume caps, couple bucks at autozone for a set of different sizes. Worked fine. Now back to tuning the carb at below 20f lol
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