Tuning a clone/gx200 pilot jet by turning?

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MattR

New Member
#1
#1
My 212 bogs just off idle and a bit above, and its hard starting after its already warm. I'm pretty sure I need a smaller pilot jet. Eventually I'll get the correct one but in the meantime I was thinking...

Could you remove the circled portion of the top of the pilot so you could rotate the jet and block those two holes on the sides slightly? Im thinking about trying out my idea in the morning.
 

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sparkwizard

sparkwizard

#2
#2
You can try but it won't do anything. There are two Orings on that jet. The jet itself sits in a round hole but in the middle of that hole, there is a slot or channel that surrounds the entire jet. No matter which way it is turned, those holes are in the fuel passage. If you plan to replace it anyway, why not experiment with blocking ONE of the holes? Maybe jam a toothpick in it and break it off? You could remove it if you experience more problems.
Just a thought....
Toothpick would be too small but you get the idea.
Honestly, I would try a larger pilot.
 
M

MattR

New Member
#4
#4
sparkwizard said:
You can try but it won't do anything. There are two Orings on that jet. The jet itself sits in a round hole but in the middle of that hole, there is a slot or channel that surrounds the entire jet. No matter which way it is turned, those holes are in the fuel passage. If you plan to replace it anyway, why not experiment with blocking ONE of the holes? Maybe jam a toothpick in it and break it off? You could remove it if you experience more problems.
Just a thought....
Toothpick would be too small but you get the idea.
Honestly, I would try a larger pilot.
Click to expand...
I didn't consider blocking a hole but you are right the mixture still gets around. I've read about drilling them so I decided why not.

I got the micro rotary bit set from harbor freight, used some nail clippers to clip a tiny piece of solder and place it in the jet and the solder sweated in there pretty good. I was worried about the plastic.

Those bits are incredibly tiny! I broke a few of the smaller ones, but I was able to drill it back out to .35mm( i think if i needed bigger I could do it by hand now) but I got the jet back in the bike and got it going!

The engine still started good and seems to get off idle a bit better but I was thinking maybe its vibrating more. I was watching idle and i was thinking was the bike shaking this much last time? hmmm
 

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panchothedog

Well-Known Member
#6
#6
With a modified 212 ( I have a few ) and a stock style ( original ) carburetor
I am drilling out the stock pilot jet to .020" . For the main jet, the one that goes up inside the fuel bowl a # 37 works well. I am near the Pacific ocean,
so basically the same elevation as you. If you are running the same type of carburetor you are very over jetted. Very rich. Your plug looks it.I don't know by how much, but you will need to drop down a bunch for that kind of altatud. Also be ready for a substantial decrease in power. For the tiny drill bits, get a tool called a pin vise. Model stores and websites carry them. About the size of a short pencil, has interchangeable collects that you put the drill bits in, and then VERY delicately and with very little pressure you can manipulate the drill with your fingers quite easily.
 
M

MattR

New Member
#8
#8
panchothedog said:
With a modified 212 ( I have a few ) and a stock style ( original ) carburetor
I am drilling out the stock pilot jet to .020" . For the main jet, the one that goes up inside the fuel bowl a # 37 works well. I am near the Pacific ocean,
so basically the same elevation as you. If you are running the same type of carburetor you are very over jetted. Very rich. Your plug looks it.I don't know by how much, but you will need to drop down a bunch for that kind of altatud. Also be ready for a substantial decrease in power. For the tiny drill bits, get a tool called a pin vise. Model stores and websites carry them. About the size of a short pencil, has interchangeable collects that you put the drill bits in, and then VERY delicately and with very little pressure you can manipulate the drill with your fingers quite easily.
Click to expand...
Wow that's a big difference! Yes I have the stock style carb. All my jets are what came with the motor originally but actually I received a set of jets 70-100 for my trip so I'll get to make some adjustments but I know it wont be perfect.

I didn't even know pin vise was a thing lol I used a beat up dremel. I'll have to get one though for the future tuning
 
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