Help! Predator 212 won't start no matter what I do

#21
Turn off gas so carb does not get fuel. You can drain float bowl on mikuni with the screw on the bottom of the float bowl. Open throttle and give a two second spray of starter fuel into carb. Pull the starter and see if it shows any signs of life. You may want to hold throttle open a slight bit when cranking.
ill make sure to try this out tomorrow, as i was busy for most of the day and havent gotten around to it.
 
#22
Turn off gas so carb does not get fuel. You can drain float bowl on mikuni with the screw on the bottom of the float bowl. Open throttle and give a two second spray of starter fuel into carb. Pull the starter and see if it shows any signs of life. You may want to hold throttle open a slight bit when cranking.
just did it, and it fired up on the 2nd pull and then died shortly afterwards. keep in mind this is a brand new mikuni i just got like 2 days ago, so i dont think the jets could be clogged
 
#23
OK Great that helps in the debug. It means the compression is not the problem and that the plug is capable of running the engine. Tell me about the 22mm carb. Have you done anything to it, did it come new out of the box or did you get it from someone like GPS that rejets them. Are you familiar with the enrichment system function? are you comfortable with removing the float bowl to look at the Pilot jet and main jets to be able to look at them and tell us what they are. Also not all of the chikuni carbs use the same jets. Most are mikuni jets but the ones GPS sells have had kehin jets. How are you mounting the mikuni to the head ? can you take pics and post them of carb installed and with float bowl off?
 
#24
OK Great that helps in the debug. It means the compression is not the problem and that the plug is capable of running the engine. Tell me about the 22mm carb. Have you done anything to it, did it come new out of the box or did you get it from someone like GPS that rejets them. Are you familiar with the enrichment system function? are you comfortable with removing the float bowl to look at the Pilot jet and main jets to be able to look at them and tell us what they are. Also not all of the chikuni carbs use the same jets. Most are mikuni jets but the ones GPS sells have had kehin jets. How are you mounting the mikuni to the head ? can you take pics and post them of carb installed and with float bowl off?
can i ask a quick question before i go out and taking apart my mikuni?
its about how I used the stock carburetor, bought a new one, and it still wouldn't start?
ill go get the pictures in a few minutes but i just wanted to ask why it still wouldn't start even with a brand new stock carb

back on the mikuni, i haven't done any work on it atm. i am not very familiar since this is my first mikuni, and i bought it from GPS. I wouldn't know the difference between types of jets or what each jet is on the mikuni, unless i know where each jet was

edit: mikuni is being mounted to the head with the GPS manifold kit
 

Lizardking

Well-Known Member
#25
Did you confirm fuel flow to the carb? Not enough fuel is reaching the carb if it runs on choke.

Does the tank have enough fuel to pass the gas line tube inside the gas tank?
 
#26
Did you confirm fuel flow to the carb? Not enough fuel is reaching the carb if it runs on choke.

Does the tank have enough fuel to pass the gas line tube inside the gas tank?
the carb did have fuel flow, so does the mikuni carb. i spray starting fluid and it ran for a second and died out.
 
#27
No problem, I was helping someone else with one from GPS and it had the KEHIN jets so when folks were telling him to get a 15 pilot and 130 main jet they did not have anything like that as their jet numbers are different than the mikuni #'s So do not complicate your life, Pick a carb you want to use then we can try to get that one working. I have little experience with stock type carbs other than putting a slightly larger main jet in them for my modified engines and they always seem to work just fine. I have lots of experience with the chikuni's that use mikuni jets but none with the kehin jets. By the way a lot of folks have issues with the stock carb like you are having and it is mostly due to not getting that plastic contraption that is the gasket and has airways in it back correctly. People put it back incorrectly and wind up with air leaks due to the air channels in the carbs.
 
#28
No problem, I was helping someone else with one from GPS and it had the KEHIN jets so when folks were telling him to get a 15 pilot and 130 main jet they did not have anything like that as their jet numbers are different than the mikuni #'s So do not complicate your life, Pick a carb you want to use then we can try to get that one working. I have little experience with stock type carbs other than putting a slightly larger main jet in them for my modified engines and they always seem to work just fine. I have lots of experience with the chikuni's that use mikuni jets but none with the kehin jets. By the way a lot of folks have issues with the stock carb like you are having and it is mostly due to not getting that plastic contraption that is the gasket and has airways in it back correctly. People put it back incorrectly and wind up with air leaks due to the air channels in the carbs.
that seems reasonable since it was running rich, explains why i mightve had the issue with it. but i do want to stick with the chikuni carburetor since i have it. do u want me to pull the carb off and go get some pictures of my setup, inside of the carb, etc
 
#29
No for now leave it installed and lets go over a few things before your next try to start it. Answer yes or no to the following questions.
1) did you install the paper intake gasket between the head and the GPS manifold.
2) is the captive O ring installed on the chikuni where you mount the carb to the gps manifold.
3) Was the carb supposed to be jetted correctly by GPS? They sell them setup but I have never dealt with them so I dont know if you have to pay extra for that.
4) chikuni does not have a choke but instead has an enrichening device. There is a brass plunger attached to the lever you use to set it on and off. When the plunger is up the enricher is on this is where it should be when you start it. It allows more fuel and air into the carb with the slide down to allow the engine to start up and idle fast. So tomorrow go out turn on the gas, wait a minute for float bowl to fill then try to start it with the enrichner on. Let us know what happens. If it does not start or pop then give it a spray of starting fluid and see if it runs then stops again. If it does that you may have a fuel flow issue. Are you using the tank on the engine or a tank on the minibike framerail?
 
#30
No for now leave it installed and lets go over a few things before your next try to start it. Answer yes or no to the following questions.
1) did you install the paper intake gasket between the head and the GPS manifold.
2) is the captive O ring installed on the chikuni where you mount the carb to the gps manifold.
3) Was the carb supposed to be jetted correctly by GPS? They sell them setup but I have never dealt with them so I dont know if you have to pay extra for that.
4) chikuni does not have a choke but instead has an enrichening device. There is a brass plunger attached to the lever you use to set it on and off. When the plunger is up the enricher is on this is where it should be when you start it. It allows more fuel and air into the carb with the slide down to allow the engine to start up and idle fast. So tomorrow go out turn on the gas, wait a minute for float bowl to fill then try to start it with the enrichner on. Let us know what happens. If it does not start or pop then give it a spray of starting fluid and see if it runs then stops again. If it does that you may have a fuel flow issue. Are you using the tank on the engine or a tank on the minibike framerail?
1 yes, i installed the gasket between the head and manifold
2 the o ring was installed on the carb when i took it out of the box
3 i read on the description before i bought it and it said, quote, "These carbs are jetted in house by our technicians to ensure your carb is running correctly. Since all engines run differently, you may need to do some final adjustments to run optimally."
4 using the tank on the engine since it fits within my frame and i dont have the money for a different one. ill let you know how using the enrichener goes tomorrow
 
#31
In case you have not checked it, on many of the HF carbs just behind the fuel inlet fitting there is a screen. If this screen gets clogged ( very common) you will have very poor fuel flow and the engine may not start.
There is a Youtube Vid on how to clean this screen.
 

Lizardking

Well-Known Member
#32
Make sure your fuel line isn't kinked or clogged. Gas should flow consistently and not drip out of the line.

If it runs with starting fluid through the carb then not enough gas is reaching the cylinder from the carb.
 
#33
In case you have not checked it, on many of the HF carbs just behind the fuel inlet fitting there is a screen. If this screen gets clogged ( very common) you will have very poor fuel flow and the engine may not start.
There is a Youtube Vid on how to clean this screen.
ill check this when I get home from school, this seems like it could be the case
 
#38
Describe exactly what happened with the enrichment on.
1) how many pulls till it started?
2) after it started did it run at a fast idle
3 after It started how many seconds did it run.
4) on the float bowl does it have a clear hose on the drain?
 
#39
Describe exactly what happened with the enrichment on.
1) how many pulls till it started?
2) after it started did it run at a fast idle
3 after It started how many seconds did it run.
4) on the float bowl does it have a clear hose on the drain?
1) 2-4 pulls everytime, would pop and show some smoke from the exhaust (light smoke)
2) it did start to run fast but then immediately after it would die
3) 1-2 seconds without me messing with the throttle, i got it to run for 10 seconds while messing with the throttle carefully
4) is the screw a valve that lets it down through that hose? cause there is a hose on the bottom of the bowl.
 
#40
Yes, you turn screw left to open and drain
Floatbowl . What I want you to do is use it to check the fuel level in the floatbowl.. you want to tape the clear hose to carb vertically then open drain screw and see how high it rises that will be your fuel level. Does this make sense? Not sure if I am explaining it well.
 
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