AllRoad 200cc Engine Start --> Rev --> Bog Down -->

[puush]

Hi all,

I have an AllRoad 200cc Dirt Bike that has been running well for past year thru all the harsh riding I have put it thru. But now i am suffering from these engine problems and two small motor mechnic shops can't seem to fix it.

First, the bike will start up and run fine. Then when I start reving the engine it bogs down and then quits while I try to give it gas. The two mechanics told me they do not think it is the fuel system. The engine is getting fuel ok. Do you guys have any suggestions of how I can fix my bike? Do you all think I need to adjust the valves on my bike or should I stay away from that? I have a 250cc buggy and i had to adjust the valves on it once to get it back up and running.

Anyways, since finding out about this glorious website I quickly found a place on the web to buy parts at low cost so yesterday I bought the following parts to try and fix my bike.

1. New Stock Replacement Carbuerator.
2. Racing CDI (up to 100000 rpm)
3. NGK Racing Coil Cable
4. New Stock Regulator

I am hoping these parts will get me started again because I miss riding my bike.

http://www.youtube.com/watch?v=LdAdMqa1m7M

http://www.youtube.com/watch?v=WC3fUCPCIcc

I should note that I have done a few mods to the bike before it stopped running. I installed FMF PowerCore Exhaust and UNI Cone Air Filter. After I did these mods it ran ok until it started having the bogging out issues..

Also, I have a 250cc Chinese buggy that I have repaired and fixed,. Like adjusting valves and replacing rear drive axle. So I think I have the abilities to fix my dirt. Any help I can get from you all will be greatly appreciated and I will get you all back if I can help with any issues. Thanks a million... 8)

[DDG1976]

If you've ordered a new carb I'm sure you've checked to make sure the choke is'nt hung up? The only other thing I could think of would be the plug.

[tigertamer]

Also, make sure that your fuel cap is breathing properly. A bad cap vent can cause your symptoms :wink:

Tigertamer

[katoranger]

Did the problems start immediately after you installed the filter and exhaust?

Did you change any jetting or carb settings?

Sounds to me like you are no getting enough fuel.

The cap vent is a good suggestion, but try this. Remove the fuel line from the carb and turn the gas on. Watch to see if you have a steady flow of gas. Place the fuel line into a catch container also. Let it run for a few minutes at least to see if it continues to flow well. This will tell you if you are venting and have no obstructions in the fuel line.

Allen

[puush]

Well, I have installed the following parts on my AllRoad 200c Dirt bike to try to fix my loss of power/shut down at high RPM.

Installed new:

- Regulator
- Ignition Coil
- Mikuni 30mm Carburator

My dirt bike starts ok and warms up ok but when I start to rev to high rpm it loses power and will shut down and then its hard to start up again. The final part I have to put on my bike is a NEW Racing CDI and hopefully this will fix it. The engine is getting fuel just fine and the carb is new.

* Do I need to "Adjust Air Valve Gap"??? According to the manual with my dirt bike it says to possibly do this if thier is a loss of power. Has anyone ever adjusted "Air Valve Gap"? I had to adjust the valves on my Chinese 250cc Dune buggy when it wouldn't start and it fixed that problem.

Any suggestions from you all would be greatly appreciated. Thanks


Michael A :?

[katoranger]

I think the chinese are referring to adjusting the valves and that may be something to look at.

Allen

[warrior91]

New Carb or not, I would really check the jet for obstruction...all it takes is a speck of crud or a weed seed being sucked into the main jet and your bike will only run on idle circut.

[DesertDog]

3 carbs later on my sons viva 250 and the bog down went away, sure wish you would'nt have bought the racing cdi , they are'nt what they are to do, there's some old threads on those here about what garbage they are.

keep working on that carb, it sounds like yur runnin rich, to big a main jet, if its a 130, drop it to a 110 or a 115 size , if its a 105 you've got blockage, get an air hose and blow it out

and while yur in there check yur throttle needle adjustment, that should be at the 2nd groove from the bottom

these carbs are easy to work on after the 12 time you've taken it apart you'll need to replace the bowl gasket and screws,,,,, lol

[puush]

thanks man. i found a mikuni carb tuning document. it is a stock 30mm Carb and I haven't adjusted the needle. I'll make these adjustments and check it out.

[john25]

Here's what has happened. I believe you are getting fuel OK. The problem is that these China bikes come with plugged exhausts & have air filters that are junk. You did two things that require more fuel. The better air filter allows it to breathe better, requiring more fuel. The better exhaust also allows the motor to exhale more so again, you need more fuel. Remember, a motor is an air pump, the more air you move in, the more fuel you need, or else you will be too lean. I have done the same mods you have on two of my kids China bikes, both a 200 & 250. Try this cure:
1. Go up on the main jet size by at least 4, ex. If it has a 98 main in it, go to a 102. Buy the next two larger jets just in case as well.
2. Go up one size on the pilot jet, and get the next larger one as well. Ex. if it has a 40 in it, go to a 42 or 43.
3. Turn the fuel screw in till it lightly bottoms, do not tighten it. Then back it out 1.5 turns.
These are your starting points. If it still won't idle right, turn the fuel screw out till it does. If you have gone past 2 full turns, you need the next bigger size pilot jet. If the motor is too rich and you need to turn the fuel screw in to make it idle right, and it's out less than 1 full turn, then you need the next smaller size pilot jet.
You will have to do tuning, there is no out. Hope this helps. :idea:

[puush]

thanks man. I will order the main and pilot jets and give it a try. Also, the dude in another post suggested I adjust the needle in the carb also, setting it to the second notch????

In your experience, do you think I need to adjust the valves on my bike or is do this just require a carb adjustment???? Thanks for all your help dudes.

Oh yah. The freakin Performance CDI didnt fit anyways.

[john25]

I would start the needle in the mid position. If you raise it, you richen the fuel. If you drop it, you lean it out. This way, you're essentially neutral to start. On my bikes, I left the needles in the middle for both bikes and just played with the main and pilot jets, along with the fuel screw adjustments.
At this point I would play with the carb due to the mods you did. Keep in mind that you did run the motor lean for some period of time, because you did the mods and then ran it without rejetting. If the carb tuning doesn't fix the running, then yes, try the valve adjustment. Typically, a motor is hard to start when the valves are too tight because of a lack of compression. That is, the valves don't quite close all the way.
Lotsa things could have happened, maybe the valves sunk in when the head got really hot from being lean, maybe it really is just time for the valves to get adjusted, maybe the ignition module is starting to fail causing the erratic running past idle. Maybe it is just too lean, a motor will backfire and sputter when it's lean, that's what my X-motos 250 did till I rejetted it.
I know this is alot to digest, but it's all part of diagnosing the problem.

[puush]

Thanks for all the info man. I can totally understand having to rejet for a richer fuel mixture since I have a straight thru exhaust and air filter.

I have rejetted the carb on my 250cc Chinese Dune buggy and adjusted the valves as well. There is straight thru exhaust and redneck air filter on my buggy also.

When you say adjust the fuel screw adjustment on my dirt bike carb, do you mean adjusting the "idle screw"?

I ordered the 2 size larger Main Jets and a size larger Pilot Jet for my dirt bike carb, so when they arrive I will stick them punks in and adjust the needle also. I should be able to do the valve adjustment also, if I have too. But like you all said, its probably a "fuel" issue and I agree.

I know when I had to adjust the valves on my dune buggie, my dune buggy wouldn't even start. At least my dirt Bike starts and runs for a while until it bogs out. Thanks for all of your help good peoples.


Michael A 8)

[DesertDog]

Thanks for all the info man. I can totally understand having to rejet for a richer fuel mixture since I have a straight thru exhaust and air filter.

I have rejetted the carb on my 250cc Chinese Dune buggy and adjusted the valves as well. There is straight thru exhaust and redneck air filter on my buggy also.

When you say adjust the fuel screw adjustment on my dirt bike carb, do you mean adjusting the "idle screw"?

I ordered the 2 size larger Main Jets and a size larger Pilot Jet for my dirt bike carb, so when they arrive I will stick them punks in and adjust the needle also. I should be able to do the valve adjustment also, if I have too. But like you all said, its probably a "fuel" issue and I agree.

I know when I had to adjust the valves on my dune buggie, my dune buggy wouldn't even start. At least my dirt Bike starts and runs for a while until it bogs out. Thanks for all of your help good peoples.


Michael A 8)



the air/fuel mixure screw is usually directley under the carb ,near the front portionof the inlet part, some air/fuel mixure screws are on the side, like some of the PZ carbs, some,

adjust the air/fuel by turning it in all the way till it stops, without force, then counter clockwise 2.5 turns , that is uaually the general rule, it gets in close proxemity ,

on some carbs u can loosen the intake screw clamp and rotate the carb to access the air/fuel screw, some u hafta take carb all the way off.

hope that is what you were asking for

[IronFist]

Here's what has happened. I believe you are getting fuel OK. The problem is that these China bikes come with plugged exhausts & have air filters that are junk. You did two things that require more fuel. The better air filter allows it to breathe better, requiring more fuel. The better exhaust also allows the motor to exhale more so again, you need more fuel. Remember, a motor is an air pump, the more air you move in, the more fuel you need, or else you will be too lean. I have done the same mods you have on two of my kids China bikes, both a 200 & 250. Try this cure:
1. Go up on the main jet size by at least 4, ex. If it has a 98 main in it, go to a 102. Buy the next two larger jets just in case as well.
2. Go up one size on the pilot jet, and get the next larger one as well. Ex. if it has a 40 in it, go to a 42 or 43.
3. Turn the fuel screw in till it lightly bottoms, do not tighten it. Then back it out 1.5 turns.
These are your starting points. If it still won't idle right, turn the fuel screw out till it does. If you have gone past 2 full turns, you need the next bigger size pilot jet. If the motor is too rich and you need to turn the fuel screw in to make it idle right, and it's out less than 1 full turn, then you need the next smaller size pilot jet.
You will have to do tuning, there is no out. Hope this helps. :idea:

Good post MAN! Glad I didn't type it. Too bad he bought all that stuff, sounds like he could have got jets for his old carb, and Bob's yer uncle.

Warrior. These are small jets, no way a seed gets stuck there, :lol: But ya, it sounds like a jet obstruction because of the lean conditions from the new air filter and muffler.

[warrior91]

I've had a wild oat seed that somehow went vertical and the small pointy end actually wedged itself into the main...36mm carb 150 jet

[IronFist]

Oh not a weed seed, but a wild oat seed. I could say so many witty things right now but I'll just go sit down.

[puush]

So your saying the Main Jet has too tight of a hole??? :twisted:

[warrior91]

Oh not a weed seed, but a wild oat seed. I could say so many witty things right now but I'll just go sit down.
:lol: :wink: :wink: Now I see.lol