Apollo Carb issues
 

I have a 250 apollo with a mikuni carb clone swap. jets are 30 and 125 at 2700ft altitude. Bike was running fine with no issues. I swapped out the square air filters to a pod filter and now the bike will run perfect with the choke on the 1/4 notch and it will die if I take the choke off. I can take the choke off and give it fuel and it will backfire/spit white smoke before eventually dying. I took the carb off and cleaned it but no change. What am I doing wrong? Carbs are the bane of my existence. :( I also have an fmf tubine core 2 exhaust on the bike but that was put on previous to these issues.

I had a similar issue recently where it would start and immediately start sputtering and die no matter choke on/off, in my case it was a bad battery. Worth a shot.

yeah I am gonna look at that too. In my several hours of tinkering with the carb and jets I found that they didn't put a gasket on mine where the engine and carb elbow meet. Had an air leak there which might be a big part of my problem. I ordered a gasket to hopefully seal that up and see where I stand after that.

I was wondering if you might have had a vacuum leak. If you revved the motor and then rapidly closed the throttle, did the engine hang, or did it promptly return to idle?

it would hang. The reason I think I have a leak is I sprayed the all the joints with carb cleaner as it ran and when I hit the one before the engine it made the engine race. I think I had this issue previous but the leak was so small I think I set the carb too rich and it compensated for the air leak until I added a better breathing setup.

I found a vacuum leak on TurboT's quad (that uses the CG200 engine), and it was an o-ring groove that was cut too deeply on the intake tube. I tried a few things, but ended up just stacking two O-rings. Fixed.

Alright so I think I have found all the airleaks and fixed them and this is where I stand. The bike will start and run perfectly and will rev smooth with the choke partially engaged. If I take the choke off completely the engine will sputter and die. (act like it is getting choked out) also if I try to throttle it with no choke on it has no power and backfires constantly.

Suggestions as to where to go from here would be greatly appreciated! I feel like I am almost there but I am missing something.

Try trimming the pilot mixture screw by turning it out a bit. The sweet spot will be where it will idle without the choke (once warmed up) and not bog when you open the throttle quickly. If the idle hangs a bit when you rev it, the vacuum leak is still present. If it takes more than two turns from gently seated to trim the pilot mixture screw, the slow jet is too small.

Apollo 250 dirt bike carburater main jet sizes
 

Hello riders !

A Long Shot...

My engine is running lean and lacks power. It won't rev up and lacks torque. (between 50 and 100 percent of max power).

http://www.motosport.com/blog/a-simp...ting-your-carb
(good info)

The spark plug looks Ok but it is white which indicates that the gas/air mixture is to low. The carburater is fitted with a 109-sized Main Jet.

I bought some bigger ones, sized 110, 115,120 and 125.

110 would make no difference.
Which one should use. Trial and error - puh - dismounting/mounting....
Any suggestion ?

Check your needle jet. That might be your issue if your problem is mid throttle

Hello
I may not have been clear on what I mean with Main Jet.
The Main Jet is, as You suggest, where the needle is operating.
So I'll give it a go and fit the big Jet sized 125, as I see You use that size.
I'm running at near see level and more air is available there.
Also, if I set the choke a bit the engine responds better.
Thank You !

RPM's over 4000, nope !
 

Hi
250cc Apollo carb. A mikuni clone. I've tried a lot.
Adjusting for idle, works very well.
Adjusting for throttle 0 - half, ok.
Adjusting main jet/ needle position, Whatever I do it's impossible to rev it up to more than 4300 rpm on the road and also when standing still !
I've tried main jet sizes 110,115,120,125. It gets even worse with sizes over 115. Needle position - I've tried to find an optimal position.
Motor runs very nice from idle to 3000 rpm. but only if I give it max half throttle. More than that - nothing happens.
Giving some choke makes no difference.
All in all - it seems to me that the engine doesn't get enough air and fuel. When i drive it, it feels like a weak 50cc moped.
Help me, please. This is not good for my mental health.
(I will gladly pay some for a new better carb. if I can't solve it)
Cheers !

Hi guys, new to the forum. I was given an 08 Apollo 250 cc dirt bike. Sat for about 2 year. He said it had fuel line issues.Tank and carb were both bone dry when I got it. Took tank off and cleaned it. Put gas in it, bike started with the help of a shot of starting fluid but gas would steadily stream out the bowl overflow tube. Bought a new Japanese keinin 30 mm carb for $20, put it on and tuned it in with no leaks for about 20 minutes then new one started leaking like the old one and noticed the header pipe getting cherry red. Was not red when not leaking. Bike runs,idles and drives great except for the fuel leak. What little info I could find suggests its a bad cheap carb or valves are too tight or compression issue. Any info would be appreciated. Thanks