Apollo 250 wont start with new mikuni carb

[MotoJunkieDillon]

After hearing all the recommendations of getting a new mikuni carb, I finally did. After installing the new carb, it doesn't want to start, I had checked to see if the carb was getting fuel by loosening the drain bolt, and sure enough fuel was in the bowl. I then held the electric start for about 10 seconds then removed the spark plug. When I was checking the spark plug, I saw there was no gas on it, it didn't even smell like gas, which mean gas isn't getting to the engine. I'm not sure what to do, all the hoses are where they should be, I had also checked the jets (which is a 100 main jet and 20 pilot jet) and they weren't clogged.

[Merlin]

Have you started with the easy stuff first. Are there any crimps in the gas lines?

[MotoJunkieDillon]

No crimps or pinched fuel lines as far as I can see

[Azhule]

What are the adjustment screws set to? Is the Pilot screw fully tight/closed? Make sure the Pilot Screw is at least 1.5 turns out from lightly seated, that is usually a good starting place

[MotoJunkieDillon]

I'm pretty positive the pilot is fully tight, so I'll make sure to fix that.

[MotoJunkieDillon]

I loosened the pilot screw by 1 1/2 turns on the mikuni, but it still isn't getting fuel the carb is clean and brand new so there shouldn't be any grime or gum in the jets.

[starsire79]

I am at 2700 ft above sea level and I run a 30 pilot and 110 main. when I had it at the 20/100 it was very difficult to start... also you have 2 screws on the carb. The one on the bottom and the one on the side. make sure both aren't fully closed.

[jct842]

Check float valve, sounds like it may be stuck shut.

[MotoJunkieDillon]

Yeah, I was thinking it was the float valve, plus the carb wasn't tuned for my location so it was definitely going to be hard to start, thanks for the advice

[MotoJunkieDillon]

Pulled the carb apart, and checked the float valve and it was perfectly fine. I might just order another stock carburetor because it sucks having nothing to ride (I do have a Z50r pitbike, but its currently being repainted so I cant ride it either, unfortunately). Im just so confused because everything on the carb seems perfect, all the lines are were they should be.

[MotoJunkieDillon]

Found the original carburetor and put it in the bike. After priming the engine, it started right up! I'm just going to leave the stock carb in the bike because it actually runs now. I will keep the mikuni carb just in case though, just glad I have the bike running and idling with no problems. I want to thank all of the people that offered advice to help get my bike running, also helping me learn a little more about carburetors.

[jct842]

There has to be some thing blocking fresh fuel on the new carb.

you might try to blow some air thru the fuel inlet with the bottom off to check the path to the float valve. I don't think I would get carried away with 120lbs of air but some thing is keeping the fuel from entering the carb.

[MotoJunkieDillon]

Alright, I'll give it a shot and see what happens

[FLASHLIGHTBOY]

Hello... if you have fuel in the bowl and you know the float is good... then your carb is sucking air instead of fuel into the motor.. because the sparkplug is not wet then this tell you it is not sucking in fuel from the carb.. check your mounting to the intake pipe... the other carb for some reason is sucking in the fuel.. could be as simple as the oring not seating to the pipe for the intake... check and make sure it is there... I have have them fall off during installation... my fault... and you could put some peratex #2 on the mount ..it is not drawing in the fuel into the intake manifold... Weldand grind had a problem with the oring cut out being to deep one time . drove it crazy to find that out..put a straight edge on the carb mount to see the oring sticking up a bit from the carb mount..

[Ride__The__Spiral]

Originally Posted by MotoJunkieDillon

Alright, I'll give it a shot and see what happens

Any update?