Yamaha Aerox 50cc problem

nollers

Would anyone be able to help. My Yamaha aerox would not start yesterday. Here is what i did: Charged battery and changed plug and sprayed petrol into plug hole. Bike started but wouldn't stay on. Removed air hose from carb and sucked petrol into carb. Bike started and revved fine. Took for drive and bike is losing power at 6000 RPMS and going back to idle. Will run and then bog out and lose power. Coughing and sputtering but will rev fine on the stand.

Any ideas? Could it be vacuum pump is playing up and not releasing enough petrol, dirty carb or something else. Was lying up for about 3 weeks.

Cheers
Dave

two wheels good

I suppose the pump is a possibility but it's working a lot of the time. Check that the vacuum hose isn't split.
I'd start with:
- checking the the carb bowl and jets are clean
- check for air leaks, inlet manifold isn't split. It may be rubber
- check air filter is clean

nollers

two wheels good wrote: »

I suppose the pump is a possibility but it's working a lot of the time. Check that the vacuum hose isn't split.
I'd start with:
- checking the the carb bowl and jets are clean
- check for air leaks, inlet manifold isn't split. It may be rubber
- check air filter is clean

I removed fuel tank today after checking was the carb sucking fuel in fine. Emptied and cleaned tank and filter (filter was grimy). How can i check / clean the carb bowl , do i have to remove carb? Could be a sticking float in carb. Have already cleaned and re oiled air filter.

two wheels good

That's progress! Maybe clogged filter restricted flow, noticeable at higher revs.
Best to clean carb to finish the job. Was there much gunge in the tank?

I'd expect 4 screws holding the bowl in place underneath carb. Yes, remove the carb. You could loosen and rotate it but it's easier to remove.
Jets should be obvious once bowl is removed.
Caution: Do not tinker with mixture adjustment screw. Don't over-tighten anything, this is all soft alloy. Use a well-fitting screw-driver if screws are tight.
(sorry , if that's all obvious to you)

nollers

two wheels good wrote: »

That's progress! Maybe clogged filter restricted flow, noticeable at higher revs.
Best to clean carb to finish the job. Was there much gunge in the tank?

I'd expect 4 screws holding the bowl in place underneath carb. Yes, remove the carb. You could loosen and rotate it but it's easier to remove.
Jets should be obvious once bowl is removed.
Caution: Do not tinker with mixture adjustment screw. Don't over-tighten anything, this is all soft alloy. Use a well-fitting screw-driver if screws are tight.
(sorry , if that's all obvious to you)

Not obvious at all. I've never removed carb before or fuel tank. It's all learn as you go i suppose. The carb is tricky to get at isn't it. I presume i remove the big rubber air intake valve first and then unscrew carb and remove .
Thanks for your help

nollers

nollers wrote: »

Not obvious at all. I've never removed carb before or fuel tank. It's all learn as you go i suppose. The carb is tricky to get at isn't it. I presume i remove the big rubber air intake valve first and then unscrew carb and remove .
Thanks for your help

Yes there was a bit of crap in the tank and the filter. Also a bolt and the plastic bit at the bottom of the fuel gauge had fallen off and was in there aswell. I sucked the fuel out through the vacuum pump and the flow was good and steady. While i was doing it i also used the carb to suck the fuel out by attaching the air line to the carb. Flow was good again.

two wheels good

Good man. Discovering your inner motor mechanic.
The carb is usually secured by two jubilee clips at manifold and airbox. It should be easier to remove than manifold which may have a security/shear-off bolt on it.
There should be a drain screw at the bottom of the float bowl. You could flush the bowl with petrol by opening the drain. Maybe postpone the carb removal for the moment.
Have you ridden it after the tank clean? Any better?

nollers

two wheels good wrote: »

Good man. Discovering your inner motor mechanic.
The carb is usually secured by two jubilee clips at manifold and airbox. It should be easier to remove than manifold which may have a security/shear-off bolt on it.
There should be a drain screw at the bottom of the float bowl. You could flush the bowl with petrol by opening the drain. Maybe postpone the carb removal for the moment.
Have you ridden it after the tank clean? Any better?

I might try flushing bowl first but not sure i can get at the bottom of it. Haven't taken it out yet after cleaning fuel tank cos i want to make sure it's gonna run right before i put it back together. I suppose i could just stick tank on and see how she runs.

two wheels good

Right. It's a different model to the Yam moped I'm imagining; on that one removing the luggage box gave easy access.
A trade-off between removing the tank again or discovering the carb was clean enough after all.

nollers

two wheels good wrote: »

Right. It's a different model to the Yam moped I'm imagining; on that one removing the luggage box gave easy access.
A trade-off between removing the tank again or discovering the carb was clean enough after all.

The carb is under the seat alright. I'm just being lazy i suppose.

nollers

nollers wrote: »

The carb is under the seat alright. I'm just being lazy i suppose.

Thanks for your help. Got her fixed this morning. Stripped the carb and the float in the bowl was stuck and the auto choke was a bit sticky.

two wheels good

Result! You sound like an expert now.

nollers

two wheels good wrote: »

Result! You sound like an expert now.

It's great when you can take something apart yourself and get it fixed. Bike fly's along now