Trouble Starting By Bashan (Read 1,483 times)

[hellspigeon]

What's up guys. I'm having starting issues. I changed the oil and spark plug and cleaned out the carb and air filter. Most days I have to charge the battery cuz i kill it trying to start up the scooter.
For a while it was running fine. I had to jerry-rig a throttle cable in an emergency to get to work a couple weeks back. The cable i was using left the throttle valve wide open (note I have a mikuni cylinder slide carb, there's no diaphragm so no vacuum lines) so i played with the fuel-air screw to compensate, didn't work.
I went back to the way I had it before and adjusted the fuel-air screw back to 2 and half turns open. If i have a full charge on the battery the scooter will typically run for the day, but I have to charge it again the next day.
Another thing is shortly after the starting problem began it developed a new issue, after i get the scooter started the wheel spin is strong enough to pull me with out opening the throttle. I thought maybe i was running it too lean so i turned the air-fuel screw down a half turn, so it should be at two turns open now. But when i get it started it still pulls strongly and i still have starting problems.
Any help is always appreciated. Thanks

[Bashan]

Did you turn the idle down? Did you check the charging voltage on the battery while the bike is running?

[jct842]

If you don't have a meter get one. Sounds like you have several problems and need to sort out one at a time. Idle speed is easy, and not the same as the mix adjustment, and can not use one to compensate for the other. Need to find out if you have a bad battery or the charging system is bad.

AND most importantly you fail to state what you are working on!

[Alleyoop]

The carb has TWO SCREWS the one on the right is the AIR MIXTURE SCREW, the SCREW IN THE CENTER is for you IDLE turn that counterclockwise to lower the idle.
Alleyoop

If you still have problems take a picture of the CARB.

[hellspigeon]

sorry if i didn't give you guys all the info. First the scoot is a 150cc motobravo with a mikuni carb and K&N air filter it also has one of those little short barrel exhaust pipes. Ill put pics of my stuff at the bottom. So I charged the battery. The meter said it was at 13.26 volts and after I started the scoot i check it while it was running and it registered 12.97V. The idle screw is all the way out so i dont think its doing anything at the moment and still it pulls while idling. Another thing I bought a new battery just make sure it was good and still have problems. Also how can I test the charging system? Thanks again guys let me know if I'm missing anything. I'll do my best to report back quickly.

This is a side view of my carb with the idle screw in the middle of the carb just above the float bowl. Throttle valve goes up and down with the cable coming directly out from the the top of the carb



This is the view from underneath the carb (the fuel/air screw is directly underneath my carb i cant adjust it unless I take it off the scooter) I circled the the fuel/air screw with red to point it out



The motor



Exhaust (Note this is an old picture; I do have a the shrouds on it)



This is a top view of everything

[cyborg]

The throttle cable has an adjustment by the twist grip back that adjuster off a few turns ,,, the high idle is the throttle cable is holding the carb open,,,

[cyborg]

That's an older vm series mikuni,,,, where'd you get that relic??,,,, they work great after setup,,, it's getting it setup that's the bear

[hellspigeon]

It came with the scooter. I bought the scooter off some guy from craigslist for 800$. I just use it to go to school and work so I need to make this thing work. The guy I bought it from neglected to tell me the long list of problems it was going to have, so I've been doing anything I can to make it run. I'll post a video of my scooter tomorrow.

[gatekeeper]

With the high idle it sounds to me that the slide is installed 180 degrees off. On the bottom of the slide there is a ramp cut into one side. That is the side of the slide that should be installed next to the idle screw.

[cyborg]

does it have the correct throttle cable on it?,,the tip of a mikuni cable is very small and fits in a slot,,if they have the big ball end on there it will hold the carb open too

[hellspigeon]

Thanks I'll check the throttle valve for the correct placement and make sure the barrel end isn't too big for the carb. In the mean time this is a video of me starting the scooter. The original throttle cable snapped and I can't replace it the way it was before. This requires me to cut off the barrel end, put the cable through the cap of the carb (barrel end wont fit), and then reattach the barrel end to the cable. Instead of this I just tie the cable to the handle bars and use my foot to give it tension. My starter button doesn't work nor does the kick start; I removed the kick start because the gear was no good, and I don't know why the starter button stopped working. Because of this I have to jump the starter solenoid with a screw driver to start the scooter. This video is a cold start after charging the battery to 13.26v, double click the image:

OR

Link to movie

[hellspigeon]

cyborg was right the barrel end was too big for the carb. I filed it down a 1/16 of an inch. Its running better now but i still need to adjust it a little. Im still charging the battery a lot cuz cold starts give me problems.