Rebuilt Carb, now a slew of other problems..help?

[mjricha]

Hello, I'm new to the forum and motorcycles in general. I've worked on and rebuilt cars for years so I am fairly mechanically inclined.

My GF got her motorcycle license and bought a 99 gz250. It was running very very rich, but other than that, it seemed ok.

I got a carb rebuild kit, the manual, and a new battery. When I opened up the carb I found it was MISSING several springs and o-rings. So I ordered all of those online, and when they came, I rebuilt the carb (cleaning everything, making sure all the jets are the proper ones, etc). I made extra sure everything was there and went where it was supposed to.

After I put the bike put back together, it starts, and runs, but wants to die quickly. If i pull the throttle alot to really open it up it also wants to die. Also, the bike will not run in the RES position, it only wants to start and run in the PRI position. When I started the bike, black smoke came POURING off the front of the engine. This had not happened previously, and smelled like burning oil, not regular exhaust. I read some other threads, and seems to be that tightening up all the bolts in that area should solve that issue right?

One last thing, how much play in the choke should there be? The choke on the bike only moves about between 3/4 and an inch, and seems very hard to maneuver. When it is all the forward (toward the front of the bike), it runs, but will die when pulled back (toward the gas tank).

Does anyone have any idea where I should even start? The bike was 900 dollars and I don't want to pour money into it, especially since it's not even mine lol.

Thank you for any help you can give me

[raul10141964]

Check the vacuum line from the carb to the back of fuel valve and check if the flout inside the carb is set at the correct level

[Water Warrior 2]

The choke is off when pushed forward to the front of the bike. Check the choke cable for kinks or damage if it is hard to use. Maybe a little lube will help too.

[gz4me +]

I agree with Raul. First check that vacum line is connected to the back of the petcock. Water Warrior2 is correct in checking and lubing choke cable. Tighting the exhaust bolts does help on the smoke issue. I changed the seals, which did help. I still get a little oil on the engine fins in that area, but have read and been told it is normal for the GZ. Welcome to the forum. The folks on here should have you going soon.

[jonathan180iq]

If it's not running in RES, then there is a either blocked pick-up screen inside the tank or some other form or obstruction in the petcock.

If the vacuum pulls the fuel through in RUN, then it should also do so in RES.

Check and see how well the bike runs if you set the petcock to PRI.

My first gut reaction when reading this was a float problem. The PO probably did some carb work because there was some sort of starting or running issue that they "fixed" by messing with the carb, as you have seen. One of the hardest parts about a new previously owned vehicle is trying to figure out what the hell someone was thinking.

If the smoke out of the front of the bike was black, then you've got some carbon build up that you need to burn off, probably caused by the all of the rich running that you said it was doing before. There is a crush copper ring gasket on both headers that you can replace to help seal the area a bit. It is kind of common for a bit of seepage here because of the simplistic type seal - but billowing black smoke shouldn't be happening, obviously.

Check your valve clearance when you can and once you get it idling and warm, then adjust your idle speed.