1986 Yamaha Jog CE50 Carb Problems (won't stay running)

[allistah]

I have a 1986 Yamaha Jog CE50 that I just put a new carb on it and petcock.  Here is the carb and petcock I bought off Ebay for reference:

Carb:
www.ebay.com/itm/151159812340?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Petcock:
www.ebay.com/itm/281246200150?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

The problem I'm having is that it idles ok and takes off ok, but once I get down the street it starts bogging down and eventually dies.  It's like it's running out of gas or something.  Then if I get it started again and let it idle for a while I can take off again full speed again until it dies all over again.

I opened the air filter and the foam was falling apart.  I don't think the air filter box is sealing very well so I was going to put a bead of silicone around the surface where the two halves go together and see if that helped but I haven't done that yet.  

There are 4 nipples on this carb, the big one up top is fuel in, then there are 3 others.  A brass barbed fitting what I think is for the oil injection, then two others that look the same but no idea what they are.  I'm guessing one is the pulse line.  Not sure what the other one is.  Not sure which is which either.  I've attached an image of the carb and what I think everything is.  If someone could tell me what I'm missing that would be awesome.

Any idea whats going on with this thing?  The adjustment screw is all the way in.  Not sure where it should go.

Any help here would be appreciated!  Thanks!!

[90GTVert]

[/img]

You should replace the air filter. Could be too much air getting in causing it to run lean and soft seize (heats up and the piston expands more quickly than the bore).

#1 Fuel Inlet
#2 Vacuum Port
#3 It's either vent to atmosphere for the bowl or another vacuum port. If it's a vac port you should see an opening in the carb like #2 would have.
#4 Oil Injection
#5 Idle Speed Screw
#6 Idle Mixture Screw

Vac ports need to be capped off if not in use. If #3 is a vent it needs to be left open.

[vlatx]

Looks like lean mixture,or low compresion.

[Sitticuss]

#3 is a vent line..start with #6 about 1 1/4 turns out.

[allistah]

Thanks for the replies.

When you adjust the needle on the throttle cylinder, what way goes rich (more fuel) and which way goes lean (less fuel)?

I'm going to seal up the air filter box with some silicone (between the two halves of the box) and put it back on. If I run it without a foam filter, will that have an impact on how it runs? Just until I get one to put inside? Or do I have to have it in there to tune it and make it run right? I'd like to get this thing running while I order the right filter.

I'm also thinking that I can just get a piece of foam myself and cut one out for it. It looks like the stock one is about 1/2" thick or something. Would that be sufficient also? I'll be sure to put some oil on it as well.

If anyone has any other ideas on how to adjust this carb please let me know.. I'm going in the garage shortly and will give it another try.

[2TDave]

To adjust the needle richer you lower the clip which raises the needle allowing more fuel.

[allistah]

Ok, I'm about ready to yank all my hair out.

I made sure the air cleaner box is sealed. I used silicone and sealed the two halves of the air cleaner box together. I made an air filter out of some foam. I cut in and it was about 1/2" thick. I saturated it in oil as well. I made sure the vent on the carb was open.

I adjusted the needle on the throttle cylinder as well and that just made it smoke more. The needle is on the middle adjustment. Nothing so far has made the problem better.

It looks just like it's running out of gas when the engine is revving up. If you rev the engine on the stand to about 1/4 throttle and the RPMs start going up and keep it there, it will suddenly run out of gas and bog down. Then you have to crank it over for about 5-8 seconds or so until it picks up again and then it will start again and start the process all over.

Is there anything else I can check? This is a new carb that was for a CY50, not a CE50 - I'm not sure if that would really make any difference. I noticed that the float has some tension on it. It doesn't flop around freely like I've seen on others. Tension into the down position. It just has a slight spring to it. Not sure if thats normal at all. I pulled it apart a couple times to make sure nothing was in there and it's been spotless every time.

I really would appreciate any guidance I can get on this.

Thanks!

[allistah]

I also wanted to say that the adjustment screw got the highest RPMs when it was 1/2 turn out when it was idling.

[2TDave]

What size main jet is in the carb you got?

[allistah]

I looked and there is nothing printed on it. Should I pull the main jet out of the original carb and put it in there?

[allistah]

Tried the other main jet and now I can't even get it to stay started.

One thing I noticed though is that after about 15 minutes of trying to keep this thing started - the bowl on the carb barely had any gas in it. The only wait I could sort of keep it started was when I had my fingers over the carb choking the holy hell out of it.

Should the bowl fill up really quick when you're turning the engine over? If so, thats not happening very fast at all.

[allistah]

Put the other one back in and still can't keep it started. No clue where to go from here..

[allistah]

How important is the rotation of the carb where it sits on the intake manifold? I noticed there are two notches on the rubber part where the notch on the carb should fit into. I have a hard time getting this new carb to fit right in the middle between them because the throttle cable is just a tad too short with this new carb. That wouldn't cause all these issues would it?

[stepthrutuner]

I think you either have a fuel flow (between tank and float valve) problem or your fuel level in the bowl (low float) is insufficient.

Conceivably there could be a molding flaw above your float valve or hose or vacuum release or trash problems too.

[2TDave]

Did you plug a vent?