carb problems?

[Guest]

I am still having some problems with my bike. It runs good then idle goes high then it will hang when reving. The petcock is bad I run it on prime and put a vacuum hose on the carb with a bolt in the end. should I cap off the petcock vacuum tube also? I am going to try to set the air/fuel screws. How do you know when it is running hot? I drove it up and down the alley and it runs ok but when it warmed up it would die at idle without giving it gas then not start with out holding the throttle open alittle. I raised the idle with the screw and it would idle faster, then hang?I changed the intake o-ring and manifold boots, put new o-rings in the carbs. I may take them off and check the float hight again. I set the depth gauge in the grove the gasket sets in, not sure if I should leave the gaskets on. I read both ways no gasket and with gasket. any ideas I can check on? seems like everything is tight and not leaking air anywhere? I tried wd-40 sprayed around intake boots but no change.Anything else to check and I will try. Thanks

[Nessism]

How far open are the pilot screws? Did you sync the carbs?

Float height is set without the gasket, or adjust the level down a couple mm if you left the gaskets in place.

How do the plugs look?

[ChicagoRob]

Nessism's your guy about carb tuning. Heck, even I don't listen to me about that. :-)

I do have a used, working petcock for you, though. PM me your address if you want it. You'd have to send some good karma my way, though.

One thing that I've found to be handy when doing this sort of thing is to have a bottle to run off of instead of the tank. It's nice to get the tank out of the way.

MotionPro makes one, but I built one out of a larger plastic juice container with a wide mouth. I cut a hole in the top to fill it, drilled a hole in the cap for a nipple, went to the hardware store for 18" of 1/4" hose, a nipple for the cap and a barbed connector to connect to the carbs. I siliconed the nipple and the cap back to the bottle, then hang the thing from my bars when I use it. It's important not to hang it too high and supply more pressure than your tank would give. I've heard of people using a 2 liter pop bottle, too, but I found the larger juice lid easier to work with.

Oh, and you'll need a hose clamp to clamp off the line when the bike isn't running. An inline filter is a nice touch, too.

And yes, I always keep the fire extingisher handy, just in case.

[scrapper]

2 1/2 turns open, haven't checked plugs yet. haven't synced carbs yet but plan to this week if weather doesn't get bad. I tried to set air screws once but couldn't get the inside ones to make the rpm's change. Will try with smaller tank this will help.

[Nessism]

2 1/2 turns open, haven't checked plugs yet. haven't synced carbs yet but plan to this week if weather doesn't get bad. I tried to set air screws once but couldn't get the inside ones to make the rpm's change. Will try with smaller tank this will help.

Tweaking the screws doesn't always cause a noticeable change in rpm. You just want to keep them all fairly similar in terms of the number of turns.

I'd try the sync and see if it makes a difference. If not, go from there.

Edit: are you running the stock airbox and filter?

[scrapper]

yes it is all stock. I thought maybe I was missing something else. I will try sync first? then adjust air screws. What about the tank cap vent being clogged? never heard of it before but should check it out. Is it easy to take apart? I haven't looked at it before, was thinking of the cars cap looks molded into one piece.

[scrapper]

MotionPro makes one, but I built one out of a larger plastic juice container with a wide mouth. I cut a hole in the top to fill it, drilled a hole in the cap for a nipple, went to the hardware store for 18" of 1/4" hose, a nipple for the cap and a barbed connector to connect to the carbs. I siliconed the nipple and the cap back to the bottle, then hang the thing from my bars when I use it. It's important not to hang it too high and supply more pressure than your tank would give. I've heard of people using a 2 liter pop bottle, too, but I found the larger juice lid easier to work with

ChicagoRob, I am wondering about a riding mower gas tank, lots of them at work, a 10 horse or bigger may work. I can send as much good karma your way as I can. Let me know if you get it.

[ChicagoRob]

The lawnmower tank sounds awesome. Much better than my crude setup.

No surprises when disassembling the rear end today, so maybe the karma did find me.


Rob