I've already cleaned the carbs thrice but for some weird reason, I think the bike is running rich because when I give it throttle, it dies. Of course, this is when the engine is cold and I cannot warm it up because it dies once it starts to build up some heat.

I have a stock exhaust and new plugs, however, I installed the KN drop-in filter. I noticed that the jets have some mild damage due to a smaller screwdriver (I think) and I'm not sure if that will be a problem though. And I also set the float height to 17mm. I have to make it run ASAP because I need to have my car's cylinder head rebuilt. Thanks.

PS: For other details that you think are necessary, just ask for it :)

How does it act if you slowly open the throttle? Does it just slowly quit running or does it burble, chug, and pop - then quit - like the choke is on too much? What happens if you add choke when it's warm - better or worse?

It idles fine? How old is the gas?

How did you clean the jets? What are the idle mixtures screws set at? Did you remove them and clean the passages? Do the screws have a washer and an o-ring on them?

Did you change the float level significantly? If so - are you sure you are measuring correctly?

what happens when you use the choke

what exhaust is on it? stock?

you "cleaned the carbs". did you insert wire through both sets of both jets? all 4 jets?

How does it act if you slowly open the throttle? Does it just slowly quit running or does it burble, chug, and pop - then quit - like the choke is on too much?

It revs down until it dies. Actually when fully open the choke, I will rev until 6k then goes down. I slowly reduce the choke to a point where it needs it to run. But it will still die after a while.

What happens if you add choke when it's warm - better or worse?

I cannot warm it up because it dies when it starts to build up some temperature.

It idles fine?

Nope. Once it runs for a little over a minute, it settles at 1k RPM and then die after a couple of seconds.

How old is the gas?

Brand new. No additives.

How did you clean the jets?

Removed them from the carb body. Sprayed with some carb cleaner, used guitar string #1 for the orifice, and compressed air to dry.

What are the idle mixtures screws set at?

2.5 turns out.

Did you remove them and clean the passages?

Yup.

Do the screws have a washer and an o-ring on them?

Yup. O-ring towards the carb body, then the washer, and the spring was the sequence.

Did you change the float level significantly?

Not really. I'm using 17mm as the height, holding the carb sideways to avoid compressing the valve's spring.

If so - are you sure you are measuring correctly?

I think so. Holding it sideways and with a caliper.

what happens when you use the choke?

I need it to start the bike. It will rev up to 6k and go down slowly until it dies.

what exhaust is on it? stock?

Stock. The 1-1 exhaust manifold.

you "cleaned the carbs". did you insert wire through both sets of both jets? all 4 jets?

4 jets? I used the guitar string 1 on the main, pilot, and the other one that's not removable. Plus, the 4 holes under the butterfly valve, he hole on the valve itself, and the mixture screw orifice. Plus I also used compressed air, reverse of the normal flow of the ports.

sounds like the petcock or floats aren't working correctly and the carbs run out of gas. watch the fuel level while the bike runs, you'll probably see it go down as the idle drops until it dies

also, i'm pretty sure the correct way to measure the float height is by using fuel in the carbs and putting a tube on the bottom and running it back up and measuring the distance between the level in the tube and the split in the carb case.

I'd re-trace your steps and make sure there isn't any debri in the carbs even though you just cleaned em.

Fuel filter new?

You can open up each bowl individually to drain the gas and then crank the starter to see if you're getting good fuel flow.

As others have said take a clear piece of (1/4" or 3/16"???) hose and make a U pointing up where the drain nipples are to check your float height.

Are you POSITIVE you re assembled correctly?

sounds like the petcock or floats aren't working correctly and the carbs run out of gas. watch the fuel level while the bike runs, you'll probably see it go down as the idle drops until it dies

That's what I'm thinking also.

If you let it sit a while will it start again? Vacuum line to the petcock routed properly and in good shape?

When it quits, open the drains on the float bowls and see if any amount of gas runs out.

..........I think the bike is running rich because when I give it throttle, it dies..........

Welcome to our site, Louie !!!

You are thinking incorrectly, the mix is fuel-lean = too much air respect to the fuel = cool flame that gets extinguished.

I would check the level of the fuel in the bowls, in addition to all the good advice above.

OK. So I found the problem—I didn't route the vacuum line to the petcock properly. Since I have a CA version, what I did before was I connected both vacuum nipples from near the ducts between the engine and carb to the T-fitting that connects to the canister and the petcock vacuum line to the coasting enrichener. So I corrected that and after a couple of attempts it ran fine.

So I grabbed my gear and take it for a spin to warm it up. When I was about to take off, I tweaked the idle screw to slightly close the butterfly doors, then the revs gradually lowered until it died. Now I'm back to the square one—it cranks but it doesn't run. I tried a little squirt of starting fluid in the intake but it didn't do anything.

PS: Before it died, it was showing white smoke in the exhaust but I think that was because it was still running cold and it's about 56F outside. Imma check the compression and spark when I have enough time maybe on Friday or this weekend but any pointers will be great.

I tested it again last night. Worked fine for the first 5mins then it bogged down and died. It cranks but doesn't start. So I power walked it on to our driveway and when I put it in its side stand, it dumped fuel. It was fuel because it's kinda clear, thin, and smells like one. So I think the carb is overflowing. I'm thinking of taking it out again, test the functionality of the floats, needle valve, and seat.

So I'm wondering, is it possible that the needle valve seat (the ones attached to the carb body not the rubber cone at the tip of the valve) to wear? If so, is it replaceable? Any tips? I'm thinking of flipping it upside down, hook a hand vacuum pump at the fuel inlet and check if it holds vacuum.

is it possible that the needle valve seat (the ones attached to the carb body not the rubber cone at the tip of the valve) to wear? If so, is it replaceable? Any tips? I'm thinking of flipping it upside down, hook a hand vacuum pump at the fuel inlet and check if it holds vacuum.

yes and yes. pull the seat out and look at it. if its oval shaped its worn down. if its a circle its fresh. you can order a replacement. i think they are $5 each at jetsrus


definitely sounds like the carbs are overflowing from stuck open float valve

It's alive! I drove it for about 20mins and didn't die!

So I cleaned the carb for the fourth time. This time, I used Qtips + carb cleaner to clean the seat real good and a hand vacuum pump to make sure that the needle valves can hold it—and they did. Tested the floats if they will float on gas—and they did. Cleaned the pivot pin and the hole to make sure they move freely—and they did.

I'm just wondering, how much RPM should I set it for idle? I live in Southern California and I don't go into high altitude places that much. It's sitting at 2k right now because I feel like having it @ 1300 sounds scary. It's like it's about to die on me.

Next: Front fork seals, and valve adj and/or carb sync

It should idle smoothly at 1300 when fully warm.

You need to adjust the idle mixture screws (start at 2 1/2 turns out) and sync the carbs.

Did you run a fine copper wire through the main jets and holes in the jet holder and remove the idle mixture screws and clean the passages?

Did you run a fine copper wire through the main jets and holes in the jet holder and remove the idle mixture screws and clean the passages?

Yup. The thinnest guitar string + carb cleaner. And the mixture screws are at 2.5 turns out already.

Yup. The thinnest guitar string + carb cleaner. And the mixture screws are at 2.5 turns out already.
OK good, I'd sync the carbs next then.