No Fuel to Carb #1, Rear Left

[MImax]

Hey Guys,

I have an 07 with 20k miles on it. Had a bad bearing in the final drive (lots of noise in 3-5 gear) when I got it, but Sean had a good one and that fixed the issue (thank Sean) and I've done 600 miles since. I rode the bike a few days ago for a few miles to a friends and it seemed fine but I never got on it. Go out to start yesterday and it fired up, but just seemed off. Felt near each exhaust header and the rear left had no heat.

I pulled the plug and it had some fuel on it and light discoloration, but had strong spark. So I figured maybe the pilot clogged so I was going to do the shotgun method just because. Pulled the bowl drain screw and nothing, no fuel in #1. I proceeded anyway just to start getting it apart. All the other carbs are fine, free flow, slides wet with fuel, blowing air through the jets launches fuel etc., but #1 has no fuel. Fuel pump works fine, the other carbs keep getting filled. Is there anything else I should try before just pulling the carbs off?

 

[Fire-medic]

Sometimes tapping on the body of the carb by where the L-shaped tube for the gas supply enters the carb body will un-stick a stuck float needle.

One way to do it is to use a 3/8" socket extension, place it by the gas supply tube for the 'bad' carburetor, and give a few sharp raps on the end of the socket extension. You're not trying to knock a hole in the body, you're just going for a dislodging of the stuck float needle. This is more of a 'get it home' fix. It can also help when one carb starts peeing-out the carburetor overflow black rubber hoses below the CV caps.

I suspect your bike sat for months, and has a gummed-up float seat, and possibly the float valve. If you want to fix it properly, you need to remove the rack, split it in-two, remove the float bowl, and check-out the seat and the float needle. The small rod sticking-out of the float needle, being spring-loaded, is probably gummed-up, and the float seat, too. Since it's all-apart, you might as-well do a complete carb disassembly and soak/cleaning. That's on all-four carbs. Jet blocks out, brass jets out of 'em, and a soak.

 

[dannymax]

Hey Guys,

I have an 07 with 20k miles on it. Had a bad bearing in the final drive (lots of noise in 3-5 gear) when I got it, but Sean had a good one and that fixed the issue (thank Sean) and I've done 600 miles since. I rode the bike a few days ago for a few miles to a friends and it seemed fine but I never got on it. Go out to start yesterday and it fired up, but just seemed off. Felt near each exhaust header and the rear left had no heat.

I pulled the plug and it had some fuel on it and light discoloration, but had strong spark. So I figured maybe the pilot clogged so I was going to do the shotgun method just because. Pulled the bowl drain screw and nothing, no fuel in #1. I proceeded anyway just to start getting it apart. All the other carbs are fine, free flow, slides wet with fuel, blowing air through the jets launches fuel etc., but #1 has no fuel. Fuel pump works fine, the other carbs keep getting filled. Is there anything else I should try before just pulling the carbs off?

Could be a plugged drain line or plugged drain hole in the float chamber

 

[Fire-medic]

Could be a plugged drain line or plugged drain hole in the float chamber

Yep, that's the simplest explanation, and one easy to check-out.

 

[BeardedMax]

I just had this on Monday. Pulled carbs and one was completely dry. Float was stuck had to remove it with pliers.

 

[MImax]

Well I pulled the carbs and I can't find anything wrong except the bowl was dry. Thought for sure the needle valve or float would be stuck but they seem to operate freely and the passage ways that I can get at have no deposits, jets are clean. Float level seems good. Nothings seems to have been blocking the fuel going in and the drain lines are clear. This is my first time messing with this type of carb so maybe I'm missing something, Anyways kind of at a loss as to what to do. Guess I will just clean them and see what happens.

 

[Fire-medic]

Well, you can hook 'em up to a gas supply and see how the gas flows & stops as you move the float and needle valve, float chamber off. Since they're apart, you can hook the gas supply to that 1 carb, alone, as they are in two pairs.

 

[MImax]

The plot thickens. I hooked up a fuel source as described and the carb functioned like normal. I reassembled the rack and tested again and yes, working fine. So I got the carbs back on and everything back in place. Took a few tries and it started.

I felt near each exhaust real quick and they were warm. Noticed a light bit of smoke, didn't think anything, shut the choke off and turned around to put some tools on the bench. When I look back there is more smoke and I am seeing smoke from the back of the motor and near the exhaust of cyl 1.
I did use light oil on the slides etc. when I reassembled, but I wouldn't think that would cause that. When I got the bike I did a coolant flush and oil/filter change and I didn't notice anything unusual in the oil and I'm not seeing the coolant level going since I filled it.

Other thoughts I'm having. Has this thing been running on 3 cylinders since I got it and I didn't know, and maybe that cyl has an issue? I don't think its possible since it seemed to pull as hard as my 600 I just sold. Unfortunately I'm out of town until next week so I can't explore more. Seems it at least has an exhaust leak and hopefully not something worse, but I will figure that out next week hopefully.

 

[Parminio]

A Vmax will run quite well on 3 cylinders believe it or not.

Also, on warmup, it's normal to see a bit of light smoke coming out the pipes. Some of it is fuel because it runs richer when it's cold and some of it is water vapor as the pipes burn the moisture out of the air in the pipes as it heats up.

You shouldn't see any at all though when you turn the choke off and the bike is at operating temperature.

 

[MImax]

Alright so there is certainly a problem. It probably has been on 3 cylinders since I got it and I was just too stupid to notice until now. The cylinder is firing now and the bike actually sounds good, but oil is burning. After 30 - 60 seconds of running the right exhaust gets a light smoke and the back of cylinder 1 starts to smoke. The exhaust clamp was loose but I tightened it, but still smoke appearing in that area. There is a drip of oil falling from that joint onto the case every minute or 2. I pulled the plug and its dark after a combined 10 minutes of running. There has not been any oil consumption or dripping previously.
I checked the airbox and there's not much oil in the little overflow box, just a light coat. I started it without the air box top on just to check the slides real quick and cylinder 1 was the only one that was having small pop from time to time.
I'm guessing the cylinder is toast? Any other way oil is getting in there, other than past the rings? I will have to get a compression tester and see what I get...

 

[BeardedMax]

How long have you ran it for. After I rebuild mine this weekend after I found the same carb was getting no fuel it smoked as well. I let it idle for a while. Pulled the cap off that plug and it stopped smoking. Plugged it back in and just let it idle for a bit. It ending up clearing on it own. Hopefully you’ll be as lucky as I was because I was also worried.

 

[MImax]

Hmm I have not run it for long, but it doesn't seem like this would clear up. I'd be worried to run it much longer or ride it. I took a short video where you can see the smoke.

 

[MImax]

Today I pulled that exhaust clamp, cleaned it well and tightened it good on there. I figured I didn't have much to lose so I bought some CRC Valve Cleaner and Marvel Mystery Oil. After work I siphoned some oil out of the case and added 500ml of the Marvel oil into the crankcase. I used the valve cleaner and followed the instructions exactly as they were (sorry neighbors) using the whole can, which took quite a while of spraying in bursts and creating more smoke. Then I let it sit for an hour , then started it up and ran it for 10 minutes at highway speed, followed by normal driving. I took it on a short 18 mile ride and it did not have any issues and no visible smoke, even parking a couple times to watch it idle and look for smoke or oil drips. It's much faster when running on all cylinders hahaha.

I will ride it again tomorrow and see what happens or if I get any smoke. Maybe there was a build up on the valves and the cleaner helped? Or maybe that cylinder had a sticking ring that just needed heat and ride time? I don't know, but it's promising at least.