Help with carb sync

[rustybronco]

One other point to consider for those that are thinking of building their own manometer: do you ever anticipate the need to go mobile? How hard is is going to be to fold up 10 feet of liquid-filled tubing to take it over to a buddy's house to work on his bike?

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That's the reason I use a vacuum gauge; it fits in a 6"x6"x5" plastic case.

[glstine]

Well the gauge actually works, I just had to get it a little closer to start with, although I think rigid tubing would work better for the part with the fluid. Think I'm going to get a carbtune anyways when I can.

Anyway I'm still having trouble with the bike. #2 and #4 are really rich at idle and puff out a bit of white smoke. I had to turn the idle mixture screws all the way in on these two and they are still rich. Turning them out at all causes the smoke to increase and the idle gets rougher.

Under no load the bike idles ok and revs fine despite being rich on 2 and 4. However, under load it is still sputtering and lacking power from take off.

Any ideas on why 2 and 4 are running rich even with the idle mixture screws all the way in and why it has no power under load? I've done everything I can think of.

[Larry D]

Did you verify the sizes of your jetting when you had the carbs apart ? Sometimes PO's will switch them out. Also, if you do take them out, get a magnifying glass and ensure they haven't been drilled out.

[glstine]

Jets are stock. I raised the float height on 2 and 4 (from 0.88" to 0.94"). Now 4 doesn't smoke if the idle mixture screw is all the way in, 2 still smokes a little. I made a video of the bike running to see if maybe someone on here may be able to tell something from the way it sounds. Keep in mind I don't have a stock exhaust they are individual turned out pipes with mufflers on 2 and 3 and just pieces of metal that look like leaves on the inside of 1 and 4. I really like the look of the pipes but hate the sound, to loud for me. Also, you may want to close your eyes watching it, I just hung the camera off my wrist so the video is a little crazy.

http://www.youtube.com/watch?v=OP9f0hfPXk8

[Steve]

Yowza. It sounds like it's only running on two cylinders half the time.

You may have ignition problems along with your fuel problems.

By the way, increasing the numbers on your float height actually lowers the floats. You have to remember that they are set while the carbs are upside down, so increasing the number is moving the float farther from the carb. When you turn the carbs back right side up, the floats are still farther from the carb body, meaning lower.

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[gearhead13]

Jets are stock. I raised the float height on 2 and 4 (from 0.88" to 0.94"). Now 4 doesn't smoke if the idle mixture screw is all the way in, 2 still smokes a little. I made a video of the bike running to see if maybe someone on here may be able to tell something from the way it sounds. Keep in mind I don't have a stock exhaust they are individual turned out pipes with mufflers on 2 and 3 and just pieces of metal that look like leaves on the inside of 1 and 4. I really like the look of the pipes but hate the sound, to loud for me. Also, you may want to close your eyes watching it, I just hung the camera off my wrist so the video is a little crazy.

http://www.youtube.com/watch?v=OP9f0hfPXk8

The main idea with 4 carbs feeding 4 cylinders is that all 4 carbs need to be set exactly the same to run right, by messing with float heights with just two you are messing them up. Set the float heights the exact same and fix what is really wrong. Sounds like your bigger problem is when you give it gas which means pilots and/or needle heights. Do your slides move freely? how clean did you get them? are all the spacers on the needles in the same positions?
EDIT: Airbox or pods?

[glstine]

Yowza. It sounds like it's only running on two cylinders half the time.

You may have ignition problems along with your fuel problems.

By the way, increasing the numbers on your float height actually lowers the floats. You have to remember that they are set while the carbs are upside down, so increasing the number is moving the float farther from the carb. When you turn the carbs back right side up, the floats are still farther from the carb body, meaning lower.

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My goal was to lower the fuel level in 2 and 4 due to the rich condition. I get spark on all 4 cylinders. One thing I didn't mention in this thread, but I think I did in another, when I replaced the starter I had to take the cam chain tensioner off. When I put the starter in, I hit the start button briefly to make sure the starter worked (this was the second time I had to put the starter back in and wanted to make sure it worked before putting it all back together, which I didn't do the first time). Unfortunately, I did this before putting the cam chain tensioner back on. I pulled the valve cover and checked the timing and it was as it should be. Is it possible that somehow it could still be screwed up?

[glstine]

The main idea with 4 carbs feeding 4 cylinders is that all 4 carbs need to be set exactly the same to run right, by messing with float heights with just two you are messing them up. Set the float heights the exact same and fix what is really wrong. Sounds like your bigger problem is when you give it gas which means pilots and/or needle heights. Do your slides move freely? how clean did you get them? are all the spacers on the needles in the same positions?
EDIT: Airbox or pods?

Airbox and OEM filter. The slides move freely, I haven't messed with the needles at all. Since there is more to the fuel delivery than just the carb settings, I suppose mainly the amount of vacuum from each cylinder, doesn't each carb need to be tweaked individually?

[gearhead13]

Airbox and OEM filter. The slides move freely, I haven't messed with the needles at all. Since there is more to the fuel delivery than just the carb settings, I suppose mainly the amount of vacuum from each cylinder, doesn't each carb need to be tweaked individually?

With your compression numbers differences in vacuum shouldnt be an issue. You need to take all variables out of the equation, not make your own by setting float levels differently. Maybe your po messed with them, been known to happen Did you pull it apart and check?

[glstine]

With your compression numbers differences in vacuum shouldnt be an issue. You need to take all variables out of the equation, not make your own by setting float levels differently. Maybe your po messed with them, been known to happen Did you pull it apart and check?

I've never taken the needles out, I guess I will do that, it's the only thing I haven't checked on the carbs. Never had a problem for 3000 miles (after the first time I cleaned the carbs) until taking the carbs apart due to the grit in them. For the first 3000 miles they only had a bench sync and I never checked the fuel level in the float bowls. That's part of what makes this so aggravating.

[Nessism]

Something fundamental is wrong with your carbs if 2 and 4 are rich with the pilot screws turned all the way in. I'd open them up to 2 turns and try riding the bike again to see if it runs better. I don't know if weak spark could cause the bike to run rich like that but it might be part of the problem.

[glstine]

Something fundamental is wrong with your carbs if 2 and 4 are rich with the pilot screws turned all the way in. I'd open them up to 2 turns and try riding the bike again to see if it runs better. I don't know if weak spark could cause the bike to run rich like that but it might be part of the problem.

This actually made an improvement, still not there though. For more information these are the plugs after making a run up and down the street with the idle mixture screws turned out (in order of 1,2,3,4). Not as apparent as I had hoped but 2 and 4 plugs are wet. I should add with the idle mixture screws turned all the way in the plugs weren't wet, just had fluffy black deposits, so I am pretty sure it is rich and not oil fouling.





I also shot a little video of the spark I get, this would be typical of all cylinders.

http://www.youtube.com/watch?v=ry97IRX6Tg4

[almarconi]

What's your voltage at the coils?

[glstine]

What's your voltage at the coils?

I get a 0.1V loss from battery to coil, battery has been keeping a charge even with all the starting and stopping I have been doing.

[almarconi]

Is it firing on all cylinders?

I would take a spray bottle of water and spray some on the exhaust header pipe, if it is running properly the water will sizzle and evaporate. A pipe that is not firing will cause the water to basically roll off. If your not firing on all cylinders I would try cleaning the carbs again.

You mentioned that you turned the engine without the cam tensioner. Did you verify that the timing marks are aligned and that the cams are aligned. It could have skipped a tooth when you turned it.

It's hard to tell from the pictures but I would expect to see a discoloration (blue/brown) in the first couple of threads on the spark plug if the bike is running properly. I seem to remember chef1366 commenting on this discoloration before. The insulator should be tan and you should see discoloration on the first couple of threads if the mixture is correct.