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  1. #1
    CB750 Member wa-chiss's Avatar
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    Oct 2012
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    Stock breather install

    Hi y'all! I'm trying to get some issues resolved with my bike. The previous owner just haphazardly slapped on some pod filters and did absolutely no tuning whatsoever. Since it's cold out and I have a daily car to drive, I decided to work at getting the bike on the road and be reliable. I tried tuning the carbs but could get either good idle:crappy running, or crappy idle:good running. It also has what I think is a Kerker 4-1 exhaust with the baffle in it. I decided to buy a stock air box and installed it. It started running much better at idle and riding, but still was never right enough to be reliable. I've heard of some people not needing to re-jet the bike with only exhaust on it. I moved the needle up one groove (moving the e-clip down one groove, it was in the middle) and that seemed to get me even closer to where it should be. I had also been experiencing the throttle sticking closed if I let it snap back closed. I figured it to be the cable sticking. I figured I'd completely disassemble the carbs for a change and see what's what. I found one of the main jet holders was bent like it was tightened too much. This was causing the needle to stick inside the holder. So I have some on order. I'm going to replace some sticking floats as I was getting inconsistent levels. I would set the heights, then turn the valve on and I'd see no fuel from the overflows. I'd go ride it for lunch and when I'd turn the valve back on after eating, it would start to leak from the overflows on one or two carbs. It would then spit and sputter unless I was at high rpm's. I plan on getting a jetting kit with different sizes and experiment with it as well as a float height tool. So, that's my fueling feud I've been in for a while now.

    Another issue I've been having is oil loss. I've watched and even had a buddy ride behind me and it's not burning it. There's none in the air box and only a drip every now and then. Not enough to leak a quart on the ground, but that's how much it's low by. I'd been having charging issues so I decided to chase it down. Found the rectifier not doing its job. I'm replacing both reg and rec with new units from Oregonmotorcycleparts.com. I started to remove the harness from the bike to inspect for circuit faults. When I removed the batter box, there was the breather just sitting there with only one hose attached hat ran up the battery box to open air. Oddly, there's 3 ports but only one hose. I know one goes on the valve cover, one to the air box, and I guess the other is fresh air, but I'm uncertain of anything on this bike from the previous owner's lack of knowlege.

    I'm terribly sorry to have dragged this out this far, but I needed to vent I guess. If you didn't read any of it that's ok. I just need to know how to hook up the stock breather assembly to the bike. What hose goes where pretty much. A picture would be fantastic, but just a description would suffice.

    Thank you.

  2. #2
    CB750 Addict motogtp's Avatar
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    On the breather I am pretty sure the third port is a drain. My 750F has a plug in that line so it doesn't really go to fresh air. I assume the breather system is meant to be a closed system and the manual calls for that line to be drained periodically.

  3. #3
    CB750 Member wa-chiss's Avatar
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    Ok. By third port, which one do you mean. There's the bottom most port, a port on the top part of the cylinder, and one on the upper most part of the breather assembly. I had taken it apart and there's a foam screen that was barely even there. I need to get some to replace it. It's on the bottom of the breather over the port on the inside.

  4. #4
    CB750 Member wa-chiss's Avatar
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    Whoops. I'm upside down. One port on top most, one about 3/4 way down and one on the bottom most that has the breather foam element over it.

  5. #5
    CB750 Addict motogtp's Avatar
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    It's hard to see in there (I haven't take off the airbox). When I did pull out the plug about a 1/4 cup of dirty liquid ran out so my best guess is that it has to be connected to the bottom of the breather canister. Some one else may be able to confirm.

  6. #6
    CB750 Member wa-chiss's Avatar
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    If the middle port is below the foam piece, then I think the bottom most is plugged, the middle port is input from the engine and the top is to the air box.

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