xs650 running on one cylinder

[rptc]

Just got done with an engine rebuild on my 81 xs650 special. Started it up after getting the motor back in and its running on pretty much one cylinder. It's getting spark, I checked it on the side of the motor. It's theoretically getting fuel, we sprayed ether into the carb on the weak side and no change. There's pressure out of the exhaust on that side. The valves are adjusted. Everything I've seen someone else has ran in to from my research on here and many other websites was checked and I'm still running poor on the right side. I rebuilt the carbs and replaced the ignition coil along with plugs and wires when the motor was pulled. I'm out of ideas and just want my bike to run strong again. Any ideas would be greatly appreciated.

 

[ippytattoo]

Did you sync the carbs?

 

[rptc]

Hooked up a vacuum gauge to each carb and they both go crazy. I guess they won't steady out without reducers in them? That's what I was told at least. Is there another way without vacuum gauges?

 

[ippytattoo]

have a look at the DIY manometer. Cheap and easy to put together and very accurate.

 

[gggGary]

If you have a motorcycle vacuum gauge set; they have a knurled nut where the hose attaches to the gauge. Turn the nut in 'til the gauge stops moving, turn it back out until the needle just starts to pulse, now do your synch.

But one side not running at all sure sounds like a carb issue beyond a slight synch problem. blocked choke or idle circuit?

 

[rptc]

I just have a pair of habor freight vacuum gauges. And I actualy went out and got everything to make a manometer. I will pull the carbs probably tomorrow and see if I find anything weird

 

[angus67]

shove a pilot jet in the hoses. it will calm down the pulsing. also, gggary, Havent you used aquarion airline valves to help with the pulsing? I have a pair of those hf vacuum gauges. Junk. make a yardstick manometer.

 

[gggGary]

The knurled nut, valve works just fine (once you you it's there and why)
I bought this gauge

after I sold my homemade 6 cylinder set, swearing I was done with KZ1300 s
The homemade manometers are great, I posted because the gauge pictured does not have any instructions and it took me a bit to realize the knurled nuts were valves. Reviews on Amazon showed that's a common "issue".
I cross check the gauges now and then, my set agrees nicely, adjustable faces would be a nice feature. Overkill for a twin but if many old bikes pass through your shop you'll need a 4 pot set sooner or later. I find a resolution of about 1/8 turn or less on the XS synch screw is easy to achieve.
The variety of adapters included is nice but I still had to re-machine one to fit "some carb" it might have been a BS38 on an XS with no intake barbs, the choke body hit the hex....

 

[rptc]

I wish I had a shop. This is just the personal garage at the house, but we do have an array of bikes there. Most are twins but we did just add a triple to the group. Do you have any pictures of what that knurled nut your talking about looks like by chance? I tried hooking up my homemade manometer last night, natural at this moment my bike is a kick only. I kicked it over and all the gas I had in the tube rushed out one side.

 

[weekendrider]

I use just one plain 1/4" valve like you find on the water line feeding a refrigerators ice maker. Pilot jets(the only thing Mikes jets are good for) will slow the pulsing but the valve allows you to start the bike without sucking the fluid into one side.

 

[5twins]

For fluid in your manometer, you need to use something heavier than gas. Most use an oil of some sort, ATF or two stroke oil.

While you have the carbs off, do a "bench sync". Look in from the engine side of the carbs at the butterfly plates. Hold the carbs up to a good light and observe the "crack" of light around the edges of the plates (mostly along the top and bottom). Adjust the sync screw so they are equal. I back the idle speed screw right off so it's not touching the cable arm. Then I adjust the sync screw until both plates are completely closed. Then I adjust the idle speed screw back until both plates open a little.

 

[XSLeo]

I might suggest following the steps in the carbguide to tear down, clean, inspect your carbs.
www.amckayltd.com/carbguide.pdf
Leo

 

[Brassneck]

+1 on heavier fluid...some type of Oil or even gas/oil mix if your oil is too heavy (but it looks horrid and gets cloudy)

You could also start the bike without connecting the manamoter, then switch the hoses when it's running... Just got to be quick or have someone help you out.

 

[rptc]

thanks for all the help and suggestions. got off work today and put 2 stroke oil in the manometer and had a buddy help me sync them. seems to be running a lot better. now to replace my charging rotor and test ride. ive been without my xs for too long now and im itching to ride it so i hope everything goes smooth from here. thanks again everyone. im sure il be asking more questions in the future