Topic: Dies if given Throttle and only firing on one cylinder

[larsensp]

I think this is my first post on SOHC4. I usually stick with hondatwins for my log and what not but really need help with this issue since my deadline of finishing before I head back to college is fast approaching.

After replacing the throttle seals with orings, my vacuum leaks were gone and on a cold start it would run on the left cylinder. After it warmed up, I'd say about 10 minutes or so of idling at 1200 and good throttle response, it starts to die if you touch the throttle at all. The right carb sometimes got gas in the float bowl but the spark plug was never wet. I have new float valves on order now.

I switched the float valve that was in the left with the one in the right carb (this one was leaking a bit if you turned it upside down and blew air through the fuel inlet). So after switching the valves and cleaning the carbs again, the problem switched cylinders. Now the right will idle at 1200 and respond to throttle for 10 minutes or so and then die if you touch the throttle. The left pipe was warm but not hot, I think this faulty valve works occasionally.

Carbs are 722a and heres what i've done so far

• new floats
  new boots
  replaced felt seals with orings
  adjusted floats to 26mm
  mixture screw is 1 turn out
  used a guitar string to bench sync carbs and then turned the idle screw CCW half a turn to lower idle
  throttle adjusters adjusted so they open and close together
  timing readjusted after checking and finding out it was off
  105 and 68 jets. both are stamped with the Keihin star
  both cylinders are getting spark

i think the new float valve will get it firing on both cylinders, but I am totally stumped at why it is dyeing when given throttle after warming up. any help is appreciated

Spencer

[flybox1]

replacing the felt seals with orings will make all the smooth turning components sticky and unresponsive.
the felt is there ONLY to keep dust and debris out.  I suggest you change these back to felt.
complete another bench sync of your carbs.
clear tube test your fuel level.  since you put in new fuel metering components, stock float height means nothing.  set your float height as the clear tube test dictates.
#68 Pilot jets?     Is that a type-o?  38's maybe?
Why do you need new float valves?  are your carbs leaking?

[larsensp]

replacing the felt seals with orings will make all the smooth turning components sticky and unresponsive.
the felt is there ONLY to keep dust and debris out.  I suggest you change these back to felt.
complete another bench sync of your carbs.
clear tube test your fuel level.  since you put in new fuel metering components, stock float height means nothing.  set your float height as the clear tube test dictates.
#68 Pilot jets?     Is that a type-o?  38's maybe?
Why do you need new float valves?  are your carbs leaking?

I read over on hondatwins that using orings would be fine and my throttle is still smooth for now. Before I was having vacuum leaks and now I'm not 


I'm replacing the float valves because when I turn one of the carbs upside down and blow air through the fuel inlet, there's a small leak that's present most of the time. I shouldn't be able to blow any air through with the carb upside down.

Can you explain or link to the clear tube test? I've never heard of it. The floats are supposed to be oem so I assumed it would still be 26mm.

I the 2 tiny jets that get orings on them are stamped 105 and 68 which is stock for the bike. I know one is called the main but I forget what the other is called.

I got the same result this morning when I fired the bike only this time the left was firing when last night it was the right cylinder. Ran great until warmed up. At the first sign of bogging when I gave It throttle, I was able to apply more throttle and get past the bog a few times. But eventually I gave it throttle and it died. I just went through every passage with a guitar string and boiled all the jets and emulsion tubes. Going to try again.

[larsensp]

This is a cl350 k4 by the way

[flybox1]

Ok.  This forum mainly deals with SOHC4s
You might get more luck if you move this thread over to the "Other Bikes" page
Primary jet / Secondary jet
Still would advise a re-do of your bench sync.

[larsensp]

Ok.  This forum mainly deals with SOHC4s
You might get more luck if you move this thread over to the "Other Bikes" page
Primary jet / Secondary jet
Still would advise a re-do of your bench sync.

Gotcha, I'll hit the hardware store tomorrow and see what I can find to adapt to the drain hole. And I'm going to make some new felt seals. You're right about it possibly sticking in the future

[flybox1]

barbed pvc hose coupler with an OD similar to your drain screw plugs are cheap and work well

[larsensp]

barbed pvc hose coupler with an OD similar to your drain screw plugs are cheap and work well

Gotcha. So right before I went to work today, I decided to try and fire it up one more time. Fired on the left cylinder as I was expecting and not so much on the right. Took it for a 2 minute drive around the neighborhood and rolled back into the garage. Opened the right carbs drain screw and gas was coming out. So I pulled the left cylinders spark boot off and tried to start it. To my surprise it came to life on the right cylinder idling around 1200. popped the left spark boot back on and the left kicked in. idle jumped to about 3000 and I adjusted the idle screws until it was around 1800 ( i didn't want it to die on me). Took it for a drive and was smiling ear to ear.

Stopped by after work and it was running on both again. Curious as to what changed. The bogging at idle is gone too. I rode it well after it was fully warmed up.

[flybox1]

maybe a plug cap was not seated properly.
remove the cap from the plug wire, cut back the wire 1/4" to get to clean copper, and then reattach.