Loss of power situation identified and corrected

A couple of weeks ago I posted a thread in which I asked for help regarding an issue I was having with my 750 Seca. When the bike would warm up sometimes it would start running rough and it would be all I could do to keep it running. Sometimes no matter what I did the bike would stall and I would have to wait a couple of minutes and then it would start up and I could ride again for anywhere between just a few more miles and twenty miles or more. I suspected it was either I had a piece of dirt in one or more of my carbs that would slosh around and get stuck in some port once in a while or else it was the petcock.

I replaced the petcock, the fuel filter, and I cleaned the bottom half of the carbs and the problem is solved. Since I did all three of these things while I had the tank off I am not 100% sure which one it was but if I had to guess I would say it was the petcock based on the fact that when I was draining the tank I had a trickle of fuel flow in both the run and the reserve positions. This leads me to believe that the diaphragm was not working correctly if at all. When I installed the new petcock, fuel filter, and reinstalled the carbs and turned the petcock to prime, the gas flowed beautifully into the carbs and I hit the starter and it fired right up. I turned the petcock to the run position and I have put 70 miles on it over the past two days with no problems.

The symptoms were a severe stumbling and loss of power and seeming to only run on two cylinders. So I thought maybe this would be a help to someone else if they are having running issues.

 

Just sounds like you were on the right track with checking for a fuel delivery problem. It could also be a plugged vent in the gas cap could cause similar problems.


MN

 

Sounds like it was the carbs to me. Petcock would have more than likely affected all 4 cylinders, not just two.

 

Actually we debated that a bit, I contend that since the feed is serial if there is only a trickle and the needles are open then 1 and 2 could get most of the trickle since the feed is between them. Normally plenty of fuel flows to fill all 4 carbs.

Anyway great to here you got it resolved! It always feels good to slay the dragons.

 

It was as Bill stated - 1 and 2 got all th gas and three and four were cold. I am pretty sure it was the petcock as the carbs looked pretty good. I had cleaned them pretty thoroughly last year and they still looked good.