Topic: Looking for Help:'76 CB550F Lacking Power

[2Shoes]

Like many others I have read about on these forums, I too have an issue with my bike not running well. With the stock airbox and filter, it slows down on any hill and just wont develop much power. Also, the rpm wont go above 5000 and there is some backfire on deceleration. If I remove the air filter completely it gets much better; but I would rather ride with the filter on of course.

I just finished rebuilding the carbs with new jets and needles. All stock sizes and the needles in the centre position. Air screws are 1 turn out from seated. This problem has existed since I bought the bike last summer and was not caused by carb rebuild. I have added the dyna s ignition. The bike starts right away.

Btw, this forum has been a HUGE tool in allowing me to get the bike on the road. I would have never attempted such a thing on my own and I am grateful for all the information available here. Thanks.
mark

[Johnie]

To clarify and help to eliminate some items here, so after you did the carbs did you get to sync them too?  Valves adjusted, etc.?  Have you tried to see if it gets any better by re-adjusting those air screws to a different setting, like maybe 3/4 or 1 1/4 to see if there is a change from where you currently have them.  How about points and timing I imagine you already checked those?  You sort of have to go by process of elimination here and work yourself back to find the problem.  You said you had this situation before the carb rebuild?  What was the compression readings?

[TwoTired]

Step 1  -  Check the head pipes for even temperature.

Step 2  -  A complete and thorough tune-up, like what is outlined in the owners manual for 3000 mile intervals, including a new air filter and carb balance.

Step 3  -  If you have stock exhaust, set the carbs to factory adjust specs with the factory parts. (#98 mains, needles with stock profile in 2nd groove, # 38 slows, Idle screws set at 1 1/2 turns.) Making sure the emulsion tubes are clean and the float height is correct @ 22 mm.

Cheers,