Topic: having a problem with top end power

[gmpb2]

 so I just finished putting together my 78' CB550 Cafe project and it was time for a test ride.  Initially, everything seemed to be going smoothly, but once I got a little braver and opened it up, it didn't have any top end power.  I went back and checked my timing, point gaps, and plug gaps.  everything checked out and was in perfect order.  there is no smoke from the exhaust and the air/fuel ratio is good.  I did change the exhaust from the original 4 into 4 to a NOS aftermarket 4 into 2 system, so could it be that the carbs need to be re-jetted?  my other thought was possibly the coils?  I don't have the equipment to check those though
Please help!

[scunny]

is the advance moving freely ?

[fastbroshi]

Are you using the stock airbox or pods?  Stock paper filter or foam?  Even with the stock airbox and filter, you may need to rejet. 

[fastbroshi]

Dingdingding!!     

[svenD]

I think the colour of the plugs after a HARD run can point the way,certain fuel additives can muddy the picture and should be avoided,white plugs = lack of fuel.

[fastbroshi]

   jetsrus seems to have a good selection of jets.  Make darn sure you're getting the right ones though.  I'd call them to make sure you get some measurements from them about what you're ordering. 
   What carbs do you have?

[scottly]

IAnd yes, I definitely plan on calling and getting an expert opinion one what size to get 

There's a guy on this forum that seems to be pretty knowledgeable on these bikes... Hmm, I vaguely recall something like fastbro...  

[fastbroshi]

   If you call to ask what size jets you should get they'll probably be wishy washy, understable since each bike is a tad different.  The best you can do is identify EXACTLY what type jets fit your carbs and then order like 2 or 3 sizes of your idles and mains starting with 42 idles and 105 mains.  I think yours were 98 stock if they're like mine.   Check post #7 here http://forums.sohc4.net/index.php?topic=5410.0   The jet needles have built in adjustability. 
   Trust me, I'm no expert.

[scottly]

     Trust me, I'm no expert.

Maybe not, but I believe you have had first hand experience with re-jetting for pods and exhaust on these bikes. What size jets and needle settings did you have the best results with?

[fastbroshi]

  I had pods on mine briefly but I decided to go with an airbox.  I was bringing my bike back from the dead so I was just trying to minimize my downtime.  But my bike's exhaust baffle was gone and I'm running a Uni filter so I did have to rejet. 
  I went to 105's on my mains and I haven't been able to source idles yet.  It will idle, but it's lean and hard to start.  Okay once it warms up though.  I've had it up to 100 and she's still pulling.  I bet it'll go 105-107mph (bikini fairing?)!  Sorry you got me talking.

[scottly]

Good info for the OP; his question was about top end power.

[fastbroshi]

gmpb2, I'd start by getting those bigger idles, mains, and raising the jet needle 1 notch (drop the clip).