Topic: 550 tuning

[svenD]

Can somone help  me with the following please!
 1.  explain" pockets" under intake valves.
 2.  tuning oilepump.
 3.  source of 41 tooth sprockets.Stock for 550 i think is 37.
 4.  effekts of the above.
  Any inputs appreatiated!
      " Slides Up"
        svenD.

[Glenn Stauffer]

Just to make sure, you are talking about a Honda CB550?

Pockets under the intakes?  I don't know that there is anything special about the intakes on a 550; are you talking about the indentations in the pistons?  They are there for clearance, but they are not present on the stock 550 pistons.

Never heard of tuning the oil pump, though I have heard of checking that the lobes aren't worn.  Unless your engine was abused or has very high mileage, I don't think you need to bother with the oil pump.

[Jonesy]

It sounds like he might me referring to some of HondaMan's "soop-up" tips. I think he mentions grinding a pocket above the intake valve and also suggests adding 4 teeth to the rear sprocket to help with the "flat spot" the 550 has around mid-throttle.

[physician]

i have the same concern about the pocket under the valves. i figure i'll understand when i'll take the head apart. probably means that you have to grind the passage to make it more straigt ti the cylinder, not a straight line from the carbs, but more of a way to make it in the axis of the valve stems. maybe  someone will clarify this, i have troubles finding the right words, my english is'nt that good today! ( i'm french speeking;))

or it may mean to radius the back of the valve...

i have not found sources for + for rear spocket, but i can have -1 -2 -3 front. i figur that -1 front is about +3 rear. i'll probably go that way.

[svenD]

 hey there!
 thankyou for your comments , yes its a 74 550 motor in a 75 500 frame standard exept 4:1 ex.I have been reading Hondamans
 notes,and would like to try some of his tricks.The "pockets" seem to be ground between valve seat & guideboss (I think) and should
 improove flow somehow.The new gearing he refers to would be easy to make if rear sprocket from similar machine could be adapted.
                                                                                                                               
                                                                                                                                   keep safe!
                                                                                                                                                   svenD-

[Jonesy]

Yes, grinding the pocket can help, but there are easier things you can try first, such as changing the advance curve, the rear sprocket and carb jetting.

You can also clean up the mis-match between the intake tubes and the head, and narrow the valve guide bosses. You could do the "pocket" mod, but I should think you would want that if you were racing. For average riding that might be more headache that it's worth....