Author Topic: finding copression stroke  (Read 1121 times)

0 Members and 1 Guest are viewing this topic.

Offline pepsoy

  • Full Member
  • *
  • Posts: 10
finding copression stroke
« on: July 18, 2007, 12:22:50 PM »
hello. with the tappets totally slacked and the valve cover on, how do you find the compression stroke on the 1 or 4 cylinder (valves closed) when the tappets are slacked and  all valves are completely closed. or does it matter? do you start with the 1 cyl at the T mark just bc it's first and go from there for the adjustment. i guess it's 50/50 on getting it right!

Offline scondon

  • No way my run was THAT slow, must be an
  • Old Timer
  • ******
  • Posts: 3,137
  • Mmmm......tasty bugs
Re: finding copression stroke
« Reply #1 on: July 18, 2007, 01:10:23 PM »
    Even with the tappet adjusters completely backed off, the rocker arm paddles will hit the cam lobe. You can pinch #1 intake rocker between your fingertips and feel it rise and fall as you spin the engine. Spin the engine until you feel #1 intake begin to rise, then look at your timing marks and spin the engine to 1-4 "T" mark. You are now on compression stroke for #1 cylinder and can set gaps for..

#1   intake and exhaust

#2  exhaust

#3  intake

 Spin engine 360 degrees(one revolutuion, returning to the 1-4 "T") and set gaps for..

#2  intake

#3 exhaust

#4 intake and exhaust

DISCLAIMER:  I may have the specs for #'s 2&3 cylinders reversed. Please consult your manual before proceeding as I am just going from memory. Process described is for a CB750
Give me..a frame to build a bike on, and my imagination will build upon that frame

Offline jtb

  • An unlikely
  • Expert
  • ****
  • Posts: 1,499
Re: finding copression stroke
« Reply #2 on: July 18, 2007, 01:13:39 PM »
Sean, I can actually wiggle both rocker arms on #1 when it is TDC on Compression stroke. 
1977 CB750F
1985 V65 Sabre
1986 VFR 750 (gone but missed greatly)

Offline scondon

  • No way my run was THAT slow, must be an
  • Old Timer
  • ******
  • Posts: 3,137
  • Mmmm......tasty bugs
Re: finding copression stroke
« Reply #3 on: July 18, 2007, 01:20:29 PM »
Sean, I can actually wiggle both rocker arms on #1 when it is TDC on Compression stroke. 

   When properly gapped,yes ;)
Give me..a frame to build a bike on, and my imagination will build upon that frame