Topic: Danielle CB550K Build - Toyon Moto Club #5

[Blackfin5]

I know....but it was my first attempt at a frame up.  I promise to do better next time.  Just leave my name out of it after you pick it up.   You can always say you got it from Brent. 

[Blackfin5]

 Inspiration comes in all forms . . . some forms less devine than others. 

[bwaller]

I wondered why my ears were burning!     Come on...you guys are the builders, I just line things up by eye.

[Blackfin5]

Geez, Brent....did you put your ear to the exhaust again?

Been surfing the forum about fork "sticktion" and seeing mention of various coating applications to the tubes and for inside the cases/sliders.  Can someone explain how coating the inside of the cases reduces friction on these rightside up old style dampening rod forks?  I see an expensive but minor decrease in friction by having slick tubes, but the case insides?

[Blackfin5]

Finally!  Got it together.  Goes into frame tomorrow if I have a couple extra set of hands.  Then I will time the new Megacycle cam.

[SOHC4 Cafe Racer Fan]

Looking good, Kevin!

[Blackfin5]

Thanks, Don.  Been a long time waiting for little things like locating sleeves (pins), gaskets.  My machinist lost my 12 x 18mm locating dowels between cylinder and head.  I was furious....because I asked him to kerp track of my o-rings and dowels.  "Err...what dowels?"

[SOHC4 Cafe Racer Fan]

That's infuriating!  So how many riders in your group have taken the plunge in getting a vintage ride?

[Blackfin5]

We now have 6 guys (1 gal sometimes) and 1 more waiting for a 550 to get here from Atlanta.  All are either 77 or 78 CB550Ks and then my 76 CB750F.  More are interested.  It's quite fun!

[SOHC4 Cafe Racer Fan]

Very cool, Kevin.  I will have to join you guys for a ride one of these days.  It'll be a bit of a haul from Long Beach, but it would be fun.

[Blackfin5]

Absolutely.   Wait for an Indian Summer day during the holidays.

[Blackfin5]

I skipped a pic or two.  126-20 Megacycle cam installed with adjustable cam gear.  Timed to TDC then to center intake #1 lobe at 104.5°.

[bwaller]

You adjusted the cam timing by their valve opening/closing timing card numbers?

[Blackfin5]

Hi Brent.
I used the degree wheel to find the lobe centerline.  I zeroed the wheel to TDC then opened intake valve to .050" lift on dial indicator taking note of the degrees on the wheel.  Then closed the valve, noting the degree.  (Added the 2 numbers + 180)/2 - opening number.  I had to adjust the cam sprocket only slightly to get the cam card intake number of 104.5. 

[bwaller]

First I suggest you use a positive piston stop to find true TDC. Don't go by the marks on the case.

You want to check & record both intake opening/closing numbers & exhaust as well using 0.040" checking clearance, that's if you start with "0" lash. Both sides have to be measured.

0.050" is what Webcam suggests, Megacycle uses 0.040" as a checking clearance.

[Blackfin5]

Sorry - I left that part out.  I used an APE positive piston stop in spark plug hole #1 and did NOT go by the slot on the right side end of the cam.  I found TDC by finding the mid-point on the degree wheel when hand turning the crank in each direction until the stop.  I did this several times to make sure I got an accurate reading.  Without affecting the position, I loosened the degree wheel and re-set it at zero degrees.  From there, I degreed the valve opening to .050" on the dial, then back to close.

But then the dilemma, instead of "squaring" the intake and exhaust lobe centerlines, I adjusted the cam so the intake centerline matched the cam card of 104.5 - really ignoring the exhaust lobe centerline.  If I had squared the centerlines, the lobe centerlines would be equidistant from card spec, which I heard is better.  BTW - I did set the lash to zero and used .050 to measure.  I did measure exhaust lobe centerline.  With intake lobe set at 104.5, the exhaust lobe centerline is 105.5.

I have seen folks time their sohc cams both ways - setting the intake lobe to the card intake; and squaring the lobe centerlines. 

What do you think?

[bwaller]

Since it's a single cam we can't open or close lobe centers like in a twin cam engine. I use 1mm checking height and "square" my 126-20. The opening/closing numbers are always close to what Megacycle advertises and LC's are 105d instead of 104.5.

I choose to even the LC's as all my clearances are very tight and advancing or retarding the cam will end in contact somewhere.

True TDC is very important, I have one that's almost 1.5 degrees off the case mark

[Blackfin5]

Thanks.  I think I will re-time the cam so that the In and Ex lobe centerlines are squared.  Note:  If using a non-adjustable cam sprocket, I find that being only 1 tooth off makes a big difference.  I would not have thought this.  I am a little concerned that over time the cam sprocket may shift on its bolts altering the cam lobe timing.  Using red Locktite.

[Godffery]

Hey Kevin, just checked out your thread.
The Rotors & Calipers look fantastic on there!

Looking forward to seeing that beautiful motor in the frame and those CR26's mounted up!

  Godffery

[Blackfin5]

Thanks, Godffrey!  Could not have done it without you.  And the brakes feel exceptional.

[Godffery]

   Your very welcome and thanks for the good word.

[Blackfin5]

I made what I thought was final check on lobe CL.  The Megacycle card for their 126-20 is 104.5 for both I and E.  The average of 4 checks with dial indicator in conjunction with degree wheel is 105.125.  So off comes the cam cover and I retard the cam 1° on the wheel.  Result 103.75.  After 7 readjusts I keep overshooting 104.5 each time.  I am being meticulous.  I think the cam may be moving an imperceptible amount when I tighten the cam sprocket bolts.  I am frustrated trying to hit the bullseye of 104.5.  Currently at 105 to 105.25.  Should I just go with it?

[MRieck]

I made what I thought was final check on lobe CL.  The Megacycle card for their 126-20 is 104.5 for both I and E.  The average of 4 checks with dial indiacator in conjunction with degree wheel is 105.125.  So off comes the cam cover and I retard the can 1° on the wheel.  Result 103.75.  After 7 readjusts I keep overshooting 104.5 each time.  I am being meticulous.  I think the cam may be moving an impercepible amount when I tighten the cam sprocket bolts.  I am frustrated trying to hit the bullseye of 104.5. Currently at 105 to 105.25.  Should I just go with it?

Yes

[Blackfin5]

Phew.  I needed that.  I was going crazy.

[SOHC4 Cafe Racer Fan]

I made what I thought was final check on lobe CL.  The Megacycle card for their 126-20 is 104.5 for both I and E.  The average of 4 checks with dial indiacator in conjunction with degree wheel is 105.125.  So off comes the cam cover and I retard the can 1° on the wheel.  Result 103.75.  After 7 readjusts I keep overshooting 104.5 each time.  I am being meticulous.  I think the cam may be moving an impercepible amount when I tighten the cam sprocket bolts.  I am frustrated trying to hit the bullseye of 104.5. Currently at 105 to 105.25.  Should I just go with it?

Yes

All you need to know.