Topic: CB550 Performance Mods, A La HondaMan...

[Muk]

i would definately like to knwo the answer to the slotting the cam question to any pics on where and how much to slot

[bwaller]

rotary table in a mill, ten degrees fore & aft I believe.

[paulages]

rotary table in a mill, ten degrees fore & aft I believe.

thanks brent- it's the mill part i'm trying to get around. 

[crazypj]

If your careful you can use a die grinder or even a Dremel.
 Personally I would only do one hole to get timing right, mark sprocket for second hole and then only grind away enough material so bolt butts up against edge. Sprocket is held centered on cam by flange so its OK for timing purposes.
PJ

[paulages]

If your careful you can use a die grinder or even a Dremel.
 Personally I would only do one hole to get timing right, mark sprocket for second hole and then only grind away enough material so bolt butts up against edge. Sprocket is held centered on cam by flange so its OK for timing purposes.
PJ

it seems to me that if you only do one hole you wouldn't be able to rotate the sprocket on axis at all.  it would pivot on the stationary bolt instead of the cam itself.

i was planning on trying my "poor man's lathe" (drill press with mill bits or burrs  ), using the aforementioned method of centering the sprocket. i'd be afraid that going at it with a grinder and no means of control at all would end bad. i might be a hack, but i'm not that bad.

[bwaller]

Paul you can even use a rattail if you've got enough patience!  Go for it man, try your idea, I'll send another sprocket right quick if it goes poorly.

[crazypj]

You only fit bolt to hole thats modified, I thought that would be obvious?
 You dont need both in there to do static timing.
PJ

[paulages]

Paul you can even use a rattail if you've got enough patience!  Go for it man, try your idea, I'll send another sprocket right quick if it goes poorly.

i need the 650 sprocket, brent. i'll probably practice in the extra 550 one i have first though. by the way, check your PMs.

[paulages]

You only fit bolt to hole thats modified, I thought that would be obvious?
 You dont need both in there to do static timing.
PJ

gothcha, PJ. i guess it is a pretty snug fit when you have the sprocket on the shaft.

[HondaMan]

I used a rat-tail file on all of them in the 1970s.
Today, I can gain access to a mill, makes a much cleaner job of it!

If you don't go against one of the stops when setting the final timing, add some blue Loctite to the bolts to hold them snugly. I also would buy new bolts each time, because I had a (bad) habit of overtightening them to make sure they wouldn't "slip" on me in a race. I didn't break any, but that's just luck...

[Jonesy]

All I did on mine was up the main jets to 100's (the originals were 90's), since the pipes were starting to turn gold. I first tried dropping the clips one notch to richen up the midrange, but it was too much and the bike would fall on it's face after giving it a handfull of throttle. Going back to the center clip position with a larger main jet seemed to do the trick, and the plugs (NipponDenso X-22's) have nice gray deposits on them. I'm running everyhting else stock- pipes (although some of the baffling has rotted out inside, likely reducing the backpressure a bit) and airbox with stock filter. Mark (HondaMan) also posted a mod to the spark advancer springs where you cut off one of the end loops and form a new one from the next coil in the spring to delay the ignition advance. You can also change the sprocket ratios as well. I just never got around to doing all that and since my wife loves the bike as is, it hasn't been high on my priority list....

Jonesy:
If you do go back inside: slot that cam sprocket and advance the cam about 5 degrees. Your wife WILL notice that! 

Hmm... Mark, you've got me very tempted to do a little more work!

One question, though.. If I advance the cam 5 degrees, how will that affect long-range touring?

[HondaMan]

All I did on mine was up the main jets to 100's (the originals were 90's), since the pipes were starting to turn gold. I first tried dropping the clips one notch to richen up the midrange, but it was too much and the bike would fall on it's face after giving it a handfull of throttle. Going back to the center clip position with a larger main jet seemed to do the trick, and the plugs (NipponDenso X-22's) have nice gray deposits on them. I'm running everyhting else stock- pipes (although some of the baffling has rotted out inside, likely reducing the backpressure a bit) and airbox with stock filter. Mark (HondaMan) also posted a mod to the spark advancer springs where you cut off one of the end loops and form a new one from the next coil in the spring to delay the ignition advance. You can also change the sprocket ratios as well. I just never got around to doing all that and since my wife loves the bike as is, it hasn't been high on my priority list....

Jonesy:
If you do go back inside: slot that cam sprocket and advance the cam about 5 degrees. Your wife WILL notice that! 

Hmm... Mark, you've got me very tempted to do a little more work!

One question, though.. If I advance the cam 5 degrees, how will that affect long-range touring?

The power comes on sooner, and it falls off sooner up high, too. Above 8000 RPM it drops off at 5 degrees advance, but not severely. There's more torque in the 6000 RPM range though. I ran 3 degrees on mine, wished I'd done 5 at the time, for country riding (lots of 70 MPH stuff). It just always felt "flat" to me in stock trim at 55-75 MPH, and this perked it up, making if feel stronger in those 4th-gear passing lane situations on 2-lane roads.

[Aaron Richard]

Quick, possibly dumb question ....What's the difference in advancing your cam VS your timing? How do you know exactly how much you advanced the cam ?

[HondaMan]

Quick, possibly dumb question ....What's the difference in advancing your cam VS your timing? How do you know exactly how much you advanced the cam ?

Those are two different things. One is ignition timing, one is breathing timing. Advancing cams is done with degree wheels, dial indicators, and true TDC detection aside from the ones on the spark advancer.

[Aaron Richard]

Does anyone have any pics with steps of the process of dialing in a cam?

[FunJimmy]

Here is an article explaining cam lobe centers.
It also covers degreeing the cam.

http://www.muzzys.com/articles/lobe_centers.html

Cheers
FJ

[HB-1fan]

Hey Jonesy, nice work and pics!
 I done this to my 12K mile 76' 550ss:(Broke a ring)
-Smoothed out casting bumps in chamber(by hand only).
-Cleaned up and matched intake ports(just like you did) with 80 grit then 120 careful not to change shape of intake or chamber, to keep factory balanced flow.
-Lapped valves and new valve seals.
-Honed and all new rings.
-2nd gen 750 carbs(not pumpers), been along time but think it needed to go up one jet size.
-K&N pod filters
-Kerker modified to be 4-2-1(poor man style) with a Yoshimura muffler.
-Dyna s and dyna green coils.
-Up 1 tooth in the rear drive.
-Silver comstars and new tires.
Approx. 6 to $700 spent.
Differnce in performance:    PRICELESS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[HondaMan]

Hey Jonesy, nice work and pics!
 I done this to my 12K mile 76' 550ss:(Broke a ring)
-Smoothed out casting bumps in chamber(by hand only).
-Cleaned up and matched intake ports(just like you did) with 80 grit then 120 careful not to change shape of intake or chamber, to keep factory balanced flow.
-Lapped valves and new valve seals.
-Honed and all new rings.
-2nd gen 750 carbs(not pumpers), been along time but think it needed to go up one jet size.
-K&N pod filters
-Kerker modified to be 4-2-1(poor man style) with a Yoshimura muffler.
-Dyna s and dyna green coils.
-Up 1 tooth in the rear drive.
-Silver comstars and new tires.
Approx. 6 to $700 spent.
Differnce in performance:    PRICELESS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Hey, HB:
With those 3-ohm Dyna coils and the Dyna 'S' ignition, I might ask this:
how is your battery voltage? If you are not running a halogen headlight, it might be OK, but if you are, with that ignition combination, you may have a low battery pretty often. There's a couple of "fixes" available, if you're having this issue now.

Also, you might want to add an extra BLACK and GREEN wire (20 AWG is enough) to the system as follows:
BLACK: tie in at the voltage regulator's BLACK wire (a 3M splice is adequate) and run to the headlight, then tie into the BLACK main feeder there (either an empty BLACK socket or another 3M connector will do).
GREEN: Make one end a ring terminal (1/4" size, red jacket) and add it to the underseat GREEN ground bolt. Run this wire to the headlight also, and tie into the GREEN there, however it needs to be done.

With the extra current imposed by the combination of Dyna ignition components you now have, the stock wiring is going to get pretty warm. This upgrade will handle it for you.

[francis8766]

Im sorry for reviving this thread. Im currently restoring my 1975 cb550f and i wanted to apply the thoughts of hondaman while the engine is still apart but im having a hard time doing such due to lack of experience.

While searching the forum, i noticed this thread but i cant find jonesy's first post regarding the mods. . Do you guys still have the pics jonesy posted?or any picture that would illustrate the mods hondaman was reffering to. . Thanks a lot

[francis8766]

Bump

[HondaMan]

Im sorry for reviving this thread. Im currently restoring my 1975 cb550f and i wanted to apply the thoughts of hondaman while the engine is still apart but im having a hard time doing such due to lack of experience.

While searching the forum, i noticed this thread but i cant find jonesy's first post regarding the mods. . Do you guys still have the pics jonesy posted?or any picture that would illustrate the mods hondaman was reffering to. . Thanks a lot

I think Jonesy's pictures got lost when the forums were moved to this server a few years ago. He did a nice job with that head! Some increased volume over the intake valves (also called 'pocket porting'), reduced sides of the guide bosses, nice smoothing of the casting marks, and a good job of matching the intake castings to the head ports is what it takes.

[dave500]

don't try and port the head as such but just knock off any obvious casting dags and lumps that don't belong,fix any mismatch between the head and manifolds you might find.

[HondaMan]

don't try and port the head as such but just knock off any obvious casting dags and lumps that don't belong,fix any mismatch between the head and manifolds you might find.

Wow, that's a REAL bad one, Dave! I haven't seen many quite that offset. They are always a little bit offset, but not often that much.

[dave500]

ive seen some doosies!maybe they selective fitted intakes to get the best fit,and now with all the mix n match parts around the errors seem worse?

[HondaMan]

ive seen some doosies!maybe they selective fitted intakes to get the best fit,and now with all the mix n match parts around the errors seem worse?

In the post-1976 era there were many that were hand-ground to fit a little better. This is sorta backward form the 750, which had hand-finished ports until sometime during the K2, after which they just shipped them as they were. I've recently been swamped with 500/550 heads for port jobs and valve freshening, and about 1/3 of them have matched intake spigots from the factory: you can always tell because they don't smooth 'em, just grind 'em!