Topic: 76 CB550 Cafe build

[tshrey]

As with every other part of this build reassembly was an adventure.  When I went to join the case halves one of the gear assemblies fell out of place, end cap came off and there is a caged roller bearing inside that.  Rollers went everywhere, had to dismantle and clean everything around my work bench to get them all. Then went to put the sleeves on over the cylinders and #4 bottom oil ring came out of the groove and snagged on the sleeve.  So I had to order a new piston ring kit for that guy along with a new head gasket.  Having done this now multiple times I can say that everything in the motor is correct 

While I was waiting for parts to come in I cut the 'hump' off the right side rearset, machine a sleeve to go in its place and then welded that in.  My last pass with the TIG on aluminum was like hitting the perfect golf shot, I was soooo happy with how it looked (not what is in this pic, other side of the rearset).  Then threw the part in the mill to mill it flat and powder coated it.




Engine went back in the frame tonight and once it was bolted solid I put the 550F kickstart on and the combination of the two was success!



Kickstart clears everything, so I pulled the starter motor and put in the blockoff I had made for it a couple years ago.  Another 7 pounds saved    Started to put the head on with the intention of getting it all back together tonight but it is so swampy out that I was sweating just standing still, so it is going to have to wait until tomorrow night.

[wolf550]

good job on that rearset. I don't know why that hunk of aluminum was there on the footpeg.
when I bought one of franks starter block offs, I took the internals out of my starter to still be able to use the cover but never got around to filling where the starter crank hole was exposed.
just an idea to keep the clean look and use your cover on there

[tshrey]

I think I'm going to get some measurements and make a mount for the cover plate.  Seems a shame to destroy a functional starter, can't be many of these kicking around after all these years.

Curious to see if the difference in rearsets (left/right) is going to bother me riding.  It was a decent amount of work to get rid of that hump.

[tshrey]

Motor is all back together.  Runs well, very smooth and no more bouncing crankshaft   Bike fires on the first kick without the choke when cold so I'm going to go down a size in the pilots on the Mikuni's (I'm already at 2.5 turns out and when I accelerate at very light throttle once I get to 4k it starts blubbering a little). 

After changing to a longer lever, different clutch pivot, stock springs and an OEM honda clutch cable I can ride the bike for longer than 20 minutes before my wrist hurts, so that is a nice improvement.  Still going to do the hydraulic clutch, will be turning a 2" cylinder of aluminum to weld into the clutch cover for a little more support. 

Exhaust was changed to an 18" Cone Engineering unit that I just welded directly to the header collector after dialing in a little bit of kick up and out.  Also welded on a mount tab and then made a hanger out of 1/4" steel.  Had 2 stains on my headers from oil on my hands when I first put them on and even after scotch brite-ing them off they would come back when the headers got hot.  Saw on youtube a trick to try - another shot of scotch brite, then wipe them down with WD40.  Smokes a bit when the first heat up but now they look new.  Only downside to the new exhaust is now my spool stand hits the muffler so I have to modify the stand a little.




It's going to be 90 and humid for the next several days, so I'm also going to take the opportunity to remove the front fender and shorten all those mounts by 3/4" to get less gap (it is from Cognito and they assumed a 19" front wheel with their kit).

Cleaning up the garage and came across some parts.  Stock sized head gasket, an aluminum spacer for the rear wheel I machined to get rid of the stock piece of lead and an extra fuel petcock.  If anyone can use them let me know, they are yours for shipping cost.

[SOHC4 Cafe Racer Fan]

I like the Cone Engineering exhaust better than the prior slip-on. I'm wondering about the placement though.  From the photo, it looks like it blocks your rear wheel stand bobbin on the right side.  Also, is it kicked up enough to avoid scraping when you are leaning the bike over?  It's just hard to tell with the photos.

[tshrey]

It's the angle, the bike is on the sidestand in the pic so you can't see the upsweep of the pipe.  I would be running my boot into the ground before the pipe.

I did have to modify my rear stand a little, not because of the bobbin/pipe distance but because when it rotated into the 'store' position the body of the stand hit the underside of the pipe.  A little extra square tubing and some welding and it is all good now.

[tshrey]

Have ridden the bike several times in the last few days.  Having never read an owner's manual I discovered through trial and error that kickstarting only works in neutral with the clutch out.  I pulled it in out of habit one time and almost kicked the bike over on to its side because there was zero resistance.  Pretty embarrassing.

Also, a question for @calj737 with the m.unit - it doesn't seem to know when the bike has actually started if I use the kickstart.  First time I did I tried to shut it off in the normal way (double press the start button) and nothing happened (I don't have a kill switch wired up).  Through trial and error I've found that I get it running and then hold the start button a second to turn on the headlight.  Once I'm in that mode I can then double tap to turn it off.  Is there another way to set this up?  Also, if I do all that when making a quick stop for gas and leave the unit On I can't kickstart it anymore, like I have to kill power through the m.lock and start over to get it going.  I don't really see anything in the manual describing this, I guess they figure not many people kickstart bikes.

[tshrey]

Stalled the bike at a light when I was messing with tuning and it take so long to reach down, flip up the footpeg and kick it and then take off while cars are waiting for me.  I couldn't take the embarrassment and put the starter back in    Did a much better job with wire routing this time so things are cleaner under the seat. Also finally set up the bluetooth on my m.Unit; I can't believe I never played with it until now.  I have the blinkers set up for a quick tap being 3 blinks, longer hold turning on and then turning off after 20 seconds in case I forget to turn them back off.  Can also run the turn signals at 10% power for running lights.  Best part is not needing the key - when you get within a couple feet of the bike with your phone it wakes up the bike.

During the heat I knew I wouldn't ride so I finally dropped the front fender down 3/4" to hug the tire a little more.  Not terribly trivial cutting that length off each mount and rewelding it in exactly the same orientation but after screwing up the first one I got the last 3 on the first try.



Also finally got the last bit of tuning done.  If I would accelerate under very light throttle once the rpm got to 4k the engine would transition to 'bababababa'; my mileage was also pretty bad for a bike like this, around 35 mpg.  I played with the throttle slide cutout, the needle height and a couple other things but in the end it turns out the pilot jet was just too big as delivered from Murray's.

Still waiting on my 34 tooth rear sprocket, working on making a rear hugger out of carbon fiber, the hydraulic clutch work continues and I've decided to try to make an intake box instead of using the two cone filters that came with the VM34 kit.  I got 2.25" silicone tubing to connect to the carbs and push their inlet back far enough that I can make the box behind the frame rails.  I'll 3d print the first version with velocity stacks inside the box that then make the connection to the silicone tubes.  Hard thing will be finding velocity stacks that are 2.25" OD, no one is going to list the OD.

[tshrey]

Got the 34 tooth rear.  So much nicer.  5k rpm is now 67 mph on the highway, everything just feels better.  Don't notice the gearing change under acceleration since this thing is so light and has some nuts.  Had to push the rear axle back with the smaller gear but didn't think what that would to my rear brake lever, just drove to work with it so high I couldn't use it    I'm putting the 37 tooth sprocket in the classifieds if anyone wants a crazy light sprocket specialists 520 conversion setup.

Still more tuning to do.  When I moved to the 2.0 throttle slides I could easily leave a stop with what I would call 'normal' driving, feed in gas while letting out the clutch.  The extra vacuum helped just off idle but that same extra vacuum pulled more fuel through the rest of the circuits so it was rich at light throttle and higher rpm.  Went down a size in the pilot and back to the original 2.5 throttle slides, now the overrich at higher rpm/light throttle is gone (and feels glorious) but I have to get the revs up leaving a stop before letting out the clutch.  Certainly drivable this way, but I'm going to try going back to the 2.0 slides and down another step in the pilot to see if I can get the best of both.

[grcamna2]

Excellent work tshrey 

[tshrey]

Found another little bonus with the bluetooth m.unit - I run a bluetooth headset in my helmet so I can listen to music.  If you do that, when you put your turn signals on you get an old-timey blinker sound in your helmet when you have your signals on    I think that is awesome.

Wanted to just do a quick check on the crankshaft today so I pulled the rotor cover and started it up.  Outside of rotor is dead smooth, but it looked like the center was wobbling.  I was like WTF mate?  Pulled the rotor off and verified crankshaft itself is very smooth.  Turns out the rotor is just a cast hunk of iron that they machine and shove some magnets in.  The center of the assembly though is still cast, poorly.  I took almost 2 mm off the cast section before it was all smooth.  That had to introduce some vibration.  Image is halfway through turning it on my lathe...



Also worked on my airbox.  Turned some velocity stacks a long time ago and they happen to be very close to the right size (I need to tack on a single thin strip of aluminum so that they are snug inside the silicone hoses I bought).  Test fitting tonight and then have to decide how to make the box to accept a panel filter.

[SOHC4 Cafe Racer Fan]

I kind of lost track with your carburetor odyssey:
- started with CR26s
- swapped to 2 VM34s with a custom 2-1 manifolds
- swapped to stock carburetors
- swapped to stock carburetors with 3d plenum and 1 air filter
- swapped to VM34s - now with velocity stacks?

[tshrey]

Yes!  CR's didn't idle for #$%*, the cold start mechanism is a disaster and they are super loud but run great above 3k.  Stock carbs are quiet, suck to tune, make everything in that area super tight to deal with but give you a nice docile bike to deal with.  Mikunis are best of both worlds, sooo much quicker than stock, lighter, easy to tune and a volume halfway between stock and CR's.  I abandoned the Mikuni's originally because of their off-idle behavior leaving a stop, but a combo of possibly more vacuum now that the motor is broken in as well as getting better at carb tuning resolved that.

I'm done with the carb swapping, I would just like an airbox for the two mikunis to quiet down the intake noise and get room around the frame rails.  The K&N's that come with the mukuni kit are right up against my wiring along the frame rails at that location.  Having a box will also let me vent the cam cover breather port into the intake instead of the janky little filter I have on it now.  The velocity stacks are just going to be the inlets to the airbox to smooth stuff out.  I got the angle and holes measured up last night, will do some welding later today.

[tshrey]

Anyone every had chatter in their clutches?  Leaving a stop I've had a couple instances of a very unpleasant sound, not a grinding but almost like the clutch basket is wobbling a tiny bit and generating a weird resonance.  It goes away once the clutch is fully engaged and only does it leaving a stop.  I don't think this happened before I put used stock clutch springs back in.  Going to pull the cover off and make sure something isn't loose in there.

[flatlander]

i didn't have this issue but when i converted mine to 7 disks i learned that keeping the stack hight very close to stock is really important.
there's also a spacer under the circlip making sure there's not too much play.

[Godffery]

Anyone every had chatter in their clutches?  Leaving a stop I've had a couple instances of a very unpleasant sound, not a grinding but almost like the clutch basket is wobbling a tiny bit and generating a weird resonance.  It goes away once the clutch is fully engaged and only does it leaving a stop.  I don't think this happened before I put used stock clutch springs back in.  Going to pull the cover off and make sure something isn't loose in there.

What type of Oil are you using? 
If it's a common automotive (not formulated for wet Clutches) it can cause the plates to slip a bit, so the chattering could be them slipping and trying to re-grab.

[tshrey]

Genuine Honda 10w40 dino oil.  I'm going to measure the thickness of everything tonight, maybe that thrust washer is worn or something.

[tshrey]

So I think first of all, it was just poor assembly on my part; I found the circlip not home so that could let the basket move outboard a little bit and I could imagine if the basket would start bouncing in and out a tiny bit that would do what I was feeling. 

But after measuring everything I noticed that the wear limit on Honda friction discs is 3mm; all of my Barnett discs are 2.7mm to start.  .3 x 6 regular friction discs means my stack is almost 2 mm shorter than what Honda calls for.  I don't have the thicker riveted 'damper ring' that the later model units had but I think I might try to find one, that would make my stack height the same as stock.  Would this slimmer height also mean when I pull the clutch lever in I have to compress the springs more?  Maybe that is why my clutch pull always felt heavier than I thought?  I don't have a good visual model in my head for what that assembly is doing.

[Godffery]

So I think first of all, it was just poor assembly on my part; I found the circlip not home so that could let the basket move outboard a little bit and I could imagine if the basket would start bouncing in and out a tiny bit that would do what I was feeling. 

But after measuring everything I noticed that the wear limit on Honda friction discs is 3mm; all of my Barnett discs are 2.7mm to start.  .3 x 6 regular friction discs means my stack is almost 2 mm shorter than what Honda calls for.  I don't have the thicker riveted 'damper ring' that the later model units had but I think I might try to find one, that would make my stack height the same as stock.  Would this slimmer height also mean when I pull the clutch lever in I have to compress the springs more?  Maybe that is why my clutch pull always felt heavier than I thought?  I don't have a good visual model in my head for what that assembly is doing.

With 2mm less overall, then there would be less preload on the springs.

[tshrey]

@flatlander I followed your clutch odyssey.  You mentioned in one post the 78 basket is a little deeper.  If the 78 is when they went to the wider top friction disc then the basket in my bike is a 78, so I have even shorter stack height for that basket.  I found an entire 78 basket in good shape on fleabay, will try that out when it gets here.

[flatlander]

ha, you found that thread? it was quite a puzzle

i think if you have the later basket that went with the wider disc then indeed, you may need more height to get the correct amount of free space. to be honest, i think the stack needs to be more than 2mm short to cause rattle but adjustment with the screw on the outside of the cover will become difficult to impossible with incorrect stack height as the adjustment range itself is only about 2mm.

the problem is that many aftermarket kits, and also many sellers of OEM parts don't necessarily understand the different specs between clutch discs and plates of different CB models, let alone different versions of of the same model. i ended up ordering just a few different parts to mix and match until i got the height i needed.

[tshrey]

I have about 4mm of gap at the top (between top steel and the wider friction disc) as it sits.  That seems excessive.  But short of this new resonance/almost grinding sound I've never had an issue other than what seems like a pretty heavy pull (but Godffery said that should make it easier, not harder).  I guess we'll see in a couple days.

[Godffery]

I have about 4mm of gap at the top (between top steel and the wider friction disc) as it sits.  That seems excessive.  But short of this new resonance/almost grinding sound I've never had an issue other than what seems like a pretty heavy pull (but Godffery said that should make it easier, not harder).  I guess we'll see in a couple days.

Yes, technically with less preload on the springs, that should result in a softer lever pull. (Unless you have heavy duty or longer springs)
So it is possible that the shorter stack is not allowing stock springs so supply enough pressure to prevent slipping?
 As for the hard lever pull;  If the cable is routed in a way that puts too tight of a curve on it, that could cause it.  Or perhaps even just a cheep cable with no nylon inner coating? 

[tshrey]

Never had any slipping issues, what I'm feeling is what I would call noisy chatter in a car.  I'm guessing I fixed it my actually getting the circlip in its groove, but I haven't ridden the bike since then.

The pull definitely got better after going to stock springs and an OEM Honda cable.  Even if I remove the handlebars and take all the curves out of the cable the resistance doesn't change, so I don't think it is my routing.

[Godffery]

Never had any slipping issues, what I'm feeling is what I would call noisy chatter in a car.  I'm guessing I fixed it my actually getting the circlip in its groove, but I haven't ridden the bike since then.

The pull definitely got better after going to stock springs and an OEM Honda cable.  Even if I remove the handlebars and take all the curves out of the cable the resistance doesn't change, so I don't think it is my routing.

Well, that is a bit of a mystery then.!?