Author Topic: The CB550 that came in from the cold  (Read 1098 times)

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Offline HondaMan

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Re: The CB550 that came in from the cold
« Reply #25 on: December 29, 2025, 12:03:06 PM »
Just a quick update: Found out why the clutch lifter wasn't working.


Fixed it  :P

What was "up" with the lifter?
See SOHC4shop.com for info about the gadgets I make for these bikes.

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Offline rb550four

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Re: The CB550 that came in from the cold
« Reply #26 on: December 29, 2025, 12:34:12 PM »
  Some guys use carb clean spray , I like to soak mine in carb cleaner ....it's getting hard to find here in NY  a bit toxic I guess  but that's what I use until I find a better way . Honda man is right , never do this stuff without eye protection !
And I have found if you can't get it clean with a spray can you may find it better with a cheap pancake compressor if you don't have a big one. One last thing , super glue for the corners of the float bowl washers.
A few Honda 500's, a few Honda 550's, a few Honda 650's, '72 cb 450, a couple 500/550/650 hybrids, and 2001 750. 
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  http://forums.sohc4.net/index.php/topic,101678.0.html             
http://forums.sohc4.net/index.php/topic,137317.msg1550907.html#msg1550907

Offline newday777

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Re: The CB550 that came in from the cold
« Reply #27 on: December 29, 2025, 05:32:05 PM »
Just a quick update: Found out why the clutch lifter wasn't working.


Fixed it  :P

What was "up" with the lifter?
Check the spring in the pictures
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 1 K2, 4 K6, 1 K8, 1 F1, 1 F3
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline ThelassianLupus

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Re: The CB550 that came in from the cold
« Reply #28 on: January 04, 2026, 10:32:25 AM »
  Some guys use carb clean spray , I like to soak mine in carb cleaner ....it's getting hard to find here in NY  a bit toxic I guess  but that's what I use until I find a better way . Honda man is right , never do this stuff without eye protection !
And I have found if you can't get it clean with a spray can you may find it better with a cheap pancake compressor if you don't have a big one. One last thing , super glue for the corners of the float bowl washers.
Thank you very much for reiterating these tips. I've had one close call with carb cleaner spraying back into my face, thankfully I do wear my glasses on shop days. And the thought has occurred to me several times that an air compressor would do a lot better than my soaking, picking, and scrubbing. Maybe if I time its usage while nobody is around to hear it. Say for instance, the EMT guy sleeping off the night shift whose space I'm borrowing.

Offline ThelassianLupus

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Re: The CB550 that came in from the cold
« Reply #29 on: January 04, 2026, 11:35:04 AM »
Just a quick update: Found out why the clutch lifter wasn't working.


Fixed it  :P

What was "up" with the lifter?
Check the spring in the pictures
Yeah, I should also elaborate that wasn't the only problem, just an oversight that was interfering with my adjustment of the lifter arm. HondaMan mentioned previously:

"First, I'll mention about the clutch plates you have: the 2.8mm thick plates are the ones Vesrah (i.e., generic imported plates) is lately selling in place of Honda's 2.71mm thick versions. In that regard, they should work OK."

The 2.8mm plates do result in a stack height that allows for adequate pressure plate separation while the clutch lifter arm is positioned correctly (horizontally aligned to arm and case markings). I had incorrectly assumed that I needed to increase the stack height from 31.6mm (with the 7 Vesrah plates), to something closer to 34.4mm (I assumed 7 factory plates would make this figure). I sought to accomplish this by swapping in three CB750 friction plates of 3.5mm thickness adding up to a stack height of 33.7mm (above wear spec as listed in my Clymer manual.

Now this is more or less the thought process I was approaching the problem with. Shifting problem=clutch problem, clutch problem: arbitrary stack value is lower than spec/ I think it's incorrect because it doesn't match what my books or the Internet says. Therefore the solution must be to come up with a new arbitrary stack height, replace parts until it's closer and then wonder why it still doesn't work..... I realize that I failed to consider the actual mechanics of this component and that's how something obvious like the lever spring having slipped behind the actuator went unnoticed while I was fixated on the friction plates.

The only parts I ended up replacing were the springs (swapped them out for weaker ones) and one friction plate. The clutch seems fine now, when I ride again I'll see how the bike shifts.

It's awesome to have access to the knowledge, knowing how to apply it is what takes real skill.
« Last Edit: January 04, 2026, 11:37:29 AM by ThelassianLupus »

Offline ThelassianLupus

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Re: The CB550 that came in from the cold
« Reply #30 on: January 05, 2026, 03:22:01 AM »
Anyway, on to my next question.

I found these jet replacement kits that I had purchased when I first got the bike. I'm pretty sure I got them from Common Motor Collective. I don't believe they are genuine Keihin parts, so the only pieces I'm considering to use are the o-rings.

I've replaced the drain plug rings, and I'm looking at other o-rings to swap. The replacement main jet from the kit seems to have a ring that's both too small and too wide. The dry fit was too tight when I tried seating the new main jet, it wouldn't go in completely. Yet it seems to not fill the groove on the main jet entirely either. I suppose this is why I've heard that the factory main jet has a "custom" o-ring.

My questions are, how would I know if I needed to replace this ring? And if I need to replace one, should I replace them all across the three other carburetors?