Topic: A couple newb questions.

[Andrew_FSBC]

I just joined here a couple weeks ago so hopefully I'm posting this is the right place. I just bought my first Honda project bike: '78 CB550K. I've owned and worked on bikes in the past but this is my first venture into this style. I have been looking for a 78 550 for over a year but never could land one. I found this one on CL a couple weeks ago and pulled the trigger.

As for my questions:

 - Bike has aftermarket shorty exhaust. Where the flange for header #4 bolts to the head the inside stud is broken and the flange is slightly askew. There also appears to be some leakage from the head gasket on this same cylinder as there is some carbon buildup. I saw the broken stud before I bought but the carbon buildup was cleaned up and appeared after my first ride. Am I doing damage if I continue to ride or should I not worry about it?

- Getting the bike up to 65 or so there appears to be some carb/fuel issues. I can't push the revs past 6500 as it will bog down. This happened going up a hill and I actually had to slow to 20mph or so and kick it down to 2nd. The bike seemed to recover after that and rode fine. Maybe some junk or water floating around in the gas tank. Definitely due for a carb rebuild and tuning either way.

- About a mile from home I noticed a squeaking noise from the front end. It sounded like it was coming from the left and applying the front brake stopped the sound. Most likely just the pads? What symptoms to bad bearings have on these bikes.

- Maybe related to the above. At 45-50 if I let go of both grips front end wobble develops immediately. It's not intense and grabbing the grips stops it. I can't feel it at all while riding. Is this Hub bearings, fork bearings, needed fork stiffener, new tire or just a quirk of these bikes?

A little info about my plans for the bike: originally I wanted to do a cafe but after some thinking and advice from several people I've decided that I don't want to do anything to permanently alter the frame. I also want to be able to maintain the capability to carry two people. I'm thinking a semi-brat style build. Maybe modify the rear fender and some LED lights, paint the frame and wheels and tins, new seat, updated wiring, minor performance mods. I have about $1k set aside for parts and I plan on doing the majority of the work myself. I'd like to ride the bike through the fall before tearing it down this winter, we'll see what my issues above determine there though.

I'll try to get some pics posted later today, I'm off to the garage to clean it up so I have some space to work!

Thanks for reading, I'm excited to be part of this community, from what I've read in the past couple weeks it seems like the SOHC family is a great one.

[oldhatt45]

Andrew_FSBC,

Sorry but the only question I can even guess at is the Wobble.

The wobble could be attributed to either Steering head bearings, swing arm bushings, Front wheel bearings, or front tire.
You need to find out which of these is causing the problem. 
This is Not just a quirk of the bike.  Something is wrong, fix it before you have a real problem.

Charlie

[seanbarney41]

Andrew_FSBC,

Sorry but the only question I can even guess at is the Wobble.

The wobble could be attributed to either Steering head bearings, swing arm bushings, Front wheel bearings, or front tire.
You need to find out which of these is causing the problem. 
This is Not just a quirk of the bike.  Something is wrong, fix it before you have a real problem.

Charlie

but it is a very common problem with these bikes and also can emanate from the rear...worn or poorly adjusted/maintained chain sprockets, loose swing arm pivot/bushings, wheels out of alignment, back wheel out of balance/true, bad tires front or rear or both....the worst part is every single one of these issues may be at work on a single bike and the wobble will never be totally gone until ALL of them are addressed.

[calj737]

The broken exhaust stud (if it is broken off and not just "missing") can be a pain to extract. But it needs to be extracted with a LEFT HAND drill bit, not an "EZ Out".  Or, if it's broken off, take your bike to someone who welds, have the weld a bolt to the end of the stud, then use a wrench to turn it out.

Don't worry, the head is aluminum, the stud is steel. You won't damage anything as you can not weld dissimilar metals/alloys together.

It needs to be replaced. When you remove the header to perform the repair, there are copper O-rings crushed into the exhaust ports. Remove these and install new gaskets. They're crush-once use only. Else, you'll have a nasty leak everywhere. And be mindful not to over-tighten the studs/nuts/flanges. That's why the #4 is whacked. Probably missing the copper gasket and some dolt wailed away over torquing it and sheared it.

Your carbs need a full and proper cleaning.


Front end wobble: check your tire pressure, bearings and what not as described. Do NOT ignore this or settle for it. It is NOT acceptable or symptomatic of these bikes.

Brake squeal is pretty common. High temp grease on the backside of pads can help. Proper adjustment can help. Swapping pad types can help.