NAVY8TR

I wanted something new to me so I picked up a 74 cb550 in almost running condition on Dec 11. My goal is to have something to fix and work on and be able to ride periodically. I still have the hawk and I'm going to keep both. I'd like to turn the cb550 into a cafe style sort of thing.

I'm starting the thread a little late, sorry. And yeah, you missed to fun part, I had the enjoyment of getting it started already. Its going to take a lot of work though cause its running like crap. The progress this month has been slow because of the holidays, it has been at 3 houses so far this month but the pace should pick up next week once I get settled back up at school. So here's a little background of the project I've already started:

Its a 74 cb550 four, it came with a spare 78 cb550k parts bike which was in boxes. Got both of them from a guy Edgecomb Maine for $500. Brought it home, took the fenders off and got all the parts organized to see what I had and didn't have. Then took some pictures (what you'll see below). I knew it would be hard to start the first try, dead battery and it had been sitting outside with velocity stack pods and no filters. I cleaned the spark plugs and set the gaps, I got it to fire a little but nothing encouraging. Took the carbs off, cleaned the float bowls which had huge amounts of rusty looking dust. Tried again, Nothing.

Then it was time to take it home for Christmas break and try to get more done while pleasing the family and gracing them with my presence Got a new battery, and jerry-rigged the 78 carbs onto the bike. the interesting thing here is that the cable-disks on the carbs open in opposite directions. Also; the 74 carbs have a manual choke, and the 78's have a cable choke. I did however get it set up and got the bike to fire up and run.

It sounded decent for a bike that had not run in a couple years but there were some obvious clanks and rattles. Next I got into the timing and points. learned a lot about the points system and setting the points gap and adjusting the timing with the condensers and rotating the disks under the points cover to make the condenser to send current at the right time. Its all really fascinating stuff and it helping me get some confidence in tinkering and a background on how technology has developed.

Took a break from that to work on other stuff. I made a bracket for the tach so I can run it as a single gauge display. I eliminated the indicator light display and worked on the forks. I am using the forks from the 78 because they have good seals. I just wanted to go through them so I drained the oil from them and cleaned everything inside. It calls for SAE 10W 30 for fork oil. I wanted to slow the compression and rebound down a little so I used 15 40 instead. Its an experiment but its easy enough to change if it doesn't work out like I expect. Took a wire wheel and scrubbed the age off the bottom tubes and I'll be repainting them before I put them on the bike. One thing I like about the 78's forks is that they are an inch shorter than the 74's so that will tighten up the steering a bit. That pretty much gets me to where I'm at tonight...I rebuilt the 74 carbs today, slapped them on, and the bike loved it. I could tell the fuel/air mix was much better than when I had the 78 carbs on.

So to sum it up I've set to spark plug gaps, points gap, set the timing, and got fresh carbs. The problem I have now is that the clanking and slapping noises in the engine got worse. I think part of it is due to the fact that when I corrected the timing and the carbs it made the problems with the valves more apparent. Tomorrow I am going to try to tackle the valve clearances and then recheck the timing after that. Oh and the compression is really low right now too #1-3-4 are at 110 and #2 is at 135. Spec is between 155 and 170. I don't expect to get those number cause it is an old tired engine but I would like to get around 145 in each cylinder.

Other things on the list:
Go through the electrical system, replace old tube style fuses with new style flat fuses, replace the clutch/clutch cable, throttle cable, wheel/head tube bearings, rebuild brakes, new tires.
After that I'll get into the fun stuff - I want to put an old harley style flat track tail on it, make some rear-sets and reposition the foot pegs, build a 4 into 2 high-mount exhaust, and eliminate the electric starter/hand controls. Then Repaint! Its ambitious but I feel like I've got a good start for having the bike in 3 different places over the past 3 weeks. Stay tuned!

NAVY8TR

Sorry there aren't more pictures of the progress so far, I'll be better about it when I get back next week and the cb and I am settled back at school. either way, heres the beauty queen, shes in the living room getting put back together. Replaced the clutch on it and stripped it down to the engine, frame and wiring harness cleaned everything with simple green, scotch-brite and Q-tips. Not even an ounce of dirt or grime on it! Not bad for 34,000 miles!

98VTRrider

Looks like a good project bike. The Hawk looks awesome, I've thought about doing that kind of detailing to mine, maybe if I do a rebuild haha. I like the CB series bikes, my dad has a 1979 CB750K in good shape. Look forward to seeing your transformation into a cafe bike.

Little_Horse

congrats on the buy.

Prepare to become addicted. I personally like the style of the 500/550 cb's engine better then the 750 aesthetically at least. These motors clatter a little bit I think because of the fact the rocker arms are built into the valve cover transferring sound better. I have chased the clatter sounds alot on my 500. Tried everything from cct adjustment to valves. In the end it didn't change anything, but I am getting good mpgs and power and its smooth and not overheating so I have resigned to being ok with it. You may too but I would encourage you to continue with checking everything anyways.

If you find you need some help with custom cafe parts let me know.

~LH

NAVY8TR

Thanks guys, I almost took on a 78 400T II hawk but found out through some forums that the cb platform (specifically the 500, 550, and 750) are the best for converting. So I went with the cb instead of a mini Hawk. Eitherway, its going to be a fun overall project. At the moment whats really grinding my gears is the low compression. I think If I could fix that I would be fine with the rattles and clanks. I've been told that if you pour a teaspoon of oil into each cylinder, turn the motor a few times and check the compression, you should find the compression to go up if the rings are bad, and compression to stay the same if the valves are bad...

8541Hawk

This is correct and also make sure that the throttle is all the way open when doing the compression tests.

RickB

Reminds me of my first bike, a '73 CB500F... They are pretty good little bikes... Congrats on the new bike!

NAVY8TR

Throttle all the way open? This will make a significant difference? Thanks for the tip, can't wait to try it out tomorrow! See, thats what I don't really like about clymer, they are good for describing how to do something very well and in good detail, and even offer insight into a problem that might be the cause of a certain symptom, but they do miss some crucial information. When I was doing the points I noticed a type-o in the manual. In the front of the book (specs/clearances/setting) section it indicates something like .4mm for a gap in the points, in the instructions part of the description on how to set them it says .04mm. Same thing with the fork oil. in the fron of the book it says to use ATF for my bike, and in the "how to" it says 10w-30. Its too late for that as I already did the fork oil, if its acting real bad I'll change it but that can wait. It was a good thing I double checked with the points though, I think I need an additional manual!

Today I adjusted the valves, set the cam chain tension, tightened the headers a bit to make sure I wasn't getting additional noise from an exhaust leak, and greased up the swingarm joints. All went well, and started it up after the adjustments. It quieted down quite a bit, the clanking rattling and knocking subsided a significant amount. And it idles well.

Question for you guys - It runs and sounds good when I let it idle or keep the rpms under 4k rpm. I could sit there and rev it all day long under 4k and it would be fine, but today, after I had it warmed up and idling good at 1500 rpm without the choke (no airbox or fliters) I brought it up to about 5krpm and held it for 10 seconds. Sounded good, no misfires. Revved it up to 6500 twice and let it come back down to idle. When I let it come back down to idle it was spitting an sputtering like crazy then died. Started it back up, and it wouldn't hold an idle and sounded like ****. I shut it off and let be. This seems to be a typical thing when I do this maneuver on the throttle. I did it before when I was running the 78 carbs, thought it could be a bad fuel/air mixture or something to do with the wrong carbs. Is it possible that I am getting unburned fuel sitting in the cylinders when this happens? My plan is to get new fuel, new spark plugs and change the oil after I do the clutch tomorrow to see if this helps out at all. Do you have any ideas of what it is? Any other suggestions of what to do to try to fix it, or figure out what it is? Thanks, Oh and I'll be putting pics up tomorrow so don't tell me my thread is worthless yet!

Little_Horse

your running issue sounds to me like a fuel flow not being enough so a couple of carbs stop working until there is enough fuel again. Also the 78 carbs are they also mechanical slides or are the vacuum slide? Vacuum slide carbs don't work well without an airbox generally if you are having issues its a good idea to put it all back together before thinking all is lost and scratching your head for hours... I have never done this .

The other thing to check when the motor exhibits your problem is whether the plugs are fouling.

Oh and more pics needed and we want to know what the "dream is" you know the plan for all the details.

BeerHunter