Topic: 1974 CB550 first timer Scrambler/Tracker build

[tanner709]

Hey guys,
New member here. Just a little background on myself and my bike. I'm from Eastern Canada, Newfoundland to be exact. I've been on a search for a bike to build and potentially convert to a scrambler/tracker style for quite some time. I've been around bikes my whole life, started a passion when I was 5-6 years old on a z50. Progressed to a CR80 when I was 14 or so, shortly after a CR125, and then progressed to streetbikes with my fathers 84 500 interceptor. I recently sold a 07 CBR600RR in search for something more practical, more upright and comfortable. I've driven everything in between over the years - I was lucky enough to have a stepdad that bought and sold stuff as much as he changed underwear. TW200s, NX250, CR500, Katanas, GSXRs, DR650, KLXs, Hayabusa, R6, CB1000, the list goes on. I recently rebuilt a 1983 ATC200 and had a lot of fun doing it, so here I am.

The problem with our climate and location, is that we get snow, and cold weather, and you truly only get 5 months of riding here at best. We also get snow, and lots of it. The province also uses salt and sand to combat the extreme snow and ice conditions which in turn corrodes anything that it touches. That makes very hard conditions to find a bike in the first place because of the lack of them, as well as finding one that is even worth wrenching on. now onto the bike;

I purchased this bike not running - I know never a good idea. But the deal was too good and I really have nothing to lose with the purchase. The bike is a 1974 CB550, well at least the frame is. It's sort of a Frankenstein bike and has been pieced together using the best parts from all 3 bikes. One good this is, that the 74 frame has never been registered in Canada and it will make for an easy process to get registered/plated and all that.

From what I can tell the bike is a K model, with lots of F model parts. Correct me if I'm wrong, I'm learning more about it everyday.

Here is the bike as it sits right now;


And here is a shot of the spare parts (not including 2 rolling chassis with 2 other engines)


The good about the bike;
- Tank and side covers recently painted, and done well (8.5/10)
- 4-1 header in great shape with minor scuffs, new slip on muffler as well, looks to be a stock supersport header?
- chrome in decent shape
- new battery, fresh oil and air filters
- massive amount of parts, including fully assembled engines, great reference for a first timer
The bad;
- was not running (currently is)
- was laid up for some time with no fluids
- unsure of electrical state, as some things have been altered by the PO
- carb bowls stuck  (#3/#4)
- headlight not working, taillight either (only in park)
- starter not working
- wrong kickstart lever
- minute leaks here and there
- old tires
- etc.

I've started working on the bike already and have a few items crossed off the "Issue List".
Things I've completed are ;
- fresh oil, confirmed filters ok
- electrical sorted enough to start
- replaced base gasket, head gasket, valve cover gasket etc.
- fixed kickstart lever issue, as it was interfering with the rider peg and brake lever
- static timing completed

The major things I have left to tackle are;
- oil leaks (still leaking due to inexperience with head gasket issue)
- starter motor
- electrical/start switch/cleanup etc.
- headlight taillight issue
- carb cleaning/rebuild

The bike is back together and not weeping oil AS bad but still not satisfactory...

One question I do have is regarding a noise that is currently in the bike after the recent head gasket replacement. It seems to have a ticking or knocking noise near the head. I've read up and found that it could be the primary chain, or as simple as a carb sync issue. I need some help from you guys to determine if this bike is worth my time and money to proceed with based on my current findings.
I will post a video tomorrow of the noise I'm referring to. I really wanna get into this farther and proceed to build that scrambler vision I have in my head.

Sorry for the long first post, the following ones should be much shorter and lots of pictures ! Thanks for reading

[calj737]

The noise is likely the cam chain needing adjustment. The carbs needing a synch make more of a knock sound.

Head gasket leak is probably due to needing to release the torque, and re-torque the head since the gasket has crushed in now. The proper method is to release the torque in reverse, in stages. The step the torque back in, full sequence at half torque, then another compete sequence of full torque. You’ll need to release the valves and remove the cover.

Once the cover is back on, set the timing, then set the valves. Then adjust the cam chain.

[tanner709]

The noise is likely the cam chain needing adjustment. The carbs needing a synch make more of a knock sound.

Head gasket leak is probably due to needing to release the torque, and re-torque the head since the gasket has crushed in now. The proper method is to release the torque in reverse, in stages. The step the torque back in, full sequence at half torque, then another compete sequence of full torque. You’ll need to release the valves and remove the cover.

Once the cover is back on, set the timing, then set the valves. Then adjust the cam chain.

When you say release the valves, you mean take the tension off each tappet correct?

I set the cam chain tension as described in the manual and this forum - at 15deg advancement, allow the tensioner to naturally adjust to position after tightening the screw, then tighten the nut.

[tanner709]

Here's a short video, not of the problem I had mentioned but first after reassembly. The noise became present shortly after a few startups. Again, I will upload a video of that as well.

[calj737]

Correct on the tappets. With no muffler on that bike, it will run like crap. The noise could easily be exhaust leaks. Did you use new copper crush gaskets and remove the old ones?

[tanner709]

Correct on the tappets. With no muffler on that bike, it will run like crap. The noise could easily be exhaust leaks. Did you use new copper crush gaskets and remove the old ones?

Yes I did replace the crush gaskets. I appreciate the help troubleshooting. I need someone to question everything I've done to help me tick off potential issues.

I did not release the valves when I completed the head gasket the first time. But I did make sure the tappets were liftied before putting the valve cover back on. I guess there's a chance I may have caused damage ? Bent a valve?

[tanner709]

As promised here is the video with the noise I mentioned

The idle is fairly low. 850ish rpm range it does subside with correct idle speed but is not gone

[calj737]

I hear a bike that needs a carb synch, possibly the cam chain is stretched, and what sounds like exhaust leaks.

[tanner709]

I hear a bike that needs a carb synch, possibly the cam chain is stretched, and what sounds like exhaust leaks.

Haha, yeah I guess I'll tackle the carbs next. Any advice on what brand rebuild kits?

Would the tensioner take enough slack out of the chain to avoid issue? Or am I thinking about the stretching incorrectly, whereas the stretch occurs between links and it no longer fits the sprocket well?

I don't believe there is exhaust leaks, it may be just the video. I cleaned up the exhaust flanges and exterior port, and the crush gaskets were new and sat in the port firmly - I aligned the header to land in the center of the gasket. I do have one semi stripped bolt hole on #1 exhaust port.

 I've ordered 2 sets of new crush rings just in case.  I plan to keep the bike and continue with the project.

I'll keep this post updated!

[calj737]

Haha, yeah I guess I'll tackle the carbs next. Any advice on what brand rebuild kits? The only thing you generally need to replace is the gasket and any o-rings. Keep the stock brass and just clean it up really well.

Would the tensioner take enough slack out of the chain to avoid issue? Or am I thinking about the stretching incorrectly, whereas the stretch occurs between links and it no longer fits the sprocket well? Hopefully the tensioner will adjust enough to take out any slack.

I don't believe there is exhaust leaks, it may be just the video. I do have one semi stripped bolt hole on #1 exhaust port. A stripped bolt is sufficient to prevent the crush gasket from being sealed. Just an FYI.

[je750f]

Sounda a little like the valve clearance.

[tanner709]

Sounda a little like the valve clearance.

I haven't measured the gaps yet, mainly because this is all new to me.

I have enough parts to build a spare head. I think I'm headed that route due to 4-5 stripped bolts. Exhaust port #1, plug hole #2, and 2 or 3 head cover bolts.
I've noticed some jb weld on the valve cover end cap as well, what exactly do these end caps do?

The more disassembly, the worse they will get. I have some parts on order and all the time in the world - we're expecting snow sometime this week 

thanks again calj for the info.

[calj737]

If you do have to swap heads, it would be prudent to "lap the valves" of the other head. Install new valves guide seals too.

The end caps (you asked) cover the end of the camshaft. The cap has 2 dowels, those have o-rings on them to seal oil from leaking out. There's a mounting bracket on the head for the cap to screw into. Those brackets are marked L and R, so keep track of that.

Almost every bolt hole in that head is 6mm, 1.0 pitch. If the holes aren't completely butchered, you can buy a "blind hole tap" to clean the threads up. A blind tap has a square cut bottom, versus a tapered tip. You want the blind style for cleaning up existing holes for bolt and screws. These are really inexpensive, and a decent set of metric taps up to 12mm is a good toolbox item to have.

The trick with taps is 10mm and 12mm have 3 different pitches each (10x1.0, 1.25 and 1.5, and the 12mm are 1.25, 1.5 and 1.75 normally). Can be easier just to buy the few that you need if you go that route.

[tanner709]

I don't see or understand how those end caps do anything. They literally just plug the holes, with O-rings, as you mentioned. Why wouldn't this just be sealed on the cover itself.

I must be missing something.

Regarding the head, yes I would like to build a fully fresh head, ensure all bolts and holes are tapped/threaded properly. Along with all valve stems/seat/seals are kosher. I wish I had the knowledge I have now regarding how painful aluminum can be, say last week lol.

I'll be making a trip to get a tap and die set on days off. I just purchased a set of JIS bits and some proper feeler gauges.

[hudstr]

The end caps plug the holes for the rocker dowel shaft. There are threads inside of the dowels so to remove just thread in a bolt and pull.

[tanner709]

The end caps plug the holes for the rocker dowel shaft. There are threads inside of the dowels so to remove just thread in a bolt and pull.

ahh gotcha!