CB550 Ups and Downs

I was pretty excited when the Honda started up on July 2nd. In the days afterwards, it didn't run as well. In fact it barely ran at all. I thought about why it would run decently and then quickly turn sour. Looking at info on the internet, I decided it's probably intake leaks from the 34 year-old carb boots.

There are some methods for restoring the boots, but the boots seem to be available from Honda so why not just order a set and avoid the playing around?

Meanwhile, I had three sets of stock CB550F needles and emulsion tubes, purchased on E-bay. I installed them on carbs 1-3. Then I ordered a set from Honda for carb #4. Not sure they can still be found, we'll give it a try though.

It's a good thing I took the carbs apart. The needle clips were on different settings - one carb had the clip set at #2 from the highest notch, the other three had the clips set at #2 from the lowest notch (stock).

The main jets on carbs 1 and 4 were 98's (stock). The mains on carbs 2-3 were 110's - probably too rich for a stock motor. I ordered a set of 100's off E-bay to replace them. That's slightly richer than stock, the inside cylinders tend to get hotter though and it might be good insurance to go that tiny bit richer.

A new MAC muffler for the stock CB550F four into one arrived in the mail today. Cost about $185, including the baffle. I think it looks great! Probably better than the stocker, which looks like a cigar.

The muffler was really easy to install - three bolts. The clamp at the headpipe junction, the bolt at the muffler and the connecting strap that goes to the passenger footpegs. That's it.

The more I look at the Honda the more I like it. There have been a lot of problems, in the end I think it will be worth it. I'm hoping to get the new carb boots and a few other pieces within a couple of weeks so I can actually ride this baby on the open road!

My CB550 started today!

It's been months and the victory arrived today! I've been working on the Honda in my spare time for the last couple of days trying to get some details sorted out. When I reinstalled the wiring harness, the only thing that would work was the tail light. A member of the SOHC4.NET forum suggested I check the wiring right at the point where the ignition plugs into the harness. I disconnected the wiring and hotwired it. The lights came on. Thus I knew the ignition wasn't getting a good connection. I cleaned the terminals and carefully plugged them back in. Then I checked to see if the ignition worked before I bolted it back to the triple clamp. The lights worked and I put it all back together.

Next issue - the starter wouldn't turn over. Back to the SOHC.NET forum and I learned about running a screwdriver across the two terminals on the solenoid. I tried it and it worked. So I could get the starter to work and it narrowed the problem down to the wiring that goes to the starter button on the right side cluster of buttons.

Last night I put some gas in the carbs and tried starting. No luck. I let it sit and this afternoon after work I put the tank on and added gas. I figured maybe the carbs weren't getting enough gas in them last night.

The motor turned over and there were a few backfires. No startup. Next I removed the ignition cover, pulled the #4 spark plug and turned the crank with a wrench. I looked and listened for a spark. I noticed that the spark was coming when the crank was at the 2-3 firing position instead of 1-4. I pulled the tank, looked at the wiring and it was correct. The blue wire at the harness plugged into the 1-4 coil and the yellow harness wire plugged into the yellow wire for the 2-3 coil. Well, I know what I saw (when the spark appeared) so I switched the yellow and blue leads. Try the starter again and the motor fired up!

That was great, now why did it start when the wires didn't match up. The answer was at the other end of the wires. The person who installed the Dyna ignition put the wrong color codes on them. The Dyna has a black wire and a white wire. The installer put some plastic on those wires (blue and yellow) but in reverse. When I put the bike back together, I wired it as indicated, which didn't work. So I removed the colors and corrected that issue to avoid problems in the future.

That's great. A few more things to take care of: 1) Fix the starter button; 2)
Secure the wiring harness to the frame; 3) Put the airbox back on; 4) Put a new muffler on.

The Honda had a MAC header when I bought it. I replaced the header with a stock CB550F headpipe. A MAC replacement muffler is on order. I have the old, rusty MAC muffler on it now, just to keep the noise down. It doesn't fit right so I probably won't ride much until the new one arrives.

I didn't clean the carbs and wonder if the pilots may have gotten clogged during the nine months or so that the bike sat unused.

Next post coming up soon!

Let's take the motor apart again

I read some posts on SOHC4.NET from others who had purchased the same piston kit as I. They had problems with excessive oil consumption BIG TIME!

The problem stems from installing the oil rings upside down. They push the oil up towards the combustion chamber instead of down towards the crankcase.

I had no idea whether my rings were right side up or not. All I did was install the rings in the correct order. The marks on the rings to indicate "up" or "down" are very small. Old eyes like mine need a magnifying glass to read them.

Further reading indicated that all of the rings have an "up" side. The "up" side of the top piston ring, like the oil ring, can only be identified by the mark. The second ring is kind of easy because it has a ridge along the bottom - intuition says to put the ridge on the bottom.

Here are the rings:

The first picture shows the second piston ring. The mark on it says "STD 3". The second picture shows the top and the oil ring. Click on the photos for larger pics and you can see the marks better. That's the mark indicating "this side up" when installing them on the piston.

Why a 3? Probably because this is a 3mm overbore kit for CB500 motors. I'm using it on a CB550, making it a 1/2mm overbore.

I spent a Sunday late morning and all afternoon, taking the motor apart down to the pistons, checking the rings, reinstalling and putting the motor back together. Good think I did this now, because about half of the top rings and oil rings were upside down as odds would predict.

I had some problems getting the cam chain on once again. At least this time I figured out how to slacken up the chain tensioner to get that sprocket and chain in place on the cam. Turn the little screw on the tensioner to the left to get the most slack. Don't try forcing the sprocket onto the cam if there's not enough slack, you might end up stripping the threads on the bolt!

So the motor is back together and we're getting close to startup day.

Changing a tire

The tires on this Honda are old - maybe 10 years, I am not sure. I've owned the bike for nearly three years now and the guy who sold it to me had the Avons on it for at least a few years.

I have a new(er) front rim and tire from a guy who had some extra parts in Mililani. I'll run that tire for awhile.

Picked up a new rear tire from Glenn's Cycle Supply in Kaimuki - a Kenda, with a tube cost about $80 bucks. The tire size is 110/90 x 18. I went with the less expensive tire (Contis etc. run over $100 per tire) because I don't plan on doing much peg scraping, just cruising.

Well I thought I'd give it a shot at changing the tire on my own. The old one was brittle and tough to get off. I had two tire levers and could just barely get the bead over one part of the rim. Bust out the sawzall, cut the tire. I didn't cut down to the bead because I was afraid about messing up the rim with the saw blade. So I levered the bead away from the rim and cut it with a bolt cutter. Both sides.

Removing the tire took awhile, probably 20-30 minutes. Putting on the new one was surprisingly easy. I sprayed soapy water on the rim, used the levers and got one bead on within a minute. Stuck the tube in, put the valve stem in place then sprayed some more soapy water on the remaining bead. It levered pretty easy until the last couple of inches. I stood on the tire to get the bead in and then used one tire lever to get the last section in place. That took all of five minutes - if that. Yeah!

Next I pumped it up and was happy to see I didn't puncture the tube with the tire lever - it was fine.

The tread pattern on the Kenda looks kind of tractor-ish. If I could do it again I might choose another tire even if it cost a bit more. I had ordered a Cheng Shin, but when I went to the shop Glenn told me that size of Cheng Shin went out of production so the distributor sent the Kenda.

That's okay, main thing there's a good tire on the bike with no cracks in the sidewall.

Putting the motor back together

Hey it looks like I'll get this motor back together this year! A set of pistons from e-bay should get the bike running nicely again. They are 3mm overbore for a CB500 = .5mm overbore for a CB550. I believe that brings the displacement to 555cc. More importantly, the cylinders will be cleaned up and aligned properly. I read in the FAQ section of SOHC4.net that the cylinders get slightly out of alignment as mileage adds up. Reboring them straightens things out and restores power. I hope that's true!

I used a set of hose clamps to compress the rings on cylinders 2 and 3. Once those were in, I moved the hose clamps to cylinders 1 and 4. I did this very slowly to make sure not to break a ring. It would be hard to find replacements.

Another Important Lesson with CB550 Motors

I was pretty excited getting at making progress on the motor. Then I got to the cam installation. On CB550's this is a tough thing to do. Gotta slide the cam in thru the chain, put it in place and then slide the sprocket in "just right". The issue is having enough slack in the cam chain to get the sprocket mounted.

I read about it, followed the procedures described online and I couldn't get it! Kept looking online and then I realized what was wrong: The cam chain was on the wrong side of the front tensioner!

Okay I have taken apart two other inline four motors. My CB400F, 30 years ago and and my Suzuki GS750 back in the mid 1980's. With both of those motors, the cam chain is pushed inwards by the cam chain tensioner at the front of the motor. On the CB500 and CB550, the cam chain goes AROUND the front cam chain tensioner guide. See the diagram below.

Now I had to pull the cylinders off after having so carefully fit the pistons in them! And that's what I did. With the cylinders off I could remove the front tensioner, turn it round and reinstall it with the cam chain in front. With that done, the cylinders went back on (easier the second time), then the head and I was back to installing the cam.

It was still tough to install the chain and sprocket on the cam, using up every little bit of slack in the cam chain and with the tensioner tightened as much as I dared. Eventually I got the chain on the sprocket and the sprocket bolted to the cam.

If you've never done this before, note that the camshaft must be TIMED to the crankshaft. Read the shop manual to learn how to do it. If that's not done correctly, the engine might not run OR the pistons might hit the valves and you're screwed. If you're off just a little, like one tooth from where the cam is supposed to be, the engine will run but it won't be nice.

The motor is pretty much back together now. Last night I worked on the wiring harness, cleaning up connections and crimping some wires. I'll put it back on the bike, then reinstall the carbs and airbox. We're getting there.

Important info when working on a CB550 motor

As you can see by the dates in these posts it's taking me a long time to work on my CB550F. Work comes first and this year I've been busy.

Here are some observations.

When I split the cases a couple of months ago I put the transmission parts in a bag. Last week when I started putting the motor back together, the bearing race seen in the photo fell off and out fell some tiny needle bearings! Usually needle bearings are "caged," that is they are held together in a race. This set of bearings has a race but they are not attached. After sitting around for months the oil keeping them in place drained out and the bearings scattered. Most of them were easy to find but I had to hunt around the carport to find the last two on the floor. There are a total of 16 needle bearings. I packed them with automotive grease to keep them together when I put the race back on the transmission main shaft.

Another item to keep an eye on is the kickstart shaft. It's easy to take motors apart and harder to remember how they go back together. I installed the two transmission shafts and saw that the countershaft was engaging the kickstart shaft. Then I was trying to remember how these two shafts should work together. When I turned the countershaft it would wind up the kickstart shaft. That's okay for starting the engine with the kickstarter but we don't want the two gears to mesh all the time.

I was having a hard time figuring this out. So I went to SOHC4.NET and looked for an answer. I did find one post with a video where a guy had a similar problem. Some other forum members made some suggestions, he said "thanks" and did not ever go back to explain if the suggestions worked. I e-mailed the guy and he didn't respond.

Next, I made a new post about the subject. One person gave the wrong answer, another said the kickstart shaft was in the wrong position, still there was not enough detail.

Then I figured it out. Wasn't that hard, just had to sit down, look at the parts and move things around.

Here are the photos:

In the first picture note that the two gears on the kickstart shaft are meshed together. They should be separated when the engine is running and only meshed together when the kickstarter is being used to start the motor.

In the second picture, the arrow is pointing at one end of the kickstart spring, wrapped around a tang on the shaft. The other end of the kickstart spring is hooked to the engine cases.

The problem I had was because one end of the kickstart spring was not properly connected to that tang shown near the arrow. Once I hooked it onto the tang everything was okay. The two gears on the kickstart shaft separated and then they would mesh together when the shaft was pushed down.

Things are moving now. And I have two more motorcycles to work on. I hope to get this Honda back together soon!

S&W Shocks for a CB550

I had been trolling E-bay for sometime, looking for a good pair of shocks to replace the stockers. There are several nice sets, available and brand new. I'm not crazy about spending several hundred bucks on a set of shocks.

Awhile ago I got lucky. Instead of looking for CB550 shocks I looked for CB650 shocks. CB650's were around for a few years, never as popular and the CB500 and CB550.

A company had an old pair of S&W's for a CB650, starting bid $15. I emailed the seller and asked for the length eye-to-eye. The seller did not reply. I checked some websites and CB650 shocks were approximately the same length as CB550's - 13 inches.

So I went ahead and bid on the shocks. I had the only bid and won, $15 plus $15 for shipping, $30 total. Okay, they were kind of ugly but they weren't leaking oil.

They cleaned up pretty nicely! I took them apart with my bare hands, no spring compressor required. Repainted the shock bodies black and found a Rustoleum paint - Marigold! - that matches that gold color that was a trademark of S&W shocks back in the 70's and 80's.

Here are the before and after photos:

You'll see them on the bike later. I still have to take the cases apart, paint them and put it all back together.

The holiday season is here. I've now owned the Honda for over two years and ridden it less than 1,000 miles. Once the oil started leaking on the engine it became less fun to ride. When the bike is back together with the oil leak fixed, a rebore and new pistons, new shocks and a rebuilt front brake I think it's going to be a fun ride!