Fixing that elusive Honda CB brake squeal - really!

Just about anyone who owns a 70's Honda CB (350, 400F, 450, 500, 550, 750 - did I miss any?) knows these brakes tend to squeal.  Honda builds some great machines and they get credit for being one of the first motorcycle manufacturers to put a disc brake on their street bikes.  This disc brake design leaves something to be desired though.

I've been riding my CB550F around the island and enjoying it, EXCEPT when using the brakes.  That squeal is annoying, even with ear plugs on.  The sound can be modulated by varying brake lever pressure.  But let's face it, when we're using the brakes we just want to concentrate on stopping and not noise levels.

So I had been doing this and that upgrading the brakes and hoping to get rid of that noise.  Some of the upgrades included a new brake piston (Kevin 400F's from the sohc4 forum) made out of a hard plastic that will not corrode, Ferodo brake pads from the old days with asbestos braking material along with the master cylinder and new braided lower line mentioned in earlier posts.

The brake's stopping performance has been great!  Just that sound...

So here's what I recently did attempting to fix the problem:

1. Read through numerous posts on the Sohc4.net forum about brake squeal.
2. Bought some high temp grease, cleaned the outboard brake pad off and coated its metal surfaces (not the brake pad material) then reinstalled it.
3. Put "disc brake quiet" on the back of the inboard brake pad.
4. Rode around with a loud brake squeal, except for just a few times here and there when it went away.

Well I had a LITTLE luck with that!  A few days later I went back and read those same forum posts again and:

1. Removed the arm that holds the disc brake pad assembly.
2. Lubricated the pivot pin and o-rings with the high temp grease.
3. Reassembled and lubricated the adjustment screw that aligns the brake pads to the disc.
4. Cleaned off the brake pad that I had already lubricated with high temp grease and then lubricated it with that same grease AGAIN (on the metal surfaces and not the pad material).
5. Used 150 grit sandpaper and scratched up the surfaces of the brake pads.  Also gently chamfered the pads on the side where the disc contacts them first (the side closer to the motor).
6. Lightly sanded the outboard side of the disc brake with the 150 grit sandpaper.

Went out on a riding about 100 miles and almost no squeal!  Hard to believe.  It was great.  Then... the noise started coming back. 

I believe the high temp grease layer between the caliper piston and the pad kept the noise away (for awhile).   That is, until some of the layer squeezed out from between the piston and the pad.  So I took the caliper apart again, put disc brake quiet on the back of this (brake piston-side)  pad, let it dry thoroughly and placed it back in the caliper.  The idea was letting the disc brake quiet dry thoroughly before reinstalling would help it set up on the back of the pad so it wouldn't squeeze out.  It took another week until I had time to ride the Honda and I'm happy to report no more brake squeal.

Vintage photo of a CB550F

I saw the August 1975 issue of Cycle World for sale on E-bay today.  The starting bid is $14.50 plus $2.50 shipping equals $17.  I just want the cover photo, so I copied and edited it with Photoshop.

Here's the picture.

Wow, it makes the CB550F look like a.... Supersport!

While we're at it, here's another vintage photo, a magazine ad for the CB550F.  Don't remember where I got it, somewhere from another website.

There's a slight leak at the petcock.  I have a spare gas tank and petcock.  I removed the petcock, cleaned it up and will swap it out with the original.  We'll see if it cures the leak.

What happens is, when the bike sits, the petcock slowly leaks fuel into the carbs (yes, the petcock is in the closed position).  Every once in awhile, the carb bowls overflow and dump a little gas on the ground.  I hope the spare petcock doesn't leak.  It's hard to find CB550F petcocks.

What's new with my Honda

After a few rides the Honda's front brake line failed.  It was a braided line installed years ago by the previous owner.  I was getting ready for a ride, grabbed the brake and fluid sprayed all over the place.  There was a small fray near the front wheel and the line had punctured.

The CB550 has a junction for the brake light switch, mounted to the fork.  I only needed the lower brake line.  Looking online, I e-mailed a guy with a good reputation on SOHC4.net.  He didn't reply to my e-mail.  So I waited a few more days then started looking around in Honolulu.  A company called Hydra Air Pacific, near the airport makes brake lines, among other things.  They put together a new lower line for me in about half an hour and about $40 bucks.  Not bad!

Next, my long time friend Felix called me up.  Felix has been a motorcycle rider off and on (like me) for years.  He had been watching the "Cafe Racer" TV show and was getting the itch for an old Honda four.

Old Japanese bikes are hard to find in Hawaii!  Not sure why but let's think...  I had seen a '77 CB550 Supersport on craigslist awhile back.  The guy was asking $3,000 and it looked okay, running but not fixed up.  Then there's the guy in Mililani who sold me a front wheel last year.  I e-mailed him to see what happened with a CB500 he had put on craigslist.  He said he still had it for sale.  He had made some changes, like taking off the expensive 4 into 4 stainless exhaust and putting on a MAC pipe.  But now his price went way down, to $1,800.

I called Felix and we checked it out.  He was pretty excited and the Honda had some nice parts, like Works Performance shocks, rearsets and aluminum rims with stainless steel spokes.  The bike still needed some finishing touches, like paint.  Felix made the guy an offer, he said yes and the deal was done.  Or was it?  A week or two later Felix called me and said the bike was going to need too much work.  I agree - Felix is married, has kids and yeah he works.  Getting that bike in top shape would take a lot of time that he probably doesn't have.

Next, Felix started looking on E-bay.  He found some interesting Hondas and was thinking about buying them.  I told him some stories about the two RD400's I bought in the mainland, sight unseen.  It really sucks to buy a bike, pay the shipping cost and find out there are problems the owner didn't tell you about.  One of my RD400's didn't run when it got here and I spent hundreds at the cycle shop getting it road worthy.  And the owner of that bike had told me over the phone "Yes, it runs."

At the same time Felix was hunting for a Honda, my friend Vince in Hilo was shipping a Kawasaki GPZ1100 back from the mainland.  Besides the purchase price of the GPZ, Vince paid a company to haul it to a motorcycle shop, have it crated and then ship it to Hawaii.  Total cost to move the bike - about $1,000.  I shared that info with Felix and that backed him off a bit about buying from the mainland.

Next - I didn't really want to do this, but Felix and I started talking about his buying my CB550.  I entertained the idea because I was finding that a lot of the "fun" for me was actually working on the bikes.  And I have two more to work on, the KZ1000 and GS550.

Another week or two went by and then Felix bought the bike.  I rode it over, then he drove me home and I gave him a box of parts, repair manual etc.  Kind of sad but I knew it was going to a good home.

Felix test rides the CB550F

Three weeks later, Felix called and asked if I wanted the Honda back!  Why?  Well, finances were running low and as much as he liked the bike he needed some money too.  He knocked the price down a bit and said "consider it a rental" for that time period.  Pretty good deal.  He made some changes including polishing parts using a bench grinder and removing rust using Oxalic acid.

So here we are again, the Honda has come home!

200 Miles and Counting

When the CB550F went back together it had 31,740 miles on it.  I've ridden it around a bit including a trip to Waianae last week, putting a total of 200 miles on the rebuilt motor.  So far, so good!

It's nice to have the starter working again with that new solenoid.  The motor smokes a little, mainly noticeable when idling.  The oil rings in this 555cc kit are one-piece, which supposedly is not ideal for keeping the oil out of the combustion chamber.  The engine seems to have burned some oil, although it's hard to tell for sure since there were some oil leaks (crank seal) to fix when it first was running back in July.  Anyways, I added half a quart to the crankcase.

The spark plugs have a tan color, looks like the jetting is okay.  It's running 100 mains in cylinders 2-3 and 98's in 1-4.  Needles are set at stock position (4th notch from the top) and the bike is running the stock Honda CB550F jets - not aftermarket stuff.

The Honda is pretty fun to ride!  Recently I picked up a '79 KZ1000 and it has a lot more grunt.  I haven't been riding the KZ much because the carbs that came with weren't properly cleaned and tuned.  That will be my next project - getting the KZ going.  At this point I imagine I will hang on to the 550 Supersport indefinitely.  It seems to be one generation behind the KZ1000, looks a bit more antique and it's easy to handle because of the lower weight.

CB550 Replacement Solenoid

Starter Problem Fixed

I had checked the old solenoid by hooking it up to wires directly from the battery.  It clicked and I figured it was okay.  Then when everything was back together the starter wasn't working.  I had wondered what could be wrong with the wiring?  I had cleaned every contact in the harness and replaced the starter switch (the right switch pod) for $100 bucks.

Well the solenoid WAS shot after all.  I found this out through a process of elimination and buying a low-cost replacement on E-bay for $8.99 including shipping from China!

The E-bay seller sent me a picture similar to this one when they mailed it.  They said 18-22 days delivery time, however it arrived in just 10 days.

The solenoid has the proper colored wiring and connectors.  The only thing that didn't match up was the rubber sleeve that holds the solenoid.  The holes in the sleeve are not oriented in the correct direction to fit the space behind the CB550 side cover. Solution - I used the old rubber sleeve with the new solenoid.

Note: They did not advertise this as a CB550 solenoid, they just advertised it as a motorcycle part.

This is WAY cheaper than what other vendors charge for a solenoid for a CB550.  If you're in need of a solenoid try the seller on E-bay: http://myworld.ebay.com/ilovegoods6699

Ready to ride

There were a few things to sort out after the engine started up in July.

1. The starter and the headlight weren't working. Both of those are connected via the handlebar switch. I took the switch apart, cleaned it up and put it back together. Still no go. Splurged and bought a new switch (costs about $100). That fixed the headlight problem but still the starter wasn't working.
2. The left side crank seal was leaking! Why did this happen? It didn't leak before the engine came apart! I am guessing that the time the crank was out of the engine (about six months) caused it to leak. The seal was leaking right where it contacts the crank. If it were leaking around the crankcase joint it might have been possible to seal it up with permatex or something.

Changing the crank seal usually involves splitting the crankcases. Yeah I could do it in maybe an 8 hour day (with all the practice I had working on the motor this year) but I would rather not.

Looking at the SOHC4.net forum, some members described removing the seal and installing a new one with the motor intact. Yesterday I gave it a try.

By the way, I did not change the seals when I initially split the engine because I've never seen one leak and I didn't have a stator puller. Finding a stator puller turned out to be pretty easy, just finding the right size bolt at a hardware store (16mm x 1.5 pitch). It cost about $6 bucks.

After removing the stator I pried the old seal out (be careful not to scratch the crankshaft). I hear there are special tools for pulling seals, next time I'll buy one. Then I used a rubber mallet and a piece of wood to slowly and evenly push the new seal into place. Oh, by the way the seal has a little ridge on it. I trimmed it off with a sharp knife as it seemed the seal would never go in with the ridge intact.

Yesterday I rode the bike a few miles and it looks like the leak is gone! It is certainly better than it was before the fix. The first time I started and rode the Honda I came home and had oil on my left shoe.

Of course another problem suddenly popped up. The headlight, which had worked when I installed the new handlebar switch, suddenly stopped working on the low beam. Funny, as I was riding the low beam started working again and then when I got home it stopped. I wondered if it was the juice in the battery, but the high beam worked consistently.

I had a spare halogen headlight in storage. Pulled it out, hooked it up and both the low and high beam worked. So the problem was the 34 year old headlight, which went into the trash and was replaced with a halogen unit. I hope the charging system can support this 55w low / 60w high beam bulb.

Okay, that leaves the starter to fix. Last month I checked the solenoid and it worked. The starter itself works, I can arc the two leads on top of the solenoid and turn the motor over. And the handlebar switch is new. So what's the problem? I'm not sure but we have all those other things tackled, I'll get the starter going by tracing the wiring or if worse comes to worse running new wires along the harness.

One more thing to remember. When I rode the CB550F yesterday the idle was a little rough and there was some backfiring on trailing throttle. I adjusted the mixture screws on the sides of the carbs and set them to 1 1/4 turns out (about 1/2 turn in from the previous settings) which richens up the mixture a bit. The bike immediately idled better. I'll take it out for another road test when the rain stops.

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!