Topic: 78 CB550 full rebuild

[sboubel]

Hello everyone,
I have been on here for a while reading and getting ideas and thought I would share my project. I have a 1978 CB550 that my Dad bought brand new when I was little. Over the past few years I have paid several repair shops a lot of money to get this thing going and every time it was done it was ok for a short time and then was just back to not running well at all. I have decided that I am going to rebuild this thing from the bottom up and add a little HP in the process. Here are some pictures of the bike before I started and the disassembly process.

[sboubel]

Here are some pictures of the engine disassembly.

[sboubel]

After looking at everything I decided to upgrade using the Dynoman Stage 2 kit which includes:
DP592/61s Hot Street Piston Kit
WebCam 358b Camshaft*
KPMI Valve Springs
DP SHP Clutch Kit
Chrome Moly Cylinder Studs
Vesrah Top Gasket Set
Cometic CFM or MLS Head Gasket

I also needed a new primary chain and cam chain and decided to replace all of the seals in the lower case as well as a few other misc. parts. Here are some of the goods.

[sboubel]

Before and after pics of valve job. I ordered OEM valve stem seals and then realized that the gasket set I ordered before had them...well I guess OEM is better or at least that makes me feel better.

[Tews19]

Wow you work fast! That bike looks minty before tear down! Did you already order dynoman pistons? 

[calj737]

The head looks much happier now. Did you have any porting work done while having the valve work performed? It would be a great complement to the component upgrades you're making.

[sboubel]

No I didn't. I realize now after I had it done that I should have done that also. Any other suggestions? I have disassembled and cleaned the engine cases and internal parts and have had everything painted. Here are the empty cases mocked up. I want to polish all of the side covers which I think will look really nice with the black.

[sboubel]

Tews19,
Yes I did order them and I have had them for a few months, should I be worried? I started this project in January so the progress is not as fast as the pictures make it seem. The bike looked good from a distance but the frame had a lot of scratches and rust and the engine cases were really ugly. I plan on having the frame powder coated, I hear that is best and I found a place that can do it a damn good price.

[SOHC4 Cafe Racer Fan]

sboubel,

Definitely powdercoat the frame.  It is more durable than painting.  If you plan to make any modifications to the frame (detabbing, bracing or mounting an oil cooler), now is the time to mock it up BEFORE powdercoating. 

As for the motor, you did a nice job of cleaning the cases.  Too bad you skipped porting.  That would really take advantage of the increase in displacement and cam by improving the intake flow via your brand spanking new valves.  It's not TOO late, but you will ended up removing the valves and reinstalling them to port it.  I would do it now while you can.  This will really wake up the motor.  You should also port the manifolds to match.

The bike has a little bit of wear and tear but it was in damn good survivor shape.  It looks like it sat garaged for most of its life.  What are your plans, aside from the engine rebuild?  Are you keeping it mostly stock?

[Tews19]

What's the plan for the tank and side covers? My first CB was a 78 550 with the black tank and side covers. Gpt it for 700 buckeroos! God I loved that bike. I wish I never sold it.

Get the frame and small tidbits powder coated for sure.  Here is a pic of my 78.

[sboubel]

CB750 Cafe Racer Fan,
Interesting you mention mounting an oil cooler because I have wondered if the engine mods I am doing if I need one. I have seen a couple posts on them but haven't seen anything that made me decide I needed one. At this point I want to do it right and make it last as long as it can so any advise is appreciated.

I haven't decided what to do with the rest of the bike cosmetically, I don't want to do anything dramatic I don't think but I have seem some really sweet CB550s on this forum that are dramatically customized.

[calj737]

those pistons from Dynoman are a nice product. Just make sure whomever bores the engine matches a piston to a bore and keeps the pistons numbered. If you really want to splurge, coating the pistons top, sides and bottom with specialized coatings will make a difference. Given that you live in SA, TX, I would definitely recommend it.

For the top, a "thermal reflective" coating. Helps bounce back the heat from combustion event back upward to plug, and isolates the heat from radiating into the piston. This in turn helps keep the oil cooler.

For the sides (skirts), a dry film lubricant application increases the lifespan of pistons and bores exponentially. Its an incredibly durable finish and aides in diminishing start-up wear.

For the underside, a thermal dispersion coating is great. This is basically an "oil-shed" coating that prevents the oil from the crankcase sticking to the piston, and further reducing heat transfer. All these little tricks add up to great savings in lower oil temp, lower operating temp, which means longer life. And, the heat in TX will take its toll on your engine more so than other areas. Should be pretty inexpensive to have it all done (I paid $45x4 locally). Given the pistons were $500, it was worth the investment to me.

[sboubel]

calj737,
When I took the cylinders to be bored I asked if they wanted all of the pistons and they only kept one, it is impossible to find a place in SATX that does any machine work on motorcycle engines so my options are actually limited to one place. What kind of place does the coating that you are suggesting?

[calj737]

Typically you can find it with some powder coaters, but not all. CycleX will do it, or I can give you the contact details for the guy local to me if you're up to shipping them.

For your pistons, since they're such high quality, I wouldn't be too fussed that they only held one. Did he in fact measure all 4 before you left and determine them to be the same? The thing with forged aluminum pistons is that they heat cycle differently than stock pistons so clearance is much more critical. If they followed the sidewall clearance data on the enclosed card, you should be just fine.

If you get stuck, and are very interested in having your pistons shot, ship them to me, and I'll have them done here and return them to you. Turnabout at the coater is about 2 weeks.

[sboubel]

So I cant find a place in San Antonio to do the porting work. Does anyone have any suggestions? How much should that cost and what will it ultimately do for me? Also will I need to order any new parts like larger valves or something? I really dont know exactly what is involved in the porting process.

[calj737]

The most popular guy about is Mike Rieck for head and porting work. He's out of Boston, but on vacation tis week. Porting is essentially smoothing the casting marks and irregularities within the intake and exhaust ports of the cylinder head. There's far more to it than that, such as enlarging the chamber in just the right places, by just the right amount, but that's the "lay" explanation.

Porting improves the flow of air and fuel into and out of the head. More air flow, more HP. If you're unable to find a good machine shop, then send your head (and jugs if you prefer) to Mike and he will steer you exactly right. Oversized valves are a great upgrade, but only make sense if the rest of the head is "tuned" to take advantage of these larger valves.

[Tews19]

Another option that you could do is a 650 engine swap. 20 percent increase in HP right away. It's a direct bolt in and only weighs 2 lbs more then a 550 engine. It would be cheaper this route then doing the head work and boring. I did the head work and boring only because there isn't a motogpwerks 4-1 for a 650.

[calj737]

For the 650 motor or frame, Tews? Head is the same as 550, no?

[Tews19]

Sorry I should have been clearer. Swap a 650 engine with harness into a 550 frame. Heads are different on a 650 then a 550. From what I've read they flow a lot better. Hence the dramatic. HP increase with not much displacement increase.

[sboubel]

I have already had the cylinders bored, valves done, ordered a lot of upgrade parts, and the engine painted so I am in too deep into this engine to abandon it. At this point I guess I really want to know if the cost and inconvenience outweigh the benefits. Does anyone know how much a porting job normally runs?

[calj737]

$250-$500 depending upon how extreme you get. Just porting, probably less than $250 I'd suspect. If you're genuinely curious, email mrieck via a PM and ask him. Provide as much detail as possible in the PM. He's on holiday at the moment, but will get back to you next week I'm sure-

[sboubel]

I took the bowls off the carbs and took some pics. Is this normal for a bike that has sat for about 2 years? I don't think there should be that must rust in there, am I right? I was planning on getting the rebuild kit at the link below. Anyone used this one and is it good?

http://www.dimecitycycles.com/vintage-cafe-racer-caferacer-bobber-brat-chopper-custom-motorcycle-engine-parts-honda-cb550-carburetor-rebuild-kit-18-2422.html

[calj737]

Rust will form in the carbs if left sitting for some length of time when the fuel evaporates and leaves behind water, as most gas has ethanol these days.

[sboubel]

So after a long break I have picked this project back up. I am reassembling the engine and after putting on the cylinder jugs I have a 1/16" gap between the bottom of the jugs and the engine casing and I am not sure what is causing it. I have added some pictures to show the gap.

Can anyone let me know if this is normal due to the o-ring gaskets on the bottom of the piston cylinders or am I doing something wrong?

[bwaller]

Are you using the correct dowel pins...the ones with the oil restrictors?