Blood Sweat Tears and Grease => Engines => Topic started by: jgmunz on Oct 08, 2017, 22:25:57

Title: Where do I start? (74' Engine Rebuild)
Post by: jgmunz on Oct 08, 2017, 22:25:57
Hello all,
          Im looking for some help here on my first build. I picked up a 1974 CB550 to build into a cafe/brat bike. Although i don't feel in over my head, I'm not too sure where to start here. The previous owner claimed he bought the bike running and he disassembled the bike last winter. It now sits in my garage in pieces... carbs, frame, 2 separate engines, exhaust, tank, etc. Ive decided I want to rebuild the engine as the top end has already been torn down, and clean/polish it while its torn apart. Where do I start with a rebuild? Im afraid I wont know what Im missing or what needs replacing once its apart, or that ill do some damage while tearing down. Any advice is helpful as i havent found any videos or anything that help my case. Ive got the motivation and the bike, all i needs some knowledge to help me get started. thanks!
Title: Re: Where do I start? (74' Engine Rebuild)
Post by: cxman on Oct 09, 2017, 07:59:16
most important question where do you live you could have a expert member right around the corner
Title: Re: Where do I start? (74' Engine Rebuild)
Post by: jgmunz on Oct 09, 2017, 12:01:58
Im located in Arlington VA, just outside of Washington DC. I know that Cognito Moto is down in Richmond, but aside from their suspension kits and other CNC'd parts, I havent looked at them as a resource. Not to mention they're far out from me.
Title: Re: Where do I start? (74' Engine Rebuild)
Post by: cxman on Oct 09, 2017, 12:23:15
devin does some motor work and sends some to me
Title: Re: Where do I start? (74' Engine Rebuild)
Post by: jpmobius on Oct 09, 2017, 13:02:22
Motivation is absolutely the key in my experience.  A little patience and planning should carry you as far as you want.  First, get an authentic FACTORY service manual.  While you're waiting on that, go through all the parts you have and start cleaning.  Catalog all your parts as best as you can and organize everything.  This will get you familiar with everything.  If there are mystery parts, don't worry, you'll discover their function as you go along.  Read the manual!!!  Most factory manuals are very thorough and well thought out, and reading through the engine section a couple of times will get you pretty comfortable with everything before you begin.  You'll also learn what you will need in the way of tools.  Set yourself up a spot as large as you can manage and clean it to at LEAST your highest kitchen standard.  A clean comfortable place to work promotes quality.  By far the most difficult skill to master is taking things apart without damage.  Old machinery can get very stubbornly glued together, so keep in mind that your first shot at taking anything apart is your best shot, and things can start spiraling the drain very quickly unless you religiously use the best quality correct tool for the job.  So get a set of high quality screwdrivers and wrenches and learn to use them - it's your best insurance against fastener damage. 

Don't make any modifications to anything and reassemble your entire bike and get it running and driving properly.  It is by far the quickest and easiest way to end up with what you want regardless of the level of customization or restoration you have in mind.  Once complete and up and running, most bikes can be disassembled down to the spokes in a day, so you lose very little work taking anything back apart to paint or modify it.  It may seem like a lot of work now, but you'll find that your bike is quite simple once you are familiar with it.  The second hardest skill to master is assembling it without scratching anything.  Practicing when there is no new paint to scratch makes it a whole lot easier to do a good job when the time comes.

So read the manual!  Take your time, clean everything and focus on one section at a time. 
Good luck!
Title: Re: Where do I start? (74' Engine Rebuild)
Post by: davidricci on Oct 30, 2017, 12:04:09

I've rebuilt 2 bikes relying heavily at times on guys here in the forum. There are You tube videos out there that are great, also as someone has all ready said, a factory manual. Patience, stop when you get too frustrated, ask the forum members to de-mystify anything you've read in the manual five times and still don't get. Use the internet to search for others that have rebuilt the same bike. Many have, and they documented the process with pictures, tips... Buy your parts from a variety of sources and buy OEM for the important parts.

Best! Have fun-David
Title: Re: Where do I start? (74' Engine Rebuild)
Post by: davidricci on Oct 30, 2017, 12:06:37
Hey, I forgot to expand on my relying on the guys in the forum "at times" comment. It's very important to learn your way through this rather than just ask each step of the way. You'll acquire skills better this way and be more self reliant. -David
Title: Re: Where do I start? (74' Engine Rebuild)
Post by: DesmoDog on Oct 30, 2017, 12:45:08
Step 1) Buy a service manual or two. Factory and something else. It's already been mentioned a couple times but it's worth mentioning again. And don't bitch that you can't find one free on the 'net. Spend the money if you have to, buying the bike doesn't entitle you to a free manual and that's not a good excuse not to have at least one. "What is this bolt supposed to be torqued to?" I dunno, what does the manual say???

Step 2) Buy a parts book. Maybe for Japanese bikes there are enough internet parts sites that have them online that you don't have to buy one, but in my experience it made life a bunch easier to just have one on my bench than to always have to search the internet for the right page.

Title: Re: Where do I start? (74' Engine Rebuild)
Post by: jgmunz on Dec 17, 2017, 22:15:31
Ive grabbed myself a shop manual and have flipped through it once or twice, but even with a basic understanding, I'm not sure what needs to be done to the bike. I bought it with the top end separated, and it had been sitting. The previous owner had planned to rebuild the top end and replace all the gaskets (which i now have), but i cant help thinking that for better or worse a full rebuild would benefit the bike and myself, regardless of the challenge it presents. Thoughts?
Title: Re: Where do I start? (74' Engine Rebuild)
Post by: echo on Dec 17, 2017, 23:51:52
I'm in the same boat, with my top end tore down now and only having done a rebuild once before.  A great resource for me has been online motorcycle course.  He is a funny guy and makes the reading fun.

For your top end job, You need to find out the condition of valves, pistons and cylinders.  there are tests and measurements in the manual that can help you evaluate this.  You will need micrometers (inner diameter and outer) to measure things.  If you dont have them, a local shop can inspect them for not too much $.  Once you know the condition of those things you can make a decision what needs to be done.  At minimum you would probably want to hone the cylinder, new rings, wrist pins and piston circlips.  Depending on what you find with the tests and measurements you might need to have a shop overbore the cylinder, you buy new pistons. There's a whole bunch of measurements to do.  On the valves, you probably want to replace valve guide seals and make sure the guides are good.  If the valves leak at all they may need to be lapped or even replaced.  once it's all clean (I mean really really clean) you put it together, make all connections (cables, electric connections, etc.).  You set valve tappet clearance and timing.  you should make sure your carbs are clean, air filter is clean, and have fresh ethanol free gas when ready to break in the rebuilt engine. 

To be frank, if you were not there when it all came apart and you are not experienced it could be a challenge to put it back together correctly.  Missing an o ring or dowel or something that you did not realize needed to be there could be a disaster.  But you can take pictures religiously and post them here as well as other forums, and real experts (unlike me) will help you along my the way. 8)
Title: Re: Where do I start? (74' Engine Rebuild)
Post by: echo on Dec 18, 2017, 00:01:25
Some other tools I have needed for my stuff in addition to the micrometers included:
-valve spring compressor
-feeler gauges
-piston ring compressor
-torque wrench

And I assume you have all new gaskets?
Title: Re: Where do I start? (74' Engine Rebuild)
Post by: jgmunz on Dec 30, 2017, 22:53:35
Yeah if it wasn't clear before hand, I purchased the bike with the top end already split. He claimed it ran before he began work, but as i wasn't witness to that I've been playing with the idea of a full rebuild for a while. I checked the link for Dan's Course and it looks like just what i need. I'm in no rush to complete the build as I wont even be able to ride the bike for two years.(I'm still in high school) This is shaping up to be the project i dreamed of. My plan as of now is to send the course link to my build buddies, read it myself and decide afterwards whether or not i want to take on a full rebuild. I think it would eliminate any doubt on whether the previous owner did anything sketchy and give me more knowledge on the machine. Ill post some pictures at some point soon so everyone can kinda see what i see as a complete novice.
Title: Re: Where do I start? (74' Engine Rebuild)
Post by: echo on Jan 01, 2018, 01:07:36
High school? Wow I would have given my left locknut for a 550 at 16. 

Don't know what you have done so far but I would start by identifying each loose part - the shop manual with diagrams will help.  Any that you can't ID, just post photos here and folks can help.

A critical step with a partially disassembled bike I think is finding what's missing.  Hopefully not much.  Again the diagrams in the manual are your map to this. 

As you disassemble things, use your impact driver to avoid stripping bolts.  And take photos at each step.  As I remove parts I  try to think about directionality - could this be accidentally put back in backwards?