Topic: Slowly - CB650 Custom 1980

[Azzarius]

I've had been looking for a mechanic project for a little while when a friend of mine suggested I rebuild a motorcycle.  The idea behind which ever project I was to choose was to learn mechanic a little bit.  So here it is, about a year ago I bought an almost/mostly running Honda CB650 Custom 1980.  I have been working on it for a little while(maybe an 1hr every 2 weeks; life usually gets in the way).  But the plan is to be able to ride it next summer or so I wish.

[SOHC4 Cafe Racer Fan]

That's a good project -- it's all there and the motor looks sanitary (airbox is intact, too).  Are you going to keep it stock or slim it down?

[Azzarius]

It's going to be a slimmed down version of that bike for sure.  It's not a style I like (the original).  I'm starting the blog about one third of the way in the project.  I'm going to try to post some of the stuff that I've done so far.

[SOHC4 Cafe Racer Fan]

More than a few of us have rebuilt/modified 650 engines. 

The 650 motor even stock is a significant hp and torque improvement over the stock 550, and only a couple of lbs more.  A few of us have installed or are planning to install 650 motors into 550 frames since they fit into the same mount points (with no mods).

Your model 1980 also has the same carburetor spacing as a 750 so you can go with larger carburetors if you decide.

The 650 air assisted forks were a neat idea but don't hold pressure too well, and the fork length is a little long -- for a cruiser stance.  The 650 frame was smartly designed with a bolt in/out frame tube to ease pulling and installing the motor.

[Azzarius]

Hi, it is true that the fork are awfully long on that bike.  I will have to lower it a bit to have a line that is much lower and make sense with the look of the project.  I will try to keep the original fork as I want to keep the expenditure as low as possible.

*******

Issue with charging system
Initial issue(s) I had with the bike.  At first the bike started well with a fully charged battery but after riding it for an hour or so the battery seemed to be depleting(the head light is always on).  I started investigating the issue and found out that the resistivity of Rotor was too low.  In reading about these bike it seems that the outer left exhaust pipe is a bit too close to the stator/rotor box and heats is up shortening its life expectancy. 

From the literature found online, it was likely that in failing(the rotor) that the R/R would also fail.  In doing the basic test on the R/R I found that it was actually burnt.  So I've changed both (Rotor and R/R) that after I changed the battery first without even looking(could have spared myself 80$ by keeping the old battery). 

One other little thing I found is that, on the left tri(under the seat), the place I should have had a 30A fuse was replace with a Bolt.  So whatever that fuse was meant to protect, the bolt wasn't doing it.  So I've installed a little 5$ fuse socket and installed a proper 30A fuse.

Once I've changed there, the charging system seemed to be working properly and keeping the battery full.

[rb550four]

   When coming up with a plan with any 650 , I 've found the handlebars to be a real stumbling point. It came from the factory with them so you figure that's the style and it must be good.  But something seems a little off with the entire design, forks too long,  seat  too low, tank too slanted.  Something needs changing.   Change out those ridiculous stock bars, I've found,  it'll make you feel better instantly.
   
   I read that this is your first bike mechanical project,  are you a new rider as well?

An hour every two weeks to devote to this project?     That's funny.
 Once you get past the idea stage and get your feet wet, you'll  be making more time for it somewhere . Happens all the time.

  The condition of your project machine is a very nice place to start and more first timers should start with similar. You'll see much progress in short periods of time with realistic goals, depending on your skills.
 Shop manual- must have.  Required maintenance schedule, do . Depending on the scope of your plan , you could enjoy riding it between  short term goals too. Nice project.

[SOHC4 Cafe Racer Fan]

Good advice, RB.

If you haven't already done so, download the factory service manual (pdf), print it and put it in a 3-ring binder for your garage.  The one on the site is for a 1979, but basically the same (including the head).

http://www.sohc4.net/cb650-manuals/

[Azzarius]

HI Guys,
Yes it is my first project.  I do ride as well, I have another bike to ride.  I started with the project before even getting my license.  The goal was really to learn and to have fun learning.   

Fuel Tank
For the tank it's true that of all tank, it's one ugly one.  It's like you said, too elongated where it attach to the frame.  I like the tank for the years before where it was more "square".  For that I will look to may be using an older one if I can get my hand on one that is not in too bad shape for a decent price.

Handle bar
For the handle bar, I've bought clip on.  I've done some dry fit to see the look and it's not bad.(I have some pics but the frame wasn't complete at that point). 

Tail
For the tail end, I've cut the frame and bought a rear hoop from harrisuluv(he is one of the user on that forum and I got a piece that was made perfectly to fit my frame). 

Seat
For the seat, I have made a seat pan, still have to put foam and fabric cover.  I still have some hope to get a tank so I'm holding on putting too much time on it as I fear a different tank will force me to change the shape/length of it.

Now, I've spent most of the winter taking the whole bike apart.  I've put all bits and pieces in little ziplock bag with tags so I can remember where the parts go.   

[Azzarius]

Oil pan
Oh, Now that I think of it another hiccup with the bike was that it leaked oil from underneath.  It turned out that the oil pan drain plug, well the hole has little to no thread left, thus leaking oil.  I've removed the pan, cleaned it up, pierce the hole from 12mm to 14mm and re-thread it and bought a new oil plug 14mm x 1.5.

[Azzarius]

front brake
Another one of my good idea was to remove the front wheel and press the brake lever.  The disk not being there, the two brake pad got pressed together and stayed there.  Another one of those moment where I thought to myself that I was an idiot to have done that.  So I've took the assembly apart.  Had a really hard time getting the piston out.  I've tried with channel lock to pry the piston out without success.  Then I've read somewhere online that with compressed air some people were able to get it unstuck.  I did just that... BOOM, the piston flew through my garage like a bullet.  I was lucky, I was alone and the piston wasn't pointing my way.

Cleaned all the parts and changed the brake fluid.  It was orange (probably rust).  I've also learned that brake fluid is not nice too any painted surface.

[rb550four]

According to Hotwheelbill
http://forums.sohc4.net/index.php/topic,145892.msg1659927.html#msg1659927
an early 750 tank fits like a glove. I haven't tried it yet, but next time a 650 comes along round here, Iwant to try that 750 tank out.
http://forums.sohc4.net/index.php?action=dlattach;topic=145892.0;attach=286748;image

[SOHC4 Cafe Racer Fan]

I like your seat pan.

The 79 fuel tank looks much better. I wasn't aware that the early 750K tanks fit, but if so that's a great idea!

[Azzarius]

Build/Restore order
I'm not sure if there is a special order in which One should attack such project since it's my first one.  In my case, I feel that I might be taking longer than I should because I am/was intimidated of starting on certain parts/system.  So I messed around with smaller bits and systems that I would take apart and put back together to ensure it is still working.  It took a while before I started working on the engine.

Documentation
Some mentioned to get documentation.  So I've downloaded what seems to be the maintenance manual for the bike.  It tells me, all the part, how to take it apart, put it back with the proper torque, service specification, etc... I also found another manual that is a bit more than just that, it does help when the service manual falls short.

[Azzarius]

Frame
It's been mentioned above that the frame can be split to remove the engine.  It's true and I think it might make it easier to get it out(even though I had some trouble doing so).  Once the engine was out I used angle grinder to remove all the paint from the frame and some paint remover spray for the little nook and cranny that I was not able to reach.  I also cut the tail as it was too long and too high.  I took some pic of the frame to which I put back the wheel and the tank to have an idea of how long I was going to install the hoop.  I only have pic of the full loop(not cut) with the whole bike.  The cut version is only a close up.  Now I've removed all bits and pieces from the frame, modified the tail and painted it. The frame is black but I only found pic of the primed frame.

[Azzarius]

Engine
The engine is the main part that I didn't know how to attack.  So I've poked around removing little covers left and right, looking underneath, trying to make sense of all of it and taking tons of pics to make sure I would be able to put it back together.   The always scary part is that I was afraid to break something... and so it happened.  In removing the long bolts that holds the cylinders and valves(it is 2 parts) to the crank case, I snapped a bolt.  I did spend about 4 weeks poking around at it with WD40, blow torch, vise grip, pipe wrench, hammer, to finally realisez that I would have to use a screw extractor(I really didn't want to have to go there).  So pierced the bolt right in the middle and ... SNAP, I snap the drill bit in the bolt.  I was lucky in my bad luck, the bolt was sticking out about 1.5cm, and the drill bit snap flushed with the bolt.  So I used a dremel to cut to bolt around the bit to be able to get the bit out.  It did work.  Then I made bigger whole, then tried the screw extractor with no luck.  Then I bought some tougher WD40(orange stuff ; with more penetrating power) and left it there for another week or so before gathering enough courage to try to go at it again.  Then decided that I was just going to drill a bigger hole, make new threads and use a bigger bolt, that day the bolt came out almost with my finger.  I did some damage to the surface when the crank case and the cylinder meets.  Hopefully the gasket will take care of it.

I then went on to clean the parts and prep them for painting.  One part that took more time than expected was the painting of the crank case (This one I kept it whole; I didn't took it apart... maybe on the next project if this one succeed). I wanted to crank case to stay grey/silver but I still wanted to paint that color, so I've bought what I though would be silver.  It turned out to be blueish silver.  So I realized that it was going to ugly because there would have been to many colors(Pearl black for the covers, chrome for the metal one, blueish for the crank case, and red for the caps).  So I ended up repainting the crank case a second time Pearl Black.  I am very happy of the result.

Once all my parts were painted I tried putting back the cylinder head on the piston.(I swore), I didn't want to buy the piston gasket holder so I used a can of Coke and some tape(0.50$), I've heard once, if it works it aint stupid right =-) and it did.   The last pic is a "fake" one.  I still have to align to cam, I am 1 chain link off the right pos now.  But I just sat the red cover to take a picture to see what it would look like once finished.

So from all the post above, this is now where I am with the project.  The update will start coming more slowly now as it will be the real pace at which my project progresses

[SOHC4 Cafe Racer Fan]

I think you might still want to deck the mating surface of the crankcase, where it meets the cylinder block.  Otherwise you may have a weeping base gasket.  It is important to keep mating surfaces clean and FLAT.

Other opinions?

[rb550four]

The digs don't look too deep in the picture from what I can see from here, but there are some high spots at the ends of the digs and threaded hole that could take a little flat file just to knock them down....the gasket should take care of that I would think...if that damage was on the top of the cylinder head and any deeper I would certainly say decking for sure. No one likes a blown gasket or a weepy head.

[Azzarius]

Hi guys,
good to hear, i did scrape all the high spot before putting the cylinder on. 

Cheers

[rb550four]

Az, was that first crankcase paint  transmission paint? I did that once by accident too. Your new paint looks good...red paint, don't like a buffed finish on the tops? Buffing isn't for everyone, just more stuff to polish, I get it. Lookin good.

[rb550four]

  Okay , I was looking at all that silicone all over the upper gasket...I thought I would ask, you are using new gaskets right?
 Also I was wondering, was the engine taken apart, just to paint it  or did you suspect something was wrong in there? I know you were getting us up to speed on your progress and maybe thought the pictures of valve seals, o rings , cylinder hone, new rings ,and stuff like that would bore us. It doesn't.
Please tell me that you are using all new gaskets...or you'll be hating doing it twice. Although it's not the favorite learning technique, what  you discover the second time round will stay with you.
 Sorry, while I'm at it, I have to ask if you have access to a torque wrench, I've seen newbs that think they can put on a head without one,  it can't be done without one.
  I ask these questions not to torment you, be a know it all or police you. I ask because I'm interested in your project and would like to see you successfully complete it with as little headache as possible. Wrenching a cycle should always be fun.

[Azzarius]

Hi rb550four,
The paint I used for the crank case is VHT high temp paint(can ;very cheap 15$).

cheers
 

[Azzarius]

hi  rb550four,
For the gasket on the cover, I wasn't planning on buying a new one, I tought that if it work for the previous guys to use that orange stuff that I would reuse the same.  Anyway, at that level, I don't think there is much pressure anyway(I might be wrong though).  I did take it apart to see if there was something wrong(wore down, etc..) with it or not.  It did make it easier to paint too.

I've bought new gasket(between the crank case and the cylinder).  The top one, I've re-used to old one(new ones are very expensive +-100$).  I'll try too find pic of the inside then, I know I have some.

I do have and use a torque wrench following the recommended values in the maintenance book. But I'm so scared of snapping another bolt that I used the low value. Ex. they were asking for 17-22lb/ft for the head and I've used 17lb/ft.

cheers

[Azzarius]

TripleTree
I'm now trying to start putting thing together.  So I first need to fix the triple tree issue.  On the original bike, the bearings were individual little beads.  I don't want to go back to that. I would like to use Tapered Roller Bearings.  Something similar to that:

http://www.dimecitycycles.com/vintage-cafe-racer-caferacer-bobber-brat-chopper-custom-motorcycle-steering-parts-honda-cb-cl-all-balls-steering-bearing-neck-kit-122-1011.html

I still have to remove the old bearing socket.  I've seen another thread on that in this forum and I will try to get it out.  I'll keep you posted on the progress.

Cheers

[Azzarius]

To answer rb550four,
Here are some pic of how the cylinders looked from the inside:  The cylinders looks pretty good and so does the piston and rings (or so I think)

[SOHC4 Cafe Racer Fan]

However they look, I presume you will replace the rings?