It's all done! And it works! Imagine that? After muddling around for months I can finally drive the damn thing.

Sure looks better than it used to. Of course, now I'll have to maintain it. One note of interest for all of you 650 fans who for whatever reason may be considering a rebuild, it still runs like a 650. I mean, yes, I'll say it definitly runs better and smoother and has a ton of more power. But, even with the carbs synced, the valves adjusted, and the cam chain adjusted the thing is still noisy. That stupid cam chain has a slight rattle, and I was hoping it would have gone away with all new parts. And it still takes forever to warm up, and you have to play games with the choke to keep it running.

Oh yeah, and it still smells like burning paint when it gets hot. The paint has held very well, but man does it stink. Actually it's almost gone now. That's it for now. There are some previous assembly pictures below. Other than that I keep this page updated as stuff breaks. (it will) :-/

Here the pistons are patiently awaiting their new home in the overbored cylinder. (Can you tell I've been working too hard on this bike?) Make sure the gasket surface is clean and the ring gaps are spaced 120 degrees apart. What I then did was took the cylinders to the sink and scrubbed them with dish soap and a relatively lint free rag. After drying them you can put a very thin film of oil to keep corrosion at a minimum, although if a little surface rust does form it isn't a big deal as the rings will instantly scrape it off and dissolve it in oil.

The flash on my digital camera certainly makes the engine appear more shiny than it is. Heck, it's almost blinding to look at in this picture. I didn't have the crazy Honda piston ring compressors needed to do this, so I had my father help hold the sleeve as I compressed the rings with my fingers. It was pretty bad, but not as horrible as I thought it would be.

So close but so far away. Was supposed to be finished when I took this picture, but somehow I managed to lose one of the cylinder head bolt washers. I decided not to try to substitute anything, as any variance in depth or hardness of the washer could effect the bolts holding ability. This sounds pretty wild, but I didn't go this far into a project to find out the hard way. Anyways, the aftermarket rocker cover gasket was almost an inch too long(?) so I decided to order one from Honda in the mean time.

Crap. Well, it was almost done. Somehow a substantial amount of dirt placed itself in the head bolt threads (yes, for now it will just be the dirts fault) so I will have to hold off on the final assembly until I can get an 8mm thread chaser to run through them. If I can't find one in a reasonable amount of time, I'll just carefully use a common tap, but that's not really a great idea because a tap takes off material unlike the thread chaser which is slightly undersized. The last thing I need to do is pull a thread in the block, so I'll just take my time and do it right.

And in the meantime I'll just stare at what I could have been driving with the amount of money I've infused into the CB. Although I don't think I could afford insurance on the ZX-12R.

SPECIAL TOOLS:

You will need a special tool to remove the clutch called a 4-pin spanner socket. It is Honda P/N# 07716-0020203 (KS 1L 26X30) and it costs around $28.00. You can supposedly obtain an aftermarket one for around $10.00, but I can't find the right one. My local shop let me take one home for a $20 deposit, so it doesn't hurt to ask. Other people have used a chisel and hammer in the groove of the bolt to get it off and on.

The Honda manual says you need a circlip remover and a slide hammer to remove the drive gear off the primary shaft for removal. I didn't remove the gear. If you are careful you can work a 10mm wrench behind the gear and slowly remove the bearing retainer bolt. Once it is out, the entire shaft with the gear can be removed. You may want to remove the gear anyways, because it will be hard to tighten the bolt back down, and impossible to get a socket on it for a torque wrench if the gear is still in the way. If you don't have a circlip remover, you will have a massive problem trying to get it off.

You will need a strap wrench to hold the rotor in place while removing it's center bolt. To actually remove the rotor, you will need a flywheel puller. Some people have said that you can use the rear axle shaft from the bike to thread into the rotor and do the same job. This is up for grabs, because the first time I tried it I ruined the axle. (Fortunately it was lent to me by the salvage/parts shop I bought the rotor from). The next time I did it, I used my own axle, but instead of tightening it all the way I threaded it in, and took a hammer to the backside of the bolt flange. This worked like a slide hammer or dent puller does, and it was successful. Diagram of this here.

CRANKCASE SPLITTING:

The old gasket maker may give a bit of struggle when separating the crankcase. DON'T pound on the area where the rotor and ignition advancer is, the walls are very thin there. Make sure you use a rubber mallet, or hammer wrapped in cloth and pound lightly. The best area to pound is the back of the transmission, there are large cast flanges here. These flanges are also the ONLY area I can see as acceptable to pry on, because they don't seal the case. SEE PIC BELOW.

Now, the Honda service manual says that it is unnecessary to remove the rotor to split the crankcase. THEY ARE WRONG, WRONG, WRONG!!! (did I mention they were wrong?) I was about to strangle my cat trying to figure out why the crankcase would not separate all the way where the rotor was, because I believed the book. REMOVE THE ROTOR FIRST or it will hold the top half of the crankcase down!!!!!!!

VALVE LAPPING:

I made a pictorial example of how I lap valves here. (***NEW***)

OTHER TIPS:

• Oil Pump:
  • Honda for some reason decided to affix the oil pump to the case with philips head screws. Please make sure you have the right bit or you will positively strip these. Even with the right bit you may strip them because they will be stuck to some degree from age. I had to slot two with a dremel for a flat head screwdriver and the other I managed to get out with a vice-grips. My advise is to replace all stupid philips head screws with smarter allen head bolts.
  
  
• Valve Cover:
  • When you remove the valve cover casting, make sure you keep all of the bolts in order. There are 22 of them, and some are different lengths.
  
  
• Timing/Primary Chain:
  • If you are just removing the cylinder head or the cylinder skirt make sure you suspend the timing chain, or it will fall into the case. You may be able to recover it, but you'll have a hell of a time trying to get a bolt or washer out, so stuff a rag in the hole. Also, if refitting the same chain onto the motor (timing or primary) be sure to install it the same way it came out. These chains develop a directional wear pattern, and if installed backwards after being ran in it can cause abnormal stress on the chain.
  
  
• Support the Crankcase:
  • When you decide to split the crankcase, you will have to remove six bolts from the top half. (remember to use a criss-cross pattern) Then you are supposed to flip the entire case over. The rods will be hanging owards the ground so use blocks of wood under the case to keep the rods free floating. Make sure that the timing chain is out of the way and not being sandwiched between the block and your support wood block, or you may scratch the cylinder sleeve mating surface.
  
  
• Rebuilding 101: Keep parts in order!
  • All of the bearing inserts are unique, and color coded on the side. DON'T just take the connecting rods off and throw them in a pile, they need to go back in their original spots, because over time they develop unique wear patterns. This goes for the pistons, valves, rockers, and just about anything else you can think of.
  • When inspecting the gears, look for rounded teeth. Pull both shaft assemblies out and check out the shift forks. The pads shouldn't be excessively worn and there shouldn't be any wear marks below the tips.
  • The transmission bearings usually last for a long long time. They are constantly under oil pressure (you did keep oil in the engine, right?).
  • Now is a wonderful time to replace seals. After 20 some years these will rot out and leak so just do it. A complete aftermarket set is about $70, Hondas gaskets are a lot more.
  • Don't "mirror polish" your gasket surface on the crankcase or anywhere else. If you look closely, you will be able to see the machining marks on all the gasket flanges from original production. If you polish these surfaces you will have oil weeping and leaks. The gasket maker needs some roughness to properly adhere itself. The finish you get from using a gasket scraper is preferred.
  
  
• Other Tips:
  • Take your time! Read the books and ask questions before winging it and breaking something.
  • Don't get off to a bad start with your new friend aluminum.
  • Don't overtighten bolts, they will easily strip!
  • Watch the cooling fins, they can break if you look at them too hard!
  • Use crisscross and 3 stage bolt removal methods for everything you can to avoid warpage.
  • The crankcase is mostly a thin wall design, it's unrepairable if you break it.