Topic: Well I'm back with a new project.

[westhewelder]

Hey guys been a long while since I've been on this forum and I'm back with another bike a 79 cb650 this time. This time I've come prepared with 7 years of weldering  fabricobbling and mechanical know how, mind you that's a drop in the bucket in comparison to the fine folks of this forum and that's why I'm here to post my project and learn with you guys. Now let's start the pictures. Here is the bike and some inspiration I'm taking cues from.

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[SOHC4 Cafe Racer Fan]

Welcome, irishcafe.

I assume that your bike is the one without the motor in the lower right.  If so that looks like a 1979 frame - much less "cruiser" than the 1980-82 models, and more akin to the CB500/550 frame geometry. 

There are SEVERAL 650 builds underway and a few with performance upgraded motors (all using a Dynoman 674cc big bore kit and different combinations of other parts) swapped into 550 frames: 
DaveBarbier
SOHC Café Racer Fan (mine)
camrector
sinister902 (Nick Edsell)
GV1390

Rustyolive did a simple transplant of a stock 650 motor into his 550

Paulages did a more complicated 550/650/750 component build

If you are contemplating an engine rebuild for higher performance, check out the Dynoman 674cc kit and (perhaps) Megacycle 126-20 cam

CDI boxes are known to sometimes fail on these bikes, so you might consider a C5 electronic ignition.

You can download the service manual on the site, as well for parts diagrams, specs, assembly/disassembly instructions, service guidelines, etc.

[Stev-o]

Ferrari?!

[westhewelder]

Not my Ferrari and the color is the inspiration gloss cabernet. I'll have to take a look at the build my engine is already blown apart. So a big bore might be the way to go

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[Bankerdanny]

Welcome back. I look forward to observing your journey.

[westhewelder]

Thanks man things have come so far with aftermarket parts and availability of parts it's amazing.

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[westhewelder]

So tonight was my first chance to start diving into everything I started by stripping and doing the old bag and tag on all the parts I'm going to keep sell and toss.

Next it looks like the motors been kept in a barrel of 40 year old oil so I started cleaning up and top end.

As the bike sits it just figuring out seating/riding position unfortunately the old seat won't help me with that especially if I'll be going to a brat style seat.

While we're on the topic of parts does anyone have any good website(prefer canadian) that you could suggest for aftermarket parts for this year of bike? Our local bike hoarder passed away unfortunately and he was our biggest supply of old parts.

[Stev-o]

Have you heard of Vintage CB750? Not sure how many parts for [red headed step brother] 650's they have?

They are in Ontario...




http://www.vintagecb750.com/products/86/new-items

[westhewelder]

Looks like they have plenty of stuff appreciate it. I remember ordering from them before total forgot about them.

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[westhewelder]

So not here's the fun part I'm not an engine guy and I bought this with full intention of putting the motor back together. The bottom end is still all one piece and this thing was caked in grease. If I pull this apart simply for a clean up and inspection as long as everything goes back where it was theoretically it should be fine If everything looks right?

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[westhewelder]

So I was taking a look at the bottom end and it seems like it's only really in need of a good clean up. Everything turns smooth but I feel like changing the drive chain and cam chain would be a good idea.. So I'm going to go ahead and order those along with a gasket kit and piston rings. Before the the cylinders need to be cleaned looks like honing is order at minimum.

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[Stev-o]

So I'm going to go ahead and order those along with a gasket kit and piston rings. Before the the cylinders need to be cleaned looks like honing...

You really need to accurately measure the bores to determine if they are within spec and just a hone and rering is sufficient. 
I typically let my machinist do it...

[westhewelder]

Well came time to do the worst part first I guess and that's clean up all the parts. Bought a small parts cleaner and just going to town with music.

Also found some used parts locally drag bars like new rear shocks and some pod filters for 100$

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[westhewelder]

So honed the cylinders and the current rings only sit .1 mm over factory. So will probably just clean up the Pistons and rings and re-install. Going to go all new gaskets but I need some advice should I touch the bottom end if everything seems OK? Or should I just scrub off the shmoo and reinstall the top end? The only thing that might bite me later is the drive chain and came chain.

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[westhewelder]

Par5s starting to get polished

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[SOHC4 Cafe Racer Fan]

So honed the cylinders and the current rings only sit .1 mm over factory. So will probably just clean up the Pistons and rings and re-install. Going to go all new gaskets but I need some advice should I touch the bottom end if everything seems OK? Or should I just scrub off the shmoo and reinstall the top end? The only thing that might bite me later is the drive chain and came chain.

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If you're that far along (out of the frame with the top end completely off), why not check the bottom and change the primary and cam chains?

[RAFster122s]

Checking clearance on crank bearings and renewing seals and inspecting or replacing ball bearings would be prudent if you are not wanting to be back inside the motor for 8-10 years or more...

Saving a bit more now and delaying completion now for that would be more cost effective in the long run.
If you intend to keep the bike a while...

[SOHC4 Cafe Racer Fan]

Even if you are going to flip it, it will flip easier if you've been through it and it does not leak or slip out of gear, etc.

[westhewelder]

Oh knowing how I am even if I keep it the rest of my life it won't be the last time it's rebuilt and revived. I have a tendency to buy and sell projects but I'll probably keep this one. My motorcycle mechanic buddy would strip his bike every three years and do a full overhaul just to give it a look over.

A lot of the modifications I'm going to have a hard time with as well we have pretty strict laws on modifications of frames and light must be dot certified etc. So I'd like to just get it on the road get through the inspection and then do the final build of what it will be.

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[westhewelder]

So this weekend I'll be working on the general mock up and painting parts taking inventory also working on the tank. Getting it cleaned up and ready for paint. Didn't pick up the exact color I wanted but decided to go with a bit more metal fleck. Hopefully I can get the tank painted tomorrow. And the constar rims are growing on me.

Where does everyone tuck the battery and wiring for that open look?

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[RAFster122s]

The non reversed Comstars look much nicer I think.   They are a cleaner look.  There were some of those which used aluminum "spokes" instead of the steel ones.  With a lot of work they can be sanded and polished to a high brillance that looks fabulous.  Once done you just need to touch up the polishing if you keep them clean and the bike isn't outside all the time.

While it takes many hours to do this you will really like the results of polished spokes and rim. I can send you a link showing the process Larry Cargill goes through to polish a set as the clear coat on the aluminum needs stripped and the silver or black finish has to be removed as well.  He shows the tools he uses to do that work. It is dirty work, but you would have the satisfaction of it being very unique with very few wheel polished like it.
Additionally, the aluminum spoked units are far lighter as well, reducing the unsprung weight of the wheels.

[SOHC4 Cafe Racer Fan]

Electronics in an electronics tray under the seat, and battery in a seat hump are common locations.

[RAFster122s]

Sometimes people put the battery under the swingarm when they delete the center stand...in a heavy metal box to protect it from a road strike if something is thrown up at it.

[SOHC4 Cafe Racer Fan]

Sometimes people put the battery under the swingarm when they delete the center stand...in a heavy metal box to protect it from a road strike if something is thrown up at it.

I cannot speak from experience but I wonder if all that movement on the swingarm is a good thing for the battery and connections.  Just curious . . .

[RAFster122s]

I don't think on bottom of swingarm is a good place personally, but I have seen it done.
The Lithium batteries, more seem to have issues with Antigravity rather than Shorai, if you go for a new tech battery.  A battery management board installed to control the charging and discharging is a good idea.  They normally use the Lithium Iron Phosphate type cells which each cell is individually a metal cased cell NOT known for causing fires, the Lithium Polymer cells are responsible for many fires when abused or overcharged...

Lithium battery fires burn very hot and are difficult to extinguish...some say near impossible and they often splatter flaming material all over near the battery... 

AGM batteries are a good alternative  to tradional wet cell lead acid and since a 650 doesn't have a kickstarter you do need one with some capacity.  Fwiw, what I have learned following along...

David