1982 CB650SC Project Bike

[carpenter183]

Just bought this bike yesterday! The seller told me it had an electrical problem. No power to the ignition. The seat is gone, the tank is rusted out and I mean holes and all. Looks like the starter solenoid was "borrowed" (stolen), but the Odometer has just over 11,000 miles, so maybe there's some life left.

I am new to the Nighthawk family, but looks like I will be spending the spring getting this bike back on the road. I know its going to be a huge undertaking, but hopefully I will learn a few things. Any suggestions & advice are welcome. I will try and post pics as I progress.

[WingNut]

  Looks like you got a couple of projects going on back there...looking forward to seeing that NH come together.  That Blue, Red and Silver looks pretty slick 

[JB1290]

  to the forum. Looks like a great platform to start with.

[Bumblebee]

No power to the ignition? If that's true, check the main fuse. It's probably corroded to dust by now. If you get ripped off bigime, that fuse is 25 cents.

[fortyhourdays]

   Where do you call home?

[cmbutn2]

I have a buddy who replaced a starter solenoid with one from a lawnmower for substantial savings. He just found one with similar specs to the OEM one.

[carpenter183]

The more I tear in to this bike, the more I am thinking its not going to make it.

Check the carnage



Chain damage. I wonder if that bolt is removable after almost being decapitated?







Notice the bike was laid over pretty hard and damaged the stator.



This tank might as well drain spaghetti



I paid $180 for this bike. I figured the parts alone was worth that, but I don't know now!

Any hope?

Carpenter

[Munkey]

Yeah, unfortunaltey most of your high demand parts like side covers and tank are missing or no good. Not sure how much engine parts can bring. If the carbs are still good, you may be able to clean them up and get some cash out of them. If the exhaust pipes aren't too bad, Bumblebee's been looking for those.

[TDodge7]

I've fixed up worse , just concentrate on one part at a time , it could live again .

[JB1290]

I too have seen and rebuilt much worse than that but, it all depends on how much work you are willing to put into it.

If nothing else, you could easily clean up and part out the bike on Ebay. You can easily make your money back from that.

[Bumblebee]

Someone rode it with a very loose chain and likely had a break at some point. Check for wear damage along where the swingarm where the chain crosses.

As noted, stator indicates crash damage. Probably 30+mph crash or a quick stop against something stationary. Check for frame and steering head damage.

The exhaust pipes are typical failure for these pipes. You can pull the hardware out and reweld it easily enough with a new piece of pipe. (sorry, I won't be after those since mine are in the same condition)

The seat can be rebuilt easily enough including making your own seat cover.

If nothing else, get it started or know absolutely why it won't. If it'll run, I'd say it's very good candidate for a rebuild or at least getting it roadworthy again.

[carpenter183]

Do you guys think the gas tank can be repaired? I will be looking through the parts fiches for compatible parts on other year models, but do you guys know which years are compatible?

Carpenter

[HandsomeSteve]

I've welded tanks before.  However, make sure there is NO gas residue left in it.  Also if it's already scaly inside you better off sourcing a tank in better condition rather than putting all the effort in to a tank that will continue to be a problem for you.

[Bumblebee]

Anything is repairable given enough effort. Is the bottom of the tank the only area that's rusted like that or are there other areas that are too thin to be reliable also? That much damage requires welding if it's done right. Since it's 3.6 gallons sitting directly above the engine, transmission and exhaust, it needs to be done right. I'd cut the entire rusted section off and weld new metal in place.

I'm not sure what years would be compatible for the tank. The 82 SC tank was a single year. It might have been used on the redesign in 83 though I'm not sure about that since the other changes were pretty extensive. The 79-81 is a different style tank and uses different mounting points. You can probably mount a standard 82 CB650 tank though finding one is not easy since there aren't many around (I;m beginning to think I may have the only one actually since I haven't seen or heard of a standard CB650 actually around in the last 16+ years) and it's not the same design so the side covers certainly won't line up.

[carpenter183]

UPDATE....Ok everyone, sorry for such a drought, but life happens and you get busy with other stuff.

I have bought several parts off of Ebay. These were parts that were missing from this bike and needed for completeness, or damaged beyond repair.
Purchases: Chrome chain guard, Honda fork emblem, used complete tank(black), used seat, new battery (Interstate), starter solenoid, and rear tank rubber.

Some good news... I hooked up the battery and most of the lights work! The turn signal relay and headlight isn't working though. I squirted some starter fluid into it and it cranked up! I had the stator/cover off and the oil drained, so I only tested it once to see if it would crank. I haven't even cleaned the carbs yet, just drained the old gas out. As you can see in my previous pics the stator cover (cap) is heavily damaged. Everyone wants a *mint* for  used/replacement stators and covers. I am still debating over weather I should buy a new stator cover since the one I have is damaged, but I am thinking of finding a good welder to repair it. What do I have to lose? I don't know if it will work or not.

I bought the black gas tank because of how great of condition it was in and its rare to find a built-one-year-only original tank.



There was virtually no rust in it.



The seat I bought was in great condition too




I do have a problem now though, a blue bike, and a black tank. I have thought about getting it painted to match the original color blue. This would also mean I would need to buy new graphics too...hmmm. Once I get the mechanicals all working good, then I will start on the cosmetics.This is still a work in progress so I hope to keep you guys updated. There are still many things left to do to this bike! brakes, stator fix/replace, electrical system, exhaust, etc.

Any advice is welcome.

carpenter

[Bumblebee]

I haven't even cleaned the carbs yet, just drained the old gas out

Be extremely careful of the air-t-connectors between the carburetors. They're brittle, spendy and requires dismounting the carburetors from the racks to replace.
If you do find yourself having to pull the carburetors off the racks for any reason, replace the rack bolts with hex head bolts and torque the rack bolts to the book numbers, no more and no less. I also have a couple threads stickied in the fuel cooling and exhausts systems subforum that you will find extremely useful.

[NightHawked]

Good advice so far. I would suggest putting your money into getting it running and see where you are at. Then move to the next big thing, and see where you are at. Tank looks great, just keep an eye for any rust before it gets to bad. Miles are good, but not the only consideration. Keep us updated.

[carpenter183]

Oh the woes of the filter bolt... This filter bolt was already in bad shape from a previous "rounding", and of course it would not come off! I tried and tried but I ended up chewing the end off with my vise grips (not recommended I know) . Now I'm having to cut it out and ruin the filter housing.



I have a new bolt and housing ordered from ebay. Any tips on removing this without catastrophic damage?

Thanks,

Carpenter

[Bumblebee]

As you learned, NEVER EVER use vicegrips on such parts. Vice grips are known as bolt head rounding tools for a reason. Vicegrips are clamps, not wrenches.

The actual threads are deep inside the cover at the engine case itself.
Blast the flange area with penetrating oil. Tap  lightly with a hammer. Let it sit overnight. That will help loosen the outer flange a little.
After that it's into fun stuff.

One option: That bolt shaft is hollow after a certain point. I can't recall how far in at the moment. If you can drill through the top of that bolt head before you round it into nothing, a big easy out should back the bolt out.

But don't grab the sawzall quite yet though.

Last resort nondestructive option once every other option has failed miserably and the head is trashed beyond hope: Take a grinding wheel and very carefully grind the remaining head off. Grind the flange of the bolt off down to the housing surface and no further. You want the flange to be completely removed. (Do not be a knuckle dragging neanderthal while doing this) Once the flange is completely gone, hit the cover with a rubber mallet up and down a few times then pull the housing straight off. If you do this carefully, you won't even damage the filter housing. Then it's just a case of spinning the old bolt out, cleaning everything thoroughly and you're in business again. I've actually done this successfully on two other engines (a motorcycle oil housing very similar to the 82 CB650 design and a tractor engine part) without a problem.

[carpenter183]

Ok, I finally got the filter bolt out. Now, I see something fishy.






Could this be a crack in the block? I could scrape my fingernail and catch both ways. Has anyone seen this before?  It doesn't seem to go further than what you see here. Could this be a crease in the casting?

Carpenter

[Bumblebee]

Not enough information. Can't tell.

Is the apparent crack into the surface or up above the surface?

Sometimes there are similar marks like that which were left behind when it was cast.

It could also be that someone cranked the living crap out of the bolt too and physically damaged the case.

[carpenter183]

Thanks Bumblebee,

I believe its just the casting surface. Not cracked.

I put fresh oil in, new gas, and cranked her up. I looked down and saw gas pouring out of the carbs.  I only have one cylinder going because only #2 head pipe was hot. I knew the carbs needed cleaning because when I drained the old gas out, the old fuel was very green in color. Bad I know. The gas seemed to be coming out of the float bowl seams. Probably bad gaskets.

So, off the carbs came, and it was gunky beyond anything I have ever seen.



There was green gunk covering the bottom of the bowls, the idle jets were clogged, the bowl gaskets were crap, and the main jet needle were corroded. These carbs need a total rebuild. What rebuild kits do you recommend? K & L is the only aftermarket kit I could find on ebay, and the Honda Gasket kit Part #16010-460-305 is pretty expensive. I need new air jet cover gaskets though. Guess I'm in for spending some dough, huh.

Also, looks like the PO jacked up the air-t-connectors between the carburetors.



Opinions?

Carpenter

[Bumblebee]

The air-t-connectors are a high failure part on this carburetor. Expect to replace them about every 5-7 years. They run $35-55 each. Replace both at the same time. Once they fail, mileage drops to about 36mpg and you lose power after about 4500rpm with a top speed of about 50mph if you play with it a lot.

[carpenter183]

Someone previously butchered this throttle valve on number 4. Both side comparison.

Side 1


Side 2

By itself..


It doesn't even look like the other three (so damaged) or maybe its from another bike entirely, just jammed in there. Who knows? I don't want to put it back in the carb, but where would I find a replacement without buying a whole new carb?  the hill's I am climbing to bring this bike back to life

[meatface]

You may spend more money than you expected. You may go through more work and grief than you expected. You may get frustrated beyond belief and just want to push the bike into a burning pit. But in the end you will have a running roadworthy bike. And by the looks of your pictures you are willing and trying to do everything correctly. What I am getting at is you could buy a used bike for say $1000 + already certified and still end up with a lemon that needs a massive rebuild. You started with $180 and I would guess you may end up spending $1000 by the time you are done. But you have one thing that you can not get buying a road ready bike. And that is the assurance of knowing that everything is 100% correct. Stick with it, you will be glad that you did.

And by the way, you are doing a great job and a great justice to the Nighthawk family.

Meatface