Topic: 81 Cb650, anyone give me an opinion of one?

[750K]

So I'm looking out for a new bike for my wife, mainly due to her Cb400T just not cutting it highway wise for her and secondly to keep her away from my Cb750 and Kz1000 haha.

Friends of mine have an 81 Cb650 at their garage, been stored indors for years (since 95) 24,000kms on it. It'll need the usual bull#$%*, fluid changes, battery, carb clean, brakes run through and tires etc... I'm going to look at it next week at some point, not too familliar with the 650, can anyone give me a heads up on anything problematic or specific I need to look for other than the usual old bike stuff?

Thankfully the guys that have it are long time bike builders and dudes I know well so they aren't going to try and hide anything haha. It needs a good home they said and they'll hook me up with a good price, I've eyeballed it one time last year and from what I remember its pretty much bone stock and in good shape albeit dusty. It was the shop loaner/erand bike for a bit so I do know it ran fairly well when it was last on the road.

Any opinions or comments about the 650 is appreciated.

[trueblue]

I have a '79 650Z, I rarely have to do anything to it other than servicing.  Be aware they have issues with their charge rotors due to the internal insulation breaking down with age.  Quite often when the rotor dies it takes out the reg/rec unit.  The '81 should have CV carbs, which give them a good bit of grunt.  The best part about the 650's is there are no points to adjust, you do still need to adjust the air gaps of the inductive pick-ups, which is a piece of piss.  I have sat on the highway all day on mine, they'll spin happily all day at 5-6000rpm.  The only real complaint I have is the handlebars vibrate like a b!tch between 4500 and 5500 rpm.  I fitted foam grips and it took care of that problem.

[Xnavylfr]

I have heard ,that the 650 was known for throwing the cam chain. This is not from personnel experience but just overheard others talking about their CB650s.

Xnavylfr(CHUCK)

[trueblue]

I have heard ,that the 650 was known for throwing the cam chain. This is not from personnel experience but just overheard others talking about their CB650s.

Xnavylfr(CHUCK)

Never heard of that one.  Mine nearly did though, but it wasn't due to design but rather a dumbarse PO. He fitted it with an extra link in the cam chain because he couldn't figure out how to release the cam chain tensioner.   

[cb650]

They are junk unless u get it and chop it up like a hardly wantabe.   LOL.
I have several and mostly been reliable.   Charging is the big issue but i never had a problem. 
Original tanks are getting hard to find. 

[seaninc]

I'm currently working on an 81 custom that's been sitting a long time. The carbs are easy to work on, but parts are not as easy to find as 750 parts.

Sent from my MB525 using Tapatalk 2

[grepper]

My wife had an 82 cb650.  I thought it was a good bike.  We did have charging issues, but after getting the rotor rebuilt and a new Reg/Rec, it was fine.  It was a good size for her and did 70 or 80 mph just fine.

[curemode2002]

I love the power mine has I am not a small guy (6'6" 360lbs.) but it does great easily hit 80+ and can go for quite a while at that speed. The charging is a bit on the cranky side for some (that has been my main issue) as this was the first few years of the solid state system. Also the isulation on the stock charging rotors is not great (if you see cracks you need a rebuild or new rotor). Part wise they are a bit harder to find as they on really had them in the U.S. from 79-82 but other than some frame and bodywork differences all the mechanical stuff is interchangable. Plus parts and bikes are cheaper since they are not as hot as the 750 demand wise.

[750K]

Thanks guys, I'm going to look at it on thursday after work and do a compression test on it. We'll see what it looks like, my recolection is its pretty fuggly but bone stock. That doesn't bode well with my wife, haha.

I've done some digging and it looks like cb450 and possibly early cb750 tanks will fit after you relocate the rear mounting tab, I can build a new seat for it so i'm pretty hopefull I can get it for a good price and bring it home on fri if all checks out. I have a tank from my 71 cb750 I'm going to bring along for a test fit.

[Jerry Rxman Griffin aka MuthaF'er]

They are junk unless u get it and chop it up like a hardly wantabe.   LOL.
I have several and mostly been reliable.   Charging is the big issue but i never had a problem. 
Original tanks are getting hard to find.

Terry,

What about that vacuum switch thing in the fuel line? Was that 1981?

[trueblue]

They are junk unless u get it and chop it up like a hardly wantabe.   LOL.
I have several and mostly been reliable.   Charging is the big issue but i never had a problem. 
Original tanks are getting hard to find.

Terry,

What about that vacuum switch thing in the fuel line? Was that 1981?

Easy enough to get rid of

[cb650]

Yes on the cv carbs.    81/82  gone on all mine.

[Tugboat]

Be aware that on the 80/81 CB650's, the slow jet is pressed-in inside a tube, rendering it inaccessable. On the later models, they fixed this, and you can just pull it out with pliers. But with the older ones, you have to grab them from the inside with a screw extractor or the like.. look it up.

[cb650]

slight correction.    all are pressed in except the 82 CV carbs.    The 79/80 are removable without much trouble.   The 81 cv's are recessed and take a deal of work but doable.  Good removal posted on the 650 site.

[Tugboat]

Thanks for the clarification

[750K]

There's no kick start on the 650, just electric start correct?

Got a charged battery and compression tester and am counting down the hours till I'm off work, got my fingers crossed it checks out.

[trueblue]

There's no kick start on the 650, just electric start correct?

Got a charged battery and compression tester and am counting down the hours till I'm off work, got my fingers crossed it checks out.

That is correct, not something you really miss though .

[BeSeeingYou]

Maybe too late but take a multimeter to check the charging system.  Sometimes there is a reason bikes sit for a long time.  Like others have stated the rotor is a known issue and expensive to replace.  My neighbor has an 83 that the rotor failed on.  I have been helping him with the bike and it seems like a decent bike to me.  The carbs are a bit more of a pain to rebuild.

[750K]

I was surprized at how clean it looked, I'm picking it up tomorrow.

All the electrics work, it's in real nice condition, 4-1 header is in great shape, Cb750 tank will mount up with no issues, pretty low milage and there are no visible oil leaks. It hasnt run in years so it will need a full tune, carb clean, the front brake sticks, needs new tires & battery. Dry/cold compression test was 120 on cyl #1,4, I couldnt pull plugs 2,3. I forgot my plug wrench from my cb750 but i'll bet they are the same.

First order of buisness after I get it running will be a new tank, smaller signals, build a new seat, drag bars or super bike bars, tires and a good detailing. Grab rail, back rest and luggage rack will get turfed as well.







 

[grepper]

That's a nice looking bike.  Looks just like my wife's 82

[onepieceatatime]

It has the comstar wheels, with single disc front brake like '80 customs had. '81 Custom model had dual disc front brake with comstar wheels. The standard model had chrome spoke wheels single disc. I also noticed that there is no air valve, and flat caps on the forks, the '81 Customs had air assist forks while '80 did not. Also has PD carbs, something from '80 while the '81 had CV carbs which will not swap with PD carbs. It looks like it is an '80 custom model with aftermarket exhaust. It does look like it is in pretty good shape though. What are you going to do with the tank? I may be interested if for sale.

[750K]

It has the comstar wheels, with single disc front brake like '80 customs had. '81 Custom model had dual disc front brake with comstar wheels. The standard model had chrome spoke wheels single disc. I also noticed that there is no air valve, and flat caps on the forks, the '81 Customs had air assist forks while '80 did not. Also has PD carbs, something from '80 while the '81 had CV carbs which will not swap with PD carbs. It looks like it is an '80 custom model with aftermarket exhaust. It does look like it is in pretty good shape though. What are you going to do with the tank? I may be interested if for sale.

yeah I had read the 81 custom had dual discs as well, oh well no biggie. PD's were better than the CV's correct? It's titled as an 81 but its a Canadain bike so maybe that has something to do with it, registered it today and picked up a new battery and a ripped up seat with which to build a nicer seat out of. The one on the bike is mint and I didn't want to tear it apart, I will be selling the stock seat, tank (which is really clean inside and out), bars and anything stock my wife wants removed from it.

Here's some pics of it outside prior to loading it in the van, I had to remove the backrest and luggage rack as well as tilt the bars down to get it through the rear doors. It changed the look huge, cant wait to get a flater seat and bars and a different tank on it. It's pretty fugly in it's 80's ness but I can see the potential it has to be something cleaner and more pleasing to the eye.

[Doggie]

Good Luck with the new bike. I have an '81 Custom and just picked up another for parts.
                                        Doug

[rb550four]

   Opinion of 81 650.... I have a few 500/550's, my favorite 4 because of the size and the lower than the 750 center of gravity.
    Came across a 80 650, really close to the 500/550 frame, a little different stance , heavier swing arm, longer forks, comstock wheels..... More power and handles better than 500/550 (I think)
    Picked up an 81 650,   Dual front discs, we want that and have been watching the threads for the upgrade , and allot of members have done it , the rest of us are planning to convert.
   Problem I've run into on the 81 is the trees are wider so it doesn't accept clubmans, the tank is a little different in position so drag bars are too low and bump the tank a low rise superbike bar  doesn't work for me either. I've seen some people use a riser system to use the bars they want but I'm not sure where they put the tree mounted fuse panel. Another thing to consider would be the angle of the mastercylinder if using a drag or superbike bar , as the master was built for an downward angled bar. The clubmans will work  upside down and spun around and the mastercylinder angle won't be an issue  and would provide decent clearance..... depends what kind of look you're after.
     Same good power as the '80, but as mentioned previously the 81 has air assist forks, haven't noticed much difference between the two.
      Lastly the 650 is a direct, no screwing around, fit for a 500/550  frame except for the wiring.
That machine that you've picked up looks to be in wonderful shape, shouldn't be a challenge to get it the way you want... nice find... you may find the same enjoyment or more than the 750 if you set it up right.
      Good luck with 'er and many happy miles.

[onepieceatatime]

yeah I had read the 81 custom had dual discs as well, oh well no biggie. PD's were better than the CV's correct? It's titled as an 81 but its a Canadain bike so maybe that has something to do with it, registered it today and picked up a new battery and a ripped up seat with which to build a nicer seat out of. The one on the bike is mint and I didn't want to tear it apart, I will be selling the stock seat, tank (which is really clean inside and out), bars and anything stock my wife wants removed from it.

Here's some pics of it outside prior to loading it in the van, I had to remove the backrest and luggage rack as well as tilt the bars down to get it through the rear doors. It changed the look huge, cant wait to get a flater seat and bars and a different tank on it. It's pretty fugly in it's 80's ness but I can see the potential it has to be something cleaner and more pleasing to the eye.

It looks like it was taken good care of, and should provide years of enjoyment.
You can check the VIN plate, to see for sure what model it is, but with those carbs, and front end, when you buy parts, you will need the ones sold for an '80. When you are ready to sell the tank, please let me know what you would want for it, shipped to 21740 (Hagerstown, MD).
The 750 tank looked good on it with your picture of the test fit, and I don't think you will have any trouble making it look more like you want it to be.

Edit...
I forgot to answer your question about the carbs...
The PD carbs are more like the 550 &750 carbs, but a little harder to find kits for. The CV carbs are vacuum slide, and are a little more forgiving of exhaust changes and pods. Pods are still not recommended with them though.