Topic: 1980 cb650c cafe project

[Myaspops64]

I’m brand new to this site, (though I’ve cherry picked droves of useful info from it) and brand new to building bikes. I’m building a cafe racer from a fairly complete 80’ cb650 custom that’s been laying around for a few years. I took everything off it minus what I figured I’d need to start it up, and once I complete that, I plan to completely strip, clean and reassemble the way I like. After spending several hours trying to get started, a clunking sound started to develop upon rolling the engine over. I believe this is a problem with the starter clutch as now when I try to roll over it just whizzes. Now I’ve taken the clutch basket out and according to other posts, I’m trying to get the trans into gear, spin the rear wheel and remove the torx bolts back inside where the main shaft was. But I cannot seem to get the right parts to turn to line up each bolt for removal. It’s almost as if maybe the trans is not shifting into gear at all. My guess is that there’s already a write-up about this somewhere on here but I’ve read so much that I would love to just ask someone for help. Thank you

[rb550four]

Hi and welcome . Do you have a shop manual? You need to get that.
 When you used the starter for hrs. , did you first check for spark? The 650's cdi units on a machine in this condition are usually fried ( usually the reason why they were parked in the 1 st place). It won't start if they aren't working.
  Did you get a new battery ? or are you jumpstarting off the car? Battery is the way to go.
Did you check , or clean the carbs? You know that they haven't seen fresh fuel in a long, long time. You must know that the carbs need cleaning if they are loaded with old fuel and heavy varnish....can't expect it to run if you don't clean them.
have you changed the oil and filter? why not? Why push years old moisture contaminated oil thru the engine?
  Have you been running starter fluid into it while trying to start it? Don't do that anymore.
Is this motor getting air...did you clean out the mouse nest in the air cleaner?
 And finally , what parts did you remove before you tried to start it figuring that it would make no difference?
Sounds like you burned the starter . Shifting forks can rust solid from crankcase moisture
Get a manual so you have an idea what you are doing. But, you should start with the basics...
  Change the oil and filter...it's cheap protection
  Get a battery and a charger...you'll need them both later on.
   Check for spark
    Check for fuel
     Check for air
   These last 3 are were you start on any engine, without any one of those the engine won't run.
     Let us know what you find... and again , Welcome!

[Myaspops64]

Thanks for the fast reply. I have already went thru and cleaned carbs, I’m waiting to get the air filter box from previous owner, but I removed the air box so I could choke the carbs(choke cable is missing) and I have checked for spark, compression and fuel. I have all 3...I was able to get the bike to run for about 3 seconds before the starter stopped engaging. I’ve changed all of the things you’ve suggested as far as getting started, and now am in the process of getting to the starter to figure why it won’t engage. I do have a manual downloaded. I’ve taken out the main shaft and now am supposed to put the bike in gear, and roll the back wheel to line up the torx bolts inside the hole from the main shaft for removal. However, I can’t seem to get the bike into gear properly...I can’t get the trans to cycle through all gears...it Seems to me (and I could be wrong) that it’s staying in neutral, even though I hear clunking through gears

[rb550four]

I have had a couple of 550's ( similar shift fork set up) where  the forks would not move on the shaft (rusted together)  due to sitting for an extended period of time (years) in an environment that allowed regular condensation to occur in the crankcase...The shifting forks are up high in the case and aren't protected by oil , so they rust to the shaft or the drum making it impossible to shift the gears......a possibility.
  I don't know how much you have taken apart but, if the bike is on the center stand , and you spin the rear wheel freely, let's  call it N . with the side case off , shift the gear watching how the shift lever interacts with the pins on the drum....is it turning the drum freely? or forceably skipping over the pins and not turning the drum? If the drum turned freely take it off the centerstand and rock the back wheel  to see if it has engaged in 1st gear, if so go through the gears it should get easier  rock the motor as you go higher thru each gear ....that way you know if you have moved into the next gear. Easier with the plugs out.
  What is the condition of the clutch by the way? Is it all stuck together from time/rust or does it work freely/ or perhaps you removed it as a unit and haven't checked the condition? While the cover is off....  Also wondering if you took a peek in the oil pan yet , just to see what is laying on the bottom that didn't come out when you changed the oil. do not flip this motor over without removing the pan first, anything laying in the pan will end up all over the lower end. dirt and metal filings are your engines worst enemy.

[Myaspops64]

I’ve taken the clutch basket out and it at least appears to be in good working order. Im wondering if maybe because I have the clutch cover off and the clutch basket out ( I am assuming this is the same thing as the drum?) if this isn’t the reason it won’t change gears? Everything inside the clutch cover looks to be in surprisingly good shape. I also should mention, #1 I am very mechanically capable, I have just never worked on a motorcycle, and #2 instead of trying to get to the starter by cracking the engine open as the repair manual suggests, I am going in through the clutch cover, behind the clutch itself and back in behind where the main shaft slides in at. There are a few torx head bolts that I’m supposed to line up 1 at a time thru an access hole by turning the rear wheel while in gear...but I just can’t get the parts inside there to move, leading me to believe that it’s not in gear

[rb550four]

 Only a 3 second run.... have you done a visual inspection of cdi s ? perhaps one unit is burned out. you can look at the back and see if they look like one of them is a little melted.... can't tell if they are weak this way ( go to cdi troubleshooting in your manual) but you can tell if they are cooked.
 As for the clutch , and gears , it's always better to test a complete unit.Like I said before, I don't know how much you have taken apart and/or put back together.  We all like pics, if you can, That way we know where you are.

[Myaspops64]

SO I’m digging into the bike right now...I’ve found that my problem lies in the gear that the starter gear turns is loose and flopping around in there, as opposed to grabbing and turning the engine over like it’s suppose to...I’ll try to send some pics, it’s just bad lighting so I don’t know how they’ll turn out. Pics coming right next

[Myaspops64]

The 1st pic. Is of the hole that the main shaft came out of. Inside the outer hole there are smaller holes in the gear. If you turn the gear the holes line up with the torx head bolts farther in...the 2nd and 3rd pics are of the gear that the starter is supposed to turn, from the ground up through the oil pan...the last pic is of the hole that the starter gear goes through, and inside is the top of the same gear...my grass is that this gear is supposed to turn the engine over, but it is just spinning free...this is the clunking noise I was getting occasionally when I rolled it over...it’s not supposed to spin free, it’s supposed to grab and roll the engine over

[rb550four]

Am I seeing the cam chain tensioner out of it's perch in picture #2 and 3  and seeing some damage on starter clutch? Zoom in on it. To the left side of the opening ,the rectangular metal with rounded edges just to the left of the starter clutch Looks to me like someone had the top end off and didn't set the tensioner in it's perch. When you click in the pic, it turns to the right, the tensioner is on the top , then zoom. Maybe the starter clutch is damaged by this, maybe it's putting pressure on the starter clutch...can't tell from here.
  So what did you find in the oil pan?
 
 Some one jump in and let me know what you all see.

[Myaspops64]

I’m assuming the starter slutch is the piece just to the right of the sprocket on the left? It looks to me like that little hole is supposed so be slid down further so the little button can poke out the hole? The guy I got the bike from said he put the head back on it so what you’re suggesting could certainly be the case...perhaps the head needs to come back off and the tensioner properly installed?

[rb550four]

  Sounds right to me.
So, what did you find in the pan?
What else did PO say he did to this engine? Might be a good idea to check it all out when the head is loose....
direction of pistons, C clips in correctly,rings in correctly, how much cylinder damage happened when it was stored, were the cylinders honed, should they have been just honed? Then you check out the valve train......
be sure to get the complete gasket package it'll save you some bucks over one at a time and you'll get the valve seals and everything else you'll need too. be sure not to loose the 2 O rings that go between the head and the jug that seal the 2 oil passages,they are a strange size and hard to get...be sure to put in the new ones.
 That is only if you trust the cleaning job in the lower case  and if PO was in there too...you may decide better to be safe than sorry and split the cases, clean and blow out every piece including oil journals and oil pump...you'll know what you have when you are done and you know this machine inside/out. Sounds like a #$%* but it's the best way to learn. You have to have fun with it, make sure that you are always in a good mood,not in a rush, and that this is gonna be fun. It will be your reward at the end of it when you have a machine that you have rebuilt, can trust and enjoy.

[Myaspops64]

The bottom of the oil pan was surprisingly clean. I mean, there was quite a bit of sludge, but no metal chunks or chips or shavings...I really don’t know if I want to get quite that deep into it if I don’t have to. It would be nice if I could just do what work I must to make it right...my guess is that the condition of gaskets and other parts will give me an indication whether I should go all out or just do the job it needs...is there a good write-up anywhere on re-situating the tensioner, and maybe removing the starter clutch?

[rb550four]

Yes , a good write up on how to do the work....in the shop manual.
 Do you know how many pounds the PO torqued the heads down? Do you think that you want to do this over again if the head gaskets or those little O rings that I mentioned earlier fail because of age or being over-torqued?
 Have you done a compression test yet...with a gauge? You have no clue right now if the pistons are in correctly, the valves bent or anything else, Right now, this is an " unknown engine", the history from any PO is always sketchy and you can be sure some information has been left out or forgotten.
 You can roll the dice and say that it's all correct and to factory settings because you may fear the work...not that hard. You may say that you don't want to spend any extra money than you absolutely have to and resent spending it.... It's your butt in the seat, Idon't know what you think your life is worth, but I would guess it should be worth at least the gaskets.
 And this is the heart of the entire project...look at the rest of that bike, you have to go through the steering /suspension/the electric, look at those forks...won't buff that rust out...you'll be blowing seals all the time.
Were we just hoping for a rattle can black paint job here...and run it til it dies. What was the plan here? It's already to late to run it til it dies, it died. Need a new plan if you want to ride this bike, gonna take an investment in your time, effort and cash.  I have invested my time and interest in this project with you so far, let me know if I'm wasting my time please.

[Myaspops64]

I’ll find out how much the gasket kit is, I have tested the compression properly and there’s just over 120psi on every cylinder...as someone who has been in the auto service industry for over a decade I can appreciate the benefits of being thorough. What I don’t want to do is get into something that I regret if it’s not seccessary. I have no problem spending time/money into doing it right. My only issue is that my wife is already questioning wether this project is worth it, though I know it is...I will do whatever I need to do it right if I can count on you to help me not screw something up

[Myaspops64]

I order the gasket kit...I’m tearing it apart now... any tips or tricks I should know at this point?

[rb550four]

 Your wife may not be that far away from the truth about the 650...it's always been the redheaded stepchild of the 550 and 750 and doesn't demand a high resale price... the more you invest in it, the less you'll back get on return. This, coupled with the condition that it's in right now, to bring it back to a road worthy machine  (forks,brakes, lighting, possible cdis,fenders,handlebars,hoop seat paints,tires,tank de-rust and sealer, battery, cables, wheel bearings, and any of the rusty bits that you'll want to replace as the project progresses) might cost a few bucks especially if you are going all new parts, fortunately there are some used parts still available that may lessen the final cost. and that's only if the engine is in half ways decent condition .
   What if you did't check everything in that engine , and went ahead and made the frame road worthy, and blow that motor on the first shakedown ride? Your investment in time, cash, and effort would be lost...besides being pissed about what was lost ,your wife would have been absolutely correct, and has reserved the right to say "I told you so". If she's like any other woman, you will be hearing this story again and again. Nobody wants that.
 So what I'm saying is take a good look at this project, do a realistic cost analysis on everything you might expect to spend before it is completed( I'm guessing at least $1200 min. but you could get lucky...if you aren't the lucky sort of fellow,expect to pay more...if there is machine work required, way more) Have you thought of what your budget might be ? Not trying to scare anyone here, just offering a reality  based  discussion that you may ponder before diving in deeper than you want to. 

[SOHC4 Cafe Racer Fan]

I'll echo what rb said about value.  CB650s do not command any decent resale value. Do NOT build this bike for resale, since you will not likely recoup costs of a build or restoration.  Some people do not like the "look" of the motor, others do not like the absence of the kickstarter; it IS a SOHC motor but most identify it with the later models that were styled as cruisers. 

The 1979 is probably more desirable for a naked/standard or café/custom project, since the handling and geometry are essentially identical to a CB550.  1980-82 CB650s are more suited for chopper/bobbers since the design/riding position is more of a cruiser. 

[rb550four]

Just saw that you ordered the gasket set. good place to start.  Go through the manual twice, get to know where to find the information that you'll need
 If it were my project..
     The engine would be out of the frame as soon as the head bolts are loose
     The head and the jug would be coming off inspecting each piece carefully for obvious damage
       measuring for tolerance of wearing parts, especially the cylinder walls
      Piston, rings and C Clip inspection next. cam chain tensioner for sure.
    If I like what I see so far I would continue to splitting the lower end and look at the damage to that starter clutch  and camchain. Then inspect needle bearings at the end of that shaft, all shaft bearings,crank bearings , the condition of each gear,crank,crankshaft seals and every other seal that didn't come in the kit. be sure to get at least shifter seal even if it looks good, crank seals should be changed especially if they are original.same with the final drive seal  Oh , they would be lots of cleaning and blowing off as we go ! Then those shifting forks would be inspected and dealt with
    Now that it has been totally dismantled, cleaned, checked and laid out in order and is viewed to be all good and questionable parts replaced... time to paint the lower end  and  top end.
   Assemble lower end. Always use assembly lube,not grease.
  When ready use air craft quality brush on  mating surface sealant for lower cases
Always use a torque wrench to specs on every bolt ,then check again , flip assembled low end upright.
   stuff rags into piston openings incase so you don't drop anything  (C clips)back into lower end.
   Piston rings, pistons and C clips in, Slide on the jugs then
Take your time with the valves , wet test them first, find out how leaky they are. valve lapping time. keep them and all parts in order. When done lapping , clean everything twice and blow it all out twice, reassemble with new seals. adjust valves.
new head gasket and those small O rings that I spoke of earlier a few posts ago, don't use anything but new on these
 So you found a used/new/the same but all good cam chain tensioner .Install it in it's perch the correct way this time,torque the head, pull up the cam chain , install cam as directed in manual  and your off to the races..,now you know what you have, no longer an unknown engine. While waiting for engine parts to come in ,the frame was sandblasted and painted,wheel bearings and brakes changed,and brake piston gasket replaced, master cylinder rebuilt /bought an inexpensive one on line, sing arm bushings checked/replaced, used forktubes  from somewhere online , stem bearings cleaned and greased, forks resealed assembled and on triple tree.
 Pop that "now I'm happy with this motor"motor into the frame, put on the oil pan and top caps, new sprockets and chain and VIOLA you got yourself a roller that you can trust.
  Boy , am I wooped. That's generally what you'll be doing, if you decide to go ahead with it and the inside of that engine isn't wasted. Sounds like fun ,right?

     

[rb550four]

   I have a 79 650...not my fave, handles like an overweight 550.
The 80's suspension is so much better than the 79 s and 550s.
   The engine cradle for the 550 and 650 are the same , I have a couple 550' s with 650 engine and suspension.... It just handles better than the stock 550's do.
  My fave is the 80 650 custom but I do miss the spoked wheels.
I think it was the 82 custom 650 that came with a dual front brake set up , if you can locate an entire front end from one of these , you'd be golden.

[Myaspops64]

I appreciate all of the input and advice...at this point I’m going to replace the tensioner and replace all the gaskets/seals etc. on my way out...the cosmetics, the forks,frame, and everything outside the engine I can handle and have reasonable access to all/any parts I may need to replace. I’m going to take the risk in not opening up the bottom end. I’ll post pics along the way, and any feedback/tips/advise I may get will be much appreciated

[Myaspops64]

What are the proper steps to remove this camshaft? And does it have to go back in in the exact same position it is in?

[Myaspops64]

I got this far...all these gaskets and o-rings were clearly replaced

[scunny]

don't sweat the camshaft. when you go to reassemble everything, you have to align the timing mark "T" on the spark advancer (right hand side of motor) the camshaft has a cutout on it's right hand side, this should be parallel to the rocker cover, doesn't matter if it's facing forward or back, the camshaft sprocket has 2 index points, these should be parallel with the rocker cover, bolt sprocket to camshaft.
should be covered in the manual, you have one I hope ? downloadable for free here.
http://manuals.sohc4.net/cb650/

[rb550four]

Not that hard ,right?
Did you check to see how many pounds were put on the head bolts?Iif they were overtightened don't reuse the head gasket. (I would never re use a head gasket once it has been used ,no matter what)
  This machine was either left outside  or in a damp dark basement for years.
I'm looking at your cylinder walls in the first pic. This engine was seized for a long time according to the rusted scar just above piston #4 and #3 and no doubt on the other cylinder walls as well .
  I am modifying my post, I just looked at all the cylinders... all damaged and if they have been honed , the damage seems deep .

 So what's your next move?

[rb550four]

I don't know how or what the conditions were when you pulled 120 across all those cylinders. did you oil them  first? How much oil did you use?
It supposed to be between 130 and 160lbs anyways.
Almost looks to me like this engine was broke loose at one point then seized again with the pistons in a different position in the cylinders.
Was this bike a project bike for the last 2 owners?
Too bad.
I see a bore job in your future.