Author Topic: 82 cb650sc first topend rebuild attempt.  (Read 1882 times)

0 Members and 1 Guest are viewing this topic.

misterpunch

  • Guest
82 cb650sc first topend rebuild attempt.
« on: May 31, 2009, 08:53:03 PM »
After humming and hawing over the oil stain where ever I parked my bike I decided to finally dive in to fix it.  My leak was weeping through the head gasket on the left side which made quite a mess after a while and since I was rebuilding my carbs I thought I'd do what i think would be called a top end rebuild.  (head and cover gaskets and general clean up inspection of everything else) This is the first time I've ever ventured this far into the innards of my bike and it's pretty satisfying that I'd have the confidence to rip it apart again if need be rather than drop it off at a dealer and stay in ignorant bliss.  Disassembly was a lot smoother than I had anticipated Making sure those magic O rings were in place on the gasket when i put it back together I thought I might even be able to ride that same day.  The assembly came to a screeching (or snapping) halt when I over torqued a head bolt and snapped it.  I feel stupid for not realizing how much pressure I was putting into it while waiting for the "click" of my torque wrench.  Now I have a nice clean half engine with a 1/2 inch of bolt threaded into my block.  Any suggestions on how to extract it?  I've never seen extractors that long and thin to be able to fit in there.  I figure the bolt will be easily replaced at a local nut bolt machine shop so I'll ask there when i get the chance. 

At the very least I have some down time to get my seat pan made and my 4-4 exhaust to get here.

I'd still rather be riding, comfy seat or not...

Offline martino1972

  • Expert
  • ****
  • Posts: 1,227
  • and still a expert welder,period...
Re: 82 cb650sc first topend rebuild attempt.
« Reply #1 on: May 31, 2009, 09:58:55 PM »
oh,that blows.......

um,take the head back off and you should be able to remove the broken bolt with your fingers....
Marti, I want you to know, I like you an awful lot, but guys have said far less and left wearing their drinks on their shirts.
http://forums.sohc4.net/index.php?topic=36933.0  (my bobber)

Offline Hush

  • Finally they realise that I am an
  • Really Old Timer ...
  • *******
  • Posts: 6,761
  • "Lady, I've heard it all before"!
Re: 82 cb650sc first topend rebuild attempt.
« Reply #2 on: June 01, 2009, 01:50:35 AM »
What firey pants said. :D
I think the thing I most like about motorcycling is the speed at which my brain must process information at to avoid the numb skulls who are eating pies, playing the ukulele, applying make-up etc in the comfort of their airconditioned armchairs as they make random attempts to kill me!!!!!!!

misterpunch

  • Guest
Re: 82 cb650sc first topend rebuild attempt.
« Reply #3 on: June 01, 2009, 01:56:40 PM »
oh,that blows.......

um,take the head back off and you should be able to remove the broken bolt with your fingers....

Well the problem is more that the bolt snapped off very low (about 1/4 inch below the first thread) and it's one of the two longer ones so that the broken piece is deep in the block.  i'm trying for a long slender extractor and if not may have to drill it out and not get any of the threads messed up.  What a damper on the weekend..

Oh and I have a parcel in that is either the pipes or the new headlight bucket.

grrr.

Offline cb650

  • Old Timer
  • ******
  • Posts: 3,864
Re: 82 cb650sc first topend rebuild attempt.
« Reply #4 on: June 01, 2009, 04:13:53 PM »
Soak it with oil first.  Use a lefthand drill bit.  You might get lucky.
18 grand and 18 miles dont make you a biker

misterpunch

  • Guest
Re: 82 cb650sc first topend rebuild attempt.
« Reply #5 on: June 01, 2009, 08:34:56 PM »
i'll check out the hardware store in the morning.  I just got a call from my OEM parts place and the little brass nipple for the tube from the automatic fuel pump is discontinued, but i was able to put the flange bolt on the order and hopefully it will be here by the weekend.

My headlight came in and it's awesome. will post pics when i get a chance.

misterpunch

  • Guest
Re: 82 cb650sc first topend rebuild attempt.
« Reply #6 on: June 12, 2009, 02:47:44 PM »
Update:

Pipes came in, they're awesome.

Had to take the entire block off to use an easy out to get the bolt out.  pistons and rings were in way better shape than i had anticipated.  Couldn't find the right "oil control dowel pin" that aligns the block on the crankcase so after 20mins of looking, I assumed that the PO lost or forgot it in the last rebuild.  Torqued the bolts on top of clean new gaskets and try to turn the crank shaft to adjust the timing.

No go.

I the good news is I probably found that dowel pin, the bad news is I have to tear even more down to get it if it is in fact in the crankcase.

Woe is me.

I'm learning by trial and error. mostly error.

I'm putting pods on it and rejet even though I'm going back to the stock exhaust.  After all I went through up to now, taking the carbs apart again is nothing if it ends up running like #$%* after the carbs are synced.

Offline manjisann

  • Hazardous Chemical Inhalation
  • Master
  • *****
  • Posts: 1,828
Re: 82 cb650sc first topend rebuild attempt.
« Reply #7 on: June 13, 2009, 03:20:11 PM »
I'm getting ready to start mine. Bummer about having to take it down even further, on the bright side, you'll be even more familiar with her when you're done. Good luck and keep at it!

Brandon
Sure it's for sale! How much you ask?? Well, how much are you willing to pay??? Now triple it, that's the price!

1973 CB500 K2 - Sold the bike and bought a Mig, Miss the bike, Love the Mig :D
1980 CB650 Custom
1971 CB500 Frame 650 engine: Project

Trip and General Ramblings blog: manjisann.blogspot.com