Author Topic: 1980 CB650c Rest-o by a crabby "old-timer" (Read 128457 times)

Frankenkit · « **on:** February 06, 2008, 05:36:04 PM »

OK, so after having been "talked into" keeping my bike, we lowered the shocks and made it actually quite comfortable. Then the work began.

Ignitors were great, but on starting it up, it sounded like arse. I said "P.O. said it might need valve job. I'd opened it up, but hadn't done much but stick the feeler gauge in, think it was 'close' and closed it up figuring I'd start on something else first. Should probably have a look."
A blessing and a curse.
We opened it up and I was shown how to do a valve adjustment, but one valve kept snapping down with every cycle (hand cranking, hadn't actually started the bike). Thought "****! It must be stuck. Hope it's not bent."

It was most certainly bent.
Got an athena gasket set from J&P Cycles for $86, (and some assorted goodies) and took the head off. Cleaned things up, started pulling valves so I could replace the valve seals (hey, they came with the set and everything was open anyway) and started lapping valves in. Two ended up being bent- the one intake valve that I knew about initially, and an exhaust valve that I hadn't known about initially. Happily, the cylinders are smooth and shiny on the inside, pistons look fine (from what I've seen) Valves are happily un-pitted and take quite well to the lapping.
Bought the replacement valves as New Old Stock from Rusty Riders at ~$13/each, which is a spankin' deal. Have some waiting time, though, because I'd ordered the first, and the day I'd gotten it in the mail, I realized the second was bent, so ordered that. School is eating a lot of my time, too, having only Saturday and a couple hours on Monday to work on it per week.

I'll include pictures when I can. So far, things are going very well and I'm really happy to have a pro over my shoulder, showing me how to do things.

Next on the list (after valves are lapped and in, head gasket in place and head on, etc etc) is a job on the fork, replacing the oil, seals and dust caps (suggestions?) and tires (suggestions on what type? Lots of people say the Dunlop 404s are good but I've read a lot of people saying they have a *lot* of road vibration at higher speeds. Looking for something pretty stable because I'll be learning to ride on this bike, and something good for wet pavement because it's oregon in the springtime.

Thanks!

750goes · « **Reply #1 on:** February 06, 2008, 09:40:32 PM »

Good going so far, at least you know the job you are doing now will not need to be done for quite a while... and you get to set the tappets on a nice clean head etc etc... all good to keep it on the road without further engine problems..

CBJoe · « **Reply #2 on:** February 07, 2008, 04:57:04 AM »

I bought a set of Bridgestone spitfire's when I was learning to ride my CB650 and they've worked out real well.

http://www.tiresunlimited.com/ALL%20TIRES/Bridgestone/Bridgestone%20MC/bridgestone_spitfire_s11.htm

What year is your 650? If they're air forks, don't listen to the manual and take them into a shop

, you can do it at home. Here's a good thread.

http://forums.sohc4.net/index.php?topic=22703.0

Cheers... Joe

Frankenkit · « **Reply #3 on:** February 07, 2008, 09:17:47 PM »

It's an '80 with regular spring/oil/goo fork.
I'll try to get pics this Saturday.
Looking up reviews on the spitfires, they look like a great deal. Thanks for the suggestion!

Frankenkit · « **Reply #4 on:** February 22, 2008, 08:12:31 PM »

Ok
This is what I started looking at today:

low old drag bars, open cylinders (see 'em peeking atchoo?)
Had to reroute a bunch of wiring, completely disconnect/reroute/reconnect some stuff, etc.
What I finished with today:

note the substantial handlebar rise? Much more comfortable.

Tomorrow I put the valve cover on and then the valve adjustment covers, start 'er up, cheer, then shut 'er down and do her forks and change her tires.

I'm excited.

750goes · « **Reply #5 on:** February 22, 2008, 11:45:03 PM »

Looking good, well done..

cb650 · « **Reply #6 on:** February 23, 2008, 12:12:14 AM »

What did you do with the old bars?

Terry

Frankenkit · « **Reply #7 on:** February 23, 2008, 08:28:59 AM »

Terry- I've got the bars but my boss (the shop owner) has the cafe racer bug, and I'm thinking he's going to want them for his next project.

TT It was the stem end. I had to drive them out through the guides, but had the guides checked by the machine shop to make sure they weren't damaged beyond acceptable use.

cb650 · « **Reply #8 on:** February 23, 2008, 10:08:05 AM »

Thanks anyway. Bike is looking good.

Frankenkit · « **Reply #9 on:** February 23, 2008, 08:28:59 PM »

Started early this morning. Little setback after little setback, some of it was feeling like getting pecked to death by a duck.

Realized that when the PO changed the wheels from the orig. mags to the chromed spokes, the wheel size increased by an inch, so going off the standards for CB50cs was wrong. Newbie mistake, and I felt like an idiot, but I'm glad I spotted the discrepancy before taking the rear wheel off, etc.

First order of the day was putting the camshaft and sprocket on, wrestling with the automatic camchain tensioner, etc. It took ungodly long and I didn't take any pictures.

After that was the valve cover. I think it was TT who said to back out all the clearance adjustment studs so one doesn't bend valves. I did as was suggested. Then the lengthy process screwing all those little bolts down. Stripped one... not because I overtorqued it, but... it just went. Fixed that with some bad language and improvisation. Replaced what the PO had bandaided with a nut/stud combo.

While fighting with valve cover, I was so frustrated, I needed to do something else. Reattached the headers and engine guard. Have nice new exhaust gaskets, so that was fun...

Sat on my bike a few times, just holding the new handlebars, workin' the clutch, grinning big. Soon. If not today, soon.

Here're the pics:

A shot from the end of the day. Valve cover on, headers/exhaust and case guard.

Here's just a shot from the front of the case guard (thanks, Paul!) and handlebars.

Frankenkit · « **Reply #10 on:** March 07, 2008, 08:23:04 AM »

Coming along...

Lubing the clutch cable, hoping I don't have to replace it... (probably will, eventually, anyway) got carbs on etc... wondering if anyone who switched to pods has an airbox? The PO screwed the cover down in such a way that one screw is permanently one with the machine, one works and one has completely pulled out altogether. $:-\$ It's the little things, ya know?

dusterdude · « **Reply #11 on:** March 07, 2008, 09:45:40 AM »

aint clean engines pretty,good job,keep it up.

Frankenkit · « **Reply #12 on:** April 25, 2008, 07:34:30 AM »

Long time, no update. My bad. School's been floggin' me dead. Took my Team Oregon BRT last weekend and am now endorsed... still workin' on the bike, though.

In some semblance of a time-line:

Everything back in, hooked up. Valves adjusted. Had her running a couple times, but not solidly. low,low,low compression. Going in tomorrow or tonight with the battery to check an see if maybe I was comp. testing with the choke in...

Fork off, rebuilt. New seals, 10wt oil. Seals were organically welded in; that was harsh. Needed much work to get out, then some love to clean off the cement.

Replaced front tire/tube. Bridgestone Spitfires.

Took levers off to be powder coated (the new one came in a little oxidized and the old one had all the paint worn off, so I'm trying to remedy that and at least have 'em match) took master cylinder off and am rebuilding it. Lots of chunky goo (sand-like deposits, etc) in the mc body... evidence that it'd been leaking (paint all eaten off, plastic looked like cr*p) ordered a new MC ($35 at partsnmore) and rebuild kit ($25 @ oldbikebarn) upgrading to braided st. steel line ($30 @ H-D, $10 for fittings) and another $25 for the caliper rebuild kit, b/c if the master cylinder had chunky munky in it, the caliper probably does, too. Following the dirs. in the Brake FAQ for rebuild when parts come in...

That's it for now. Praying I don't have to take the head off again + reseat the head gasket, but there's no evidence of a blowout or anything- it's all clean, no oil seeping past or anything. *sigh* we'll see.

Now that I know how to ride, I've got the bug bad and it's hurtin' to see the bike still sittin' in the garage...

750goes · « **Reply #13 on:** April 25, 2008, 03:27:37 PM »

Hey Kitsune, you have been doing a lot of work on it..

low low compression - don't like that - but you said a valve adjustment has been done - first place I would check is to make sure valve adjustment is correct.....
amazing how you find lots of things that need to be done...then you have to do them - you got the bug.....
compression check should be done

when motor is cold
plugs out
carbs off if you can
or
choke fully closed (no choke)
and throttle at wide open
crank until compression does not get higher - usually 3 seconds on the electric start - if you have a good battery

measure each cylinder twice - once in a "dry" mode
then again with a "wet" mode (squirt a teaspoon of oil down each cylinder before you crank it for the wet test)

can you post these results ??

Frankenkit · « **Reply #14 on:** April 25, 2008, 10:08:14 PM »

Can do. I know the pistons are ok because she red 150-155 across the board before she was apart. Did the valve adjustment and only one was tight. (4) but that doesn't account for 1 being low, also.
current reading is 90 across the board.

I'll post results tomorrow if I can.

eurban · « **Reply #15 on:** April 26, 2008, 01:40:54 PM »

Low compression across the board most likely means that either your technique, gauge, battery or starter motor aren't up to snuff.

Frankenkit · « **Reply #16 on:** April 26, 2008, 06:39:09 PM »

I'm using a standard, store-bought compression tester... Battery was a little low, but not sure if that'd impact compression that much.

Didn't get into the shop today... won't be able to work on the bike 'til Wednesday...

mystic_1 · « **Reply #17 on:** April 27, 2008, 06:04:43 AM »

Kitsune,

Are you using the same gauge and technique for checking compression as you did before the teardown? If so, than any error introduced byt he instrument itself should at least be consistant. If you're using a different gauge than before, or doing then test differently, then I'd be concerned about what TT is saying.

Sometimes it's OK to be wrong so long as you are consistent in your wrongness

As far as the cause of the low compression, is it possible that your cam timing is off?

mystic_1

eurban · « **Reply #18 on:** April 27, 2008, 06:18:09 AM »

Mystic, I agree with what you say about the gauge and consistency. Just make sure that things like intake and exhaust restriction are the same (carbs vs no carbs for the test, throttle wide open, choke off), things like battery condition (has probably sat a while since last test) and charge, as well your technique for holding (if applicable) the guage to the spark plug hole etc etc.

Frankenkit · « **Reply #19 on:** April 27, 2008, 06:49:36 PM »

The gauge is the type specifically made for motorcycles, screws into the spark plug hole. Actually different from the one initially used because that one, at whatever point, broke. It's not mine, actually, it's the one that belongs to the shop owner, I just get to borrow things... it's not 'standard' it's actually supposed to be a pretty nice model, he got it new just recently. *shrug*

Frankenkit · « **Reply #20 on:** May 04, 2008, 05:55:56 PM »

OK, Went in yesterday, hooked up throttle (not sure why it was unhooked?) put in the choke, comp tested all 4. 110-120 across the board. That was pretty good. Got the brakes hooked up, etc. etc.
Wouldn't start.
Cranks like a pro, blue-white spark on all four, gas comes to the correct level in the carb and tries to start on ether. Somehow in translation, however, it's not starting. Pulled the (new) spark plugs and they're dry, no sign/scent of fuel. I'm thinking the idle jet might be buggered, but then wouldn't at least one carb let enough through to have at least one or two pistons fire? Checked all the newbie stuff, the run-stop-run switch and all... all was in order.

Any ideas?

CBJoe · « **Reply #21 on:** May 04, 2008, 06:43:11 PM »

I apologize if this was listed earlier, but did you change the intake manifolds?? If you have bad air leaks between the carbs and the engine then fuel wont make it's way into the cylinders.

I'm sure someone will chime in with something better, but until then thats my 2cents.

Cheers....Joe

CBJoe · « **Reply #22 on:** May 04, 2008, 06:47:05 PM »

Are all 4 plugs dry

Are you sure that fuel is getting to the carbs?? If you open the bowl drains, is there fuel present?

Joe

Frankenkit · « **Reply #23 on:** May 04, 2008, 06:59:19 PM »

All 4 plugs are dry. It totally floors me.

I was thinking of the intake manifold, that there might at least be air leaks, which would prevent proper vacuum. That's the first thing I'll look into tomorrow.

Another thing:
I used Kreem on the tank and though it's not sagging like a plastic bag *visibly* I can see in the hole for the petcock where it might not be allowing gas through like it should. I'm running an inline fuel filter right now just to be safe (don't need kreem or rust powder inside my carbs) thinking I'll use the Kreemed tank until it goes bad, then use MEK to strip it out. Any suggestions/ideas?

Also thinking my clutch feels like it has kind of a hard pull. ordered a new clutch cable (old one was melted through in some places, I worked some WD-40 through and got rusty mud out...) will keep old one coiled up in a saddle bag for 'emergencies'. I'm wondering, though, if that will loosen/soften at all with the new cable and once I ride the bike a bit? As it is, it feels like it's really going to kill my hand.

CBJoe · « **Reply #24 on:** May 04, 2008, 07:10:20 PM »

Did you get the carbs pushed into the manifolds properly?? I actually ran my '80 CB650C for 5 months with only two of four carbs pushed into the rubbers properly ( I wondered why it was running lean

). If the manifolds are old and hard it can be a real ($*#) to get them pushed in all the way. I had to sit in front of the bike with a 2X4 set across the intakes and pull with all my might.

If you unhook the fuel line from the carbs, does fuel flow freely?? I'd check each of the bowl drains to be sure that each has fuel flowing properly.

cheers...Joe

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Author Topic: 1980 CB650c Rest-o by a crabby "old-timer" (Read 128457 times)