Author Topic: 1980 CB650c Rest-o by a crabby "old-timer" (Read 131131 times)

Frankenkit · « **Reply #600 on:** May 22, 2009, 05:38:18 PM »

that brings me back to a curiosity of mine, where the dude who'd been helping me with my engine stuff seriously advanced it, hoping it'd help it start and run better. I wonder if he advanced the timing too far, then, sacrificing top end speed.

scunny · « **Reply #601 on:** May 22, 2009, 05:49:02 PM »

I'd pull the sensor plate, mark it so you can just put it back to the same position and see wether your advance mechanism is free moving

mystic_1 · « **Reply #602 on:** May 22, 2009, 07:30:49 PM »

Woah, wait.

Re-set the timing to stock spec, then see how she starts and runs.

mystic_1

Hush · « **Reply #603 on:** May 22, 2009, 08:10:56 PM »

I'm with Scunny, it would be a quick check to mark where the plate is with a black felt tip then back it off say 1/4 inch to see if top end speed increases.
That vibration (stop enjoying it

) could be unbalanced front wheel as well Kit, it's not so vital on rear wheel but front will cause a good vibration (there's a song in there somewhere!).
If you are gonna look at your pulse coils to retard it slightly you might as well remove them once marked and pull your advancer.....two things that I can put my finger on that helped me get some serious speed out of my old 79, replacing what I thought was a good air filter and greasing up the advancer mechanism.
Take it all to bits on say the kitchen table (it's only a wee thing about size of cotton reel) and grease any point that looks like it might need to pivot on, I used some of that amazing dielectric grease you told me about as I didn't have any really fine grease and it worked well.

Frankenkit · « **Reply #604 on:** May 22, 2009, 10:35:32 PM »

mmmmkay... guess I have a project for Memorial Day. I hope I don't seriously f*ck up my top end speed/power by retarding it a little if it needs it. The advancer lubing might do more for me though. who knows? MickeyX said she easily pulled 85+ in 5th before she scared herself #$%*less, and that's even before the synch, so I might not have even been in 5th.

Hush · « **Reply #605 on:** May 23, 2009, 12:37:20 AM »

I get into 5th around town?
Use your gearbox more miss.

Don't worry if you do find that you have retarded it too much, it's only 2 small bolts to drop the pulse generator cover off and 3 screws to slacken to re set it, something you can do on the side of the road.

Still if the advancer is dry or rusty you will do yourself a huge favour by lubing it.

Frankenkit · « **Reply #606 on:** May 23, 2009, 07:42:12 AM »

so before I excercise my reverse midas touch (touching it and it turns to crap) to lube up the advancer, I'd:
* take the cover off, sharpie marker mark where the pulser generator is (preferably BEFORE and AFTER taking off the little nut that holds everything together because someone was an idiot and turned my engine with the LITTLE one thereby both tightening the hell out of it and mashing the corners off)
*find some way to get that nut off that doesn't involve vice grips because VGs won't fit in there...
*remove the 3 screws that hold the pulser generator on and in place
*check alignment again
*remove pulser generator
*slide off advancer
*clean and lube (derust and grease)

...and then installation should be roughly the reverse of that?

Soos · « **Reply #607 on:** May 23, 2009, 08:42:37 AM »

Actually your advancer should have a alignment pin on it allowing only 1 way instillation if seated properly.

As for the sharpie mark for the timing plate, great idea.
And at least if you HAVE to damage anything to get it off, you have a donor bike at least.
IF you do damage something beyond repair, I'm sure someone will have spare bits you can have for free/cheap.

l8r

Frankenkit · « **Reply #608 on:** May 23, 2009, 09:04:53 AM »

well I'll try NOT to damage anything beyond repair, anyway.

Hush · « **Reply #609 on:** May 23, 2009, 09:51:47 AM »

Yep all of what you said girl plus just what Soos said about alignment for advancer cam, there is an off set pin that is the only way it will fit, it aint rocket science seriously, can't be I didn't screw it all to Hell.

And when you put your pulse plate back on after lubing advancer etc, set it back 1/8 inch anti clockwise to see if retarding it helps, you can actually leave the retaining screws just a little lose and run the bike with the pulse cover off, adjusting the pulse plate as it runs till you find the sweet spot.

mystic_1 · « **Reply #610 on:** May 23, 2009, 10:02:35 AM »

The only reason that setting the timing to a non-spec setting would be if something else was wrong, and that's no reason. If the bike doesn't run properly with the correct ignition timing, locate the problem that's causing this.

mystic_1

Frankenkit · « **Reply #611 on:** May 23, 2009, 04:57:33 PM »

Quote from: Hush on May 23, 2009, 09:51:47 AM

And when you put your pulse plate back on after lubing advancer etc, set it back 1/8 inch anti clockwise to see if retarding it helps, you can actually leave the retaining screws just a little lose and run the bike with the pulse cover off, adjusting the pulse plate as it runs till you find the sweet spot.

now, is that what you and Soos were talking about when you said you set it so you find the max rpms, then back off just a little?

mystic_1 · « **Reply #612 on:** May 23, 2009, 05:22:46 PM »

When's the last time you drove the bike with the timing set properly? I just don't understand the assumption that the factory timing spec is wrong.

Quote from: Kit on May 22, 2009, 05:38:18 PM

that brings me back to a curiosity of mine, where the dude who'd been helping me with my engine stuff seriously advanced it, hoping it'd help it start and run better.

So, did it?

mystic_1

Frankenkit · « **Reply #613 on:** May 23, 2009, 05:35:06 PM »

I never got to ride it at factory spec. While we were rebuilding the motor, we saw that the pulser coils were both fried, so paulages sold me a pair plust the timing plate. We put it on and because he wasn't getting the bike to start well (probably actually a carb issue) he advanced it.

I've never actually run it at stock spec.

Soos · « **Reply #614 on:** May 23, 2009, 07:10:29 PM »

Quote from: mystic_1 on May 23, 2009, 10:02:35 AM

The only reason that setting the timing to a non-spec setting would be if something else was wrong, and that's no reason. If the bike doesn't run properly with the correct ignition timing, locate the problem that's causing this.

mystic_1

Stock (factory set) timing is great for a motor with little/no miles.
As chains stretch, and parts wear, timing will need modified to give best results.
Not that it really amounts to much, but it exists.
Mabey 1-2 degrees over 40,000+ miles and 30 + years of age?
Not saying the factory stock timing will not give good results nonetheless though.

Heck, i've seen motors 10 degrees off, and the owner couldn't tell.
'Till it got timed properly.

Adjusting timing to hide other problems, is difficult at best.
But once you have the timing set to a "acceptable"(whether with timing light, or by ear) you can continue looking for the power loss problem(s) left. (if any are left)

l8r

Frankenkit · « **Reply #615 on:** May 23, 2009, 07:55:40 PM »

well, I marked where the timing plate was, took all that off and cleaned/lubed my advancer. It was really rusted and squeaked/grated when I moved it, so maybe this'll make a difference. MickeyX wanted to take it for a test ride out on the highway, so I handed her the keys and I'm hoping it goes well.

scunny · « **Reply #616 on:** May 23, 2009, 08:01:35 PM »

hope it all goes well for you, those advances are easily overlooked.

Frankenkit · « **Reply #617 on:** May 23, 2009, 08:03:37 PM »

Oh and on the timing plate thing, it seemed to be right in the middle of the possible adjustment range... so we'll see. I should properly time it.

Hush · « **Reply #618 on:** May 23, 2009, 08:04:32 PM »

Aw Mickey screwed you over, you should be riding it Kit ha ha ha............If it runs like crap or worse than it did before you have the spot marked to return it to your original settings.
As Soos said, time and wear will play merry Hell with the factory settings so you will have to play a bit to find that right spot.
I'm betting a huge improvement in acceleration and top end speed since you cleaned the advancer....see girls can do anything.

MickeyX · « **Reply #619 on:** May 23, 2009, 09:16:43 PM »

Well, it seems okay to me. I easily hit 65mph in 4th gear. Buried the needle in 5th and had plenty left. I think it really needs a carb tune though. It's just holding back a bit yet. I can feel it. I did over 65mph in 5th at 5.5k rpm. I'm not sure how that measures up to your bikes. I think we should go ahead with the carb tune. If it feels like it's holding back afterwards, we can recheck the timing then and retune the carb.

Have a great weekend everyone and I hope you all get a chance to get out and ride it like you stole it.

Hush · « **Reply #620 on:** May 23, 2009, 09:58:37 PM »

Sounds good.

carlsboss550kay1 · « **Reply #621 on:** May 24, 2009, 01:59:18 AM »

hi there, kit!

so, its 4:38ish in the morning, and i started reading this resto-thread at around 11:30pm last night....couldn't "put it down", as it were!

its just more fuel to the carbs to get my 550 running proper and reliable, and i can't tell you what a valuable resource your thread will be on the journey.

its hard to comment on everything that has sparked an "oh-oh-oh!" in my head over 45 pages, but a few things popped out and really stuck with me, and i hope that it pleases you to know that your journey will make the passage of those who choose to tread your path an easier trail to navigate....

1. i share your sensibilities...stock, baby...stock. however, should stock prove "unreliable" (those cv carbs are looking mighty good to me...hope they can work with a 550!), purism be damned, and gimmie what lets me get from a to b and back without trouble! (but at least lets make it look "stock" as possible! hell, only the cb-geeks are gonna really know!)
2. i envy the bike-bond you can share with your dad (though i, too, got my humour from the old man. you remember that sh*t in your oil pan? that stuff, as humour....), and i only hope that what i learn from you lot here (and like it or not, kit...you're now a teacher. an imparter of wisdom.) will allow me to one day develop such a bond with the poor soul who gets born as my progeny!
3. if chaps are a**less, how exactly does one sh*t them?

i really don't know what exactly i'm trying to say...i feel like i've just experienced everything that you went through for the better part of 3 years in only a few hours, and its really quite difficult to articulate the effect that it has on me.
so i'll just say "congratulations! that is an enviable machine you've built..."

and if it comforts in any way, think of any future or current "bugs" like this....go out to the garage, throw your leg over samson, and try to get him to start/run like delilah does...thats how far you've come!
and though the journey may not yet be over, well...if it were, that would mean the bike or yourself had merged with the infinite...
so really, the bugs are a good thing!

ride on, sister...ride on!

Frankenkit · « **Reply #622 on:** May 24, 2009, 07:59:37 AM »

um, yeah. anyway, I'm going to be doing static timing (just bc I don't have a timing light) but keep the marks I've made on my timing plate just in case it's not an improvement.
I just need to figure out how to get to TDC for sure. I always feel a little creepy trying to make sure it's TDC. ...and speaking of all this, for static timing, does it need to be TDC compression, or just TDC in general?

so... that, and I need to synch the carbs, but first I need to figure something to support the tank somewhere off to the side so I can reach all my carbs.

so... yeah. I think that's it for now.

Hey Carlsboss (your subline makes me so think "Teenage Wasteland", btw) thanks for the kind words... this has definitely been a roller coaster of sorts, but you're absolutely right. Samson is about where Delilah was (or was when we got him, now he's a few select parts short...

) and that kind of transformation is really a little mindblowing. Sometimes, like hauling at 65mph in ...uh... 4th gear, around 8.5k rpms, I really try not to think about how many pieces it was in before.

mystic_1 · « **Reply #623 on:** May 24, 2009, 08:28:49 AM »

You want TDC on the compression stroke. What I do on my 750 is to pull the #1 intake valve inspection cover, then rotate the motor until the intake valve opens and then closes, then continue rotating until the T1-4 mark lines up. The F1-4 mark should be just before that. My understanding is that the points open just prior to TDC because the spark happens just a bit after the points open (probably milliseconds) and the flame front takes time to travel through the combustion chamber, so by the time force is applied to the piston it's just at the beginning of it's down stroke.

Consider this, if you timing is advanced too far, then the power from combustion is applied while the piston is still on it's up-stroke, effectively fighting against the engine's rotation.

You want to set the timing so that the point just starts to open when you reach the F1-4 mark. At fully advanced timing (above 2300-2500 rpm on a 550 according to the book) the point should open between the two hash marks earlier on. From the sounds of what you said earlier, your advancer was pretty grunged up so it wouldn't surprise me if it wasn't working at all previously.

Regarding supporting your tank, pull the bike up next to a workbench and set the tank on the bench with the petcock hanging off the side. Use a longer fuel line to hook it up. It's best if the tank is at or near the same height above the carbs as when mounted.

Oh, and regarding your progress to date, it's both impressive and commendable. One thing is for sure, you've gained a TON of knowledge about this bike, not to mention engines in general. Your "sticktoitivness" is also to be lauded.

The grin you get when you crack the throttle is the payoff.

Best of luck to you.

mystic_1

Hush · « **Reply #624 on:** May 24, 2009, 09:42:10 AM »

+ everything Mystic said.
Being a fiddler rather than trained mechanic I use this really lame way of finding TDC.
As Mystic said remove plug, I use #4 just cos it's closer to pulse generators, remove valve cover on #4 and rotate engine using large socket on the "big" nut at pulse gen.
Once advancer shows TDC, pop a thickish screw driver straight down on to #4 through plug hole, when I say straight I mean so it won't jam on the up stroke.
If you find piston at close to top of stroke all good now check valves by tapping them (see fiddler) if they are both fractionally loose (OK you can use a feeler guage) then I'd say you are at TDC.
So that's piston almost at top of "up" stroke, valves relaxed and not depressed (so closed) and timing marks are?
This is the bit that gets you as close as this method will allow, check timing marks....if you are miles off carefully rotate engine until screwdriver is again moving up showing piston on up stroke, check valves for slight loosness, check timing marks...adjust as required.
Hey it's my extremely unscientific way of checking timing on a bike, but it is simple and it does work.

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Author Topic: 1980 CB650c Rest-o by a crabby "old-timer" (Read 131131 times)