Author Topic: 1977 CB550F IDK (first build) (Read 178030 times)

minimo · « **Reply #525 on:** November 11, 2015, 05:30:29 AM »

No oil leaks. The only thing out of the ordinary as far as outside appearances was the rear wheel was skewed to the rider's right, the sidewall rubbing against the brake stopper arm slightly.

Could not get the bike into any gear. Thinking it had something to do with the clutch assembly I popped the cover and found that the right side looked normal.

Nothing really out of the ordinary under the left crankcase cover. No oil spill.

I'm afraid of the worst case scenario is having to take the engine off the frame again and peeling it back from the header on down... Before I begin to do that I'll pop the bottom cover off first to see if any parts have fallen down there. calj737, you suspect the cam chain?

calj737, I'll get those pics to you today. That's the innards (wiring) of the turn signal switch assembly, right?

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minimo · « **Reply #526 on:** November 11, 2015, 06:03:10 AM »

Re: left side panel - well, I've done away with side panels and have relocated (crammed) electrics under the seat. I'll do my best to lay stuff out for your eyes to see how I've routed things.

goldarrow · « **Reply #527 on:** November 11, 2015, 06:07:40 AM »

Glad you're ok and didn't crash. I wonder if your wheel locked up is related to gears are being difficult to shift as you mentioned earlier.

I've got 650 motor to drop into your frame if you're up for it

minimo · « **Reply #528 on:** November 11, 2015, 06:21:18 AM »

Thanks, goldarrow. I didn't crash and managed to skid the bike off to the shoulder of the road - even managed to keep the engine running somehow. I imagine it'd been worse had I taken it out during the day when there's more traffic on the road that I took (around Griffith Park/Travel Town). But, I feel a mix of exhilaration from the ride and a bit bummed; still determined nevertheless.
The gears were shifting fine and smooth for a while. Like I mentioned, I even got it up to fifth gear. But, I'm thinking maybe the clutch cables could have been more snug - I say this after I loosened them a little bit before the darn mishap last night. But as far as I can tell, the clutch looks fine and unscathed. I'm afraid it's something to do with the transmission, possibly.

I appreciate your 650 engine offer. I'm going to investigate my engine some more but I will keep that in mind. Thanks!

minimo · « **Reply #529 on:** November 11, 2015, 06:30:21 AM »

Totally gear-locked, I'm afraid

What do you think, calj?

goldarrow · « **Reply #530 on:** November 11, 2015, 06:31:28 AM »

Case can be split without tearing down top end

minimo · « **Reply #531 on:** November 11, 2015, 11:59:15 AM »

Nupe. Pretty darn stuck

What now?

minimo · « **Reply #532 on:** November 11, 2015, 01:32:41 PM »

Man, I'm a little afraid to check...

The idea behind the cam chain tensioner is that it's spring-loaded, so when the adjuster nut is loosened, the slotted screw bit self-adjusts to put pressure agains the chain, and then you hold the screw in place and tighten the nut, is that not correct?
Perhaps I didn't get that right?

minimo · « **Reply #533 on:** November 11, 2015, 01:45:40 PM »

I get some movement on the cam chain adjuster... Minimal on pushing the screw but it can turn a little both left and right with slight/sluggish return.
I removed the #2 inlet tappet and there's no visibility of the chain; neither on #3 inlet nor outlets. I imagine there'd be a window if I removed the whole carb assembly rack??

minimo · « **Reply #534 on:** November 11, 2015, 01:53:08 PM »

Argh

Thanks, calj737. Report back tonight (PST).

SOHC4 Cafe Racer Fan · « **Reply #535 on:** November 11, 2015, 02:37:26 PM »

"How'd you get the beans on top of the frank?"

I feel your pain. Hopefully if it's a broken cam chain, it didn't do too much damage before seizing the motor.

SOHC4 Cafe Racer Fan · « **Reply #536 on:** November 11, 2015, 02:38:35 PM »

Oh, and I've lost the other chain, too. Lucky it didn't take out my Achilles or seize the rear wheel. I had a sprocket lose a tooth or two and throw the chain.

minimo · « **Reply #537 on:** November 11, 2015, 02:41:49 PM »

Thanks, CB750.

Ha, had to look up that reference. Ha, classic! Yeah, that'll pretty much sum this up.

SOHC4 Cafe Racer Fan · « **Reply #538 on:** November 11, 2015, 03:36:08 PM »

minimo,

Whatever happened can be repaired or rebuilt. You have already done the hardest part, and all of us have experienced a big step backward.

Hang in there!

Don

minimo · « **Reply #539 on:** November 11, 2015, 03:36:56 PM »

Cheers, Don!

The going theme throughout this build has been "four steps forward, two/three steps back."

goldarrow · « **Reply #540 on:** November 11, 2015, 03:45:13 PM »

I'm curious as to what causes the wheel to lock up, can't wait to see your finding.

minimo · « **Reply #541 on:** November 11, 2015, 07:08:20 PM »

Well, we're on to something here:

Teeth from the cam sprocket is my guess. Hopefully that's all it is. Gonna pop the cam cover to dig deeper...

minimo · « **Reply #542 on:** November 11, 2015, 07:14:06 PM »

#shards

goldarrow · « **Reply #543 on:** November 11, 2015, 07:17:51 PM »

Wow. Just when you fixed something, then something else happen. Those don't look like cam sprocket teeth though

minimo · « **Reply #544 on:** November 12, 2015, 12:52:46 AM »

Treating this investigation like an onion.

First, peeled back the cam cover to reveal everything as normal. Then came the cam sprocket and cam (oh, what fond memories). So far so good there - I could even turn the engine from this point, but nothing broken yet and looking down the cam chain void I could see no noticeable sign of wear. Removed the carb rack assembly and exhaust. Holy 550 communion time with the rubber pucks to reveal the six header nuts (I'll have to replace these pucks, amen).

Popped off the header - thank goodness my gaskets are still clean and seemingly reusable.
Removed the cam chain tensioner and guide. This is where I noticed something a little off with the chain tensioner. A while back I had to replace the part 'cos I somehow broke the thread off of the adjuster bolt but now, having the two I compared them...

My original one on top and replacement on bottom. Did the replacement bend a little during the mishap, perhaps? Was this the design of some of the earlier 550s? Here's another look at them stacked on top of each other, the replacement on the bottom (a slight angle up compared to my original). Should this make any difference?

Anyway, onward with the investigation. Pistons and rings are all still looking good and even the cam chain looked fine. Since I was able to turn the engine, I gave a look on the underside of the engine case and there it was, the wreckage:

Gear on the right. Whatever it was knocked the hell out of those teeth! What could have caused this? I was shifting fine up to fifth. Things happened fast when the mishap occurred but I do remember for whatever reason I was downshifting from 5th to 4th and I was slow on letting go of the clutch; I think I wanted to downshift slightly and that's when the weirdness happened. First a clink, then a thud, and then a thunk and rear wheel locked up...
Crap. What now? Keep peeling back, I suppose? I gotta get that gear out. Do they even sell replacement parts? Should I be looking into getting another engine?

Check out this gangsta lean

I'm getting the hang of this rebuild. All this peeling only took a couple of hours (with some distractions in between).

Meanwhile, feast your eyes on my early Thanksgiving smorgasbord.

Stev-o · « **Reply #545 on:** November 12, 2015, 05:08:38 AM »

Sorry to see, that is not very common. Did you have the lower case open previous?

BTW - don't reuse exhaust gaskets, they are a 1-time use.

SOHC4 Cafe Racer Fan · « **Reply #546 on:** November 12, 2015, 07:30:57 AM »

Keep peeling the onion. Something doesn't smell right to cause that kind of gear damage. Hopefully, just a gear or trans replacement. Also that cam tensioner is clearly bent.

minimo · « **Reply #547 on:** November 12, 2015, 09:41:43 AM »

Thank you very much for the offers, calj737. I am tempted to take you up on them. I will let you know, but there is no rush. Like CB750 Fan is saying, I'm going to keep peeling the onion. I've taken the build this far, and yes, Stev-O, I have had the lower case open previously (by yours truly) so I want to learn what I may have done or installed wrong.

I'm tempted to swap out the engine and call it a day. That not only sounds easier, it'd probably be a lot safer at this point. But I can't help wanting to dig deeper for discovery, which is what this whole build is about anyway (not to mention digging deeper into my pockets, sheesh).

Thanks for the heads up on those exhaust crush gaskets, Stev-O. I will change them.

Anyone have any opinion of my cam chain tensioner? No big deal/still useable?

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knowsnothing · « **Reply #548 on:** November 12, 2015, 12:05:23 PM »

Quote from: minimo on November 12, 2015, 09:41:43 AM

I'm tempted to swap out the engine and call it a day. That not only sounds easier, it'd probably be a lot safer at this point. But I can't help wanting to dig deeper for discovery, which is what this whole build is about anyway (not to mention digging deeper into my pockets, sheesh).

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Sorry to hear about your troubles. It will make it that much sweeter once you get it all worked out.

If i was you, I would do both. Swap the engine AND keep peeling the onion and repair that one too. That way you get to ride and have something to wrench on and when its back together, you have a spare!

minimo · « **Reply #549 on:** November 12, 2015, 12:11:02 PM »

Quote from: knowsnothing on November 12, 2015, 12:05:23 PM

Sorry to hear about your troubles. It will make it that much sweeter once you get it all worked out.
If i was you, I would do both. Swap the engine AND keep peeling the onion and repair that one too. That way you get to ride and have something to wrench on and when its back together, you have a spare!

I like the way you're thinking...
I'd heed your advice if storage/space weren't issues with where this is all taking place...
calj737, can you give me a sweet friendly deal? Is your engine a '77 550F?

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Author Topic: 1977 CB550F IDK (first build) (Read 178030 times)