Author Topic: I dropped my '74 CB550 and now it's a mess. Help!  (Read 5419 times)

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Offline TwoTired

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Lloyd... (SOHC4 #11 Original Mail List)
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Online robvangulik

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Re: I dropped my '74 CB550 and now it's a mess. Help!
« Reply #26 on: September 07, 2017, 04:46:49 PM »
Hence the question mark. Octane isn't a substance and therefore can't be combusted. It is a reference to the ability to resist knocking, see your own link....
But i don't like to contribute to this totally offtopic play with words, i think (and that is just my opinion!) that Delta and yourself should take your dispute elsewhere, than we can wait for the opening poster to gather his courage to respond in his own topic.......

Offline TwoTired

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Re: I dropped my '74 CB550 and now it's a mess. Help!
« Reply #27 on: September 07, 2017, 05:04:09 PM »
Hence the question mark. Octane isn't a substance and therefore can't be combusted. It is a reference to the ability to resist knocking, see your own link....
But i don't like to contribute to this totally offtopic play with words, i think (and that is just my opinion!) that Delta and yourself should take your dispute elsewhere, than we can wait for the opening poster to gather his courage to respond in his own topic.......


Definition of octane

    1:  any of several isomeric liquid alkanes C8H18

Seems it is a substance, after all.
Perhaps you're confused with the term "octane rating"?

I agree, that Delta's dispute should be curtailed.  If he will, I will.

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline evinrude7

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Re: I dropped my '74 CB550 and now it's a mess. Help!
« Reply #28 on: September 07, 2017, 05:09:58 PM »
So I just picked up a 74 CB550 over the weekend. I already know the bike has a charging problem. I'm a pretty new rider and this is my first bike with a kick starter. On Sunday night I managed to drop it while trying to kick start it. I had ridden the bike for many hours every day all over town prior to that, but since then, a couple of weird issues have popped up and I don't know where to start diagnosing whatever I messed up.

  • It won't kick start at all now without full choke (parallel to the ground) and the throttle twisted pretty good at the same time. It roars to life but dies immediately before I can adjust the choke.
  • The electric starter struggles but will eventually start the bike with no choke and no throttle.
  • The bike idles just fine after it warms up for a couple minutes and I can rev the engine as much as I want and it returns to idle right away, but it completely bogs down and dies under any kind of load, in any gear. Prior to dropping it the other night I rode it all over and it was very solid feeling and responsive in every gear.
  • There is a fast clicking sound coming from the engine. I can't be certain this is new, but now that I've really been paying attention it is quite obvious.

I've done some googling and decided to start with a new rectifier/regulator as the first troubleshooting step in the charging system fix because the part was cheap and easy to install.

I've checked all the spark plugs and none of the cables or boots are loose.

I'm really at a loss here about how I managed to make such a mess from a fairly low-impact drop in my driveway.
I've ordered a shop manual that should arrive tomorrow. Can anyone give me some clues or steer me in the right direction with what to start troubleshooting?

kyle, how's the bike? 
cb750 k6 - ugly

Offline Deltarider

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Re: I dropped my '74 CB550 and now it's a mess. Help!
« Reply #29 on: September 08, 2017, 06:12:35 AM »
Quote
It defies all the laws of physics to expect the same or more power from less oxygen delivered to an internal combustion engine.
 An intake choke physically restricts oxygen delivery, anywhere it exists in the intake duct.
It doesn't matter what fudged or mis-labled charts, graphs, and opinions of uneducated, biased persons are presented here, regardless of their nationality.
It's not the first time I have to put it to you that the cover doesn't necessarily need to be a restrictor. It could be if the opening that the CB500s in other markets (like US) had, was precisely matched for maximum power output. But that isn't the case, so what if the opening is overwide to begin with? What negative effect does our cover then result in? But there's more. What if the gauze net other markets have, cause extra turbulence? And what if the cover we have here, allows less turbulence? So what if that cover in combination with the rejetted 649A carbs, all in all is... fine?
Back to some basics, shall we? Here's a simple test that any uneducated, biased or unbiased person, can do. For reasons of impartiality, I won't do the test myself, but I invite owners elsewhere, regardless of their nationality, to do it.
Open your buddyseat and remove the tooltray so the top of your aircase is fully open. Start the engine that is already warm enough to run with chokes off. You may choose to run it at idle or above, say 2500 rpm. I don't care. Now cover half of the opening with a piece of carton that you have cut at forehand. Any change of rpm yet?:D Now slide that piece of carton further over the top over the aircase, by and by covering more and more of its opening, further and further until you hear the rpm drop. Now look at the opening that's left. Isn't that amazing? You may take a picture and show it nonbelievers. But hey, don't fudge it, OK? Owners of an CO-tester, again regardless of their nationality, even the lunatics are welcome, are kindly requested to report if they see any change in CO before the rpm drop.
Now here's my question. Why, if the topic is idle, choke etc, why, when I add something, why bring up the 649A carbs and the aircasecover we have again? What's this with your needle always in the same groove. I feel I can't even discuss a fuse or a taillight or you'll come riding out warning the members that they should know, I have a cover over my airfiltercase. So what?
As far as the laws of physics, I'm pretty confident my bike respects them. Now, :-[ ahhh...  :-[ I've never told this anybody before but I come straightforward now: before every ride, my bike and I, in the intimitacy of our garage, always pledge allegiance to the Law of Physics. "I pledge allegiance to the Law of Physics and to the universe for which it stands, one world under Einstein, indivisible, with liberty and a whole lotta fun for all.”
Now although my bike never gives a blink - he is not like that, you know - I'm sure he understands and agrees wholeheartedly.
« Last Edit: September 09, 2017, 03:26:55 AM by Deltarider »
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Offline ilikepinkcrayons

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Re: I dropped my '74 CB550 and now it's a mess. Help!
« Reply #30 on: September 08, 2017, 08:27:32 AM »
To get back to Kyle... this sounds stupid, but do you have fuel in your tank? The first time I ran out of gas, i didn't have very many miles on the fresh tank so it didn't occur to me that I was out. There was a brief time where I could get it to idle, but the second I put load on it, it just died. After that, I couldn't get it to start. After THAT, panic set in, drama ensued, but in a moment of clarity, I remembered...the petcock! Flip to reserve. Vroom vroom.

Whenever something's wrong, I remember these seven words: air, fuel, spark, suck, squeeze, bang, blow. 90% of my problems on this bike have been resolved while inspecting the first three words (fuel has been the #1 culprit).
1968 MGB
1975 CB550K
1981 Volvo 244 GLT

Offline Deltarider

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Re: I dropped my '74 CB550 and now it's a mess. Help!
« Reply #31 on: September 08, 2017, 08:50:54 AM »
Quote
suck, squeeze, bang, blow
  :-[ :-[ :-[ Moderator... please...
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Offline magnum56

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Re: I dropped my '74 CB550 and now it's a mess. Help!
« Reply #32 on: September 08, 2017, 08:58:32 AM »
Quote
suck, squeeze, bang, blow
  :-[ :-[ :-[ Moderator... please...

Really !?!  ... you've never heard that simple reminder of 4 stroke basics ... Intake, Compression, Spark/Power, and Exhaust.

(sigh)
« Last Edit: September 08, 2017, 09:04:33 AM by magnum56 »
'74 CB750K

Offline BomberMann650

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Re: I dropped my '74 CB550 and now it's a mess. Help!
« Reply #33 on: September 08, 2017, 09:07:40 AM »
Quote
suck, squeeze, bang, blow
  :-[ :-[ :-[ Moderator... please...

Really !?!  ... you've never heard that simple reminder of 4 stroke basics ... Intake, Compression, Spark/Power, and Exhaust.


Grow Young magnum!  Just a little juvenile humor 😁

Offline magnum56

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Re: I dropped my '74 CB550 and now it's a mess. Help!
« Reply #34 on: September 08, 2017, 09:22:33 AM »
Quote
suck, squeeze, bang, blow
  :-[ :-[ :-[ Moderator... please...

Really !?!  ... you've never heard that simple reminder of 4 stroke basics ... Intake, Compression, Spark/Power, and Exhaust.


Grow Young magnum!  Just a little juvenile humor 😁

No worries here ... I get the humor, but was unsure if the call for moderation was posted in jest.

By the way ... I'm kinda old too. 
'74 CB750K

Offline Deltarider

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Re: I dropped my '74 CB550 and now it's a mess. Help!
« Reply #35 on: September 08, 2017, 12:13:55 PM »
To be honest: I didn't know what was ment but... I didn't give it much thought either.
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Offline kylenoland

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Re: I dropped my '74 CB550 and now it's a mess. Help!
« Reply #36 on: October 21, 2017, 03:13:56 PM »
Thanks for all the replies, it was really helpful to read through everything. In case anyone cares for an update, I guess I got lucky with my rectifier purchase. Once I installed the new one everything sort of fell back into the plae and the bike felt like it did before the drop.

I still have a charging problem, but all the advice to favor lower gears while riding in town has definitely made an improvement.

I picked up a shop manual and multimeter today. I'm going to test the stator according to a couple of YouTube videos I found and see if I can determine at what point the charging system is falling down.

Thanks again! This bike is a blast : )

Offline Gene

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Re: I dropped my '74 CB550 and now it's a mess. Help!
« Reply #37 on: October 21, 2017, 04:43:54 PM »
I still have a charging problem, but all the advice to favor lower gears while riding in town has definitely made an improvement.

There will always be a charging "problem" - at least compared to modern bikes - but it sounds like you're on your way to vintage fun-land :)
*1973 CB750K3 (Bow)