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Author Topic: Newbie here saying Hello  (Read 1070 times)

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Offline 78 k550

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Newbie here saying Hello
« on: May 18, 2005, 03:57:03 pm »
Hey All,
 I've been doing alot of reading the last couple day's and must say what a great group this is. I'm not new to bike's just street bike. I have a few Bul's running around. I got a free 72 cb500 last summer in hope of riding it, well all the little project's I have going on. I got it to fire on 1 and 3 but the exhaust pipes are cold after running. The carbs seam to be ok. I have spark at the plug but it might not be to strong. Well while cruising my local junk yard I noticed a motorcycle out back. It turn's out to be a 78 550K complete mostly. It is missing the start switch (Anyone have one) and headlight bucket. I have a spare bucket for my 72 so I will see if it is compatable.  The paint is faded and is the Alpha Red. I bought this not even knowing if it ran. I had it home for a couple hours. I took out the point's filed them set them and put some gas in it and she fired right up. LOL It looked like a sand storm with all the loose partical's in the exhaust that blew out when I reved it up. Oh, I need a tack also, the 500 is slightly smaller. I need to get my lisence and swap out the tire from the 500 to the 550. The 550 has a nice 4 to 1 pipe and the 500 has a kerker 4 to 1. Are they the same exhaust. Will they swap out with each other? Enough for now. I can't wait to ride in the mountain's. I live in CO.

Paul
Paul
Littleton, CO

76/77 CB 750F, 
75 GL1000, (AKA GL1-242 NGWClub),
76 GL1000 LTD
84 GL1200 Standard
6 Bultaco's= 42, 49, 121, 152, 167, 188

MetalHead550

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Re: Newbie here saying Hello
« Reply #1 on: May 18, 2005, 05:21:47 pm »
Welcome!  Does the exhaust on the 550 look original?  Could be an F model(supersport) cuz they came with a 4-1 vs the K model which was 4-4.  Should be no problem swapping.  Lots of parts on ebay but check the for sale/wanted section of the forum too.  Youre in the right place!

Offline 78 k550

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Re: Newbie here saying Hello
« Reply #2 on: May 18, 2005, 05:44:53 pm »
The 78 has the side plates and say's K on it. The pipe look's aftrermarket. Will the rear wheel swap out? The guy had the wrong spacer in the back. While I was swapping it out I noticed the hub had alot of rust on the surface. I'm going to be taking what ever parts I can off the 500 for the 550.
Paul
Littleton, CO

76/77 CB 750F, 
75 GL1000, (AKA GL1-242 NGWClub),
76 GL1000 LTD
84 GL1200 Standard
6 Bultaco's= 42, 49, 121, 152, 167, 188

Offline TwoTired

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Re: Newbie here saying Hello
« Reply #3 on: May 18, 2005, 06:40:28 pm »
For the 500- The 2 coils operate 1-4 and 2-3 respectively.  Both plugs fire each revolution but only one is starting it's power stroke.  Since the problems are on 1-3 it is most likely a carburetion issue with clogged jets.  Pull the plugs and look at them.  They tell quite a story about what is or isn't going on in the combustion chamber.  Usually if they are wet and smell of gas, then it's an ignition issue (maybe a fouled plug) if they are dry and not firing then it's a fuel issue.  Of course other things can cause problems, too.  But, that's usually where I start with an unknown bike.

You'll find that the frames between the 500 and 550 to be different enough that parts swapping will be quite spotty.  I think the rear wheel might go okay, I'm not certain, though.  But, if it does, expect to move everything that's on the axle.

The exhaust systems will interface with each of the two engines.  However, the mount locations for the mufflers will be different.  If your aftermarket mounts aren't adjustable you'll have to make some adaptations.  Neither of the 4-1s have the same flow characteristics as the stock exhaust systems (which were also different from each other between the two bikes)  If jetting wasn't addressed when the replacement exhaust was installed you may have some performance issues.  A friend of mine has a CB550K 77, I think, with a Kerker.  And, he can't get it to sustain 80 MPH. It runs okay below that and he has other bikes. So, he just ignores the problem and just uses it around town. The 77 and 78 had carbs different from the earlier models and I think they were all tuned toward the lean side.  Other issues include possible carbon fouling of the plugs and flat spots in certain throttle positions.

FYI, the K models were stock with 4 into 4 pipes.  The F model cb550s were only made from 75-77.  They had 4 into 1 and carbs jetted and tuned for that configuration.

As for parts missing from the bike...  If you can't find these at local breakers, eBay will have it if you're patient.

Any CB550 tach from 74 to 78 will work on your bike.  The printing style and colors of the dials will not be period correct unless you get one from a 77 of 78 model.  Don't try a CB750 tach, as it will not read correctly due to different gearing even though they look the same.

The starter push button switch disintegrates when a leaking master cylinder bathes it in brake fluid.  Any switch from an SOHC4 from 69 to 78 will work in your housing, I'm pretty sure.  The stock switch interupts the headlight during start so it is somewhat unique for fit and function.

Good luck with your bike's resurection!

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 78 k550

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Re: Newbie here saying Hello
« Reply #4 on: May 18, 2005, 07:09:55 pm »
Thank's for the reply. It helps alot.
Paul
Littleton, CO

76/77 CB 750F, 
75 GL1000, (AKA GL1-242 NGWClub),
76 GL1000 LTD
84 GL1200 Standard
6 Bultaco's= 42, 49, 121, 152, 167, 188

 

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