Author Topic: 1975 CB550 Sat since 1983 (Read 20040 times)

Tews19 · « **Reply #50 on:** September 19, 2012, 01:17:09 PM »

Thinking gas in tank as well

saxamaphone · « **Reply #51 on:** September 19, 2012, 01:27:36 PM »

I just went and checked to make sure. I've been checking that over the past few days. The tank is 1/3 full. There plenty of gas coming out of the tank (turned to "on" and "reserve" and the carbs are filling as well. I've drained them a few times in the past couple of days. I even took them off to make sure the jets were clean yesterday.

It does sound like it might not be getting gas. Could doing any adjustments to the points and ignition timing affect the spark plugs? Reaching for straws here...

Here's another thing. When I first was checking and adjusting the timing the points would literally spark at the F mark. You could hear it as well. Now, I still get a reading but I don't see or hear a spark. More info just in case.

mono · « **Reply #52 on:** September 19, 2012, 01:33:29 PM »

Quote from: saxamaphone on September 19, 2012, 01:27:36 PM

Could doing any adjustments to the points and ignition timing affect the spark plugs? Reaching for straws here...

Here's another thing. When I first was checking and adjusting the timing the points would literally spark at the F mark. You could hear it as well. Now, I still get a reading but I don't see or hear a spark. More info just in case.

Yes, very much so. if your timing is off, it isn't going to run and can sound like it's fuel-starved (been there, done that!) -- clean and adjust your points per the manual. even the slightest gap difference can make it not run, it's kinda crazy.

saxamaphone · « **Reply #53 on:** September 21, 2012, 11:41:37 AM »

Finally got it going! I'm feeling pretty stupid at the moment. One of the spark plug caps wasn't on quite enough. For some reason, one of them feels like it's on but then needs an extra hard push after that. Now it runs.

Once started, it sounded very good at first, then the knocking and cam chain noise started coming back. The high idle blip was gone however.

I then checked the point gap and timing again. The gap was good however the timing had changed a tiny bit.

One weird thing is when I'm adjusting the 1-4 timing plate, it can look like it's not getting spark on the multimeter, but if you screw in the screws then it will be getting spark at that position. So I've set it by moving it a tiny bit, tightening, checking, then repeat until there is spark.

Using the screwdriver to the ear method, the knocking sound seemed to be coming from the area of the transmission. The valves sound very smooth. The knocking gets better when you have the clutch in and at higher rpms. Sometimes there's also what looks like exhaust coming from the back end of the gear case. Doesn't really look like smoke but could be. I'm going to see if I can look in there this weekend and see what's up.

One more set back: after getting the rust out of the tank a few weeks ago, a leak developed yesterday. It's at a spot on the underside that had been fixed. I know this is common but still frustrating. I'll probably have to seal it now. I'm thinking of using Por-15 simply because it generally has good reviews and I can actually go buy it, rather than having to order something like Caswell's tank sealer.

RAFster122s · « **Reply #54 on:** September 22, 2012, 08:40:35 PM »

Be sure you clean and degrease the tank before you POR it, proper prep with any sealer is critical.

Crankcase could have excess pressure from blowby on rings.
There is a oiler in front of the front sprocket that can clog. Isn't the crankcase vent near that area of the case as well?

Hopefully with some running and a good oil change or two after every hundred miles the rings will seal better. With bikes that have sat it is sometimes a coin toss on their revival that they weren't parked with issues that time erases from the PO memory.
Oil passages to the head can have issues that can wreck the cam and head.

Clutch rattle?

Sounds like you have a running example some tuning and care can bring back to the streets again with some tlc.

RAFster122s · « **Reply #55 on:** September 22, 2012, 09:07:11 PM »

Also, like Tews said, carb sync can be amazing how it eliminates some noises on a motor. Be sure your timing is spot on and adjust the cam chain if you haven't. Then when those are rock steady sync your carbs.

Your smoking could be worn valve guides.
Give it more time to settle in and change the tires before riding, don't want to drop it because of bad tires when you have them on hand. Make certain the spokes all sound similar when struck with something hard to make them reasonate like a guitar string. Loose spokes invite disaster on tubed tires if they break.
Learned that lesson the hard way on a used bicycle I was commuting with on the way home one summer evening after a long day at work. One or two spokes broke after crossing some gravel in the bike lane at a street crossing doing about 15-20. Tube blew, tire punctured, rear end snaking back & forth... rim wobbling and warped. I was lucky to stay upright, not eat it and to not end up in traffic. Bike lanes aren't very wide when things go squirrelly on you.

saxamaphone · « **Reply #56 on:** October 02, 2012, 10:54:25 AM »

Hi guys, I've been getting a few things done recently. I'll update with some photos too.

Right now I was wondering if anyone has replaced their glass gauge face covers with anything else, like plexiglass or plastic? Finding someone to cut a glass circle that small and thin is proving difficult and expensive.

DustyRags · « **Reply #57 on:** October 02, 2012, 11:26:52 AM »

I had a knock coming out of my transmission after a top-end rebuild a few days ago- timed it, and it went away. Seems like the cylinders firing in no-quite-perfect time or with varying amounts of fuel can cause the engine to slightly speed up or slow down, and every time it does it switches from "pushing" to "pulling" the gears in the transmission (depending if it's driving the gears, or the momentum of the gears is beings lowed down by a slower piston). I hear a carb sync will fix that- that's my next step too.

Get that timing spot on. I did mine by checking the timing (use a blinkylight), adjusting the plate, checking the timing, adjusting the plate... and snugging down the screws each time, but not really tightening them- just enough not to move. When I had it all sorted, I cranked them down nice and tight.

saxamaphone · « **Reply #58 on:** October 02, 2012, 11:35:08 AM »

Definitely good advice Dusty, I static timed it but going to do a dynamic timing with a light after I get my tach back on the bike. Just fixed it yesterday but I'm looking for something to replace the cracked glass cover now.

Here's an embarrassing question: I borrowed a very old timing light from a friend's father and it has the red and black clamps for the battery but it also has a third wire with a spring on it. I've read that it attaches to the spark plug but I'm not sure where. Between the top of the plug and the boot? Or between the boot and the wire to the coil? Not sure if it will still fire the cylinder with this spring between them.

DustyRags · « **Reply #59 on:** October 02, 2012, 11:52:08 AM »

H'm, not sure. I know my Clymer manual explains that, if you have one, check that. I'm at work right now, so I can't get to it. Google? I have an inductive one that came with the bike, and boy howdy is it easy to use! Don't have a tach either, so I just went by ear. Maybe the wire coil is an old inductor?

Amazon's got an inductive timing light for about $17 right now. Might be worth it. http://www.amazon.com/Tooluxe-Xenon-Automotive-Timing-Light/dp/B000TE46SY/ref=sr_1_2?ie=UTF8&qid=1349203876&sr=8-2&keywords=timing+light

saxamaphone · « **Reply #60 on:** October 03, 2012, 01:01:18 PM »

I found a place here to cut the glass covers for the gauges today, for $5! So I'm getting a few extra. They are 9.2cm (diameter) and 2.3mm thick just in case anyone needs that info.

While I'm waiting for them to be cut, I started addressing an exhaust leak at the #4 exhaust. Everything is fitting tightly there but I realized one thing I hadn't done yet is replace the copper exhaust gaskets. I took off the Mac 4-1 to check out what condition the copper gaskets were in and this is what it looks like:

Pretty dirty in there, no? The marks are from my finger. I wasn't able to get the copper part off. It's very flat. Any suggestions for getting that out? Or maybe it's only a copper film left from the gasket?

TwoTired · « **Reply #61 on:** October 03, 2012, 01:17:10 PM »

The exhaust gaskets are doughnut shaped when new and flattened when the header is cinched up.

The copper IS the gasket, and it will pry out with a right angle scribe or small sharp tip screwdriver.

Always support the muffler end of the header in final position when cinching down the new ones. Otherwise, the top of the gasket will crush more than the bottom and leaks will develop.
Learned that one the hard way.

Ever look at a campfire site the morning after? Pretty dirty there, isn't it?

Cheers,

saxamaphone · « **Reply #62 on:** October 03, 2012, 01:35:58 PM »

I'm glad you didn't say "wow, you need a new engine!"

You're absolutely right about the campfire analogy. That's great advice about supporting the headers in place as you tighten. You can see in one of the pictures below that the gasket wasn't crushed evenly around. Thanks very much.

Of course right after I posted that, I went back out and got it out by prying from the inside of the ring rather than the outer edge. I have replacements already luckily.

The exhaust is brand new and I've only run it maybe a dozen times, mostly just idling it while working on it. Is it normal for the inlets of the headers to get so caked with carbon so quickly?

Same one with the flash.

Here's the exhaust outlet without the gasket just for kicks:

The old gasket, very crushed.

DustyRags · « **Reply #63 on:** October 03, 2012, 01:46:50 PM »

Given how idling engines will put out more soot, I wouldn't be hugely surprised by this. I mean, you can hold a piece of tin over a candle and get a soot layer almost immediately- it happens fast. But it won't keep building up.

TwoTired · « **Reply #64 on:** October 03, 2012, 05:41:49 PM »

Ideally, the exhaust deposits would be a light tan. However, these engines idle rich, and choke operation adds even more black soot. A good long run on the freeway 20 minutes or more, ought to blow out the carbon and leave lighter deposits. Of course, that is with an all stock engine, induction, and exhaust system. Change something, and the carbs are almost certainly providing less than ideal mixture ratios over some part of the operating range.

Cheers,

dergs713 · « **Reply #65 on:** October 03, 2012, 06:35:59 PM »

good luck man if you have any q's ask me. just got my 75 550 on the road. sitting since mid 80's as well.
matt

saxamaphone · « **Reply #66 on:** October 05, 2012, 11:12:30 AM »

Glad to hear you've got your bike going Matt. How's it running so far? Does it feel like it has kick when you start off, say from a red light?

I'm trying to sort out all sorts of little problems (it starts and idles well luckily). Persistent cam chain noise, an idle that hangs at 2-3k rpm occasionally, and knocking that I'm hoping will go away when I get the carbs synced. I'm waiting to do that until everything else is done.

saxamaphone · « **Reply #67 on:** October 05, 2012, 11:57:15 AM »

Here's a little update of the stuff I was able to get to over the last few days.

Installing the new exhaust gaskets. I ended up using a tiny bit of grease to get them to stick in place while getting the headers in place.

I took apart the speedo and tach and luckily both turned out to be the same easy fix. Here's a link to a separate thread about that: http://forums.sohc4.net/index.php?topic=113301.msg1274551#msg1274551

I then had to replace the glass in the speedometer because the original was cracked. I found a place to cut the glass for me (cheap so I got extras

but discovered that they were cut a tiny bit to big to sit snugly in the speedo. So I took a small diamond file to one of them and after about 30mins of filing, it fit in well. I opened the speedo first and during the process realized there has to be a better way. I picked up a small paint can opener from Home Depot and a large enough plumbing clamp. That made the tach go much better.

The metal ring around the speedo wasn't getting high enough to crimp down so my friend and I built this little thing, similar to this way http://youtu.be/oJxG6Y70qwE.

I also finally got a timing light that worked. I had borrowed a couple from my friend's dad but neither worked. He warned me about that since they hadn't been used in 20 odd years.

Here's some questions hopefully someone can help me with about the timing:

Should the F mark be pretty much stationary in the light? Mine wobbles a bit left and right but not really outside the timing mark.
Also, do you time 1-4 with the gun attached to #1 spark plug, check the advance at 2500rpm or so, then repeat with #2 spark plug and 2-3? Just wanting to make sure I did it right.

Should the advance marks ever go to the left of the timing marker? Mine did by just a bit at around 3k rpm. They were also seeming to move a bit left and right, although I found it hard to hold the bike steady at 2-3k rpm.

Thanks and have fun riding (or just wrenching in my case).

saxamaphone · « **Reply #68 on:** October 05, 2012, 12:38:21 PM »

One more problem I'm seeing: the new Mac 4-1 exhaust is leaking around the clamp that holds the header piece to the muffler. It leaks water mostly and steam/exhaust as well.

Anyone experience this kind of thing with Mac 4-1s? I've tightened the clamp pretty tight and no difference.

TwoTired · « **Reply #69 on:** October 05, 2012, 12:56:02 PM »

A low point water (condensation) drain is a good thing.

saxamaphone · « **Reply #70 on:** October 05, 2012, 01:13:19 PM »

Thanks TT, good to know. It'll help in avoiding rust there as well. My stock pipes were unfortunately rusted through all over that area.

TwoTired · « **Reply #71 on:** October 05, 2012, 01:18:29 PM »

The stock pipes had a low point drain, too. They are supposed to be checked periodically for clogging.

saxamaphone · « **Reply #72 on:** October 05, 2012, 01:23:53 PM »

It's too bad no one checked for that on this bike over the years. I'm hoping to find some stock pipes down the road sometime.

Any thoughts on this spark plug wire? When timing the bike yesterday, I noticed occasional idle hiccups where you could see the timing light skip. Basically strobing steadily with the occasional miss. Made me think perhaps one or more of the cylinders doesn't spark occasionally so I checked the wires to see if anything was up. 2 and 3's seem like there isn't much wire left to make contact with the spark plug cover.

TwoTired · « **Reply #73 on:** October 05, 2012, 01:32:38 PM »

Do the plug caps screw on tight?

saxamaphone · « **Reply #74 on:** October 05, 2012, 01:36:52 PM »

They are mostly tight except the #2 cap is a little bit loose when on all the way on. It's still snug but has a bit of wiggle room.

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Author Topic: 1975 CB550 Sat since 1983 (Read 20040 times)