Topic: This noob bought a non-running bike, finally got it started today... what now?

[mj1176]

Hey guys. Thanks for all your help, first off -- I try to be a google-fu master and refrain from making posts and so far it's been an amazing learning process. But I'm at a point where I just don't know enough to decide how to proceed. Get ready for a long one, or scroll for the TL;DR.

I'm new to motorcycles. I've got a very general understanding of the important stuff and one failed CX500 project under my belt (bought it, put like $500 into aimless things only to find out it had bad compression, sold it for what I paid to a better mechanic than I). About three months ago when my buddy told me he was selling his '75 CB550F, which I had seen running about a year prior, and he'd give me a good deal on it. Said it ran great when he garaged it during a move, then it sat in the rain for a couple days and wouldn't start, so he put it back in the garage and it sat until I saw him, about 6 months later. I went to look at it and it looked pretty good for 40+ years old... had brand new tires, good stock paint, clean chrome mostly. Came with a Clymer manual and a nice chain lock. So I bought it. (Obligatory pic here: http://i.imgur.com/FXnY3Wy.jpg)

It also came with a receipt from it's most recent servicing, which was about a year ago at Limey in Austin, TX. This was from when he first took it to them after buying it, and they did the basics to get it running - carbs cleaned, new spark plugs, timing done on the stock points, new oil. The notes said the points were on their last leg and it needed a Dyna, but that otherwise it was a pretty standard CB resurrection job.


It still had months old ethanol gas in it so I emptied the tank, did some basic de-rust and cleaning with vinegar, and dried with alcohol. The petcock was beyond #$%*ed (previous owner also mentioned it leaked after he tried to rebuild it) so I replaced it. I happen to have one of the finicky dual output ones that you can only get from dgs on Ebay for $100, lucky me!

Then I took a look at the carbs, they weren't siezed or anything but they didn't move as freely as they should and I could see some varnished gas and corrosion in some of the inlets. I knew I'd want them clean regardless of whether it ran at this point so I took them off the bike and back to Chris at Limey (can't recommend him enough!), who stripped them down, put them in the ultrasonic cleaner, and replaced what needed replacing.

I got the carbs back on the bike, and the throttle felt very sticky. Tried lubing / adjusting the cables, no difference. A whole replacement set with push/pull and clutch cables was only $30 shipped so I got one. And a Dyna S. And a new seat cover, because why not?


And that brings me to today. I replaced the throttle and clutch cables and adjusted them with no issues, all throttle stickiness gone and the clutch feels like butter. Installed the Dyna with no problems and after double and triple checking both the 1-4 and 2-3 positions I'm fairly sure they're in proper static timing. Put the new petcock in the tank and fitted a couple inline fuel filters before the carbs, which made for a bit of a wonky fuel line arrangement on one of the outlets but I tested it and it seems to flow normally. Threw a fresh AGM battery and new spark plugs in it, set it at 1/2 choke, petcock on, killswitch to OFF, spun the starter for a second and then flipped the switch to RUN while it was spinning, sure enough she coughed and started right up! (Which felt pretty damn amazing by the way, thanks for all of your help in getting there!) A labored idle for a few seconds, then after adjusting the idle screw to about 1200 rpm it was stable... just not sounding good. I know that's vague and I don't know what a "good" running CB sounds like, but that's what worries me.

I know it's hard to hear what I'm talking about via a video but here's a video:

Just doesn't sound "good. If I had to describe it I would say it sounds like there's what you'd call a "knock" but I'm really not sure, and that specific part of the sound really doesn't come through well in the video. And according to my roommate, who's a much more experienced gearhead than I, the sound you can hear in the portion where the camera is behind the exhause is probably a misfire, which I also don't know anything about.

So, at this point, I'm just trying to figure out where to go next. I know it probably needs the carbs synced and I may have found someone close to me in Austin who's willing to bring over a sync tool to help me do that. I also bought some feeler gauges in order to set the valves properly, I do hear a bit of that sort of clattery sewing machine sound that I'm pretty sure means I need to adjust the valves?

Also, the first and second time I ran it, after I stopped it I noticed some fuel leaking from the drain tube that comes off the plenum. I cleaned the floor thoroughly after each time so I could check for it the next time, and on the third time it didn't do it. Not sure what that indicates or if it's just some "old bike first start" funkiness.

Any help would be appreciated!


TL;DR: Bought a '75 CB550 that had run for awhile then sat for 6 months, wouldn't start,  had carbs cleaned and installed Dyna ignition, new oil, replaced clutch / throttle cables, new spark plugs, got it running. But now it sounds kinda weird and I don't know what to do next. Here's a video:

[jonda500]

I don't hear anything too bad - just the usual primary chain rattle when there's no load on it (yes synching the carbs will help this). Sounds to me like it just needs a good long ride to blow the 'cobwebs' out (then drain the oil while it's hot and refill with new oil even if you've already changed it).
John

[b52bombardier1]

Make sure the oil is JASO MA rated for wet clutch engines. Regular car oil can damage the clutch friction disks - car oil can be too slippery.

Rick

Sent from my SAMSUNG-SM-N900A using Tapatalk

[DaveBarbier]

I agree, actually sounds pretty good. My 550 has a different but faint noise if I run it in neutral on the side stand. If I pick it up and hold the clutch, it goes away.

Regarding the ignition, I'll only say that these bikes never need electronic ignition. Often times it's more of a headache. Points are cheaper and easy to set. I think that was just an up sell. In my opinion, and I don't own nor ever used a Dyna, points are superior as a whole. Meaning reliability, ease of use and service, performance and cost.

Next, does your petcock have an internal screen? Since you cleaned your tank you don't need the extra fuel filters. They could give you issues when you're at higher RPMs and the carbs are demanding more fuel. As long as your tank is clean then there's no need. Just don't pour sand in your tank . Assuming the tank is actually clean with no rust flaking off.

I just read that you didn't adjust the valves yet. Do that NOW! Do ALL in the 3k mile service in the manual. The bike sounding like a sewing machine means it's running well, haha. Angry sewing seems more like it.

What are you calling the "plenum" where you saw fuel leaking?

Nice bike!

[CycleRanger]

Howdy from near Austin! 

[mj1176]

I don't hear anything too bad - just the usual primary chain rattle when there's no load on it (yes synching the carbs will help this). Sounds to me like it just needs a good long ride to blow the 'cobwebs' out (then drain the oil while it's hot and refill with new oil even if you've already changed it).
John

Glad to hear, I'll do that and report back!

Make sure the oil is JASO MA rated for wet clutch engines. Regular car oil can damage the clutch friction disks - car oil can be too slippery.

Much appreciated, I'm currently running Rotella T 15w40 based on the recommendations I've read here, should be good.

I agree, actually sounds pretty good. My 550 has a different but faint noise if I run it in neutral on the side stand. If I pick it up and hold the clutch, it goes away.

Regarding the ignition, I'll only say that these bikes never need electronic ignition. Often times it's more of a headache. Points are cheaper and easy to set. I think that was just an up sell. In my opinion, and I don't own nor ever used a Dyna, points are superior as a whole. Meaning reliability, ease of use and service, performance and cost.

Next, does your petcock have an internal screen? Since you cleaned your tank you don't need the extra fuel filters. They could give you issues when you're at higher RPMs and the carbs are demanding more fuel. As long as your tank is clean then there's no need. Just don't pour sand in your tank . Assuming the tank is actually clean with no rust flaking off.

I just read that you didn't adjust the valves yet. Do that NOW! Do ALL in the 3k mile service in the manual. The bike sounding like a sewing machine means it's running well, haha. Angry sewing seems more like it.

What are you calling the "plenum" where you saw fuel leaking?

Nice bike!

Thanks By the plenum I mean the air chamber between the airbox and the carbs, in this image it's #12, leak is coming from tube #17.

The petcock does have an internal screen, but the tank is...well, scary inside. It's got a botched kreem job and some rust, I cleaned the flaky stuff out as best I could but the inline filters are a stopgap solution until I can decide whether I want to get a new tank or have this one de-rusted and red koted by someone who knows what they're doing. I'd really love to keep the stock one because I love the stock paint but...it's really not in good shape. Also gives me an excuse to pick a different color!

re: the ignition, from what I understand the last time the points were adjusted (back at Limey around a year ago) the plate had to be adjusted to the maximum spec of the three screw holes. So I guess what you're saying is the Dyna wasn't necessary in the sense that I could have either extended the screw slots in the plate or replaced just the worn points and kept it going? I did keep the original points setup so I could always go back if the Dyna dies on me, but it was an easy install and the bike seems just rearing to go on the first kick/button push, so I'm pretty happy with it.

I'll be performing a valve adjustment and carb syn in the next day or so, then a quick ride to "shake the cobwebs off" as Jonda says, throw some new oil in it, and I'll be back to update y'all

[70CB750]

Welcome.

[Phinn]

The fuel leak sounds like a float problem. I can't tell from your post exactly what your carb guy did, but if I were you, I'd verify the float settings and the integrity of the floats themselves before proceeding. Even if you set them exactly right, the float valve will wear a divot into the float's tab that interferes with its smooth operation.

Did you look at your plugs to see what the combustion conditions are?

[DaveBarbier]

Thanks By the plenum I mean the air chamber between the airbox and the carbs, in this image it's #12, leak is coming from tube #17.

Does sound like a float is getting stuck and the bowl is overfilling. If the fuel level is rising in that bowl enough to go out the intake plenum then it could also be flowing into the engine, which would thin out your oil.

Normally, during an overfilling carb bowl the brass overflow tubes inside drain the fuel out on to the ground. If that's clogged then it won't drain and it'll spill out of the next highest point. I'd check the oil level and see if it's higher than normal. Rapping on the bowls with a screw driver handle can unstick a stuck float.

So I guess what you're saying is the Dyna wasn't necessary in the sense that I could have either extended the screw slots in the plate or replaced just the worn points and kept it going?

I don't know the exact circumstances but I'd say it wasn't necessity. You never need to elongate the slots. You'd just need to clean or replace the points, gap them per the manual and set statically and then verify dynamically by running the bike and using a strobe. Since it's working obviously no need to change it . It did sound like you were unsure of the idle timing. Best to double check it and also check the advance with a strobe.

I'll be performing a valve adjustment and carb syn in the next day or so, then a quick ride to "shake the cobwebs off" as Jonda says, throw some new oil in it, and I'll be back to update y'all

Cool!

[calj737]

Before you commence adjusting carb floats, drop the bowls and clean the internals. With rust and a failed liner, I would suspect debris is causing the overflow, not float height.

It's easy enough to reclaim that tank. Some acetone inside will eat the liner and there's a myriad of methods for de-rusting. Whether you re-line it is dependent upon whether there are pinholes afterwards.

[Duanob]

Yep, what cal said. You can tell if it's just debris when you get some over flow just shut your tap off and on a couple of times and if it clears up it's just some tiny crud on the float valve.

If there aren't any holes in the tank there is no reason to line it. Lining a tank over rust is just a lazy man's quick fix that won't last too long. Then you will have bigger problems with the liner flaking off where there was rust and really clogging your fuel system.

Rotella 10W-40 should be fine that's what I've mostly used. But "car oil" won't damage anything and if it's not synth oil it won't be too slippery for the clutch. And that's all I'm going to say about that for the sake of another long divisive oil thread. FWIW I can't even find non-synthetic motorcycle oil anymore locally. I've been to two motorcycle shops and my local NAPA store. All newer bikes can use it fine but not many stores cater to our old scoots anymore. I've found EBAY works good for hard to find stuff even NOS parts and supplies and tools.

BTW Pics or it really didn't happen! 

[mj1176]

Thanks Dave and Phinn, checking the floats and making sure the drain tubes are clear will be added to the list for today. @ Cal and Duanob, that pretty much confirms what I thought regarding the tank... I love the original paint but I think no matter what happens I'm going to have to just strip it down inside and out if I want to run it on the bike long term. Maybe there's someone on here who wants the stock painted one I have and has a repaintable one with a cleaner interior lying around?

Is the picture in my OP not working? Or do you want pics of how it sits now? Still gotta get the new strap attached to complete the seat cover replacement but I'm down to post a couple recent shots tomorrow... it's got new grips, been cleaned up, certainly looks better than when I got it!

[calj737]

Don't swap or discard that tank. It can be saved and re-used. It's actually very easy to purge the insides.

[BomberMann650]

That noise didn't go away with increased RPM.
So I can't say I agree it's "just primary chain slap"

And there's a burble, so either rich mix or a valve aint seating.

Sounds a lot like my bloo hahha

[mrbreeze]

Before you do a carb synch (which is the last part of the tune up).....Make sure the float heights are verified. Look up "clear tube method".....many threads about it. Adjusting float height per the book (measured height) should get you in the ball park to run but not always precise. These bikes are kinda finicky about all cylinders running together. When dwell, timing, valves, cam chain are all adjusted properly and you have even compression between the cylinders, it should run strong with the carbs (clean carbs) all on the same page.

[Bankerdanny]

Follow the procedures in the manual to set the valves and adjust the timing chain, both of which should be done with the engine stone cold.

You should find out from your shop EXACTLY what carb parts were replaced and what brand of kits was used to replace them. Generally speaking all that needs replacing on even the oldest and grungiest carbs are the gaskets and float needle. The jets and slide needles should just be cleaned and reused. The brass parts in many carb kits cannot be relied on to actually be the correct jet size and needle profile. Even the float needles can be suspect. You will find lots of threads here about needles that are too short and allow for overfiling of the carbs. Genuine Honda float valves are worth the upcharge.

[mrbreeze]

Good point Danny. Steer away from cheap carb kits if possible.....Keyster comes to mind but there are others.

[mj1176]

Wow, thanks for all the input y'all... so, just so I'm clear, you're recommending I check the bowls for debris even though the carbs were pulled apart and cleaned? The shop only replaced the gaskets and I verified that no aftermarket jets or needles were used, so I think I'm good there... between the petcock filter and the in-line fuel filters I installed could there really already be debris in the carbs? The bike has only run for a total of about 30 minutes since I first got it started. Either way, my next step is definitely the valve and cam chain adjustment, then start again and see if the running condition has improved. Will do this as soon as I get off work and get back to y'all ASAP. Thanks again!

[mrbreeze]

Get a good strong flashlight and have a peek into the tank. If you see rust...there will be problems. It does no good to go through all the hassle of cleaning the carbs if the fuel supply is full of debris. The filters will quickly clog and give you delivery problems. An aftermarket filter of the right type and routed properly shouldn't be too bad of a problem but I would still use the stock strainer in a clean tank ahead of it.

[Bankerdanny]

You said that the bowls only leaked a couple times then stopped. Since you have a 550 with screw on float bowls, I would take a wait and see attitude and see if the problem recurs. It's easy for the 750 guys to recommend pulling the bowls since theirs is held on with a clip. To get them off the 550 carbs you really have to pull the carbs, which is a pain in the ass.

[calj737]

If your Kreem liner is failing, it can pass the filters and coagulate in the carbs when exposed to Ethanol-based fuel. It's a simple diagnosis that may prevent you from yanking down the carbs. It doesn't take much at all to upset a float valve...

[Duanob]

If you want to see what ends up in your carb bowls take a white or light colored small plastic bowl and drain the contents of the bowls into it. If you have a clear tube tool that's a great time to check the float heights as mrbreeze mentioned.

http://www.ebay.com/itm/Mikuni-Carb-Float-Level-Tool-Suzuki-GS550-GS650-GS850-/272077723396

[mj1176]

Ok y'all, finally had a chance to do some work on the bike. Fixed some things, found some new and pressing issues.

I had already done the timing when I installed the Dyna and everything is good there, so next step was valve adjustment -- did that according to the Clymer manual and using the go / no-go technique (thanks sohc4 folks!) with no issues. Then I adjusted the cam chain tensioner per the book as well - TDC for cylinder 1, 15-degree adjustment measured by the spring holder screw, loosen the lock nut on the chain tensioner. The screw did not visibly move when I loosened the nut all the way, so I checked it for movement according to the book. It wasn't seized, but it only moves about a quarter of a turn or so in either direction...not sure if that's within proper spec. I turned it all the way counter clockwise as and let it return, which it did about 1/8th of a turn, then tightened the nut back down. I also got my hands on a carb sync tool, one of the needle gauge style with dampers. I checked the tool for any inconsistencies across the 4 gauges using cylinder 1 at idle and from what I could tell only one of the gauges was out from the other three, and only by about .5 mm of vacuum. I noted that on the gauge and proceeded to start the bike, and warm it up by letting it idle at around 1200 rpm. It already idled smoother and more consistently than before the valve / cam chain adjustment, quite happy with that, but it still seemed a bit labored, and died twice in the first couple minutes before it would sit and idle without me doing anything. I was moving around the bike to hear how it sounds while waiting for it to warm up for the carb test, and that's when I noticed I had about a 1" diameter hole in my muffler right where it meets the collector after the end of the headers. I investigated further and it turns out the entire joint between the muffler and that collector was rusted out and leaking heavily. I removed it and cleaned up as much rust as possible... the headers are fine all the way down to the collector, and the 2 inches or so of the collector which the muffler is supposed to attack to is completely rusted away. Here's what it looks like: http://i.imgur.com/GlYMnqX.jpg

 My current plan was to see if I could have someone cut off the rusty garbage at the end and weld another 2" OD pipe to the collector so I can attach another muffler (I have a Mac cone style with a baffle laying around, seems a pretty similar length to the stock one and I confirmed it has the same baffle/flow style. But for now, it's got no muffler and is exhausting out the collector at the end of the headers. Not sure if it's even still worth me trying to diagnose the running condition until I get a proper muffler on there, but I was hoping y'all could help me out with that. I also don't know how much my seemingly quite dirty air filter is affecting the running condition, but I ordered a Uni NU-4055 that should be here tomorrow so I'll be able to see if that makes a difference pretty soon.

I was on a roll so I decided to try to sync the carbs anyway. Perhaps predictably, it was a little hard to tell if I was doing it right. I was following the Clymer manual and also going on threads I had read here; right off the bat I was confused by the fact that most of the internet says "it doesnt really matter how much vacuum the individual gauges read, only that they all read the same," whereas the Clymer manual says proper operating range is 16-24 mm hg, and my gauges seem to read in "mm of vaccum," not sure if those both refer to the same unit. While idling my carbs were all reading somewhere between 5 and 10, so I tried increasing them one by one (loosened lock nuts, tightened adjustment screw per manual) in order to get them all up into the proper range before syncing them. This caused some issues; every time I made an adjustment the idle would start to bog down a bit and I'd have to blip the throttle to settle it, then adjust the idle screw a little to get the idle RPM back up to around 1200. It would do this every time I increased the vacuum on each carb, and finally I got to the point where the gauges were reading around the 12-16 range, but I had screwed in my idle screw so much that I probably only had two or three more full turns before it stopped. Again, I don't know what's normal or spec, but that seemed like way too far in to be needed just to keep the bike at 1100-1200 RPM, and the increase in vacuum on all the carbs didn't seem to make it idle any better...the adjustment screws were also getting closer to the end of their adjustment range, not sure if that's ok or if it indicates problems. So I decided to just revert the changes I had made and sync the carbs in their original reading range from 5-10. I got them all back down and synced right at 7 on the gauges, and the bike was idling slightly better than before I started the sync. Still not what I'd consider smooth, still a bit labored and jumpy, with the occasional small blip of a hundred RPM or two. But it definitely didn't sound like it wanted to die and that's progress. I'm going to take a short and gentle test right tonight to "shake out the cobwebs" as recommended and then make another video to record how it sounds and report back here. Onwards and upwards!

[DaveBarbier]

Yeah I'd say that collector has seen better days. Depends on the thickness of the metal but it could be fixed. I'd see what the welder says.

The cam chain tensioner screw won't be loose, it will be fairly tight and only rotate a bit then spring back. At least that's how mine is and it's in good shape.

As far as the sync goes, I've also read and have been told that the measurement doesn't matter as long as they're all the same. I'd stick with that and not what the clymer says. The clymer is actually a crap book in some respects. Typos and some things aren't explained properly in my experience. The factory service manual is much better and can be downloaded for free of the site.

Any leaking gas anymore?

[mj1176]

No more leaking gas. After you all explained your thoughts on it I gave each float bowl a light tap with the rubber end of a screwdriver and remembered that the first two times I had it running I forgot to turn off the petcock. Ever since then every running test I've done has resulted in no fuel drips so I think I'm in the clear there.

[mrbreeze]

I don't know if it has been mentioned but get a fan or 2 blowing on the engine when you are doing the synch. If you spend too much time fiddling with it while running you can overheat it.

[DaveBarbier]

No more leaking gas. After you all explained your thoughts on it I gave each float bowl a light tap with the rubber end of a screwdriver and remembered that the first two times I had it running I forgot to turn off the petcock. Ever since then every running test I've done has resulted in no fuel drips so I think I'm in the clear there.

Hopefully you won't be leaking anymore, but the tapping with the screw driver handle is only for a float that is currently leaking fluid. Like, as fluid is coming out, you tap on the bowl and it'll stop.

But since you had fuel leaking out the plenum, to me that means that a float overflow tube is clogged. It should never get up that high to come out the airbox or engine side. You can remove the bowls and spray carb cleaner through the tubes to make sure they're clear.

Something else that can help your possible poorish idle is removing the plug caps and trimming off about 1/4" of plug wire to get to clean copper. Might help to test the resistance of the plug caps too will they're off. Should be around 5k ohm. They only cost like $2 a piece if you need to replace them.

[mj1176]

That sounds like a plan, I'm all about clean copper connections and clean plugs. I'll do that tomorrow -- the test ride went pretty great, she's spitting and coughing a bit on deceleration but from what I understand that's to be expected running it with no muffler? I'm over the moon right now -- as a new rider, avid tinkerer, and lover of all things Honda... I'm just ecstatic. Thank's again for all the help y'all. Now to get it in perfect running condition 

video of how it's running now after the tuning / break-in ride will be posted tomorrow, hooray for progress

[BomberMann650]

Ah, the ol Italian tune-up ride.

[mj1176]

Still no video of post-tune running, it's been a hectic week. But I put in a couple more rides and it seems to be running way better. Starts and idles easily, still a couple hiccups here and there but I'm going to wait until I get the exhaust fixed before I try to diagnose any of that. Right now my main focus is the tank, I searched and the availability and cost of replacements are prohibitive to me riding the bike again ASAP, so I decided to give up on preserving the stock paint and strip it down to the metal to see if the pinhole is isolated or if the rust had really spread. Turns out - not the stock paint after all! There was a bit of bondo underneath where someone had filled in a dent, and on the bottom of the tank I can see a little bit of what I'm 99% sure is the stock orange flake color this tank originally had. So I feel a lot better about giving up on preserving the paint. The pinhole definitely seems isolated but the inside of the tank is pretty cruddy, so right now I'm just trying to decide whether I can tackle the prep myself or if I should just bring it to a radiator shop and have them take care of it. I'm pretty confident I can properly apply POR-15 myself. Hopefully by the end of this week I'll have the tank at least ready for the POR and then I can tackle the exhaust.