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Hello,

I am the owner of a $180, back-yard-dwelling '82 GL500 Interstate with ~20k miles. It has no title, no keys, no battery, and has been sitting outside for the past 5-10 years. I believe it has a 2012 inspection sticker on it, so I suppose it hasn't been sitting quite as long as some other barn finds.

BUT, the bike is complete, with seats, all luggage, fairing, etc. At <$200 including a Uhaul trailer, I figured it would be a fun coronavirus quarantine project to see if I can get it running. The engine doesn't turn over, and that's the first thing I'm testing. But I have no idea if the electrical aspects of this bike work either, so its a bit of a wild card.

And now to cut to the chase:

  • Bike is a cheap project, with dreams of restoring but uncertain return on investment. More interested in keeping budget low and learning high, not looking for quick fixes as first option (i.e. $400 eBay engine swap)
  • Removed engine. could turn crank 180 counter-clockwise and back, but has a hard stop after that 180-degree turn.
  • Removed cylinder heads:
    • Left cylinder appears ugly with a little rust staining and blackened valves...but overall seems to move smoothly without serious issues.
    • Right cylinder is brutal. ~1 mm rust build up around upper half of cylinder wall. When turning crank by hand, piston moves downward below rust, but stops abruptly of course when it nears the rust.
  • Considering options:
    • try and scrub away the rust and cross-fingers that rust did not cause real pitting, and a little honing could make the engine operational as-is (I won't hold my breath for this option)
    • Split engine front and rear covers, inspect, and--assuming all is good on pistons and below--buy a $50-100 case block on eBay to swap onto my old engine.
    • If engine bottom end is a mess below pistons, likely will sell bike for parts in a slow, agonizing, and unrewarding fashion
I'll attached a few photos. Please watch this video to see the right cylinder + piston in action.

The day I brought it home:
199667


Removed cylinder heads:
199668


Right cylinder and valves (note extra wear on intake valve surfaces)
199669

199670
199671


Left cylinder and valves (note intake valves are more blackened)
199673
199672
199674


Some of my main questions:
  1. Should I be concerned at the blackening of the valves and piston combustion surfaces?
  2. Is the right cylinder head salvageable with the ugly rust on the valves?
  3. Should I even bother cleaning the rust off the right cylinder wall with some CLR & elbow grease?
  4. Anyone have a great GL500 engine laying around that they'd sell cheap? ;)
Thanks all for welcoming me to this forum. Looking forward to participating and learning.
 

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Discussion Starter #2
I will add a couple more important bits of information:

I drained all oil and it looked smooth and black with no metal particles. Oil filter also appeared normal without any metal.

Coolant was a surprisingly clean when drained, clear green that looked like it could be brand new from last week.

I have plenty of time on my hands for this project. The only reason I would push the project with urgency is my own emotional drive and desire to accomplish something on this bike and learn.
 

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I'd suggest just cleaning it thoroughly, be carefully to remove all garbage before moving the pistons afterwards. Replace valve gaskets, before inserting new gaskets polish the valves, you need to take them out. Remove the cylinder head gaskets and polish the heads and engine surface. Be careful not to add any nasty fissures. My CX engine looked about the same when I began working on it but now it runs like a young calve :)
 

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Before you invest too much money you should check the possibility of titling the bike. The no key is a minor issue. The ignition cylinder has a number stamped on the barrel, that is the key code. it would be nice to have since the bags, trunk and ignition all use the same key. quite handy. Enjoy the Shop Time.

Steve
 

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Before you invest too much money you should check the possibility of titling the bike. The no key is a minor issue. The ignition cylinder has a number stamped on the barrel, that is the key code. it would be nice to have since the bags, trunk and ignition all use the same key. quite handy. Enjoy the Shop Time.

Steve
Thanks Steve. I will definitely be titling it before putting any money into it. But even that will be a few bucks...so I wanted to see what I was getting into before deciding to restore or part out.
Curiously enough, the key code was nowhere to be found on the ignition barrel, but I found it behind the helmet lock. I am in no rush to buy keys though...as I am a long way’s away from needing the luggage or seats. I’ll need to buy a new ignition barrel, though, as this one has been tampered with via screwdriver, and the plastic assembly under the barrel is broken. You think a new ignition barrel could match my existing key code for the luggage and helmet? Or will I just have to live with a separate key for ignition?
 

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Discussion Starter #6
I'd suggest just cleaning it thoroughly, be carefully to remove all garbage before moving the pistons afterwards. Replace valve gaskets, before inserting new gaskets polish the valves, you need to take them out. Remove the cylinder head gaskets and polish the heads and engine surface. Be careful not to add any nasty fissures. My CX engine looked about the same when I began working on it but now it runs like a young calve :)
Thanks for the optimism Hermannson! I am not holding my breath, but I will do my best to make do with what I have. Glad to hear you had good luck.
It’s gonna be a tedious process, but I’m looking forward to it.
 

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Alright, I cleaned off the surface rust and sanded it as well as I could. The piston and crank now move freely when turned by hand. I'm happy! Pitting isn't as bad as I expected. Here is the video:

I'm tempted to take the advice of Hermannsson and just buy new gaskets, clean the valves, and put the engine back without cracking the case. Is that just my own lazy foolishness kicking in? I'm afraid that by cracking the case and investigating more deeply, I would manage to ruin something. What kinds of dangers am I facing by taking the lazy way out? Poor compression? Early death of pistons/crankcase?

Photos below:
199738

199739

199740
 

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Looking at photos I don't think its totally unreasonable to consider leaving crankcase intact. I would hand hone cylinder walls more with emory cloth, maybe 220 grit first, 400 next. Vacuum out residue and lube with marvel oil or other light oil. I agree that further disassembly could open a can of worms, but also acknowledge that not doing so may not produce satisfactory results. Unfortunately when such damage occurs things are not at optimal conditions. As advised by all, several retourqueings of cylinder head bolts is advised with new gaskets, and coating gaskets with copper coat may also provide a permanent seal. After starting a compromised motor it may take some running to free stuck piston rings, and extra oil changes are advised.
 

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I have no knowledge of availability of pistons for these motors, and if a bore job would be required they would be required. Mainly with hand honing, or even a drill driven carbide hone all grit must be removed to avoid ring damage. One could invert motor and use spray solvent to flush fine grit from cylinders. You are taking a risk doing any repair, but honing will only remove a minute amount of metal in this situation, and with a valve and head cleaning and new valve guide seals you may have a viable engine as long as piston rings can make a complete seal. I've heard of many mechanical miracles occurring with a careful mechanic guiding the process. :)
 

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If it fails you are out the cost of a gasket set and your time. The learning experience is always a win, and it may result in a winwin if the motor functions acceptably,,, it's your call, hopefully others with similar experiences will give advice.
 

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Low buck builds can always be interesting. For the bottom end, maybe pick up one of those cheap usb boroscope cameras and see if you can get a bit of a look through the oil fill, timing hole etc etc. See if you see any additional nastyness and go from there.

Sent from my Pixel 4 using Tapatalk
 

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Ya, where's the fun if money is no object? My first bike, 64 Suzuki 120, 200$, current cx650c 500$ before total overhaul,, didn't have crankcase apart but probably 1500$ more in parts ,,, it adds up! If someone wants a new twisted twin Moto Guzzi is still in business as far as I know,,,:)
 

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Ya, where's the fun if money is no object? My first bike, 64 Suzuki 120, 200$, current cx650c 500$ before total overhaul,, didn't have crankcase apart but probably 1500$ more in parts ,,, it adds up! If someone wants a new twisted twin Moto Guzzi is still in business as far as I know,,,:)
Moto Guzzi isn’t a twisted twin. The heads aren’t twisted like the Honda’s are, hence the nick name fir the Honda.
 

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Good point, also not water cooled, and not a Honda! Best bikes of all I've had, from a cl125 to the current vt1100c,, accessible to a shade tree mechanic like me, parts available, incredible engineering, great bikes and pioneers in many aspects of motorcycle history. Ride safe and free:)
 

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Little known fact but Honda first put electric starters on bikes, I luvd the 175s, 350s, 450s and 750s that had both!! Easier to turn motor to set valves and points,,, points! Dang I'm old,,,,;)
 

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Both meaning kick and electric, Ive pretty much wrenched and ridden em all except goldwings, my loss I think, and have the tshirt from sidecar Bob, the art of wrenching:)
 

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Discussion Starter #17
Hey obo515, thanks so much for the optimism. If you couldn't tell, I am reallly biased against going deeper into this engine, and was fishing for confirmation that my laziness is OK :)

Looking at photos I don't think its totally unreasonable to consider leaving crankcase intact. I would hand hone cylinder walls more with emory cloth, maybe 220 grit first, 400 next. Vacuum out residue and lube with marvel oil or other light oil. I agree that further disassembly could open a can of worms, but also acknowledge that not doing so may not produce satisfactory results. Unfortunately when such damage occurs things are not at optimal conditions. As advised by all, several retourqueings of cylinder head bolts is advised with new gaskets, and coating gaskets with copper coat may also provide a permanent seal. After starting a compromised motor it may take some running to free stuck piston rings, and extra oil changes are advised.
I don't care if the engine will run perfectly with stock power and smoothness, but I am hoping it could at least run as-is. I'm already strongly considering replacing the engine case as a whole, so worst case scenario I figure I try my luck with the original engine...and blow it and ruin the pistons and bearings and replace the case + new pistons. I think I'm gonna take that gamble from what I'm reading here, and after examining the old engine oil which looked very good. After all, I hear Hondas are tough.

I have no knowledge of availability of pistons for these motors, and if a bore job would be required they would be required. Mainly with hand honing, or even a drill driven carbide hone all grit must be removed to avoid ring damage. One could invert motor and use spray solvent to flush fine grit from cylinders. You are taking a risk doing any repair, but honing will only remove a minute amount of metal in this situation, and with a valve and head cleaning and new valve guide seals you may have a viable engine as long as piston rings can make a complete seal. I've heard of many mechanical miracles occurring with a careful mechanic guiding the process. :)
I'll take your advice and get some better fine emery cloth and do as thorough a job hand-honing as possible. Great idea with flipping it upside down and trying to spray/vaccuum out any unwanted debris too.

If it fails you are out the cost of a gasket set and your time. The learning experience is always a win, and it may result in a winwin if the motor functions acceptably,,, it's your call, hopefully others with similar experiences will give advice.
Either way I'll keep this post updated. First step is carefully removing and smoothing the surfaces of the old gaskets. The gasket sets I'm finding are ~$120, so I will probably make sure I can title this bike before I invest that money. If anyone has spare gasket sets they are willing to sell at lower cost, I'd love to hear from you.

Low buck builds can always be interesting. For the bottom end, maybe pick up one of those cheap usb boroscope cameras and see if you can get a bit of a look through the oil fill, timing hole etc etc. See if you see any additional nastyness and go from there.

Sent from my Pixel 4 using Tapatalk
This is a great idea! I have fairly high confidence the bottom end is OK, simply because the oil I drained looked smooth and without any debris. But it may be worth $50 or whatever for a crappy Harbor Freight scope. Thanks DrewNJ!


From what I understand, buying OEM oversized pistons is near impossible for CX500/GL500's, so I'm not really considering that route. How can I test that the pistons rings get a good seal with my redneck-honed and pitted cylinder wall? Do I need to buy a micrometer? Compression test? Just see if the engine burns oil when I put it back together and run it?
 

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Go with it and see if it runs if that sounds reasonable. I got a gasket set on Ebay for 80$ for my cx650c, everything included, may be more now but worth a look,,, I think your main problem was an open valve during disuse which allowed moisture to corrode the cylinder, the rest is probably fine,, I would disassemble the heads and clean and lap valves as a precaution, and install new guide seals which are included in gasket set. Good wrenching!
 

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Just checked ebay,, 50$ for complete set, free shipping ! Other set only 70$ ,wasn't sure of your model of bike,,, amazingly cheap:)
 

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Also, if someone can confirm that my surplus 650 head gaskets will fit your bike they are free to you. I have no intention of ever removing the heads on this bike, just retorqued them and it perfect. Just a thought, they may be different but cx parts hav great interchangeable features,,,
 
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