Honda CX 500 Forum banner
1 - 20 of 26 Posts

·
Registered
1980 Honda CX500C
Joined
·
23 Posts
Discussion Starter · #1 ·
Hi there, me again, lol. So I've been researching parts and prices for the triple bypass I planned on doing this coming winter. Along with possibly upgrading electrical system. I think I have a good parts list compiled now just need the money to get everything. I've had suspicions something was up with the engine. I did an oil change, and I'm afraid my suspicions came true. I have Alot of what looks like aluminum shavings in the oil and filter housing. My guess is timing chain is so worn that it's hitting the case. Now my question is this. Should I be looking at a total engine rebuild when I drop it out of the bike ? I already have a head gasket to replace and I wanted to go thru it all and fix or freshen up or replace what is needed. Another question is, is there anything I should ck before I tear the motor out of her ? Compression maybe, just to see where I'm at ? The high idle circuit'?' test for the stator ? Anything else I should be looking at ? I am kinda feeling overwhelmed with the upcoming project as I don't want to miss something. Also I couldn't resist the ride today and put over a hundred miles on her. I know not the smartest move but I had to. The Old Lady was a champ and kept on rolling. I'm hoping if I can get the motor running like a top. I'll work on cosmetics and put another 45k on it following my pops' lead. Anyhow, thanks for reading and if your in Wisconsin I may most certainly need a hand with something or advice, or knowledge. This forum is great. I've learned so much about my bike just reading thru the threads.
 

·
Registered
1978 CX500 "The Grub", 1983 GL650I "Nimbus"
Joined
·
11,052 Posts
Where are you in Wisconsin? It's a big place, and parts of it are closer to other places. If you're in, say, Hudson, you'll find help over here.
 

·
Registered
1980 Honda CX500C
Joined
·
23 Posts
Discussion Starter · #3 ·
Where are you in Wisconsin? It's a big place, and parts of it are closer to other places. If you're in, say, Hudson, you'll find help over here.
Hi there, I'm about 30 mins N of Milwaukee. Hudson is about 4 hrs away from what I see, which isn't that far.
 

·
Super Moderator
'84 CX650E that is evolving into a GL500
Joined
·
17,275 Posts
If the particles in the oil are aluminum you probably don't need to worry much if you stop using it until you fix the cause. When the camchain tensioner adjuster isn't set correctly or as often when it should be, the chain is excessively worn or one of the guides breaks the chain can rub and cause wear as shown in the pic below (ignore the tensioner - this one was a 650). When this happens the damaged part can usually be used unless it has worn through to the hole for the bolt. If a significant portion of the bolt's head is worn off I'd advise replacing the bolt (I didn't replace the one in the pic).
The aluminum particles generally find their way to the sump without doing any harm on the way and either get caught by the filter or come out with the oil. I'd recommend cleaning out the sump with mineral spirits (buy a gallon jug of generic paint thinner - it is the same thing as Varsol but a lot less expensive) when you have the engine apart and if you are really concerned about some being left in the engine you maybe do an oil change a few hundred miles after you put it back together.
209280
 

·
Registered
1980 Honda CX500C
Joined
·
23 Posts
Discussion Starter · #5 ·
If the particles in the oil are aluminum you probably don't need to worry much if you stop using it until you fix the cause. When the camchain tensioner adjuster isn't set correctly or as often when it should be, the chain is excessively worn or one of the guides breaks the chain can rub and cause wear as shown in the pic below (ignore the tensioner - this one was a 650). When this happens the damaged part can usually be used unless it has worn through to the hole for the bolt. If a significant portion of the bolt's head is worn off I'd advise replacing the bolt (I didn't replace the one in the pic).
The aluminum particles generally find their way to the sump without doing any harm on the way and either get caught by the filter or come out with the oil. I'd recommend cleaning out the sump with mineral spirits (buy a gallon jug of generic paint thinner - it is the same thing as Varsol but a lot less expensive) when you have the engine apart and if you are really concerned about some being left in the engine you maybe do an oil change a few hundred miles after you put it back together.
View attachment 209280
Sidecar Bob, thanks for the info. I tried adjusting the tensioner. Either I did it wrong or it's way out. When the bolt was loose I tapped on it and heard what I thought was the adjuster moving. There is alot of chatter in the motor though and something isn't right. I guess it doesn't pay to do a compression test since I have a head leaking on the rt cylinder. Also there is a ton of gas in the oil, thinking my buddy who rebuilt the carbs put the wrong jet in or something. My gas mileage is horrible, runs like crap and rt plug is always fouling out. I'm probably going to park it until I can get some funds together, then tear into it. Would like to get Murray's carb book and clean and go thru them myself. Unless I find someone who's done it before. Thanks again.
 

·
Super Moderator
'84 CX650E that is evolving into a GL500
Joined
·
17,275 Posts
Fuel in the crankcase oil is very bad. It can quickly ruin the bearings so DO NOT run the engine again until you figure out why that is happening. An incorrect jet is not likely the cause. It is more likely to be caused by the float valve not closing correctly (you should also find fuel coming out of the overflow/drain hose if that's the case).

Murray sells Mikuni carbs that are set up specifically for these bikes. Larry wrote the book on how to clean and set up the original Keihin carbs. I would highly recommend getting Larry's book and going through the carbs yourself to make sure they are done right.

When you set the camchain tensioner adjuster did you turn the engine to the correct timing mark? If not do it again but follow the instructions in the FSM carefully. If it still rattles you may have a broken camchain guide (when the one in my GL500 broke it sounded like a diesel on a cold morning at idle and perfectly normal above 2000 RPM).
 

·
Registered
1980 Honda CX500C
Joined
·
23 Posts
Discussion Starter · #7 ·
Fuel in the crankcase oil is very bad. It can quickly ruin the bearings so DO NOT run the engine again until you figure out why that is happening. An incorrect jet is not likely the cause. It is more likely to be caused by the float valve not closing correctly (you should also find fuel coming out of the overflow/drain hose if that's the case).

Murray sells Mikuni carbs that are set up specifically for these bikes. Larry wrote the book on how to clean and set up the original Keihin carbs. I would highly recommend getting Larry's book and going through the carbs yourself to make sure they are done right.

When you set the camchain tensioner adjuster did you turn the engine to the correct timing mark? If not do it again but follow the instructions in the FSM carefully. If it still rattles you may have a broken camchain guide (when the one in my GL500 broke it sounded like a diesel on a cold morning at idle and perfectly normal above 2000 RPM).
Thanks for the info. Been a minute or two since I've been on here. I haven't noticed any fuel leaking from the drain hose. Haven't started it either. Pretty sure I had the timing marks right. Still need to dl fsm and print it out. I would love to get them carbs from Murray as I've read they really boost performance but again money is an issue. Idk, maybe I should try and save up for them carbs, an Ignitech or Rae San and do it up. Would I need to run pod filters and get rid of the h pipe with that set-up ? Just curious, haven't looked into it really. Thanks again
 

·
Super Moderator
Joined
·
5,155 Posts
Pods with Murray's carbs. You could delete the H-box for more performance.

No need for Ignitech or Rae-San if the bike runs OK.

Use your limited resources to sort the engine problems, luxuries after the engine is sorted.
 

·
Registered
1980 Honda CX500C
Joined
·
23 Posts
Discussion Starter · #9 ·
Pods with Murray's carbs. You could delete the H-box for more performance.

No need for Ignitech or Rae-San if the bike runs OK.

Use your limited resources to sort the engine problems, luxuries after the engine is sorted.
Ha ha, thanks, your right. I just hate having to do things twice. Before I tear into it, I'm going to run the stator test( think that's it ) and make sure everything is fine with ignition. If I find an issue then that will decide it. Unsure why the rt cyl is fouling plugs so much. If the ignition isn't firing properly, carb issue or if the head gasket going is the sole problem ? Or a combination of it all. I didn't really notice that it wasn't firing at all, or that rt side was cooler. I suspect the carb is the issue with that one. Getting stuff set up in the garage as far as where I'm putting the engine to work on and will hopefully be getting into it soon. I sure do miss riding the Old Lady.
 

·
Super Moderator
Joined
·
5,155 Posts
... if the head gasket going is the sole problem
Just read in the first post in this thread that you have a cylinder head gasket to replace. What makes you think that it needs to be replaced; symptoms?

Doing a thorough and complete inspection and diagnostics before spending time and money on an engine can save you both.
 
  • Like
Reactions: D-Fresh

·
Registered
1980 Honda CX500C
Joined
·
23 Posts
Discussion Starter · #11 ·
Just read in the first post in this thread that you have a cylinder head gasket to replace. What makes you think that it needs to be replaced; symptoms?

Doing a thorough and complete inspection and diagnostics before spending time and money on an engine can save you both.
I could hear it backfiring out by the head. Also there's black carbon built up where it's leaking. Unless I'm mistaken and that's not the head gasket ?
 

·
Registered
1978 CX500 "The Grub", 1983 GL650I "Nimbus"
Joined
·
11,052 Posts
Pictures, please?
These are water cooled engines. If combustion gases were reaching the outside via a head gasket leak, they would need to pass through the fire ring, the water jacket, and the outer seal of the gasket. You would see other, very obvious indicators if that were the case.
 

·
Registered
1980 Honda CX500C
Joined
·
23 Posts
Discussion Starter · #13 ·
Wood Artifact Font Tints and shades Metal
Pictures, please?
These are water cooled engines. If combustion gases were reaching the outside via a head gasket leak, they would need to pass through the fire ring, the water jacket, and the outer seal of the gasket. You would see other, very obvious indicators if that were the case. Here's a quick one I took.
 

·
Super Moderator
Joined
·
5,155 Posts
That looks like a leak due to the seal for the valve cover on the spark plug well. Remove valve cover and examine the O-ring.
 
  • Like
Reactions: Randall-in-Mpls

·
Registered
1980 Honda CX500C
Joined
·
23 Posts
Discussion Starter · #16 ·
That looks like a leak due to the seal for the valve cover on the spark plug well. Remove valve cover and examine the O-ring.
It's between the head and the cylinder. I've pulled the rocker covers off before to adjust the valves. I'm pretty sure I kn ow what I'm looking at. It's back firing and leaking oil res from there. Idk if any coolant is in the mix. I'm an average mechanic so if I'm missing something let me know.
 

·
Super Moderator
'84 CX650E that is evolving into a GL500
Joined
·
17,275 Posts
That's definitely oil (with some dirt collected in it), not carbon. Carbon is black, not brown.
It could be from a leak in the head gasket between an oil passage and the outside but I would look at the valve cover's centre seal first too. It is very easy for that seal to become displaced when the cover is removed to check the valve clearances or other routine maintenance and leak. When that happens oil comes out through the hole above where the oil is.
You could confirm this without removing the valve cover by cleaning the area really well, applying a fine powder (flour, talcum, whatever is handy) and running the engine until the oil re-appears, then looking for tracks in the powder.

Neither real backfiring (firing back through the carbs) or afterfiring (unburned gasses exploding in the exhaust, often erroneously called backfiring) would cause oil to come out there.
When does the "backfiring" happen? Maybe we can help you deal with that.
 

·
Registered
1980 Honda CX500C
Joined
·
23 Posts
Discussion Starter · #18 ·
That's definitely oil (with some dirt collected in it), not carbon. Carbon is black, not brown.
It could be from a leak in the head gasket between an oil passage and the outside but I would look at the valve cover's centre seal first too. It is very easy for that seal to become displaced when the cover is removed to check the valve clearances or other routine maintenance and leak. When that happens oil comes out through the hole above where the oil is.
You could confirm this without removing the valve cover by cleaning the area really well, applying a fine powder (flour, talcum, whatever is handy) and running the engine until the oil re-appears, then looking for tracks in the powder.

Neither real backfiring (firing back through the carbs) or afterfiring (unburned gasses exploding in the exhaust, often erroneously called backfiring) would cause oil to come out there.
When does the "backfiring" happen? Maybe we can help you deal with that.
It was happening on decel of the throttle. I don't want to run the engine rt now because there's gas in the oil along with aluminum. I'm kinda stuck on what to do ? Tear the motor apart and rebuild ? Find a rebuilt motor to swap ? Idk anymore.
 

·
Registered
1980 Honda CX500C
Joined
·
23 Posts
Discussion Starter · #19 ·
It was happening on decel of the throttle. I don't want to run the engine rt now because there's gas in the oil along with aluminum. I'm kinda stuck on what to do ? Tear the motor apart and rebuild ? Find a rebuilt motor to swap ? Idk anymore.
I appreciate the help on trying to figure this out. Just not sure what I should be doing here.
 

·
Registered
1982 GL500i
Joined
·
462 Posts
That is the condensation/rain drain hole for the spark plug wells. A Valve Cover tube seal may be leaking, or it could be a loose or damaged spark plug. Backfiring/misfiring can be the spark plug connectors arcing in there as well.
 
1 - 20 of 26 Posts
Top