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Discussion Starter · #1 ·
The weather here has been just shy of perfect for being outdoors. The only drawback has been the wind that seems to settle in around 20-25 MPH. Temps have been in the upper 70's and low 80's with partly cloudy to sunny skys for the past couple of weeks. In this region, this is the "sweet" time of year. It doesn't last long before the mercury climbs about the century mark and the humidity goes along with it. I digress...



Decided to get out and enjoy some of the nice weather this evening on the bike. Went through the pre-ride ritual, and then started it up. As it sat idling, I heard a noise that was not constant and varied in intensity periodically. Not tappets and not a lower end knock; a quick listen at the back of the motor narrowed it to the cam chain. Okay, so the cam chain needs some attention. No big deal, we'll just make that adjustment and I'll be on my way.



Pulled the inspection caps, plugs, and rotated the motor to the appropriate cycle and postiion. Put a wrench on the tensioner bolt and found it was loose. "Ahhh, that confirms my finding of the cam chain making the slapping noise." Did the obligitory "adjustmet taps", and went to the torque the tensioner bolt. No tighty. Nothing. Not even a grab.



Perfect... No ride today, obviously. And before we can enjoy the above weather, time will have to be taken to dump the lump and find out what happened. The cam chain was adjusted about 300 miles ago by myself. I vaguely remember thinking that when I tightened the tensioner bolt back then, that it didn't quite feel right. It torqued down, but the wrench was in a goofy spot and I passed it off as being a "slip" rather than a fastener problem. I am not sure if it pulled the threads and it finally gave up, or it the tensioner bolt twisted and sheared; that will be determined when I get the cover off and get eyes on.



Is this a typical issue with these bikes, or am I going to be dealing with a difficult to resolve problem? I have noticed that the tensioner bolt doesn't appear to be available anymore. If it is the threads that have stripped, then a heli coil should take care of that (I am hoping this is the issue). Besides fixing the issue and a thorough clean up of any debris, is there anything else to be wary of?



The origional plan was to ride the bike for the summer and fall, then in the winter pull the bike entirely apart. Basically do a frame up freshen up/restore. Paint, polish, repair issues, replace bearings, bushings and seals, tires, hoses, open the motor and give it a freshen up (stator, cam chain & tensioner, clutch, seals, the works), rework the wiring, ignition (ignitech), carbs, and basically start next year off with a "new" bike. That is still the ultimate plan, so I'd like to get the tensioner addressed and get it back on the road as quickly and inexpensively as I can. The major stuff will be addressed this next winter.



My current plan is to yank the motor and open up the cover to assess the issue, any collateral damage and make the repair. I will also perform and autopsy of the oil filter to see if there is any metal (aluminum) present. If there isn't, a thorough inspection and clean up of the interior (assuming the chain has taken a bite of the case) will be done. If there is aluminum found, then how deep does the tear down need to go? Am I overlooking anything?
 

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Though I don't know a lot about the issue at hand, I have seen others discuss it, so it does happen. As to shavings or flecks in the filter/oil, silver colored ones might lend to some aluminum wear back by the cam chain, and may not be all that worrysome. If the flecks are gold or bronze color, that is a much worse scenario, and could mean the demise of the motor's big end shell/bearings. Virtually end game from what I've read. Keeping my fingers crossed for you, hopefully you just let the tension bolt come out of the threads and it won't re-engage.
 

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It's a pretty straight forward fix. If the tensioner bolt is broken I would probably cut the threaded section off flush, find someone with a lathe who could drill into it and either thread it and put lock tight on the bolt or weld the new threaded section in place. Then cut it down to the right size.
 

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Discussion Starter · #4 ·
Nothing was visible in the oil out of the crankcase. Pulled the oil filter housing, and there is aluminum in the oil. Not a ton, but enough to know something isn't happy inside. The aluminum particles were pretty fine, about the size if it were sanded off of something. No visible copper. I'll open up the paper filter tomorrow after it drains off real well and see what there is inside. Hopefully it stopped at the filter! If not, it might get interesting.




Motor comes off tomorrow, and we'll take a look see. Figure out what is needed and get parts on the way. In the mean time, fingers are crossed!
 

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I used to have an '82 CX500 that had this problem of not being able to tighten the cam chain tensioner bolt. On that bike the problem was the threads in the case itself were stripped out. I was able to successfully repair the stripped out threads using a Heli-coil insert.



This is a general statement not directly about this post: It is my opinion that if you've got your motor out anyway, the threads of the cam chain tensioner ought to be lubricated with heavy grease. Keep in mind that the bolt is steel and you're tightening it into aluminum.
 

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Dash has a good point, and that's what it sounds like you are dealing with. If you just noticed the noise you are most likely fine once you get those threads fixed. After you get things sorted and back together I'd probably put some really inexpensive oil in, run it a little and change it again after a little bit to make sure there aren't anymore contaminates in there.
 

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Dash has a good point, and that's what it sounds like you are dealing with. If you just noticed the noise you are most likely fine once you get those threads fixed. After you get things sorted and back together I'd probably put some really inexpensive oil in, run it a little and change it again after a little bit to make sure there aren't anymore contaminates in there.


Ditto.I use the cheapest 20w engine oil.Run for 50 miles ish and then drain and replace with 15w40 diesel engine oil as a safe engine flush.
 

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Discussion Starter · #8 ·
Well, once I get into it and see what the problem is, it will be sorted. If by chance the bolt did break, I will knock off a half dozen or so of them made so that some spares will be around. No need to set up to make a single part.
It's nice having access to a machine shop!
 

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Discussion Starter · #9 ·
Well, the engine is on the bench and have cracked open the rear cover. The culprit for the spinning bolt was... stripped threads. Fixed with Heli-coil. Piece of cake. But...



Looking at the cover where the cam chain would do its chewing yielded more quandry. The chain has been against it, but just enough to scratch the surface of the aluminum. It hasn't removed much material at all. There was more aluminum in the oil than what would have come from the area that the chain has contacted. There was not any aluminum found in the rear cover. Where to go looking??




I did look at the cam chain tensioner real close, and there is some embedded aluminum in the plastic on the tension side where the chain rides. It has been there long enough that it has a groove worn into it from the chain. That will be remedied with a new tensioner. Will throw a chain at it as well.



There is some oil leaking around the area(s) of the tach cable and fan. It was pretty nasty looking up there behind the fan. I didn't have a bolt readily available to yank the fan off, but will remedy that in the morning. Is the shaft seal a typical culprit for the leaking, or is it the typically the tach drive cable (or both)?



I am going to finish up the investigation in the morning and get parts on the way to get it back together. The weather is too pretty to have it sitting in the shop torn down! Sorry to all of those in the cooler climates that are dealing with more cold and white stuff!
 

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Check the clutch basket.Has the casing been gouged?A worn/slack oil pump chain can hit this and cause metal take-off.The front engine cover should be taken off anyway and the sump cleaned and the Oil pump taken off thoroughly cleaned including it's strainer as metal particles may be held inside.I fully strip mine to clean them.



Also even a small wear on a bolt head can produce a lot more metal flecks in the oil that you would think.The whole block needs flushing through to remove ALL metal debris.I use a car power washer and then compressed air to blow though and dry.Very careful and low power on the rear engine case so as not to damage the Stator etc.

You can also use Carb/Brake cleaner down oil-ways before power flushing.The more time you take and better cleaning the less chance of F.O.D(Foreign Object Damage) down the line.
 

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Mine has (thanks to Lynn) has been perfectly maintained under total perfection. Covererd, semi-heated in the garage and he fires it up running temp every month or so.
 

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Well, the engine is on the bench and have cracked open the rear cover. The culprit for the spinning bolt was... stripped threads. Fixed with Heli-coil. Piece of cake. But...



Looking at the cover where the cam chain would do its chewing yielded more quandry. The chain has been against it, but just enough to scratch the surface of the aluminum. It hasn't removed much material at all. There was more aluminum in the oil than what would have come from the area that the chain has contacted. There was not any aluminum found in the rear cover. Where to go looking??




I did look at the cam chain tensioner real close, and there is some embedded aluminum in the plastic on the tension side where the chain rides. It has been there long enough that it has a groove worn into it from the chain. That will be remedied with a new tensioner. Will throw a chain at it as well.



There is some oil leaking around the area(s) of the tach cable and fan. It was pretty nasty looking up there behind the fan. I didn't have a bolt readily available to yank the fan off, but will remedy that in the morning. Is the shaft seal a typical culprit for the leaking, or is it the typically the tach drive cable (or both)?



I am going to finish up the investigation in the morning and get parts on the way to get it back together. The weather is too pretty to have it sitting in the shop torn down! Sorry to all of those in the cooler climates that are dealing with more cold and white stuff!


For the front leak, it could be either, and there's also an o ring just below the cam shaft that could possibly be old and dried and leaking. If it's leaking out of the tach cable seal, some silicone sealant will fix that right up, that seal is a pain to get out and there aren't any left to buy new. Glad you were able to fix the bolt, and good idea replacing the tensioner and chain. While you're at it you should also replace the oil seal behind the water pump on the rear cover.
 

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Discussion Starter · #13 ·
Thanks for the advice!



My intention was to yank the front cover off the engine this morning, and ended up going to five different places trying to find a bolt to remove the fan. After dealing with some of the world's finest and friendliest customer service (yeah, right!), I lost all enthusiasm after coming home empty handed and decided to spend the day working in the yard. I figured I had better take my frustraions out with a chain saw and axe, rather than mess with the CX today and do more harm than good.



I am about to go machine a bolt to get the fan off. Once that happens, I'll get the front off and see what's happening behind that curtain. Then I'll make a list, check it twice and hopefully get parts here before the upcoming weekend.
 

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You didn't mention where you looked for the bolt, but I found mine at an Ace hardware. Couple bucks.
 

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Discussion Starter · #15 ·
The search for the bolt started at our local auto supply. We were good to 12MM. SOL on the 14MM. On to Northern Tool (same story), Tractor Supply (SAE only), Home Depot (reaching for anything), & Lowes (the last straw). The closest ACE Hardware to us (that I know of) is 20 miles or so away and kind of a pain to get to. After the first five and an hour of time wasted, I gave up on the bolt as far as a purchase.



So, when you can't buy it: machine it. That's exactly what I did. It took about 45 minutes to whip up by the time everything was cleaned up. It could have been done in about 20 minutes, but I got fancy and machined a 14MM hex head on the end. It worked like a charm and is in the tool box for next time.



As for the oil leak on the tach drive, two of the four bolts weren't tight. It looks like oil was leaking in the area of the two loose bolts and around the tach drive cable. A gasket, o-ring and shaft seal (if available) should remedy that. As for the tach cable seal, I guess that will be a good place for a dab of silicone.



The front end is open and the engine is clean; no aluminum or other debris anywhere in the case, front cover, clutch cover or rear cover. Aside from where the cam chain touched the case, I am not finding anything that looks like it is being ground.



What am I overlooking? Unless there is another place I needs scrutiny, the source must be the thread debris and where the chain nibbled on the case. I am perplexed about the case being clean.



The plan now (unless I need to check something else) is to order the gaskets, o-rings, seals, cam chain, tensioner, and slap it back together after a good clean up. I haven't checked the oil pick up strainer yet, but will make sure it is sterile before closing it up.
 

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The only other place that comes to mind is if the cam followers had been inserted incorrectly.You can shine a light down the head with the covers off and see if the cups that hold the bottom of the push-rods are at the correct angle but this is a rare occurrence and would usually mean some one had had the cam-shaft out and at that mileage it seems doubtful.

I think I would do what you are planning to do and check the oil again after whatever time you deem fit say between 100 and 500 miles and just change again anyway for peace of mind.

Also if you or some one has used any Alloy paint I had some come off and get into the oil and make it look like there were metal flecks in it.I had swapped a front cover that had had some Alloy paint spray settle on in when I had done a bit of hack painting in the garage and without knowing used that front cover on my Bitsa CX.

When I dropped the oil and felt the particles I knew they were not,"Real" metal.
 

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The search for the bolt started at our local auto supply. We were good to 12MM. SOL on the 14MM. On to Northern Tool (same story), Tractor Supply (SAE only), Home Depot (reaching for anything), & Lowes (the last straw). The closest ACE Hardware to us (that I know of) is 20 miles or so away and kind of a pain to get to. After the first five and an hour of time wasted, I gave up on the bolt as far as a purchase.



So, when you can't buy it: machine it. That's exactly what I did. It took about 45 minutes to whip up by the time everything was cleaned up. It could have been done in about 20 minutes, but I got fancy and machined a 14MM hex head on the end. It worked like a charm and is in the tool box for next time.



As for the oil leak on the tach drive, two of the four bolts weren't tight. It looks like oil was leaking in the area of the two loose bolts and around the tach drive cable. A gasket, o-ring and shaft seal (if available) should remedy that. As for the tach cable seal, I guess that will be a good place for a dab of silicone.



The front end is open and the engine is clean; no aluminum or other debris anywhere in the case, front cover, clutch cover or rear cover. Aside from where the cam chain touched the case, I am not finding anything that looks like it is being ground.



What am I overlooking? Unless there is another place I needs scrutiny, the source must be the thread debris and where the chain nibbled on the case. I am perplexed about the case being clean.



The plan now (unless I need to check something else) is to order the gaskets, o-rings, seals, cam chain, tensioner, and slap it back together after a good clean up. I haven't checked the oil pick up strainer yet, but will make sure it is sterile before closing it up.
On the front cover, make sure you don't lose the oil pressure orifice from between the cover and the block. I have mentored too many people who didn't know it was there and lost it.



On the rear cover, since it is off how much of the adjuster hole is left? Now would be the time to change the cam chain if it is less than half. Also, you should consider changing the cam oil seal and the mechanical seal on the water pump. You don't want to have to pull the engine and buy a new rear gasket in a few miles because the mechanical seal didn't line up perfectly when you put it back together.



What kind of machine shop do you have??? Is your lathe large enough to handle a flywheel??? If so you may be able to make some money resurfacing flywheels for the 650 owners who have starter clutch problems ... and the few 500 owners who have the same problem.
 

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Discussion Starter · #18 ·
The only other place that comes to mind is if the cam followers had been inserted incorrectly.You can shine a light down the head with the covers off and see if the cups that hold the bottom of the push-rods are at the correct angle but this is a rare occurrence and would usually mean some one had had the cam-shaft out and at that mileage it seems doubtful.

I think I would do what you are planning to do and check the oil again after whatever time you deem fit say between 100 and 500 miles and just change again anyway for peace of mind.

Also if you or some one has used any Alloy paint I had some come off and get into the oil and make it look like there were metal flecks in it.I had swapped a front cover that had had some Alloy paint spray settle on in when I had done a bit of hack painting in the garage and without knowing used that front cover on my Bitsa CX.

When I dropped the oil and felt the particles I knew they were not,"Real" metal.


Shep, thanks for the suggestion on the cam followers. I will take a look and see if anything is amiss. I have the entire service history (at least as far as I know) for the bike and there hasn't been any work done to the top end aside from the adjustments. It got a round of seals at 11K, but the bike was twenty years old at the time.





On the front cover, make sure you don't lose the oil pressure orifice from between the cover and the block. I have mentored too many people who didn't know it was there and lost it.



On the rear cover, since it is off how much of the adjuster hole is left? Now would be the time to change the cam chain if it is less than half. Also, you should consider changing the cam oil seal and the mechanical seal on the water pump. You don't want to have to pull the engine and buy a new rear gasket in a few miles because the mechanical seal didn't line up perfectly when you put it back together.



What kind of machine shop do you have??? Is your lathe large enough to handle a flywheel??? If so you may be able to make some money resurfacing flywheels for the 650 owners who have starter clutch problems ... and the few 500 owners who have the same problem.


The adjuster is a slight bit under halfway of its travel. I could probably get away with just a tensioner, but since I am in there... may as well do it all. As for seals, all of them will be replaced. Same goes for the o-rings. Frugality has bit me too many times in the past, and the expense isn't worth the risk.



As for the machine shop: 13x40 lathe, 10x50 mill, and a whole lot of goodies to compliment each. Also have welding equipment for each of the process (TIG, MIG, Stick), oxy/ace rig, 20 ton hyd. press, and a few other toys. There's not a whole lot that can't be tackled!
 

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Shep, thanks for the suggestion on the cam followers. I will take a look and see if anything is amiss. I have the entire service history (at least as far as I know) for the bike and there hasn't been any work done to the top end aside from the adjustments. It got a round of seals at 11K, but the bike was twenty years old at the time.









The adjuster is a slight bit under halfway of its travel. I could probably get away with just a tensioner, but since I am in there... may as well do it all. As for seals, all of them will be replaced. Same goes for the o-rings. Frugality has bit me too many times in the past, and the expense isn't worth the risk.



As for the machine shop: 13x40 lathe, 10x50 mill, and a whole lot of goodies to compliment each. Also have welding equipment for each of the process (TIG, MIG, Stick), oxy/ace rig, 20 ton hyd. press, and a few other toys. There's not a whole lot that can't be tackled!
i think you mean.......you could probably just get away with a new chain
 
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