September 2010 9
Tappets. That’s what I’ve heard is a common cause for the noise. From what I’ve learned, the tappets shouldn’t make noise if there’s enough oil and oil pressure around them.
Cam chain. I’ve heard this could be slapping around.
Before I took the bike off the street to restore it, in addition to the tapping, the oil light was flickering. It seemed to come on most frequently when the bike was idling, and went away (for the most part) after accelerating.
The dipstick in this bike was missing the stick. I figured it fell into the oil and got crushed by the motor. I thought the remains may have clogged the oil pump strainer. So I dropped the oil pan to check it out.
My theory was that the clogged strainer could have caused a reduction in oil flow/pressure and therefore have caused the tapping noise to get worse.
The strainer was clean but there were some pieces of something relatively solid in the bottom of the pan. One of the pieces looked like it could possibly have been metal. Don’t want to think about that to be honest.
So, what should my next step be? Should I take the top end off?
Tappets will always make some noise, but it should not be distinctive or loud. If it is a rattling/slapping sound it could be a wearing cam chain, chain guides, or tensioner. If it’s a distinctive tap tap tap then it could be a damaged valve guide or slightly bent valve.
If your cam chain slack is adjusted, and your valve clearances are in check, then it’s time to pull the valve cover and start looking around. If you can’t spot the problem there then you may have to pull the head.
Do your best to locate the source of the sound. Rest a flathead screwdriver against different parts of the top end while running and put the handle to your ear. The screwdriver will work as a rudimentary stethoscope to help you pinpoint the location of the sound.
Let me know how it goes.
Here’s a video I made just before I started taking the bike apart. You can hear for yourself.
Let me know if this helps to narrow things down. Meanwhile, I’m going to try to figure out what kind of rig I can put together to let me work on the motor without putting the whole bike apart. If you have any suggestions there I’d love to hear those as well.
It sure doesn’t sound healthy. Sorry mate.
Sounds like a valve issue to me. Could be a broken guide, bent valve, or broken spring.
Pull off the valve cover and see if you can spot anything. Check the valve clearances before you go as far as pulling the head off.
If you can handle a big mess – With the valve cover off, remove the spark plug wires so the bike can’t start, then hit the starter. Oil will fling everywhere as the cams spin, but the sound will be more audible with the cover off and you should be able to determine the location.
I took the valve cover and oil filter off. In the oil filter I didn’t find anything that seemed major to my untrained eye. There was a little bit of grit in there. But it was really a little bit, and I really don’t think it was metal.
Now the bad news. Here are pics of what I found under the valve cover. The right hand exhaust-side of the motor was clearly cooked. The other three corners of the motor looked fine.
Here’s a couple of pics which show the two camshafts.
http://picasaweb.google.com/Laran.Evans … directlink
This one in particular shows the differences between the two shafts:
http://picasaweb.google.com/lh/photo/gh … directlink
The second piece of bad news is that I saw what looked like a small mound of dirt or gunk near the center of the motor, between the camshafts. I don’t know what it is.
You can see the gunk in this photo: http://picasaweb.google.com/lh/photo/zB … directlink
So, what are my options? What’s in order to get this motor back in order?
This is the worst of the scoring:
http://picasaweb.google.com/lh/photo/uY … directlink
There’s similar scoring in other spots, but not quite as much.
http://picasaweb.google.com/lh/photo/XK … directlink
As for the pile of gunk sitting in the middle of the motor, I think I might know what it is. Silicone. You can see how whatever jabroni opened the motor last applied so much silicone that it squeezed out of seal and into the motor. In fact, I’m not sure I even saw a gasket in there. Could they have just used silicone? Here’s a pic which shows how far over the inner edge the silicone sits:
http://picasaweb.google.com/lh/photo/qw … directlink
One last thing I noticed is that the part in the top-middle of this photo (which isn’t numbered and therefore not named in the schematic on bikebandit) is bent up a bit. Sorry for the slightly fuzzy photo.
http://picasaweb.google.com/lh/photo/m_ … directlink
The other three seem to be fine (straight). So, A) what’s the part called? And B) is it really bad that the part is bent? I’m pretty sure it can’t be good or even normal.
So, I’ve been doing all of the work on the bike myself to this point. The motor is clearly going to be a project unto itself. Anyone know any good books on engine rebuilding?
I know of a motor for this bike for sale on ebay for $50. It’s in unknown condition with unknown mileage. Would it be a good move to buy it?
The bottom line question here is, can this bike be fixed? It’s a rare model. Honda only made the DOHC motor for one year. So parts for the most part have to be scavenged. NOS/OEM parts are nearly impossible to find, at least they have been so far.
Thanks for all the pictures.
Yep, that cam is TOAST! When was the last time the valves had been checked on this bike, I bet they were SUPER tight.
I would also be very suspicious of your oiling system. If your light is coming on like it shows in the video then you may have a partially clogged line, or the oil pump may be slightly damaged. Either way you are going to have to do some testing with the oil system to make sure flow is adequate.
Your next step is removing the cams from the head. I’d bet that your cam journals and valve caps are toasted too, but you never know, you might get lucky. Pull out the cams and give them a look.
Putting silicone around the valve cover is very common and is only a problem if it gets into places where it shouldn’t be. I often use a VERY thin layer around my valve covers to prevent seeping. Your previous owner certainly used quite a heavy amount.
Yes – Jump on that parts motor for $50. One way or another you are going to need some parts! $50 is cheap, and even if the motor turns out to be beat, you can sell off some of the good parts and double your money.
Gonna pick up the parts motor this weekend.
Is the scoring on the camshafts something I should worry about?
Yes, that camshaft is going straight into the garbage. Or hang it on the garage wall!
The other shaft looks OK but I would pull it out and give it a close inspection. You’ll also want to take a very close look at the cam journals. If there has been a oil starvation issue then the journals will show the effects.
So here are some pics from the new motor I bought this past weekend for $50. How does the wear look on those cams and journals? There’s one that I’m a bit concerned about. How bad really is the damage?
Looks like the cam just has a couple very light scores on it. Can you feel them with your finger? From the photos it looks like it’s serviceable.
The journal however doesn’t look so good.
If you have a shop that works on motors nearby you might bring the head down to them and ask if they do repairs and how much they’d charge – but likely the repair would cost more than finding a replacement head on eBay.
**Warning, bad advice begins now**
If it were me, and this was just an around town bike that I was tinkering with, I would be tempted to just put it back together using the best parts and see how much life I could get out of it. However, if you want a long term reliable bike, don’t do this. The scoring in that journal will only get worse, and eventually something will fail.
**end of bad advice**
So the scores in the cam aren’t noticeable to the touch. And the journal, that looks like a baby version of what I found in the bad motor. So, I don’t feel very good about the idea of just putting everything back together and hoping for the best. I’m glad you told me that you’d just slap it back together though. It gives me a little counterpoint to what I keep reading about how incredibly delicate the engine components are (gotta be put back in the exact same spot, wear patterns and such).
Now, if I did get a replacement head on ebay, would it be appropriate to put the existing cam (possibly after a bit of work) into the replacement head? Would wear patterns or whatever cause problems?
Yes, make no mistake about it, if you reassembled using that head with the scores in the journal, it WILL fail. The question is how long it will take, and how much other damage it would do. If little metal shavings found their way into the bottom end it could kill the whole motor.
If you intend to ride this bike for a while, search out a replacement head that is nice and clean. You can part out your $50 motor to make that $50 back and enough to cover a replacement head.
Finally got the cylinders free after a little coaxing and want to change the oil in the bike. Just not sure if it’s a special oil or just 10W40.
Great! It’s always a joyous moment when a stuck motor is shaken free. 10w40 will be just fine, it may even be factory spec for the bike, I can’t remember off hand. I run 10w40 in virtually all of my bikes for normal driving conditions.
Thanks for the reply. I was getting conflicting answers. Well last night we hooked some juice to it and it cranks over great, but the carbs are a little gummy after all those years. My 18 year old son, who owns the bike is pretty happy with it so far. Any hints on what to look for, or just give them a good cleaning?
Thanks for your help.
I sure how your CX500 carbs are better than mine were:
Just take your time and inspect each jet and passage very carefully. For a good primer you can read my article on How to Clean a Motorcycle Carburetor.
If you have any specific questions please go right ahead and post them here!
I took this engine apart to replace the kick-start shaft. During reassembly I noticed the return stop for the kick-starter was broken off. Is this a major problem or an inconvenience, and is there a recommended fix for it? (photo at the link below)
http://www.facebook.com/profile.php?ref … =687434043
That’s a somewhat common issue on a variety of kickstart only bikes. The problem isn’t so much having the stop break, but having the pieces get lost and can do more damage. Make sure you get EVERYTHING out. If you strip your cases a talented aluminum welder can certainly fix it.
Is this a kickstart only bike? Or does it have electric start too?
The bike has an electric starter. I got this bike from my son and the electric starter never worked while he had it. When the kick-starter shaft broke off he gave up on it.
The alternator was messed up and the solenoid was missing, parts were hard to find so I decided to replace the kick-starter shaft while I looked for parts for the electrical system.
I don’t know how long this stop has been broken, but there were no pieces of the broken stop inside the engine when I took it apart.
I’ve started putting it back together and think I have all the parts for the starter I don’t know if it’s going to work or not…
Assuming that you can’t leave it in the bike while working on it. I have two motors now. So I’m wondering what kind of rig I can use for holding an engine while I’m working on it. It’s not a problem if I work on it on it’s side. But I’m not sure if that’s going to work throughout the whole process.
If you’re handy with a welder you can build a jig.
Me? I just put it right on the workbench and don’t use anything to hold it. If it rocks around I just wedge little blocks of wood under the sides.
My typical workspace looks like this:
Hi everyone i have a problem with my 83 v-65 magna it is putting fuel up through the breather and running bad it won’t idle give it fuel it will only go to 1500 rpms and fuel starts coming out the breather. had it to honda they said they set the carbs to there spec’s they also broke the signal light of it now it is running worst than it was before. any ideas.
If you have fuel coming out the carb overflow lines (draining out the bottom of the bike) then you have a sticky float, damaged float, dirty float needle, or otherwise gummed up fuel system. When fuel is rushing in and dumping out the overflow the level in the carb bowl is too high and will cause the motor to run poorly. You need to pull your carbs and give them a good inspection.
So I took off the oil pan and have been trying to scrape the gasket off with a razor blade. It’s not going super-well. Any other suggestions? Grind it off with a wire wheel?
There are gasket remover sprays that can be found at any auto parts store. Spray it on, let it sit for 20 minutes, then scrape with a razor. It will come off like butter.
You can also use an engine degreaser or brake cleaner, they tend to work just as well in my experience.
For any lingering bits of gasket that you can’t get off easily you can use a scotchbrite pad and rub, just be careful not to get the dust anywhere it shouldn’t be.
I have a 1980 Yamaha XS 1100LG Midnight Special that I think needs the carbs cleaned and re-calibrated? Bike has 18,000 miles on it and ran well last year. But……I left gas in it without stabilizer (DOH) and think that is the problem. Bigger problem is ……….I’ve never done the work myself. Dealer can “burn through $800.00 pretty quick” barring any other problems.
1) Know any mechanics in New Jersey that would fix it?
2) Where can I get info on dismantling/cleaning myself?
If the carbs sat with fuel in them for a season then it is likely they need to be cleaned up. It doesn’t take much to clog up the jets.
To answer your questions:
1.) I never recommend taking a bike to a dealer. In my opinion, part of being a true motorcyclist is having the knowledge and skill to repair and maintain your own motorcycle. Motorcycles are about independence, and you lose that autonomy when you become reliant on a dealer.
If you have any questions along the way post them here and we can help out!
My pistons look like this:
http://picasaweb.google.com/lh/photo/IM … directlink
I’ve heard all sorts of different methods for cleaning them. Each one seems to come with a warning. Some chemical cleaners are ok, unless they’re used on alloys. Wire brush and a drill is effective, but be careful not to scratch the heads. Oven cleaner, carb cleaner, aircraft stripper, etc.
I used the nylon brush on my drill to clean one of the pistons. It seemed to clean up well except for a few spots that the brush couldn’t reach. It did leave the top of the piston looking “brushed”, but very gently. Will that texture cause any issues? I’d imagine it would give more surface area for carbon to collect on. But can’t think of anything else it would do.
I’ve also heard that sanding the sides of the pistons is a good idea. Is there anything to this? What grit, if at all?
There are all sorts of ways to clean the carbon off. Simple carb cleaner, engine cleaner, or brake cleaner will all work reasonably well. As will gasket remover. Just spray some on, let it sit a bit, then scrub with a stiff plastic bristled brush. Most should come right off. You can use a scotchbrite pad for the remaining.
It’s usually best to remove the pistons for cleaning so you don’t get carbon debris and chemicals down into the bottom end.
As for sanding the sides of the pistons? No! I would not recommend this. If you are sticking with your used pistons and bores then don’t touch the sides other than a cleaning. Microscopic groves build in the cylinders, rings, and pistons over time and you will have the best seal if those continue to be aligned. If you are replacing your rings for new then it is a good idea to hone the cylinder, which can be done with very fine sandpaper and plenty of oil, or with a ball hone (or at a shop).
Can it be fixed? Or do I just have to buy a new one? Can I buy just the body? Or do I have to buy a whole new carb (which probably means buying a whole set of carbs which seems like a waste).
I was surprised to see the tear. I hadn’t noticed anything in terms of hesitation, idle issues, etc. What symptoms would I expect to see from a torn diaphragm?
If you just have a small hole or tear it can be repaired. Since you haven’t had any significant effects yet I assume it is a small split. If it is bigger you might be best off replacing it with another used piece.
You can repair them with all sorts of glues, but supposedly the best glue to use is Gorilla Glue because it is resistant to gas fumes. The gas exposure will deteriorate other glues fairly quickly. I’m sure you’ve seen Gorilla Glue, but if not, you can get it at any hardware store.