Engine Knock - that elusive noise!

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I haven't taken any measurements yet, but I think it is safe to say that this is a piston skirt, wrist pin, rod bearing and crank bearing knock! :smilie_happy:

Some more pics:
81_Engine 016.jpg
81_Engine 017.jpg
 
Soooooo......is anyone interested in a slightly worn engine? :smilie_happy:

Should be cheap to put back together. Only needs main bearings, rod bearings, all eight valves, all sixteen springs, new rockers, cams ground, crank ground, stator, water pump, gasket kit and spark plugs! :laptop: :help: :smilie_happy:
 
slabghost":3bkyqmms said:
Wow! Amazing that it ran still and didn't just fly apart. :shock:
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I still contend these engine are bullet proof! :music2:

Take a look at the video of me riding and that is what it sounded like all the time I rode. Some high RPMs on the highway too! Now I know why the engine sounded like a diesel! :smilie_happy:

It all adds up; 169k miles, sat for extended period between owners, kid trys to make it into a drag racing bike ( :Awe: ) someone adds some sand to the oil, I rode it with the carbs leaking gas into the intakes before I realized it, every oil change was SHINEY and sparkley( :hihihi: ) lots of noise on start up before the oil pressure came up, oil pressure drops off as soon as the oil heats up (which causes the knocking sound at 3K RPM no load).

Any other opinions out there?
 
More of the mystery knock unfolds! As I was trying to pull the crank, I left #1 and #3 pistons connected, but the crank would not come out??? It was like the pistons were stuck?? Removed #4 so that only #1 and #3 are connected and rotated the crank to TDC on #1 and tried to pull....no dice more than halfway out. I noticed while rotating the crank it hit some hard spots???? TDC on #1 or #3 produced a noticible amount of force to keep the crank turning past. I pulled the center bearing and put the end bearings back in to be sure I wasn't just pulling on the crank side ways.

With the bearings back in...TDC on #3 is producing a real hard flat spot as the rod changes direction! Same on #1 but not as bad. When I was doing the timing belts and whenever I was rotating the engine with the stator bolt, I always noticed this but always attributed this to the cam shaft and valve spring pressure. WRONG!! It is something much deeper!! (More to come on that in the next post)

I measured the skirts on #2 & #4.....the skirts side to side at the wrist pins #2 - 74.51 mm and #4 - 74.10 mm. The service limit is 74.850! :shock: (Can you say bad wrist pins?)

The cylinders were way out of limit also. Limit = 75.10, #2 - 74.51 mm, #4 - 74.62!
 
Last pic.....upper rod bearings on #1 and #3 pistons and yes....they are toast also!
81_Engine.jpg


Did some more measuring with the same results...basically, all of the piston skirts are worn, the cylinders are worn at the bottom, the wrist pins are loose and there are flat spots (oblong?) on the crank at each journal.

(BTW, my cylinder measurements were typed backwards in the previous post. Should have read 75.41 for #2 and 75.64 for #4.)
 
Conclusions?

That elusive knock at 3K RPM (at least on this engine) is rod knock! :party: (Finally, an answer!)

That noisy start up video.....worn out crank and rod bearings! :Egyptian: :Egyptian: :salute:

My final conclusion.....these engines are near bullet proof!!!! 169K miles with worn out rod bearings, worn out main bearings, loose wrist pins, worn down piston skirts, worn down cylinder walls, worn inner springs, flat spots on the cam shafts, worn out valves and it was still starting every time, no smoke, 160's on the compression and good power in the higher RPM's!! What can I say........Honda did a real fine job engineering these engines and OEM parts really held up great! :thanks: :moped:

I am ready to close this file! :whip:
 
Dan, since I have uploaded the videos in the past already, should we have a quick reference section for troubleshooting that includes the videos? I have relabled them on YouTube for rod knock and bearing noise. I can upload the bearing pictures to my gallery for reference. Might help others in the future that come looking for answers for knocking noises. :read:
 
mcgovern61":7ahx99mf said:
Dan, since I have uploaded the videos in the past already, should we have a quick reference section for troubleshooting that includes the videos? I have relabled them on YouTube for rod knock and bearing noise. I can upload the bearing pictures to my gallery for reference. Might help others in the future that come looking for answers for knocking noises. :read:
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Great idea Gerry, I'll put that together.
 
mcgovern61":3lga4s7k said:
Dan, since I have uploaded the videos in the past already, should we have a quick reference section for troubleshooting that includes the videos? I have relabled them on YouTube for rod knock and bearing noise. I can upload the bearing pictures to my gallery for reference. Might help others in the future that come looking for answers for knocking noises. :read:
Click to expand...

Have a look under the Engine section HERE
 
Wow! Nice work Dan! Those videos really load and play twice as fast as from YouTube! :clapping:

It is interesting to watch and listen to the engine run in the oil drop video and the one on the road.....even with the bearings near completely wiped out, that engine ran like a clock!

For anyone interested in the parts, PM me! joedrum has dibs on the cam shaft pullies!
 
Thanks Gerry, it's always good to know sounds to look out for, especially when you're using an engine you don't know and relying on the fact that it's only done 50k, so it oughta be good. Yeah?
 
The last part of that post was supposed to be a little tongue in cheek. The first 1100 I bought in 84 with 1500 miles on it took about a mile and a half to squirt coolant up and in an arc out of cylinder #4 onto my right thigh, so I get that mileage doesn't count.

This motor, I believe is good and everything came apart pristine when I bought the bike and even found a burnt up alternator plug to explain why I got it for a grand, sold the major majority of it for parts but no-one wanted the frame and motor, so I decided to make use of it myself.

Having already rebuilt the parts of the engine that needed it (front, back and oil screen) I've found no evidence of major engine problems, but yeah I could be wrong, we'll find out when I try to start it.
 

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