Knock, knock, where's the knock?

Blueknyt · April 23, 2014, 04:59:12 PM

well Jack, for me pulling apart the engine to be sure once everything else is checked short of splitting the cases isnt a second thought, in truth, even though you can pull the top end inside the frame its just easyer on a bench. I am one that hears a noise I have to KNOW NOW! ive blown up engines and tranys away from home/transport Vehicle and well, vehicle recovery blows. ive even replaced a oil pump, crank rod and bearings on the GS on a friday afternoon after work(started knocking on way home) and had it back together to go to work sat morning. it wasnt an ideal rebuild and i was worried about it holding, but after a week and over 150miles i didnt care, that engine is still in the GS to this day and i ran it as daily transpo for 2 more years. I am ashamed ive let the bike sit and it now needs tires,chain,battery,a complete carb overhaul and posibbly a new gas tank. too many damn projects not enough cash.

gsJack · April 23, 2014, 05:10:43 PM

Well I put the clutch cover and signal generator parts back on today after checking the balancer right side bearing yesterday. Left the cover off the signal generator so I could see the rotor and with plugs still out cranked it some more. Knock from #2 cylinder was a bit louder and clearer today and it seemed to me it knocked once each time it passed the upper right pickup indicating it knocked with #2 at or near TDC. Could be a worn piston pin knocking on changing piston direction or possibly be a broken ring and or land I guess. Don't know but if I find something else to ride this summer I'll keep the GS in the garage and maybe feel like pulling that head to see what happened next fall.

Don't know what I'm looking for piresito, my problem with the GS is the #2 cylinder so maybe a thumper without a #2 cyl? I kinda like that little CBR250R single but maybe that little Grom would be more suitable, only 225# curb weight about half my GS so I could probably still pick it up.

PS to bluekynt, know I couldn't R&R engine without help, probably have to strain to lift the head off now.

Old Mechanic · April 23, 2014, 06:29:12 PM

Why not just replace the motor as an assembly? At 100k miles you certainly have got every miles worth out of the bike.

http://www.ebay.com/itm/02-Suzuki-GS500E-GS500-500-ENGINE-MOTOR-VIDEOS-/190772712258?pt=Motorcycles_Parts_Accessories&hash=item2c6af09342&vxp=mtr

Just an example, it might even be close to your location.

Just thinking out loud.

regards
Mech

gsJack · April 23, 2014, 09:51:14 PM

Replacing a GS engine that needs major work is always a good alternative if a simple fix can't be found and now that I know what is wrong with mine I'll be thinking about it. Ten years ago when I was a kid of 70 it would have been a piece of cake but now it seems beyond me physically. Thanks Mech.

robfriedenberger · April 24, 2014, 02:32:23 AM

gsJack......

Maybe you could mentor some youngsters and teach them a few tricks and get free labor in return. I wish some one would of taught me a think or two when I first started working on cars.....

piresito · April 24, 2014, 08:34:28 AM

Quote from: gsJack on April 23, 2014, 05:10:43 PM
Don't know what I'm looking for piresito, my problem with the GS is the #2 cylinder so maybe a thumper without a #2 cyl? I kinda like that little CBR250R single but maybe that little Grom would be more suitable, only 225# curb weight about half my GS so I could probably still pick it up.

Didn't knew about the Grom, just Googled it! It's nice...for training knee downs and wheelie in the parking lot! ehehe

See it like this, you problem is with one of the cylinders, so it's good to know that you have other cylinder that keeps pushing the bike! You're never on foot! So...how about the CBR500?

gsJack · April 24, 2014, 01:34:46 PM

I was just kidding about getting a bike without a #2 cylinder piresito but I do have some interest in those 2 bikes. I've liked that little CBR250R since it came out, looks like fun. My interest in the Grom was rekindled recently by a thread in another forum I belong to about a Ducati guy having some fun on a track with his Grom.

http://ohioriders.net/index.php?/topic/104348-first-track-ride-with-the-grom/

I have made it home about 10 miles on the #2 cylinder of my GS when the #1 went out and before the GS years I made it home about 30 miles on 2 cylinders on my CB650SC when a bad coil dropped the other 2. Your point is well taken but if the bike falls over away from home you can't get home if you can no longer pick it up.

Blueknyt · April 24, 2014, 05:07:28 PM

Jack if you lived closer, i would be more then willing to muscle the wrenches for you. I might even have enough parts laying around to fix yours ( if i knew where i put em all)

Badot · April 24, 2014, 11:08:37 PM

Re-read one of your later posts Jack... when you said the noise gets worse when you disconnected the one plug, that seems similar to what my bike does, only mine is from about 3500-4500 RPM.

This noise similar by any chance? I apologize for the nausea inducing camera movements, but I was trying to use the video to pinpoint where the sound was coming from. http://s1198.photobucket.com/user/Dydler/media/sound_zpsb0dd26e1.mp4.html

My noise is more pronounced under load, seems to come from left side, gets substantially louder when only running on left cylinder (only running on left in video) and noise disappears when running only on right cylinder. Again, occurs mostly from around 3500-4500 RPM and for some odd reason seems loudest/most pronounced directly over the gas tank.

Also, for you other guys... if a ring/land was damaged, would there be scoring visible in the cylinder due to this?

gsJack · April 25, 2014, 09:38:18 AM

No, that doesn't sound at all like my noise Badot. Besides sounding different the rpm's are completely different. Also you think your noise is with engine running on the cylinder making the noise and my noise is from the right cyl with the engine running on the left one. Have you confirmed which side your noise is from, running side or opposite side?

After checking at idle with wires pulled one at a time I thought my noise was from the running left cylinder but discovered when spinning the engine on starter without plugs it was from the right cylinder. Might be worthwhile trying that with yours if you haven't yet, put an ear close to the plug holes while cranking w/o plugs and see if you can hear it like I did by chance while checking for the counter balance brg problem.

Do you have an optical scope to look into the offending cyl with? I don't and all I can see in my right cyl thru the plug hole is a very dirty carboned up piston top. I do think keeping on running with the noise might score the cylinder more if a broken ring/land is involved but will not if I have a loose piston pin problem. I took another short ride yesterday and never noticed the noise like before except when coming to a stop. Don't hear any problem at the 3500-4500 rpm your hearing yours.

Blueknyt · April 25, 2014, 08:30:01 PM

jack this may sound stupid and feel free to wack me with a rubber chicken if it does, but, are all your engine mount bolts tight? while i dont mean torqued, but no play between frame, mounts, tabs and spacers or case guards if equiped?

gsJack · April 25, 2014, 08:59:42 PM

Yes, I checked them when putting the clutch side cover back on a couple days ago. I had the front 2 bolts out a couple years ago to remove rusty case guards and had to soak the top one with liquid wrench and drive it all the way out. Decided not to paint and put the guards back on and socked the engine mount bolts down real tight to stay forever or so I thought.

prmas · April 27, 2014, 03:06:08 AM

Badot, often a cracked ring land will not so much score a bore as "polish" it as the piston is softer than the bore. Given enough time it will wear a mark in the bore but not scratch/score it in the normal sense. If the rings are broken the sharp ends will usually score the bore. I have listened to your noise a few times but cannot make it out. The nearest that I can guess at this stage is that it sounds like a compression leak but that does not fit your description. Sounds often do not travel well on the Interwebs. Is there any staining or leakage around the headgasket or exhaust ports?

Macka

Badot · April 27, 2014, 11:27:11 AM

Quote from: prmas on April 27, 2014, 03:06:08 AM
Badot, often a cracked ring land will not so much score a bore as "polish" it as the piston is softer than the bore. Given enough time it will wear a mark in the bore but not scratch/score it in the normal sense. If the rings are broken the sharp ends will usually score the bore. I have listened to your noise a few times but cannot make it out. The nearest that I can guess at this stage is that it sounds like a compression leak but that does not fit your description. Sounds often do not travel well on the Interwebs. Is there any staining or leakage around the headgasket or exhaust ports?

Macka

At this point I've said **** it to the problem. exhaust gaskets and head gasket were both inspected, no problem found, then replaced, no problem found. It's an old beat up 23 year old bike that's gone over 8,000 miles making the noise by now with no noticeable adverse affects or changes, I'm just going to ride it until it dies.

I simply posted the video and the question to see if it would help Jack at all.

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Knock, knock, where's the knock?