Clacking from cylinder - Loss of power

[Devaclis]

2004 GS500F

8k miles

Maintained meticulously

Wife left yesterday to start a long ride.  Bike was runnning flawlessly.  Cresting a hill passing a car the power decreased.  She pulled in the clutch and the bike died.

Waited a few minutes on the side of the road and then checked the oil.  NONE on the dipstick.  I checked it the night before and the level was in spec.  She went and got 2 more quarts of oil to bring it BACK into spec and tried to start the bike.  Loud clacking comming from the cylinders.

I got the bike home and pulled the valve cover.  No scars on the cams, cam chain is tensioned.  Checked the oil and it was a bit over full (Must have been from sitting nad having the residual oil drain to the bottom)

I pulled the plugs out and turned the motor over by hand.  NO clacking, weird.

I put the plugs back in and did not connect the plug wires.  Turned by hand, no clacking.  Cranked with starter, no clacking

I then put one of the plug wires back.  Clacks LOUDLY.  I removed the plug wire and connected the one on the other side.  Clacks LOUDLY

I have no clue what could be wrong here.  It sounds like the pistons are topping out on a valve by why only when a plug is connected and wired?

Any help would be GREATLY appreciated.

Thanks,

Dana

[kml.krk]

unfortunately I don't know what the clacking is caused by, but when you check the oil make sure the bike is leveled.
you said you checked the oil on the hill - this may be a reason why it looked very low, and then after you add it was overfilled. Bike MUST be leveled before you check the oil.

good luck and I hope you fix the problem soon!
KML

[bill14224]

Sounds like crank bearings to me.  I hope to God I'm wrong, but in any case the engine burned almost 2 quarts of oil in one ride.  8,000 miles?  Sounds more like 80,000, or mercilessly beaten by the previous owner.

I will say a crank bearing prayer for you.  Good luck.

[Devaclis]

I had another buddy suggest crank bearings too.  I am going to find out tomorrow after work.

[Bridger]

Reasonably speaking, crank bearings is all it can be.....No good...

[sledge]

Dont forget or dismiss the balance-shaft bearings. 

[Chanse]

Run a compression test?

[The Buddha]

Rod bearing. See those guys get whacked around by suction and compression in the motor. No spark plugs = no suction or compression. The rod bearings are DOA dude.
Of course CB is a mirror image of this. But I'd call the rod beairngs firstm CB second.
Cool.
Buddha.

[The Buddha]

CB = counter balancer.
Cool.
Buddha.

[Devaclis]

Yeah, I pretty much confirmed it by puttingthe pistin ad the top of the cylinder, removing the plug and then sticking a screw driver in there.  It moved down just a hair (while the other piston did not and the crank did not move).

Gonna pull the motor tonight and get the rebuild under way.  Should be pretty simple.  I just need to procure the parts, which may be tough.

Thanks for the help guys

[natedawg120]

yeah a buddies prelude did the same thing, sounded terrible.  We popped the head and started tapping pistons and one dropped an eight of an inch = spun the crank bearing.  The bad thing was the his crank was also f-ed cause he drove it around 5 miles home after the banging started.  hopefully you will have better luck and good luck.

[The Buddha]

Yeah, I pretty much confirmed it by puttingthe pistin ad the top of the cylinder, removing the plug and then sticking a screw driver in there.  It moved down just a hair (while the other piston did not and the crank did not move).

Gonna pull the motor tonight and get the rebuild under way.  Should be pretty simple.  I just need to procure the parts, which may be tough.

Thanks for the help guys

Should be ... lets see ... impossible.
Everyone who is worth a 10mm wrench as a mechanic - werase, dgyver .... many many many more on here before I'd in very small letters put Buddha ... has one or 3 ... or 42 in their garage/shop/basemnt/coffee table.

The problem is, crank bearings in over size isn't available. You have to weld the crank and turn it to within a squillionth of an inch, and micro polish that rod journal as well as all other journals that have any wear on them and get them all back to the exact original size.

Your measurement with the screwdriver - does not preclude the other journal being bad, neither does it preclude any other bearing being shot.

This one is just so bad ... your peak to peak clearance is enough to move with a screw driver.

In a bearing situation where you need to build and retain oil film strength on the 2-10 psi it makes when it gets hot ... you will have to make sure your valley to valley clearance is under a certain amount - usually in 1- 2 thou and the peak to peak needs to be not less than 1/2 a thou maybe.

Basically weld and turn the crank to exact original size +/-  5/10,000 of an inch micro polish it and buy all new bearings all around - for every spot there is a bearing in. Good luck with that, we just have better things to do maybe. Not me, but the rest maybe ...

You could, but it will cost you 500-1500 bucks. I'd sell you my GR motor for the low side of that $. Weld up ears and throw it on. Figure the exhaust and carbs etc should work as is. You may be home free - 650 CC GS500 ... for less than rebuild cost.

Cool.
Buddha.

[Devaclis]

So replacing rods, crank bearings and crank is a no-go?

[The Buddha]

If you're option for armageddon - first Price those parts.

Then you are assuming that is all the wear on it.

What if your crank bearings - the ones in the case - the babbits - the freaking idiotic moron's who let it run in plain aluminum ... have wear.
What about CB.
What about transmission - though wear comes to these quite late.
What about cam - oh yea lack of oil pressure kills them, but they never react first - its scoured but not dead. Remember the famous honda V4 eating them due to lack of oil pressure ...

This is the order of how expensive these will be. In decreasing order of cost.
Fix your GS.
Buy a new GS.
Buy a used GS of similar vintage.
Buy my GR motor and shoehorn it in and figure out the rest.
Buy a GS motor - well if you can find one, but for the 500 I'd ding you for on a GR motor you could get a GS ... someone could sell one out of their running GS for $499 and buy mine and toss it in for 500 and figure it out ... yea ...

This aint no tire you can patch back up and get down the road dude. Do it right and it will last a long time. Screw up, even a little and you're not going to make it out of your driveway.
Cool.
Buddha.

[Devaclis]

Yeah, I have had nothing but bad luck with EVERY suzuki I have owned.  My Hondas have gone through hundreds of thousands of miles with few issues.

I will part out the GS.  No use in investing any more money in a company and a product that build sub par equipment.

Anyone want to buy any of that sub par equipment?

Like I said, I took meticulous care of it.  You can't prevent the damage cause by manufacturing and R&D problems, I guess.

[Devaclis]

Soo, I pulled the motor and got the top end disassembled.  I found the the front of the left cylinder liner has a crack in it.  I can't seem to locate any replacemets for these anywhere.  I may just have to purchase a new jug set.








I have not begun to tear into the bottom end yet to check out the crank and bearings.  I have a machine shop that specializes in fixing cranks after situations like this.  They said they would give it their best shot and make sure everything is factory spec'ed.  We will see.  I really would hate to purchase a new crank and bearings.

[mach1]

does the piston move side to side? if so you rings could be gone and your piston was clacking around in the bore and smacked you wall and gave it a big crack.

[Devaclis]

No, they were tight.  There was also no metallic residue on the oil or on the magnetic drain plug.  The oil looks pretty good.