Killed my Engine

Zero compression at all 4 cylinders pretty much sums it up. Does anyone know if the FJR engine is a zero clearance engine? I see that the pistons have valve reliefs in the dome, so I'm hoping that means there is some valve to piston clearance.

Starting around 20k miles I would occasionally hear a bit of rattling that was traced to the cam chain area. It was very light and would come and go without any regularity. The chain tensioner was tested and seemed to be OK. At 34k miles it was rattling a lot more often and with greater vigor. As I approach 40k miles my engine would often sound like a diesel with the chain clattering. As the chain clattered I could watch the tach wander in synch with the noise and I was getting vibrations that could be felt in the engine & chassis. I was hoping to get through the 10/13 fall foliage ride, then tear it apart and repair it at my leisure.

The rapid spiral to death started Saturday morning when I retracted the cam chain tensioner plunger then released it again. Upon release it seemed to make a strong and full release. I tapped the starter button, but was wholly unprepared for the mechanical racket that ensued. I was so stunned that I may have delayed releasing the button as quickly as I would have, if I had been expecting a problem. Poof, just as quick as that the engine was dun fer. Immediately after the mechanical cacophony the engine would spin like mad when the starter was pressed but there was no sign of firing. I had some hope because there were no bad mechanical noises when the engine spun. The garage gremlins had hidden my 10mm compression gauge fitting so I was left to do a bit of field troubleshooting. No codes, the cylinder identification sensor does not produce an error code or a reading on the diAG screen. The spark plugs looked good; using the diAG test function I could fire all 4 plugs with bright blue sparks. Putting it in 1st gear I could turn the rear wheel by hand (ignition off) but it took major effort so there was some initial hope that the compression was good. Using an audio tube I couldn't hear the cams moving in the bearings, which took away some hope. Then the garage gremlins finally coughed up the 10mm fitting and I did the compression test. If some of you as far away as the Mississippi River and the Gulf Coast heard a loud primal scream around noon today, it was me, after reading the compression gauge. My guess is that the cam chain has come off the crank sprocket.

I'm really time challenged right now so I might have to seek a dealer in the NH area for a resurrection. This will be the first time a dealer will touch my bike since some early warranty issues were resolved. I'm really pissed/bummed about this. I'm going to make one more quick pass at it tonight to see if I have missed anything else while troubleshooting.

Unfortunately, it looks like I'm going to have to cancel the 10/13 fall foliage ride. Details to follow tomorrow.

:angry: uke: :angry: uke: :angry: uke: :angry: uke:

Alan, bad news that I'm sorry to hear. I'm assuming you don't have the YES warranty.....

Sounds no good, Alan.... in fact, it all sounds rather grim.....

I am wondering about this sentence:

The rapid spiral to death started Saturday morning when I retracted the cam chain tensioner plunger then released it again. Upon release it seemed to make a strong and full release.

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Uh... say what? Can you elaborate on what a "strong and full release" means here?

Sounds bad but hope for the best. If the chain just managed to drop off the crank sprocket the cams may not be turning causing no compression.

I can just about guarantee you that the engine is not "free spin." Few engines are, actually, despite many that claim to be. If a cam stops turning and a valve is held open enough it will hit the piston. Reliefs are there for running clearance, not for "free spin" purposes. But, there are a lot of places the cams can stop and not hit the valves into the pistons so cross your fingers.

PM me and I'll give you my phone number and talk you thru what to check. It really isn't that hard to correct, hopefully. If you can do a valve lash check you are there with some info. Even if something touched the head will have to come off but certainly nothing worse than replacing a few valves.

To make you feel better it is highly unlikely that ALL the valves could be bent....damn near impossible. Point is that no compression can come from just the cam not turning, not because of a bent valve. Stop turning it over until you find out more!! You'll just do more damage.

The rapid spiral to death started Saturday morning when I retracted the cam chain tensioner plunger then released it again. Upon release it seemed to make a strong and full release.

Click to expand...

Uh... say what? Can you elaborate on what a "strong and full release" means here?

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I short-cut the full story here. This is what I was referring to: From the FSM

d. Remove the screwdriver, make sure the timing

chain tensioner rod releases, and then

tighten the cap bolt to the specified torque.

With the cam tensioner out and in hand, the plunger appeared to fully extend, though the spring force was not uniform. This is an indicator that the CCT needs to be replaced, but in error I didn't feel that it was bad enough to cause a problem beyond the chain rattling which I already had. The plunger action didn't really feel rough, just a bit non-linear from fully compressed to fully extended. The first time I had the tensioner out ~20k miles ago the spring force seemed to be pretty much uniform so I just reinstalled it. 20/20 hindsight says that I should have gone with my gut feel and replaced it.

I'm pretty sure that the tensioner was left in the 'soft' area of operation and didn't supply sufficient force to keep the initial chain snatch wind-up controlled. I'm really hoping, and expecting that the chain has popped off the crank sprocket and no more damage beyond that was done. I will replace the chain, slipper and tensioner as a set, then mechanically time the intake and exhaust sprockets with the crank sprocket.

Let me tell you how much I have enjoyed removing the tensioner from the engine! A good set of tools rule, the only thing I lack for a job like this is a complete set of tiny Japanese fingers.

ionbeam said:

Starting around 20k miles I would occasionally hear a bit of rattling that was traced to the cam chain area. It was very light and would come and go without any regularity. The chain tensioner was tested and seemed to be OK. At 34k miles it was rattling a lot more often and with greater vigor. As I approach 40k miles my engine would often sound like a diesel with the chain clattering.

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And I thought I was a procrastinator.

In reading this, my problem is that if the chain has come off, where would it go? Slack would be evident in riding high on the sprockets, with a possible jump, changing cam timing.

So I'm not the doomsayer that others have been in this thread. You may not actually be too bad off.

If the cams aren't turning, I would expect compression in at least one cylinder. I'm not sure if there's a point somewhere that has at least one valve open in every cylinder, but my mental imagery is letting me down at the moment.

With no compression, it might be possible that the cams are turning, just timed way bad, resulting in exhaust valves opening during what should be a compression stroke, and what should be an exhaust stroke would have the intake valve open early. Maybe. Mental motion picture getting fuzzy again.

My only experience with this is actually a late-80's GM 3800 V6, the crank sprocket had nylon teeth, many of which were missing when this happened, but the chain jumped 4 or 5 teeth, which killed the engine completely, but with no damage at all other than the timing chain and sprockets, already bad. I'm hoping you find something like that, just jumped a few teeth, new sprockets, chain, and tensioner and you'll be all right.

So stop screaming. You're interrupting our parties down here. B)

Edit: wanted to add that if you had piston/valve contact, you would have heard a serious hammering noise. Don't ask me how I know, but it has to do with an automotive timing belt jumping 2 teeth.

Alan, this is bad news. Sorry to hear about the trouble, hope it works out without too much damage.

Sorry, can't offer any more than what has already been contributed. Only to re-emphasize what Jestal said...

Stop turning it over!!!

Pull everything and find out what's up.

I think wfooshee is right, where/how could the chain come off unless it broke.

I would surmise from viewing the cam drive illustration (https://parts.yamaha-motor.com/partimage.gifx?d=92020,2,0) that one of the three cam-chain guides has worn through or disintegrated due to low chain tension, possible allowing the chain to slip/not engage the crankshaft sprocket. Most likely the aft side tension guide has gone bye-bye, which would explain the tensioner events you experienced. You'll probably find bits of worn Delrin in your oil-pan. Hopefully, your valves survived intact. Only a head removal will tell for sure, which you'll need to do to recover the cam drive tensioner(s). Good luck!

I too have, in my distant past, witnessed a matched set of eight bent valves result from my wife's POS '82 Ford Escort timing belt slippage due to an on-the-road water pump replacement (by a moron)!

Sorry to read this, 'beam. I can't be of any help here, but I hope it's a simple and cheap fix.

Kevin Daly said:

I think wfooshee is right, where/how could the chain come off unless it broke.

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Still new here, but I believe the approprate thing to say here is GUNNY.

I got my FSM out and have to agree with wfooshee and Mr. Daly.

Best of luck.

What more to add. BUGGER.

Hope this isn't a worst case but I would also suggest stop turning it over. Or at lest do it by hand.

The racket and subsequent 0 compression pretty much says it all-bent valves. If a chain slips, mis-times,and a valve hits, several things can happen. Valve stops and bends, valve stops and chain breaks or both. Though it might just be valve time, the piston is soft enough that likely the hard valve carved out a likeness of itself, but ugly like a Picasso, not pretty like a Monet. Sorry to hear it Beamer.

Ion,

Sorry to hear about your situation. I wish you the best for a positive outcome. Let me know if you need warranty assistance.

May the force be with you!

Sorry to hear about your FJR problems. Hope you can figure it out soon. If I could help I would but this stuff is WAY OVER my head!

Tom

Be very carefull turning the engine over and/or turning the cams to re-time everything. Even if valve(s) are not already bent they could still be bent if you turn the crank to TDC and then try to time the cams. The safe bet is stick some pieces of dowel down the spark plug holes so you can judge where the pistons are so that you can turn the crank with the pistons away from TDC to safely turn the cams back into time. Then bring number one piston to TDC to time the cam chain.

If you have the pistons away from TDC you can turn the cams over and watch each set of valve stems closely and/or check valve lash. If something is bent then the valve stem will not come completely into place so this is a quick check for something bent.

If you really want to be sure close intake and exhaust valves in each cylinder one at a time and put compressed in at the spark plug hole and listen for leaks out the intake and exhaust. Really the only sure way to tell that nothing is bent unless you want to retime it all and then do a compression test.

Look at the crank end of the chain carefully. If the chain gets loose or too much slack in it it can double over on itself, jam into the gap around the crank sprocket and really do some damage.

Hopefully the chain just disengaged from the crank by hanging a bit low due to slack and the cams stopped in a "safe" spot.

jestal said:

Hopefully the chain just disengaged from the crank by hanging a bit low due to slack and the cams stopped in a "safe" spot.

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Wouldn't this statement from the original post indicate that it was NOT in a safe spot?

I tapped the starter button, but was wholly unprepared for the mechanical racket that ensued.

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Something else just came to mind. You can put a socket on the end of the crank and spin the motor by hand. If you do that slowly, you should be able to hear if there is any contact with the pistons and the crank. Also, if you take the valve cover off, you should be able to see if the cam chain is spinning, right? And, if the cam chain was broken, you would be able to pull it through from the top, right?