Strange noises

[LarsBloodbeard]

Something just doesn't seem right.  Perhaps I'm imagining things or overreacting, but I'd like your guys opinion... 

I keep hearing a rattling noise almost like pinging (sounds like a marble in a paint can), but it occurs at certain RPM's.  Giving more or less throttle gets rid of it, and it doesn't matter if it's under load or not.  Maybe it's just a loose bolt somewhere?

Then I came to a stop this morning and there was a loud "ka-chunk!" sound and my engine stopped.  I was certain it had seized... but then it started right up.  I looked around thinking maybe something fell off, but there was nothing on the ground.

I'm really confused here.  Where should I start looking?

[ace.cafe]

Pretty hard to say.
If I were to go on a hunch, I'd say to slightly retard the ignition timing and slightly richen the pilot circuit, and re-set the idle speed accordingly. Not too slow on the idle speed. 1000 rpm is about good.

[LarsBloodbeard]

Cool, that's along the lines of what I was thinking.  I will tweak the timing later since I don't have a big enough screwdriver with me.  I swapped the pilot for a 30 last night, as it was seeming to be a bit lean.  I didn't quite have it adjusted right though and the idle was way low once it warmed up and stalled a couple times.  I've never had the engine die with a loud noise like that though.

[AgentX]

Something just doesn't seem right.  Perhaps I'm imagining things or overreacting, but I'd like your guys opinion... 

I keep hearing a rattling noise almost like pinging (sounds like a marble in a paint can), but it occurs at certain RPM's.  Giving more or less throttle gets rid of it, and it doesn't matter if it's under load or not.  Maybe it's just a loose bolt somewhere?

If you figure it out let me know ASAP!  I have a similar rattle coming on as I open up the throttle.  Backing off makes it go away, and riding harder either also makes it go away or simply drowns it in other clatter; kinda hard to tell.

If I back off throttle then accelerate extremely gingerly, I don't hear it.

But this is happening at low throttle openings, like 1/3 or so, and on flats, downhills, and uphills alike.  When I really hammer it going up a hill in 4th/5th it doesn't make this rattle (or at least it's masked by the exhaust note and other engine noises) or any other distinct ping. 

I am really, really confused.  It sounds like Snidal's description of ping, but lacks the metallic high pitched edge some others have told me is associated with the phenomenon.  And it doesn't seem to be affected by altering the ignition timing in either direction.

Indian riders claim it's a variety of things, including the sound of lash in the cam gears.  (Which, they further claim, will lessen as it breaks in...first time I've heard of break-in resulting in closer tolerances!  Must be metal shavings from elsewhere accumulating between the teeth and welding themselves in place.)

But I'm not sure it's an ignition timing issue anymore.  I can't find higher octane fuel, or toulene spirits to add octane to regular gas:  paint thinners come in old water bottles so I don't know what's in them, and I can't exactly find an MSDS or anything at the roadside shack.  Had been hoping to see if higher octane would have an effect based on Ace and others' advice.  (Just as a test, not as the cure necessarily.)

For what it's worth, though, my bike also likes to die off during sudden stops but there's no ka-chunk or other loud noise associated with it.

[ace.cafe]

Could be bearings going bad.
That's extremely common.

[maxrotor Afro Samurai]

Ace....as in the main rod bearing?.. or other bushings all over?.. or crank bearings?...

Ace.. think i read you mention something on ceramic bearing.. was that concerning the wheel bearings?.. or did you replace main crank with ceramic bearings?

I been thinking alot on this lately... replacing everything with higher qual bearings.. all throughout... ceram if possible.. slight perf increase?

[LarsBloodbeard]

Sounds exactly like my issue, AgentX.  I checked the timing about 5 times, and it's spot on.  I might try advancing it anyway just to see what happens.  Also, I'm running 100 octane.  Just filled up with 91 to see if that makes a difference.  Usually when I hear a ping think "is that pinging?", give a bit more throttle and it gets louder, then I think "yep, definitely pinging."  This however, is just like you describe.  Only certain RPM's, and uphill or straightaway makes it no worse or better.  I looked around for things that might rattle, and even held my keys while riding to see if that was it.  But it really seems to be coming from the engine.

I made some adjustments to my idle screws and now it idle's fairly well and hasn't died or made scary noises like that ka-chunk, though I'm getting some backfires when engine braking so I think I'm a bit rich.

[ace.cafe]

Sounds exactly like my issue, AgentX.  I checked the timing about 5 times, and it's spot on.  I might try advancing it anyway just to see what happens.  Also, I'm running 100 octane.  Just filled up with 91 to see if that makes a difference.  Usually when I hear a ping think "is that pinging?", give a bit more throttle and it gets louder, then I think "yep, definitely pinging."  This however, is just like you describe.  Only certain RPM's, and uphill or straightaway makes it no worse or better.  I looked around for things that might rattle, and even held my keys while riding to see if that was it.  But it really seems to be coming from the engine.

I made some adjustments to my idle screws and now it idle's fairly well and hasn't died or made scary noises like that ka-chunk, though I'm getting some backfires when engine braking so I think I'm a bit rich.

Backfiring on engine braking means your throttle is closed, and that puts the carb on the pilot circuit.
So, that's what you have to adjust. Use your little angled screw.
I can't tell you which way to turn it, because it can happen with too rich or too lean. Too lean is more common, but it can happen either way.

[ace.cafe]

Ace....as in the main rod bearing?.. or other bushings all over?.. or crank bearings?...

Ace.. think i read you mention something on ceramic bearing.. was that concerning the wheel bearings?.. or did you replace main crank with ceramic bearings?

I been thinking alot on this lately... replacing everything with higher qual bearings.. all throughout... ceram if possible.. slight perf increase?

The main bearings and the rod bearing are known weak points in the Bullet.

Ceramics aren't available for the roller mains yet, but there is a ceramic ball bearing for the drive side. I haven't tried the ceramic in that place yet, but I'm waiting until the roller mains are available in ceramic, and then I'll try them all at the same time.

What you need are top quality main bearings from the major companies, and be sure that you aren't getting any counterfeits. The set of 2 main rollers and the drive side ball bearing should normally cost between $150-$200 for the 3 bearings as a set. Maybe you might find a good deal that is about 2/3 of that cost, if you were lucky.
If you are seeing the main rollers for $10 each, then you know it's junk, even if it looks right. You can't tell by looking at it, if it's counterfeit. They look good, but they don't hold up in the engine.
Don't buy bearings on Ebay.

[LarsBloodbeard]

Backfiring on engine braking means your throttle is closed, and that puts the carb on the pilot circuit.
So, that's what you have to adjust. Use your little angled screw.
I can't tell you which way to turn it, because it can happen with too rich or too lean. Too lean is more common, but it can happen either way.

I put in a 30 pilot jet and the air bleed isn't screwed out very much, that's why I figured it was too rich.

[ERC]

The sound your hearing "sounds" to me like a rod bearing to me.   ERC

[LarsBloodbeard]

The sound your hearing "sounds" to me like a rod bearing to me.   ERC

Hmm.  I wouldn't doubt it.  I'm sure the lower end is in terrible shape.  The alternator output shaft is slightly askew for sure.  I can't afford to dig into that lower end yet though, plus I don't have any other mode of transportation for the next month.

This would also make sense with the amount of metal particles that the valve & rocker grinding themselves down added to my oil.  I spent forever cleaning it out of the timing side.  The oil filter is silver in color because of it, so I'm sure plenty circulated through the engine.  I really should have split the case and gave it a superb cleaning over the holiday weekend, but the amount of work I've put into this thing lately is really wearing me down.

[Arizoni]

In my experience, a worn rod bearing will clatter lightly at low speeds and becomes increasingly loud as the engine speed increases.  It doesn't come and go.

Speaking of sleeve bearings, worn main bearings can be pretty quite when the engine is idling or just cruising along easily.  When the throttle is opened they start to clatter and the harder the engine is working, the louder the knocking will be.

With the rolling element bearings on the crankshaft they might sound similar to the sleeve bearings on a crankshaft, especially if the fit of the outside race into the aluminum housing was getting loose. 

[AgentX]

For my part, I thought it couldn't possibly be bearings since the bike has about 700 miles on it since its rebuild.  However, the quality of the stock RE bearings is of course suspect, and I'm confident they were installed with a big hammer, because that's the only way anyone installs bearings around here.  So I guess it could be.  I'm probably just going to ride it with my fingers crossed unless/until I figure out another possible cause; the bearings only need to last a few more months before I get out of India and build a new engine myself.

(I just made a crude wheel bearing press out of bolts and washers and people told me it was a waste of time and $1.50...)

[ace.cafe]

People pound them out and in here in the US too.

It's so easy to just heat the case to 250-300 degrees F, and they almost fall right out by themselves, and you can just drop the new cool bearings right in.
Hardly any work at all.
And it doesn't risk rolling or shaving any metal out of the bearing seats in the engine cases.

I just don't know where these people got the idea to beat these things with a hammer.