Guess the Sound! (prizes!) [solved]

[NightRyder]

http://s5.yousendit.com/d.aspx?id=1GE7AA28M624L1NBRB7OEGVFAM
The main sound is a tssk (but sounds more like a tick in the video, think of a tick make by air..), at 4-5 and another at 7-8 seconds into it. There are more, but thoes are the easiest to hear. It comes from the front left of the engine) You can see that the rpm's drop with the sound. [the rpms are up because the choke is on, doesnt matter to the issues if its on or off though]

Alright, first person to tell me what it is wins! er, as for a prize, you can call yourself Sound Master for a week. :lol:  

Also, so no one thinks it should be in spam/offtopic, I don't know the answer.

What it shouldn't be:
Valves- checked and replaced shims tonight.
Carb - did that thing a few times.
Air leak - checked/rechecked/did the spray flamible substance test too.
Sparkplug - shouldnt be, it was doing it, i replaced them, still does.

It sounds like a gasp of air. But power drops a bunch when it happens. (might be a missfire?) Makes for impossible slow control, and creates large surges when at anything over 10mph. (below that and it might drop so much power it might die, happened twice trying to ease out from a stop off up a hill.)


Before anyone says search; I think the only thing left to check is the electronics, and see if the whatever-its-called-that-powers-the-sparks is ok. (not that i know how to) I just wanted some input. Thanks.

[RVertigo]

Cam Chain Tensioner...

If you're in the Seattle area I can show you what mine sounds like...

[NightRyder]

Aw, I forgot to say that was the first thing i did to the bike.

As long as it still springs, its ok, right? Or is there a certain tightness you need it to be?

damn, i would travel down there now, if its ok. This is getting on my nerves.

I have taken the bike apart 4 times, and done the carbs twice. And I havent even gone 3 blocks on it. (i go around mine a few times, realize the problem is still there, and it goes back into pieces.)

[RVertigo]

I mean...  camshaft endplay  

[NightRyder]

Ah, but that was harmless, wasnt it? It shouldnt cause engine problems, right? The engine power dies, then comes back. I figured when people would say harmless, it didnt include harmless problems, just harmless sounds.

[RVertigo]

:dunno:

Mine does it sometimes...  Generally when I rev it just a little, around 2-2.5K...  It'll dip the RPMs down to around 1K and come back.

I figured it was just camshaft endplay and didn't worry about it...  (But, I didn't pay much for my GS)...  Now I'm just used to it and avoid small revs.   :dunno:

Hopefully someone smart will reply.  

[NightRyder]

But when your riding around, does it loose power then surge back up? Not just a little, alot.

[RVertigo]

Only if I'm low revved...  The surges may be unrelated to the camshaft endplay...   I was just trying to win the "Guess the Noise" prize.   :lol:

[NightRyder]

Ah, well then.. you can have the 3rd place prize. You only owe me $0.50

[GeeP]

I know precisely what that sounds like!  It's a General Electric 16-cylinder 7FDL diesel with a loose governor rod, coked up rings, and a high idle.  (At least that's what the first 4 seconds sound like.)   :lol: :lol: :lol:

Sounds like misfiring to me, so it's probably an ignition problem.  Can't really hear it well, but it could also be a mixture issue.  If you're positive your carbs are OK, I'd check to see that the ignition system is in good order.  

[NightRyder]

I know precisely what that sounds like!  It's a General Electric 16-cylinder 7FDL diesel with a loose governor rod, coked up rings, and a high idle.  (At least that's what the first 4 seconds sound like.)   :lol: :lol: :lol:

Ah, but is that a good thing or bad? :lol:  :mrgreen:

Sounds like misfiring to me, so it's probably an ignition problem.  Can't really hear it well, but it could also be a mixture issue.  If you're positive your carbs are OK, I'd check to see that the ignition system is in good order.  

Alright, at least one vote for ignition stuff. Now to figure out how to check that...

[NightRyder]

So... the coils and, signal generator seem fine, I think (tested via. ohms test). I did some tests around from around here, and they all say test A, and if A is no good do B, C D etc. Well for both A turned out good. There are some other electronics on the right side of the bike I havent messed with, but other along with not knowing their name, I don't know what they do.

I have swaped coils and plugs, and the problem seems to stay on the left, although it may not be one side or another. (it seems like it, but I don't have any baseline)  . I even put in new gas. Still does it. The engine works better now; revs drops/rise and everything smoothly, it fires right up, etc. Except when it p00f/toof's. Then everything goes haywire. RPM's drop, surge, engine doesn't respond to throttle... Then when it recovers (2 secs) all seems ok. Repeats every 1-40 seconds. AAAAAAAhhhhh :x This is driving me crazy and I cant think of anything else to mess with :dunno: . Someone give me something else to check. I admit it might be something I already checked, but I think I did a fair job checking.

[NightRyder]

Ok, new diagnosis. I believe (85%), it is backfireing into the carb. I am searching currently, but not finding much so far that helps.

I also get an occasional sound like there is air (exhaust or fiel/air, I don't know which) going the wrong way. It doesn't pop like a backfire, and it doesn't blow the carbs off, but it does slow the engine down a lot.

goat explains it exactly. now the problem is trying to find the solution.

[TheWall]

Intake valve not seated or may be bent?  How else could it backfire into the carb?

[NightRyder]

I have no idea at all. Even after searching forever x 2. How would the intake valve get bent? Hitting the piston? That doesn't sound likely, does it?


... great now I'm contemplating taking the engine down that far. Agg, that means taking the cams out, along with a bunch of other things that might not get back togather right.

[TheWall]

I have no idea what could cause it.  Someone else (dgyvr) on this site mentioned how to check if the vlave is bent or not:

.....
Bending a valve depends on the timing setting when you were rotating the motor. There is an easy way to check for bent valve without removing the head. Pull the exhaust, carbs and plugs. Shine a light into the spark plug hole. Rotate the motor while looking into each of the in/ex ports. If you see light continuously through the cycle then you have bent a valve.

I would check the left side intake valve with the above method.

[NightRyder]

Ah, nice the infamous flashlight valve check. I saw it mentioned but didn't find how to do it, and must have given up on it. I'll do that right now.



Edit:
Well, I am not sure if it is good news or bad, but the valves check out ok. Good because: there are large points where there is no light. Bad becuase: I still don't know what is wrong.

Rotate the motor while looking into each of the in/ex ports. If you see light continuously through the cycle then you have bent a valve.

This does mean, continuously in each port, not both at the same time, right?

[TheWall]

Check one port at a time while rotating the engine through its complete cycle (several turns should do it)  You should see light when that port is open (intake port: letting in fuel and air) and see no light when the valve is closed (intake: when the cylinder is firing and expelling the exhaust).  You have to rotate the engine enough (while watching 1 valve) to make sure you don't see light during the stages the valve should be closed.  It may not be it, but it is something else to check.  
I know you checked the carbs but  make sure the carb boots that connect the carbs to the cylinder head are on good and there aren't any holes in them.  Mine was running on 1 cylinder and I found out which one by comparing the warmth of each side of the motor with my hand.  Obviously you want to make sure you don't burn yourself though.

[NightRyder]

Yeah, I did the test right then.

My boots are good, tight with no cracks too.

The left side is cooler, but only a bit. At one point I could leave my hand on the right for 2 seconds, and the left for 4. But later it was more like instant on the right, and 1 second on the left. So it is cooler. It does fire though. After a long warm up session, the plugs will be black, but if I wait a long time, the left one will clean up and ash over a bit. (which I thought meant lean, but I also though lean meant hot. so..     )



Edit: here's a tidbit. I would think it was normal/ok but meh. When I took a look in the ports, I had to take off the carbs and tank. But I left the tubes connected and gas in the float bowls. The point is, when I pulled the carbs (had to tilt them alot, 80* up) out gas came out of the engine side holes. I would think this should be normal, but  :dunno:.

[TheWall]

Actually I don't know if that (gas pouring out) is normal.  It hasn't happened to me when I have pulled off my carbs.  Does the throttle butterfly valve (brass disk in the port of the carb) seal correctly in the carb?