Loud gear sound when revving?

And don't forget the minor possibility the spark plug is tapping. Had a head and plug combo on something, if I turned it down to torque spec it would just touch. 5 pounds less torque it would not touch. Had to put spacer washers on the plugs to ensure they would never touch the piston.

Im pretty sure I had that on one of these engines too, but it was a defect in the head technically, low seat on the plug, if I used the stock gasket it was fine, but upon putting a new half-as-thick gasket the piston would touch the spark plug.

Annoying stuff.
 
My engines all made loud gear noise when new.
Keep putting a tiny bit of grease (and wipe up the excess) on the gear teeth every second tank of fuel and the noise will go away.

Now my black No-Name well worn motor makes huge gear noise on deceleration only???
I am guessing that the previous owner just ran it WOT all the time.

It is funny, if you quiet the exhaust, the next thing you hear is the intake.
Quiet the intake, you hear the gears. Quiet that, you hear the chain.

My snowmobile has a very quiet 4 stroke engine in it, but with the quiet engine, the track noise became so noticeable that the manufacturer replaced it with a more silent design.
Sled stuck in deep soft snow, really quiet:
full
 
My engines all made loud gear noise when new.
Keep putting a tiny bit of grease (and wipe up the excess) on the gear teeth every second tank of fuel and the noise will go away.

Now my black No-Name well worn motor makes huge gear noise on deceleration only???
I am guessing that the previous owner just ran it WOT all the time.

It is funny, if you quiet the exhaust, the next thing you hear is the intake.
Quiet the intake, you hear the gears. Quiet that, you hear the chain.

My snowmobile has a very quiet 4 stroke engine in it, but with the quiet engine, the track noise became so noticeable that the manufacturer replaced it with a more silent design.
Sled stuck in deep soft snow, really quiet:
full
At least it's stuck with the track down :)
 
I found out that the cause of the pinging was a lean condition, and I found a huge air leak in the carb and sealed it with silicone. Once that cured, the pinging went away completely.
20170304_124233.jpg


The problem of lost power is still there, though. I'm noticing that oil is being spit out from the head, and the exhaust. When I first pull the carb and adjust something, or let it cool for a while, it will run great for a minute and then act like it's starving for fuel and I have to pull the enrichment lever and it gets better until even that's not enough.

Are these places where oil is leaking from, the problem?
 

Attachments

  • 20170304_124307.jpg
    20170304_124307.jpg
    161.2 KB · Views: 170
  • 20170304_124301.jpg
    20170304_124301.jpg
    129 KB · Views: 160
I'm not sure what you mean by "oil injection tube", could you explain a little more?
2017-03-04 17.12.jpg


These are your primary and secondary injection connections. I usually would connect the 2 of them together with a tube and an airsoft bb stuck in the middle if the tube to make it closed. Currently on my carb I just heated the middle of the tube with a lighter and pinched the hot plastic together.

The 3rd is the breather, leave it open with a plain tube. That should help you with actually adjusting carb settings accurately. I have a thread where I modified a jet meant to be used for this carb to accept the more common Dellorto style jet acting as an adapter by tapping threads into it.

If you need to figure out the air idle adjustment or how to set the idle the right way just ask. I have plenty if hands on with this style carb do I can probably help point out issues.

Also there's supposed to be a rubber seal that goes in the carb that sits between the carb seat and the intake's end. The black ring inserted in the carb in this pic, doesn't work well if installed backwards btw.
20161003_123331.jpg
 
So, it looks like I only have the primary oil injection tube that's in front of the air filter. I sealed it off with a screw.
20170304_154450.jpg


My float level is parallel to the edge of the carb, and my needle only had one very lean clip position, so I cut my own grooves in it and I have it in the 3rd position.
20170304_154621.jpg


I don't know if this is a good way to describe it, but if I let the bike sit for a bit with the fuel on, it starts fine and runs for a bit, then as if that reserve of fuel in the carb is being used faster than its being replenished, it dies like it needs more. I've filed out the pilot and main jets slightly and it seemed to help a little but I haven't made much progress into getting the engine consistently running. The pinging comes back too, when it runs out of fuel, so it's becoming too lean as I run it.
 
Maybe there's something blocking fuel flow, because I pulled the hose off and turned the fuel on and nothing came out, and after shaking the bike a little, it started smoothly pouring out.
 
Back
Top