Strange Whirring noise By Doug in San Diego (Read 6,957 times)

[Doug in San Diego]

Hello All Docs

I have developed a strange whirring noise. It is tied to RPMs and it sounds like a medium pitched whirr

I took off the variator and ran the bike without it, and the noise was exactly the same, so I know it is not tied to the variator, belt, or clutch.

Side note- at times I have to hit the starter twice, as my 160cc piston and cylinder seem to have a good amount of compression

My thoughts are perhaps the bearing that the variator shaft runs on?

I really need some advice on this

Is it OK to keep riding?

Help guys!

[Bashan]

Hey Doug, couldn't be the cam chain could it? Sometimes when they first start to need a little adjustment they'll whir a little. That, of course would be on the left side also where you seem to be hearing it. Maybe you could give the tensioner a little nudge and see if it makes a change in the sound, if so that's it. Rich

[Doug in San Diego]

Ok

it has gotten worse


Now it sounds like someone put a few large washers in my crankcase

Somewhere between a scrape and really loud valve clatter

No loss in power and it still runs great

Help me please

[jake aka:ventoscoot]

Doug, I can't remember who your manufacturer was on your 59mm kit. Mine was NCY, and you saw the pics of my cylinder. I did not notice any "whirring" sounds or similar before the metalic clacking, but I hope that is not what yours is.

[Bashan]

Actually I was thinking of you Jake as I was reading that. The other thing that rings a bell is a guy had a progressive noise like that and it turned out to be the connecting rod. If it's that you need to park it before catastrophic failure. Rich

[runningslow]

Does it sounds anything like this?


If it does, STOP RIDING IT and change the oil. When you go to drain the oil, hold a strong magnet in the stream. If it comes out clean, you're lucky and you're just changing the oil.

If it doesn't come out clean, you may want to read my thread: THE MATRIX REBUILDING

[Doug in San Diego]

Yep

That is the noise

I skimmed your thread, what was the final verdict. Or better yet, what should I do now? (after the oil change)

What is causing that noise? Is it fixable?

[Bashan]

Josh, did you ever finally determine what was wrong with that motor? Rich

[runningslow]

Aug 20, 2010 7:58:46 GMT -6 Bashan said:

Josh, did you ever finally determine what was wrong with that motor? Rich

Nope. I just stopped digging when I deemed a complete replacement to be cheaper. I suspect its one of the main crank bearings, but I never opened the crankcase to verify.

[on a side note: If all goes according to plan and I can convince the wife... I'm about 1 week away from paying off the new motor.]

[Doug in San Diego]

OK Docs

So we've determined that some catastrophic defects lurks within my engine.

What do you think it is?

How hard is it to open up the crankcase and have a look around?

I need some help here guys (a new motor is not really an option)

[mapbike]

I noticed that in one area of the reference it states that the correct engine oil is 5W-30 and in another place it says 10W-30, everything else I have seen or heard on this subject has point to a quality NON Full Synthetic 10W-40 or 15W-40, I've been running Valvoline MAX Life 10W-40 Semi-Synthetic, I'm just a little cutios as to why the Full Synthetics are not Recommended for these engines, is it that the oil pumps in these engine is not strong enough to move the much stickier Synthetic oils? this is the only thing Ican come up with that might pose an issue for these engines if the pumps in them just dont produce enough pressure to move the synthetic oils like it will the much more fluid conventional oils, I run a mixter of standard Castrol HD30w & 5w-20 Royal Purple Full Synthetic in my High output GX200 Honda Clone, the reason being that I cooked a couple of Connecting Rods trying to run full Synthetic in it because the stickier oil would not flow between the Rod & Crankshaft under the force of the rod dipper scooping up the oil, the synthetics are much better lubricants than conventional oils but they seem to require a good pressurized oiling system or they will starve the components of lubrication and we all know what comes next.........screach............!!!!!!!!!

Anyway if some of you gentlemen know more about all this than I, please ring in here and explain the reason for the NON synthetic Recommendation on these GY6 engines.

I'm gonna start a new thread asking "what oil do you run in your scooter and why?"

Thanks & God Bless all
Shan

[Cruiser]

Viscosity is what determines how well any oil will flow at a given temperature. 10W-30 oil will flow the same in a given pump whether it is dino or synthetic. If we were talking about pancake syrup, then stickiness might be an attribute to consider. Dino (non-synthetic) is recommended initially to allow the engine to break in properly by letting the parts wear in together allowing the rings to seat properly. Some people feel that the synthetic lubricates so well that it won't allow parts to wear in. You certainly can keep using dino oil after break in, but most people will switch to full synthetic because of the superior lubricating qualities. Most synthetics have a wider range of viscosity like the the 5W-40 Rotella-T which is what I use. When the engine is cold, the oil flows better to allow better lubrication (5W) and when the engine is hot, you get the protection of 40 weight oil. Synthetic also has the ability to maintain its initial viscosity ratings longer than dino oil. Since most scoot engines do not have true oil filters, I feel oil which is designed for the most severe service like synthetic diesel oil is appropriate after the break in when you no longer need to "wear in" parts.

[erictheviking666]

I've only ever used Castrol Syntec 10w30 in mine since after the initial break-in. I now have 10,150 miles on my 50cc and have never had the motor apart. I definitely believe in full synthetic only after the break in.

[Doug in San Diego]

Well I did an oil change

No metal in the oil, but about a Tablespoon of blue paper gasket material???!

What the what?!

No change in the noise after the new oil

Looks like a tear down is in my future (bummer)

[jake aka:ventoscoot]

Keep us posted!! Hope all goes well!