Heard a pop, now won't start

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bitsnpieces

New Member
Dec 9, 2010
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Melbourne, AUS
Just refueled, got a good fast run for a bit, heard some pops here and there, assumed it was the oil between the fuel, then one last pop and engine stops.

What happened?

I don't have any tools on me at the moment either...
 

yendorrodney88

New Member
May 5, 2010
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campbelltown nsw australia
Just refueled, got a good fast run for a bit, heard some pops here and there, assumed it was the oil between the fuel, then one last pop and engine stops.

What happened?

I don't have any tools on me at the moment either...
Hi bitsnpieces,it sounds like it could be your sparkplug it happened to me a while back,I had a spare stock sparkplug which i put in and went for a ride it started straight away but about a mile or so it started to pop and backfire and then just died,I got back home and put the old stock sparkplug back in and has been going great ever since,goodluck yendorrodney88
 

bitsnpieces

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Dec 9, 2010
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Melbourne, AUS
Had a look at the spark plug and its gone black.
Tried cleaning but still no good, too bad the car trick didn't work. :(
Might try again.

What causes it to go black so quick?
Bad fuel mix? Bad plug? Going at maximum speeds for too long? Something else?
 

breno

New Member
Aug 19, 2010
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Syd. OZ
I had the exact same thing happen to me today ended up being the magneto failing.
Have you ever had oil drench ur magneto before? I figured out it was the magneto after checking all wire connections, changing over the plug then swapping out the coil with a spare. Alot of mucking around I know.
 

bitsnpieces

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Dec 9, 2010
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Melbourne, AUS
Here's what I've found so far:

Spark plug is black, covered in dust/dirt, so is that caused by not having enough oil in the mix, or too much oil in the mix?

And I've had a look at the magneto and it is very difficult to turn. When you turn it, it makes that churning sound like pumping in air - mine is very stiff now and when I get it to turn, it's only sucking in a fraction of air or something; barely makes the pump noise.

I would believe my wiring is still good, intact, they don't look anything bad, and my slight petrol leaking has been fixed (added that white tape to screw).

So my guess is, other than the spark plug (which I did some quick sand paper work to clean off the dirt, which works for cars, which I hope will work for this until I get better ones), I'm guessing it is the magneto, or something to do with it.

Any suggestions?

Edit:
I opened up the case for the magneto and the clutch and also the other cover for the clutch. I managed to loosen things a little so the turning of the magneto isn't as stiff anymore, and clutch handling is a little bit better.
It still doesn't make that pumping sound when I turn it though, even when I turn directly from the clutch nut (like when you're feeding the chain through), it's a very soft pump noise, not like the normal one...

Tried it again, no go.
So either my magneto is definitely dead, or my spark plug isn't feeding it juice; I'm going to have to try that spark plug trick tomorrow when I get some time.
How does it go again? I put the spark plug on its side at the top of the engine where the plug normally goes, tape it down to hold it secure, but what needs to be in contact again? Which part of the spark plug to -any part of the top of engine- I'm guessing? Or does it require something more specific?

I'm thinking... Could it be more? Something more internal like the air intake?
 
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GearNut

Active Member
Aug 19, 2009
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San Diego, Kaliforgnia
A black spark plug is caused by a rich fuel to air ratio. Too much fuel. Try raising the clip position one notch on the slide needle to lower it in the slide. This will reduce the volume of fuel that the carburetor adds to the incoming air. Only move the clip one notch at a time. Tuning takes small adjustments, not big ones.
The oil to gas ratio used will not foul a spark plug if the carburetor is tuned properly.

As for checking the spark, you want the hex, or wrench flats, of the spark plug to be in good contact with anything metal on the engine. Any paint on the metal part is a no no.

If your cylinder head is painted black, try using a head bolt instead. In a pinch, you can use a piece of bare wire wrapped around the metal portion of the spark plug and squash the other end of the bare wire under the head of a side cover screw.
 

bitsnpieces

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Dec 9, 2010
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Melbourne, AUS
Ah... Thanks for clarifying. I will have to work on that screw to find a good feel during idling once this is all fixed I guess.

Might pick up a new spark on Tuesday, when I have time to go out.

Will give it a shot in the mean time... If cleaning it can help at the moment, that'll give me transport to get a new spark...
 

breno

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Aug 19, 2010
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Syd. OZ
Where abouts in Australia do you live? In the mountains or not?

What clip setting is the needle set on at the moment with the carby?

What brand of 2 stoke oil and type (synthetic or not) are you using and which fuel supplier and octane?

What oil to fuel ratio are you on?

An easy way I've found to check the electrical side is working is to take off the small sprocket cover put a 19mm socket [may need to be grinded down a tad sometimes to fit in (the socket that is)] in attach a drill and run in reverse with the plug out and the choke off.
This will tell you 2 things 1 there is fuel vapour coming out of the spark plug hole and 2 there is a spark immiting to the head stud bolt that has no paint on it.

Also it doesnt hurt when its all together to try and get a feel for how much compression there is when the clutch is out and u are turning the back wheel by hand.

If u are running a 44tooth sprocket and the engine is hot/warm you should be able to start the motor by turning the wheel by hand if you try hard enough and arent a wimp..LOL
 

bitsnpieces

New Member
Dec 9, 2010
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Melbourne, AUS
My engine is a 200W kit from Rock Solid from South Australia.
50cc 200 Watt Engine Kit

Before shipping any of their products, they do at lot of the construction (eg. my carb was already fitted to the engine with the clamp and everything a lot of people recommend using to prevent leaks), they do the run-in so the customer doesn't have to, and they run it on the dyno for around 2 hours at full speed to make sure parts and soldering and everything is good to go.
The head person mentioned that the real test is once it's on the road though of course to know if everything is aye okay.

I live in the suburbs and the closest mechanical place selling parts is approximately 8km away, about 6 miles I'm guessing; and yes I'm a wimp. When my bike broke down, I had to push pedal a good 15km give or take (12 miles?) and I struggled. I used to do around 20km (17 miles?) without too much struggle, both to and back so 40km total.
My rear is hurting like heck and I can barely sit on it now... Thought I had ordered the gel seat when I ordered the bike... Must have forgotten...

I was messing with the screw a bit to find a good idle mix and it may have been 3/4 in at that time, but I rarely idled because I was on a long large highway which was where I was going at full speed, probably more than the rated 20km/h rated by the manufacturer, and it popped and stopped.

I was using Valvoline 2 stroke oil at about 35:1 ratio, give or take a bit more, can't tell exactly as it's hard to measure on a bottle where the fuel is as dark as the bottle itself so even the measuring guides on the side was tough to see during the first 100ml worth.
It's a synthetic enhanced oil since the petrol station I was at didn't have Penrite... No station seems to have Penrite... So I'll need to buy some at Autobarn or something. The manufacturer recommended Penrite at 35:1, it'd save me the hassle of figuring out a good ratio of other oils and if they're the right one or not. 10:1 if I use Opti Oil.
With the Valvoline though, I didn't get much power. It'd chug along the ride, maybe at about 10km/h.

I ran out of fuel during my test ride and needed more oil to mix, so I bought Castrol 2T Self Mix, which now that I look closer, doesn't mention synthetic anywhere. The ratio I used with this was probably about the same.
My bike struggled to get started at first, it'd start, and when I turn off the choke, it'd stop. If I leave the choke half way, it'd work. Eventually after a bit, I could turn the choke off and this was when I was flying down the highway. I heard some popping noises here and there and just thought it was the oil between the fuel, just getting the mix going, and possibly the air and after a while, one last pop and it stopped. The pops weren't anything loud or bangs, just small pops, but still easy to hear.

In all honesty, it'd be my own fault really that it would burn out, but it's all a learning experience that's worth it in the end.

The fuel I use is Premium (Unleaded 98), not sure what you guys would refer it to as. It was the fuel recommended by the manufacturer.

I'll give it a shot with rotating the wheel, so I have a few things to do now tomorrow.
As mentioned previously, maybe in another post, when I first received the kit and was putting it all together, while feeding in the chain and rotating the front sprocket, I could hear like a pumping and suction sort of sound, like the sound of when you start a lawn mower and pull the string, and initial bit. So everything's good. Now when I try that, I hear nothing; it just rotates.

It was extremely stiff when it first broke down, but after coming home and taking the coil off (still connected to the wires as it was soldered on), and the two horizontal frames that surround it and the magneto (I'm guessing), I had a look to see for any loose wiring on the back side, just in case, and all looked well. But as GearNut says, looks can be deceiving.
Anyways, I was unable to take the magneto itself off as trying to rotate the nut only turned the magneto instead, but same thing, just moved, no pumping sound. Put it all back, re-adjusted the clutch so that it wasn't getting eaten too quickly, and was able to make it rotate easier and not so stiff anymore.

I had checked my spark plug which was covered in black so there was definitely a bad carbon build up, tried cleaning it using the sandpaper trick like you would with a car spark plug, as a temporal fix, tried to start the motor, and nothing. When I engage the clutch, the bike would just come to a rapid stop. The pumping noise is so minuscule, it was mainly just rotating and nothing was really pumping through to start.

I will have to check the pistons tomorrow to see if they are still functioning, and the fuel vapor and spark thing you mentioned.
 
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bitsnpieces

New Member
Dec 9, 2010
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Melbourne, AUS
Here's the problem:



How can I raise the piston or whatever it is inside to pull that bit out?

Hopefully that will get things going until I receive replacement parts as part of warranty...



EDIT: Nevermind, got it, turn magneto. Let's hope this works...
 
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bitsnpieces

New Member
Dec 9, 2010
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Melbourne, AUS
Hm... Still doesn't start.

When I manually rotate the magneto (quite stiff still), everything turns, but when I rotate the front sprocket, the magneto doesn't turn.
I looked on the other side where the clutch plate and rubber and all were, the big and small gears; the plate just skids across the rubber underneath, so it doesn't catch on to rotate the entire gear to rotate the small one to rotate the magneto.

Any suggestions?

I've tightened the plate as much as I can, it seems the small one is still stiff, something now making it hard to turn.

Any ideas what it could be? something still stuck inside my engine? o_O
 

GearNut

Active Member
Aug 19, 2009
5,104
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38
San Diego, Kaliforgnia
So where did that come from? It looks like a piece of the piston skirt. If it is is fact that, something else caused it to fail. You could very well still have a foreign object still inside the engine, or more than likely the piston has been damaged in such a fashion that it no longer will move properly up and down the cylinder.
I wish I had whatever that is in my hands to inspect it and determine what it is, if it failed due to poor metallurgy, or if the engine sucked in something. Heck, it could also have been caused by bearing failure and bits of the bearing went flying about inside the engine, finally resting between the piston and a cylinder port.
 

bitsnpieces

New Member
Dec 9, 2010
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Melbourne, AUS
Oops, forgot to attach a photo of the piece I took out.



Just received an email from Raw Motors that they don't ship to Australia...
Argh!

Any other company other than Rock Solid ship to Australia? I could really use a motor as soon as possible... Rock Solid doesn't open again until after January 10th for me to deal with warranty...

Would it be easier to just buy a new engine? Since the other parts all work fine from what I can tell, I just need a new engine in replacement to whatever broke inside there, and also my magneto and gears and all; that'd be easier right?

Just need someone who ships to Australia...
 

GearNut

Active Member
Aug 19, 2009
5,104
11
38
San Diego, Kaliforgnia
That looks like machining debris left inside the cases from the factory, or a UFO. Unidentified Foreign Object.
As for an Australian dealership, sorry, I am of no help there.
 

bitsnpieces

New Member
Dec 9, 2010
195
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36
Melbourne, AUS

The problem is that it's running on a 1.2kW engine which is 1kW over the legal limit without a license; unfortunately ZBOX doesn't believe in a 200W engine which is why I had to go with Rock Solid, who are twice the price...

Well... I ordered a replacement engine from Blow By U which is a Grubee StarHawk, which they initially quoted me for a StarFire Gen II... So I have to double confirm with them...

It's not a huge deal I guess... Just means I'll have to turn off the engine with police nearby so they don't get sketchy about the motor and checking for the power rating...