Does your scooter have a blown engine?
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- Опубликовано: 14 июл 2024
- Tools used in this video:
Compression Tester: scooter911.com/shop/lang-moto...
Leak Down Tester: scooter911.com/shop/performan...
Parts shown in this video:
Spark Plug: scooter911.com/shop/ngk-cr7hs...
Big Bore Kits:
-scooter911.com/shop/blue-line...
-scooter911.com/shop/ncy-cylin...
-scooter911.com/shop/ncy-cylin...
Engine oil: scooter911.com/shop/genuine-4...
There can be many reasons your scooter wont start. There can be an issue with the carburetor, or maybe your ignition system is malfunctioning. But if your engine has a mechanical failure none of those factors will matter.
In this video a Wolf RX50 scooter with a 49cc 139QMB engine is examined to discover which internal component has failed resulting in low compression. The only way to know if your scooter has low compression is to use a compression tester. In general, good compression on a 139QMB is anywhere from 140-180 psi. Low compression would be from 0-110 psi. Typically an engine with less than 100 psi will not run at all. An engine with over 100 psi might run but it might exhibit symptoms such as stalling, hard to start, low top speed, smoking or poor fuel mileage.
To perform a compression test, remove the spark plug and thread the test hose of the compression tester into the spark plug hole. Then hold the throttle wide open and crank the engine. The needle will climb every time a compression stroke occurs. Take your reading when the needle stops climbing or after 15-20 compression strokes.
If you find your scooter has low compression you can determine which internal engine component has failed by using a Leak-Down tester. A leak down test will utilize compressed air to pressurize the engine's combustion chamber. In an ideal situation very little to non of the compressed air will leak out. If the valves do not seal tightly because they are bent or burned the compressed air will leak out. You will be able to determine which valve is not sealing by listening to the intake and exhaust systems. If the piston rings do not create a seal between the piston and the cylinder walls the compressed air will leak into the crank case. You can detect that air leak by pulling a plug such as the dip stick. If you can hear a rush of air you know the crank case is being pressurized.
In order to use the leak-down tester the piston must be brought to top dead center of the compression stroke. With the spark plug out, turn the engine over by placing a socket on the extruded plastic nut on the cooling fan. Using a small screwdriver or something similar feel for the piston to reach its highest point. The piston is now at top dead center but you do not know if it is the compression stroke or the exhaust stroke (where the exhaust valve will be open). Pressurize the combustion chamber with the leak down tester and check to see if air is escaping out of the exhaust. If it is rotate the engine 360 degrees forward to top dead center again and retest.
Timestamps:
00:00 - Intro
00:52 - What is a wolf RX50
02:18 - The engine has low compression
04:07 - Checking for spark
05:08 - Testing the engine's compression
06:51 - Using a leak down tester to determine the problem
13:45 - Inspecting the engine after teardown 
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YES YES YES a scooter 911 video, definitely needed this on a Saturday afternoon
More to come guys????
Always more to come. Thanks for being here on Saturday afternoons!
@@Scooter_911 👍🏼
love me some Scooter 911!! Too few and far between, though..
We're working on more videos! we hope to have them out more regularly. Thanks for sticking around!
How is the taotao doing today 😂@@Scooter_911
I sure miss the videos. Thanks for posting. Now, weird drink Friday 😮
Thanks for sticking around. We'll be doing our best to keep new videos coming!
Just got a Peace 50cc scooter for free. Previous owner said “it wouldn’t start when I last tried to ride it 3 years ago”. I have 0 experience working with engines, and am so glad I found your channel. Hopefully I can get this thing running.
Good luck my friend!
Here I am with 2022 ScootStar RaceStar 150CC that is well over 3000 miles with regular oil changes and valve checks
You earned it!
My sym 150 has 25,000 on it now 😊and only needs a carb.
I was ready to see the big bore upgrade. Bummed it needed a whole new engine, and the video was over. Keep the videos coming!
We're not done with this wolf yet!
Just found your channel, it’s quite enjoyable to watch, though the upload frequency can be erratic.
I'm working on that my friend! Thanks for watching!
Cant wait for another Cub vid.
If you do swap out the engine it would be good too see the process involved and checks on the swing arm bolts etc great video!
Duly noted my friend!
Excellent sir, thanks for sharing!
Thanks for watching!
Nice troubleshooting. Seems like those Chinese scooters need more routine maintenance that others....
They certainly do. It costs the manufactures money to develop better parts and the point of these scooters is to have a very low price point.
Not all chinese scooters do, but you get what you pay for.
For good service you need to rebuild the engine and transmission every 1000 miles.
@@billmilligan1705 Maybe better to buy a Honda for the long run!
I foolishly bought a DongFang almost a year ago and similarly to the owner of this scooter, I put regular motor oil in hoping for the best... my reward was a burnt exhaust valve, a bent crank arm, and best of all the bottom half of the piston exploded, there were plenty of metal fragments when I opened the engine. I installed a new crank, and top end, and sold the thing as soon as I could haha. Clearly I'm no mechanic, but at least that whole debacle led me to this channel, love your vids man!
Wow that really was a debacle! Thanks for watching and better luck with the next one!
LOVE Scooter 911❤
Thanks so much!
Thanks for putting this information on a video. Keep them coming
Shout out from southeast Michigan..
Appreciate your videos..
I have a honda elite sa50 upgraded with polini variator/clutch/70cc corsa cylinder/v8 exhaust/gears, and more.. I LOVE IT..
Thanks to Me, you, and a couple guys from Detroit scooter tuning group, I was able to build this fun thing.. so thanks man.
Glad to hear it! Keep it shiny-side up!
Could also be headgasket, or stripped spark plug hole on a leak down
It certainly could!
That looks way nicer than most of the Chinese scooters near me.
Thank you.
Thanks for watching!
Good Video
Well Explained
Thank you very much!
❤excellent all the ways
2000 miles? I'm betting kilometers, and I bet it's off by about 30%.
What are the correct valve adjustments for 50cc GY6? I have found a manual where it says to set both valves at 0.002inch/0.05mm. Is that correct?
Mine was still running decent just smoking terribly out the VC breather(I'm runnin scooterarmy88 BBK ncy cam ncy cdi and a uni filter) so I got anilother set of rings (they didn't charge me for them) but piston was slightly scratched but we were able to clean it up and rehone the cylinder, but still can't figure out why I'm leaking oil from the center of my crank seal.and over heating.
No power on my wolf blaze2..new battery fuse in wrong I think plz help
Ever work on a 85 Honda gyroS tg50? Would you want too? Took a ride put it away. 3 years later ...Starts ,won't run. No lights, horn trunk signal. Got new batt (Always worked before starting). Don't want to scape it .want to ride it one last time. Then auction it off to a high-school student. Specific note...this scooter has 9k miles.
I havent done much with Gyros but the service manual will always tell you everything you could need to know! If the bike has sat for 3 years it is likely the carburetor will need to be rebuilt. The fuel in the carburetors floatbowl deteriorates and plugs the jets.
Cleaned it and yes I have the service manual still no run.
I'm thinking with 9k original mileage it's at it engin end ?😢
@@mv4463 it's not outside the realm of possibility but I would make sure to test the compression and verify you have spark before you condemn the engine
ughhhhh i was expecting a video of supercharging a scooter!
I'm a little late but anyway you could help me... my scooter got wrecked an I put all the plastics back on it but it sat in my garage for 2 yrs... well I took the battery out an drained gas out of it but now it's just beeping like it's been put in security... an won't even attempt to turn over like it's being stopped by the beeping an for some reason it's got the 4 ways on... I appreciate any help from anyone willing to try anything so I can take my test on it
What happend to the most hated scooter? You still have it ?
Sure do! It's coming back in a big way!
@@Scooter_911 oh wauw ! Now I'm truly excited! I thought you abandoned it completely.
Luckily im wrong 🤩
The oil story, bollox.
I got a given one of these chinese scooters and I can honestly say run away from it get honda or yamaha. I've still got 2 old 2stroke peugeot ludix scooters and They great little things to mess about on.
Ah yes there is no substitute for a quality scooter
🍕🍕🍕🍕🍕
Thanks for that!
Great video ! Glad you’re back !
Thanks for sticking around!
Time for an 80cc big bore kit. Just make sure that you reject the carburetor properly.