50 cc scooter help

kharlton · Derestricted Danger Joined: 02 Jul 2017 Karma :

Hi there guys (and girls you never know). Before you say it i know chinese bike are not great but was given it by a friend after mine was stolen. I sorted out the electrical problems but am having an issue with power.

The engine starts ok every time and on stand rear wheel will spin with a twist of throttle, but put it to the ground and well even at full throttle i can hold her in place. the engine is trying but no power to pull bike. It revs up ok i have checked carb its clean and free, air filter is clean too. fresh fuel is getting through to engine fine.

I have checked rollers they are little worn but nothing major, with cover off variator is moving belt as its meant to. I am at a total loss.

Now was reading an old post and they recommended to take the exhaust off and see if power comes back( it did for his bike). Now mine is a 50cc 4 stroke gy6 copy engine should i try this? and can anyone else think of a reason or something i might check.

thanks

Commuter_Tim · World Chat Champion Joined: 09 May 2013 Karma :

That's the great thing about having 50cc scooter in the title, you already know going in that there is going to be zero punctuation.

Seriously, do yourself a favour.
Nobody is going to try and read that.

People can be remarkably helpful here, but they will only put in the effort you do.
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kharlton · Derestricted Danger Joined: 02 Jul 2017 Karma :

Sorry i never think of punctuation its not often i take pen to paper this way. no excuse i know i should know better at 48 but does not come up often

Nobby the Bastard · Harley Gaydar Joined: 16 Aug 2013 Karma :

Paulf · Nova Slayer Joined: 24 Jan 2017 Karma :

Clutch ie the pulley at the rear
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Past bikes simsom mofa 1s, suzuki hustler 250 (£35 in 1973), suzuki ts125k, mz150, yamaha yb 100, honda pc50, honda vision 50, all 2 stroke - then cars - honda pcx 125 (sold) own honda fes 125 and Mrs 125 spares or repairs. Started 1972 all accidents walked away no insurAnce claims

Teflon-Mike · tl;dr Joined: 01 Jun 2010 Karma :

Why on earth would taking the exhaust off help power 'come back'?
Back up start from the top.
-Engine runs.
-Rear wheel spins up on stand
-Bike no move, when wheels on floor
That what you got?
If the engine wasn't making power... it would stop running! so it's making 'some' power.
It makes enough power to make the back wheel spin.. in the air... so ts making enough power and enough revs to make the centrifugal clutch engage.
Put it on floor.. load on wheel; NOW the engine still makes enough power to run.. just dont move the machine...
Still rev.. if t revs high enough to engage the clutch now but didn't have the power to puch the thig alng the floor... it would bog, and try and stall
If it sitll revs, just dont move.... its making power.. its just not moving
anything....
Hmmmm.... where can 'power' go mising between a running engine and a back wheel not turning, in a bike with o gearbox?
I know! Its taking a holiday out the exhaust pipe! Shocked

Look at the clutch, mate... 10:1 it needs new slippers and springs.
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kharlton · Derestricted Danger Joined: 02 Jul 2017 Karma :

kharlton · Derestricted Danger Joined: 02 Jul 2017 Karma :

Tankie · Crazy Courier Joined: 24 Feb 2017 Karma :

If it's a two stroke, I bet the exhaust is blocked
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Snowdonia Rider · World Chat Champion Joined: 17 Oct 2014 Karma :

Can't most people hold a 50cc scooter back? I remember as a teenager doing this with a friends and we were having a right old laugh.

OP, what did you ride before? You sure it's actually broken and not just gutless?
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kharlton · Derestricted Danger Joined: 02 Jul 2017 Karma :

kharlton · Derestricted Danger Joined: 02 Jul 2017 Karma :

Nobby the Bastard · Harley Gaydar Joined: 16 Aug 2013 Karma :

kharlton · Derestricted Danger Joined: 02 Jul 2017 Karma :

Really? Are you 5 years old?[/quote]

No i'm 48 and yes my zip 50 had my arm in a sling for nearly two weeks after that stunt cost a fortune to replace the panels after it dropped.
i don't expect that out of a 4 stroke engine but i don't expect to be able to hold it still with 3 fingers . was always taught that power was fuel air and exhaust fuel and air are ok though i think the 85 jet might be a bit big in the carb would of expected to see an aftermarket exhaust with that size jet and manufacture seams to recommend a 75 but if they had it running like that with standard exhaust is it possible its coked up?.
I'm trying resolve issues before throwing money at it so helpful coments are welcome

Nobby the Bastard · Harley Gaydar Joined: 16 Aug 2013 Karma :

kharlton · Derestricted Danger Joined: 02 Jul 2017 Karma :

help full comments are useful. my grammar may not be perfect but that last comment just show how immature and foul mouthed you are. please if you cant be help full then say nothing thank you

Nobby the Bastard · Harley Gaydar Joined: 16 Aug 2013 Karma :

Teflon-Mike · tl;dr Joined: 01 Jun 2010 Karma :

It's a four stroke moped; by law, it shouldn't be capable of exceeding 28mph, or it's no longer a moped.

Speedo optiism may suggest thats's about 35 on the dial; but, seperate issue.

WHAT on EARTH are you talking about; power is fuel and air and exhaust.. and the air's OK?! And the exhaust you want to take off, you are worried is coked up... on a four stroke!?!? is OK.. but you are fretting about jet sizs?!?!?

POWER is Force x Speed; end of. That is SI definition of the stuff.

You aren't getting the thing to move.. so no speed or force.. so no power at the back wheel... GO CHECK THE EFFING CLUTCH SLIPPERS!

You sound like you have far more ideas than know-how, that are going to help you make a darn site more problems than you'll solve.

Motor runs; its making power, its not getting where its useful. This does NOT suggest you should be diving in looking at carburettor jets, exhaust pipes, or aything else! Suggests your clutch isn't hooking up, and or your belt is slipping.

Sort THAT, get the book, do a service; BEFORE you start any more poking and proddngs i the dark, with wild ideas that an engine suddenly needs a totally different carburetor jetting.. as stuff wears out!
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My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

Paulf · Nova Slayer Joined: 24 Jan 2017 Karma :

Just a quick question what colour is your clutch outer, if it blue or any colour but brassy yellow colour (passivated). As everybody has said it your clutch is not allowing full power to be transmitted or there is oil on your drive belt, or the drive belt is very very worn. NOT ENGINE!!!!
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Past bikes simsom mofa 1s, suzuki hustler 250 (£35 in 1973), suzuki ts125k, mz150, yamaha yb 100, honda pc50, honda vision 50, all 2 stroke - then cars - honda pcx 125 (sold) own honda fes 125 and Mrs 125 spares or repairs. Started 1972 all accidents walked away no insurAnce claims

andyscooter · World Chat Champion Joined: 30 May 2009 Karma :

it defiantly sounds more like a gear or drive issue then engine

if it revs freely on the stand but not under weight something is slipping at the back

unless the engine is dying when on the ground
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