Loss of power when rolling off... - [Not JUST Carb!]

[Visitor Q]

So, I has a new shitter. A Chinese shitter, in China.

It's a 125cc 4-stroke single, made by Zongshen, and 180 quids worth of fury.

It was running better last weekend when I bought it, but now it (a few nights ago and) tonight kept losing power until a gradual stall.

So, from cruising in 5th at 80kph, the moment I roll off the engine starts to bog down.... and working through the box does nothing, until it stops. Then lots of faffing about with the choke settings (on the carb), and usually a few goes kickstarting it without the lights on... and she roars to life.

And about 5 minutes later, the same thing. Ad nauseum. Unless it goes away completely, and life is sweet and problem free...

Just curious what smart people think is wrong with it, I have a couple of ideas, but I'm an idiot. So, what do you guys reckon are the best things to check.

Shit in petrol tank, dislodged by spirited/off-piste riding, clogging the jets. Or a clogged fuel filter. Or both.

Or the carbs aren't breathing right.

Or the battery/HT lead is fubared.

I'll get out and look at it/take it to the mechanic tomorrow, but any heads up/shared wisdom would be great.
____________________
China traffic/travel bike vid - When I make a sweeping statement, please add the word 'statistically' in to the sentence before you bitch...
From September 2014 to January/February 2015 I will not be using any English, nor reading any. As such, I won't be on here. PM at will, but I won't be checking/posting unless in emergencies. Certainly not for the first couple of months. Please berate me savagely if I break that rule...

[Hetzer]

First possibility is it's chinese. If it's not that it could be its chiniseness. And, failing that, most likely that it was made in china.
____________________
"There's the horizon! Ride hard, ride fast and cut down all who stand in your way!"

[jjdugen]

Fuel supply. Blocked filter, blocked tank breather.
____________________
The CBR900RR has been sold. Aprilia Falco worms its way into my heart.
Try Soi 23 on Amazon for a good read.... Self promotion? Moi?

[stephen_o]

Ditto the above,blocked tank breather my GPZ was a sod for it last yr
____________________
current scoot 2009 Yamaha YBR250 + Current Pootle 2013 Nissan Leaf

[SQL]

I had same symptoms from loose sparkplug

[temeluchus]

check the float height, if it is too low, it might be flooding.
____________________
Some shite cruiser. Now with guns and FREEDOM!

[Fisty]

It's Chinese, It could be anything from the carb to the rear wheel being made of Chinese helmet cheddar.
____________________
Quietly and consistently taking the piss.
TL1000R | Hayabusa | ZXR400 | TL1000S | Bandit 400 V
Fatter and faster than Fret

[gavbriggs]

I can almost guarantee there is water in the tank and the carb. Clean both thoroughly and the bike will be fine.

The seals on these Chinese tanks are made of tissue paper or something similar and don't seal anything.

[Visitor Q]

Cheers, it seemed like it was a fueling issue.

I shall have my man in the shop do it for me, and cost all of 3 quid.

Thanks guys.
____________________
China traffic/travel bike vid - When I make a sweeping statement, please add the word 'statistically' in to the sentence before you bitch...
From September 2014 to January/February 2015 I will not be using any English, nor reading any. As such, I won't be on here. PM at will, but I won't be checking/posting unless in emergencies. Certainly not for the first couple of months. Please berate me savagely if I break that rule...

[tbourner]

Aren't you supposed to lose power when you roll off the throttle?
____________________
Trev, now a biker?
Looking for first big bike.

[Visitor Q]

[Visitor Q]

[Hetzer]

[Visitor Q]

[lihp]

You lose power when you close the throttle?

[Visitor Q]

Well, leaving aside the just jesus-fucking-wept stupidity of being forced to ride (a normally 15 minute ride - 30 today with stops and fucking around) to the misses flat to 'help' with some work she is being tested on (singularly)... that she hadn't done, and doesn't need to give in any time....


BIKE!
Picked up bike last night, carb was cleaned and that was about it. Couldn't communicate with the very busy mechanic, thought I'd see how it went. It was /ok/ until I got to the gate of her compound, where it died as soon as I rolled up to the gate.

Rode home this morning, absolutely fine, literally not a problem. Parked up, beauty.

5 hours later, went to ride back to her place, complete cunt from the moment I left. Had to ferociously kick it every 500m after it died.

Looked at it while waiting at hers, only obvious problem I could find was a split in the air hose leading in to this thing [coming from an open but filtered - like an inline fuel filter - hose just behind the engine, it has a hose leading to the out-manifold of the carb, and one leading to the other side of the engine next to the exhaust - what the fuck is it?]

https://cdn.bikechatforums.com/files/imag0008_783.jpg

Never seen anything like it, at least not on a single Retard I am.

Anyway, then rode the bike around the carpark. Not a single problem, blattered about and the throttle was mostly responsive.

Then came to ride the cunt home. Had to restart it literally every 200m, sometimes getting to 500m. I tried going slowly. I tried choke on and choke off and choke in the middle. Bastard was just determined to die.

Experimented with abusing the shit out of it for 2 minutes kickstarting it until it started... or by the end just waiting 2 minutes and then going again. I tried protecting the loose electrical shonkiness from shaking to see if that was the problem. Nope, just still died for no apparent reason.

I am a sad panda.

The mechanic, when questioned last night, just offered to sell me a new carb, saying the old one seemed 'quite old'.

Current plan is to swap the spark plug and see if that helps. Maybe the slightly loose ht lead too. New carb is 6.50, which is cheap, but have no spare cash until the end of the month. Really should get some more tools than I have now as well, haven't even got a spark plug spanner - and I've got nowhere to work without drawing an inane crowd. And the mechanic doesn't speak a word of English

China sucks.

Anyway, help?

What else could it be? He did fit a new ignition to the bike just before this problem started... Loose connection under the barrel? Have to ride the bike distance tomorrow and Saturday, so really would like to solve it tomorrow.
____________________
China traffic/travel bike vid - When I make a sweeping statement, please add the word 'statistically' in to the sentence before you bitch...
From September 2014 to January/February 2015 I will not be using any English, nor reading any. As such, I won't be on here. PM at will, but I won't be checking/posting unless in emergencies. Certainly not for the first couple of months. Please berate me savagely if I break that rule...

[Robby]

The thing with the split hose looks like an emissions control valve. Useless thing. If the split was between the carb rubber and the valve, that would explain the problem - big air leak.

The ignition barrel is a possibility. I have come across a similar problem on a CBR125 where the wiring for the igntion barrel was routed so it was getting pinched by the steering lockstops, giving intermittend failure to start when it was earthing out on the frame. Check the wiring from the ignition barrel to see if any of it is exposed.

A dirty carb or similar is unlikely. It was running well, it has started running poorly. Petrol cleans carbs, carb faults like this don't appear suddenly.

So my money is on an air leak, easily fixed by disconnecting the emissions valve from the carb and plugging its hole on the carb rubber, or an electrical fault, starting with the last thing that was "fixed".

Do also make sure the spark plug is screwed in.

[Visitor Q]

[Visitor Q]

Oh, I should say that the mechanic 'fixed' the air hose from the treacherous Emissions bastard thing to the inlet manifold.... with some random hose he found on the floor. Which may be so thin it is collapsing... but I still don't really understand how it works.

As for blocking it off, I would do, but it also runs a pipe in to the engine...
____________________
China traffic/travel bike vid - When I make a sweeping statement, please add the word 'statistically' in to the sentence before you bitch...
From September 2014 to January/February 2015 I will not be using any English, nor reading any. As such, I won't be on here. PM at will, but I won't be checking/posting unless in emergencies. Certainly not for the first couple of months. Please berate me savagely if I break that rule...

[bladerunner]

Bonny...you sure it ain't fuel starvation....blocked filter in the tank or between tank and carb.....or maybe on some bikes a fine mesh in the spigot on the carb. If it's on tank side and it's getting blocked then if you pull the fuel line off the carb you'll see if it's flowing enough
____________________
Current bikes...cbr929, KDX200's, Rd125lc mk2, RGV250's

[Visitor Q]

Well, certainly not sure it's not that. I had asked the pillock to change my fuel tap filter, but he didn't understand (didn't charge me at least).

Just spent a fun 3 hours in the sun, being pestered by locals (and a horde of my students as well). Had the carb off and cleaned/inspected (fine) - and set the float a bit lower -, airbox filter inspected and cleaned... and tidied up the gash electronics as much as I can.
Got back at the ignition, WD'ed all connections I could find but wasn't able to check much more than that. The barrel comes as a complete unit, including wires, so asides from the highly likely 'faulty piece of 2 quid crap' element, I'm not sure how else to really check it. Certainly not buying yet another multimeter to feebly stare at.

Will need a hacksaw to get under the seat/tank, turns out they use utterly arse quality nuts and bolts too. For a 3 year old bike, in a country that seldom rains... this thing looks like it's been dredged out of a river.

Fucking China.

Anyway, put it all back together. Starts a lot easier, especially once warmed up. Idle is running one minute low, one minute high, one minute low... generally weird. Just blatted it around the estate, no problem... the moment I pulled up it cut out again.

Off to the mechanics now to get a new spark plug, and maybe new HT lead. And a new in-tap filter as the old one is gungy. He's probably still going to try to sell me a whole new carb, which he can whistle for.

Also Robby, tried blocking off the intake manifold hose to the ECV thingywhatsit... ran, but rougher than with it in. I also had to swap a bolt from somewhere else to properly attach the flange/intake thing that the carb bolts on to. Only one bolt attached (of two). Words fail me.
____________________
China traffic/travel bike vid - When I make a sweeping statement, please add the word 'statistically' in to the sentence before you bitch...
From September 2014 to January/February 2015 I will not be using any English, nor reading any. As such, I won't be on here. PM at will, but I won't be checking/posting unless in emergencies. Certainly not for the first couple of months. Please berate me savagely if I break that rule...

[garth]

Erratic idle could be air leak.

As for cutting out, check it isn't the connections to the kill switch, also. Don't know how that circuit works, but it'll either be a case of joining them or literally unplugging the switch. Also check the sidestand switch.

It's easy to remove that emissions bollocks, you will just need to plug the hole in the inlet manifold and blank off the cap where it goes into the head. If you unbolt the steel pipe that goes into the head and cut it off flush, you can just put a nut and bolt through to blank it off.

[Visitor Q]

She lives!!

Rode to the shop, still died outside.

New sparkplug, job done.

Only new quandry is why she cuts out at traffic lights unless you blip the throttle, even with the idle set high...

But anyway, for now she is back to useable transport again. Hurrah!
____________________
China traffic/travel bike vid - When I make a sweeping statement, please add the word 'statistically' in to the sentence before you bitch...
From September 2014 to January/February 2015 I will not be using any English, nor reading any. As such, I won't be on here. PM at will, but I won't be checking/posting unless in emergencies. Certainly not for the first couple of months. Please berate me savagely if I break that rule...

[Robby]

[Visitor Q]