Lexmoto street 125 runs poorly under throttle :(

[john24ssj]

Hello guys,

I'm still battling my girlfriends 125.

So what's the problem? It runs like arse!!!

Does start up eventually but the moment you give it gas it just cuts out. So turning the throttle just seems to make it sputter and if you give too much it just cuts out.

If you warm it up to it being properly hot it doesn't cut out but it still sputters/bogs.

Similar to these videos: >>Video 1<< and >>Video 2<<

Any ideas what could be causing this? Or just how to diagnose/check for what's at fault?

Thanks
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Bikes: Honda CBR600Fi, Kawasaki ER5

[Rogerborg]

Get your girlfriend's tips out for the lads.

Plug tip(s). Colour of.

The main jet is blocked, most likely, or the needle is riding high / the jet has dropped out, or the float isn't floating.

If you narrow your girlfriend's location down to better than "UK", someone local might be up for a quick fiddle.
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[john24ssj]

Thanks for the reply Rogerborg

I will take the carbs apart again and see if they are ok. I wish I could remove the stupid spark plug it has the most awkward size. None of my key fit nor the spark plug that comes with her bike.

Also she is based in Wales, Cardiff
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Bikes: Honda CBR600Fi, Kawasaki ER5

[Rogerborg]

[john24ssj]

Well at first the bike didn't start at all so I took the carbs out and just cleaned the bottom part and that fixed the bike not starting up problem.

But then it had the issue of sputtering under throttle but would rev up just fine with choke on.

So I took the carbs apart and gave a good clean to the main jet and the all passageways. After that the bike did start up fine and I think revved ok as well, but then we ran into the problem of bike not starting due to dying battery

Now we replaced the battery with brand new one but the sputtering issue is here. Also it seems to run worse witch choke on for some odd reason.
Also she had one of those open air filters without the air-box so today we fitted a proper air-box but didn't change much

Also she doesn't have much of a welsh accent as she is German
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Bikes: Honda CBR600Fi, Kawasaki ER5

[Rogerborg]

[wr6133]

What size are the jets in the carb? and what is the standard size? The cone filter fitted may have been done properly and had the carb rejetted to suit in which case just bunging a box back on will have made things worse.... or it may have been done half arsed with the standard jet left in which would mean the box has now put it right.

Don't change things unless you know what those changes effect or you are going to create even more problems that will confuse with the original problem.

[john24ssj]

Yeah the jets were just awful with gunk all over it and yes after that I did fit a small in-line fuel filter but I am still suspecting the fuel tank might be quite dirty.

Rogerborg you do seems to know a right reply for anything


I don't know what size the jets are I would assume standard that's why I though to get the airbox because it seemed like the engine is just getting too much air and not creating pressure difference to suck up the petrol.

Ok I will clean the carbs again and use the cone filter and then try with the air-box. I will also try to remove the sparkplug and see if it's running lean or rich.

And thanks replies guys, much appreciated
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Bikes: Honda CBR600Fi, Kawasaki ER5

[cresad]

Hi

We had a similar problem on our son's bike ( a Hongyan 125 ) It had been standing for a couple of years. I ended up cleaning the original carb about half a dozen times before I gave up and bought a replacment off ebay. We still had the new one play up a couple of times until a final strip , another new filter and draining the tank and filtering everything that came out ( it was about 3/4 of a tank ). It's been runng fine since - fingers crossed. I bought myself one of those cans of compressed air that they use in computers to help with blowing through the jets properly as I couldn't get to the compressor. Another thought might be to get hold of one of those ultrasonic cleaners that pop up in aldi now and then.

Adam

[wr6133]

[john24ssj]

Ok I got the bike over mine now so should be easier to take a look at it.

I will try to remove the tank and see if it has any dirt in it. I'll remove the spark plugs and inspect them and also take out the carburettor and see what size is the main yet and if it's clean.

Anything else I should take a look at?
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Bikes: Honda CBR600Fi, Kawasaki ER5

[john24ssj]

So took a proper look today at the bike.

Under the fuel tank found a big hose that was pinched so I un-pinched it.

Emptied the tank and found lots of water in the petrol and petrol was quite cloudy :S

Took the fuel tap apart and it was dirty as hell, full of junk, so cleared it out.

Took the carbs apart and main jet holder had this white gunk all around it so cleared all that off.
And the main yet had 110 written on it.
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Bikes: Honda CBR600Fi, Kawasaki ER5

[john24ssj]

Hello

Just wanted to you know that with the water removed the bike works like a charm!!! Starts on the first touch and runs just fine.

Who knew that petrol engine wouldn't like a bit of water xD
____________________
Bikes: Honda CBR600Fi, Kawasaki ER5

[Rogerborg]

Winner!
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike