Did a good run on saturday on my suzuki 125. Been blasting along the by-pass ever so fast for me (55 mph!) for about 25 miles including up a very long hill, so the poor little thing worked very hard. When I was slowing down and dropping through the gears the engine just cut out...no warning. Just stopped which was very alarming for a learner like me. It started fine when I tried so I set off but it did the same thing when I was slowing down to stop a couple of miles later. Again it started fine and it hasn't done it again since and I've done about 40 miles since then....but I've got this niggling fear it will happen again. What should I be looking at? Ideas please Min x                                                                                                                                                                             

  It was probably out of breath Minnie lol. Trying to go up hill and keep the petrol flowing is hard for a little un.   Seriously, I hope you get a sensible response and it's not a serious problem.                                                                                                                                                                              

I'm sure people will be along with ideas soon.   I had a similar problem on an XJ900 years ago. It kept cutting out after 5 or 10 miles, I would stop and then it would start up again and wouldn't re-occur on that trip. I never found out what it was but someone did suggest in my case it could have been the petrol cap creating a vacuum because the breather hole was blocked? Doesn't sound like that could be your problem though Min, guess there will be plenty of ideas soon! PS. Mine usually waited until I was in the fast lane of the motorway to cut out - Most disconcerting!                                                                                                                                                                                 

Thanks for that insightful gem Sandi lol... being a lady of a certain vintage and (ahem ahem) size I do indeed have empathy for my lovely little suzuki ...but believe me she was going like a little rocket ...well, till she stopped!                                                                                                                                                                             

OMG Rattay, I don't even want to think about it happening whilst it's wound up at speed No, it's always as I'm slowing right down to come to a halt anyway & I've dropped down through the gears                                                                                                                                                                             

Kaz had something similar last year when she did a trip over here, it got here fine then when we did the stop start through Buxton her bike kept cutting out every time she went through the gears slowing down ... No warning or spluttering ... The guys did some road side repairs in Buxton.

If memory serves me right (I am sure Kaz or one of the blokes will correct me) there was a screw missing (I think) that held the carb in place.

Drop Karey (as it was her bike) or Mr_P (he helped fix) a PM

Hope it helps :-)

Lol!  Karey's carburettor was hanging off.  I don't think it's that as it wouldn't run full stop until we fixed it.   Mike's superdream used to do this, and it was down to fuel evaporation in the carb due to the heat.  However, again, I'd have thought that wouldn't be a problem.   So... I'm going to give a guess...  If it did it twice, and then hasn't done it since, it's possible that it's muck in the carb/fuel somewhere, and perhaps there was a blockage.   If there's a fuel-filter in the fuel line, I'd recommend cleaning or replacing the element.  If there isn't a filter, then *maybe* a filter would help, but this is total guesswork, as it's very hard to diagnose when not acutally in front of the machine when it's doing it!                                                                                                                                                                               

Hi Minnie   Check your oil first it may be low and causing the engine get a little bit to warm                                                                                                                                                                              

checked the oil before we set off Chris & was fine so that wasn't the issue...but thanks for that ...keep on working those grey cells                                                                                                                                                                              

Aye pet, dirty or contaminated fuel is favorite gremlin here. If you had just fueled up before the run, it's possible to get water or debris in the fuel especially if garage had just taken a fuel delivery. I would clean/replace fuel filter and also drain tank and filter existing fuel through a cloth. It's unlikely to let you down completely so don't worry bout that.

If it's running ok at the min dont worry about it you could try getting a mate to ride with you and do the same long hard running for a few miles then slow down  see if it does it again but dont think it will so as thay say if it's not broke dont fix it

sounds to me like theres muck in the main jet cross over ports there are two jets one for idle and one for full throttle but allso along the main jet tube there are a line of holes to aid the cross over from idle to main jets so i bet that there is a build up of dirt in there  causing fuel starvation when closeing the throttle ,but alowing you to start the bike with idle jet again need stripping down job for a fairly competent spanner weilding  freind you may have ! 1/2 hour to an hours worth of tea making  i'd say                                                                                                                                                                              

Thanks every one for having a think about this one Thinking about it, this happened a couple of times last autumn too before it was garaged for the winter. At that time a mate suggested I stop using ASDA petrol & only put decent stuff in. I did fill it up on sat morning & with shell v-power which claims to clean the engine & pipes....so so much for that!   I'm thinking Ian and wheely's suggestions sound logical. Hmmm...deffo not up to stripping down a carb/ fuel system but can do tea and even a roast dinner with yorks puds   I think I need to check out bike maintenance courses at my local tech                                                                                                                                                                             

go do the course minnie there good for basic maintenance you'll meet like minded folk  and probably be able to fix your bike at same time ! i did one years ago and throughly enjoyed it                                                                                                                                                                              

Always good to have a basic knowlage of where the bits go and what thay do                                                                                                                                                                              

"shell v-power which claims to clean the engine & pipes"
There's your problem, the petrol cleaned out the muck which stuck in your main jet. 

Hope you find the culprit. Sounds like a carb clean would be a good idea though.                                                                                                                                                                             

hi minnie..... might be something as simple as a tweak of the mixture screw if its running a bit rich that will cause the same symptoms... easiest way to see whats happening inside the cylinder is take a look at the colour of the spark plug electrode ....... if its black and sooty its too rich .... if its a light biege to greyish too lean.... needs to be a milk chocolate colour for normal-ish running  .... or a dodgy spark plug could do it if you have got an old one stick that in and see what happens ..... always best to start with the easy tests first before the full post mortem lol ..... hope this helps .......nellie .........                                                                                                                                                                             

If the bike was running fine at the time then it could be electrickery at work, check the clutch and side stand switches if it has them also the cut out switch.                                                                                                                                                                             

Minnie.. is it a marauder single cylinder 125. As it happens I have one of those, AND it did the same thing as your describing, only when coming down the gears, when your not on the throttle. previous suggestions on here are bang on the money for the one re the issue I had. there was crud blocking the jets, and stuff. so when the bike is coming down off the revs thru the box, the revs increase, and the venturi pressure still increases even with no air flow sucking up  a bit of crap into the jets. only under certain conditions. when coming to a slow down or stop. when the bike has cooled from a run. if you turn the  fuel off, diconnect the pipe to the carb. then undo the flat head drain screw at the very bottom of the carb, after putting a dish or somthing under the overflow pipe/drain pipe hanging off the  little  pipe at the bottom the carb will empty its fuel, and hopefully most of the crud in the float bowl, too, if you use a white dish you should see the crap in the bowl. then just tighten everything back up put the fuel pipe back on turn the fuel piep on and try again. 5 min job and may well cure your issue. if you want i can take some pics for you of how to do it using the one ive got?                                                                                                                                                                               

Hi, Minnie, you don't say how many miles your Suzuki 125 has done? and what year? Has your bike had regular oil changes and oil filter, and clean air filter. Is your Suzuki 125 a four-stroke or two. If you have a four-stroke and you have thrashed it and it stops on a closed throttle expect a dirty pilot jet simple to do for a person whos has done it before If you have a high mileage bike it could overheated the spark plug. fitt a new plug first and see if its the same its the cheapest option you might have coke or carbon in the head not allowing the valves to close properly coursing lake of compression. warning messing about with carb mixture settings is not a good thing to do if the spark plug is black take it to a dealer they will set it up for you. If you have a two-stroke and it keeps cutting out with high milage it again might be lack of compression the crankshaft seals might need replacing.Having a motorbike needs servicing regularly not when it stops.If you have a bike that is over twenty years old you might have rust inside the fuel tank and with the ethanol we now have will rot the tank quicker and the plastic filter inside the tank might have got clogged with distortion making a restriction for fuel to get out and the rust could make the petrol cloudy like staining and it will not want to flow through the carb small jets.