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ybr 125 Starting Problems

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Hi, My stepson purchased a 2007 YBR 125 last autumn. Lovely little bike, but it has just started being unreliable. If he leaves it out in the sun it becomes impossible to start. When its cooled down...hey presto....its starts and runs beautifully. The local Yamaha shop has been shall we say, very cagey and dont seem to be able to diagnose the problem dispite it being connected to thier computer. Has any one ever heard of this fault and if so what can he do to rectify it?

Update...it wouldnt start again today....so we used our logical brains and threw and bucket of cold water on the tank and engine area....and guess what!! IT STARTED...Does this help diagnose the problem??

Thanks

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If it's only just started in this warmer weather when sat in sunlight, my first guess would be something like a fuel vapour lock in the injection system. Is there a Prime position on the fuel taps of these things, or some other way of dumping neat fuel into the system? If there is, try switching to that just for starting and then back to normal once it's running.

HTH

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There was someone on recently with the same issue. I would imagine, it is EFi yes? that the ambient temp sensor that will be needed to allow the bike to decide if choke is needed may be going out of range in strong sun, as in the cdi is trying to lean the system right out so it will start without choking the tree huggers.

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I have exactly the same problem with my 2007 injection YBR 125. It starts and runs fine generally, but I know that after a journey I cannot park it up anywhere in direct sunlight because I know it will not start again! If I park in the shade it's never a problem. The only way to start it after exposure to sunlight is to leave it in the shade for an hour or so. It does not even have to be a very hot day for this problem to arise, so I'm not convinced it's a heat issue. I have yet to try the bucket of cold water technique.

If anyone knows the cure for this please let us know!

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Hi, My stepson purchased a 2007 YBR 125 last autumn. Lovely little bike, but it has just started being unreliable. If he leaves it out in the sun it becomes impossible to start. When its cooled down...hey presto....its starts and runs beautifully. The local Yamaha shop has been shall we say, very cagey and dont seem to be able to diagnose the problem dispite it being connected to thier computer. Has any one ever heard of this fault and if so what can he do to rectify it?

Update...it wouldnt start again today....so we used our logical brains and threw and bucket of cold water on the tank and engine area....and guess what!! IT STARTED...Does this help diagnose the problem??

Thanks

I had a same problem. In service they told me it is not uncommon problem with fuel pump. They changed my fuel pump under warranty (so if costed me no money and I guess they had no reason to lie to me). Since that it works great, I tried to leave it in a sun at 35 degrees celsius half a day and it starts without any problem. My YBR is 2007 same as yours.

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Same problem with a YBR 125 injection here in germany. But the workshop told a different story: If the pressure in the tank is too high, the valve is shutting off.

I did not believe that until the owner of a '09 wrote in a bulletin board that if he removes the gas cap the YBR can be started after a few seconds.

There should be the valve in the gas cap, that does that work. Mabe it was just luck? There was nothing exchanged on warranty.

Greetings, Martin ('05 YBR owner)

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There are a number of other forum posts on this topic that all relate to YBR Injection models, most notably one that replaced the fuel pump:

1. I turn ignition on and engine light comes on, but pump does not prime, engine light still goes out after about 5 seconds.

bike wil not start as no fuel getting through. I fitted new pump and worked fine for a very short time then the same symptoms came back, any ideas please, thanks

Any idea's if the rectifier was faulty would this stop the fuel pump or if there is a fuel pump relay on this bike, or anything that may control the pump thanks

2. just went to start my bike.... it started up as usuall then it stalled itself, turn the key again and the orange light comes on as usual, but theres no electronic sound like normal. and the bike wont start,... ticks over, but doesn't fire. this also happened on Sunday and a previous occasion.

i assumed the electronic sound was the fuel pump engaging ?

now the previous two times ive had to wait about half hour, and it magically sparks up with out problems.

any idea what this could be... ill try and answer any questions i can.

this is a Yamaha YBR 125, 2008 model, just over 10 thou miles on the clock.

3. in the last week, my bike has failed to start 4 or 5 times now. every single time, is when the bike is sitting in direct sunlight, i have to wheel the bike in the shade (if there is any) wait for it to cool completely down before i can start the bike. ive asked a few bike nuts, and they have all said, "Fuel evaporating from the carb"

is there any bikers on here suffering the same thing, if so how can i solve it, ive got my local yammy dealer picking the bike up tuesday. but im going to a motorbike show on sunday and dont want to risk the bike failing on me.

4. I had noticed that lately my 08 reg Yamaha YBR 125 has started to sometimes stall when sat idle with the engine running on the stand. Also the engine hum seems to dip as though it will stall, but then sounds normal again. Tonight when i went to drive home from work it would not start, it turned over but would not engage the engine and start. I kept turning over and eventually with some throttle it started. It seemed to be o.k and i pulled away, only to get a little way down the road and the engine seemed to begin to die, almost like it had run out of petrol? (but i have a full tank) Again i turned it over in vein until eventually it kicked in and i could pull away. This happened about 6 times on the way home. When i was at high speed it was fine, no problem at all, but at low speed or at a stop it wanted to cut out. I don`t think it`s a major problem, but am not sure what to check or what the fault may be? I cannot afford to put the bike in for a check up and i believe it could be something tiny, that i could sort myself! I am a motorbike novice and have no idea what to look at. My friend says it sounds like it could be muck in the carburetta?

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Same problem with a YBR 125 injection here in germany. But the workshop told a different story: If the pressure in the tank is too high, the valve is shutting off.

I did not believe that until the owner of a '09 wrote in a bulletin board that if he removes the gas cap the YBR can be started after a few seconds.

There should be the valve in the gas cap, that does that work. Mabe it was just luck? There was nothing exchanged on warranty.

Greetings, Martin ('05 YBR owner)

When I had that problem one of the things I tried was removing a gas cap. It didn't help. Only thing that helped was getting a bike in a cooler place and wait for few hours.

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I have asked a germany Yamaha dealer. He told me that they do not now anything like that with the YBR 125. I told him that there are several people with the same problem.

He told me that there is a diagnosis tool for the injection models ('07 and later). That might be able to find the problem.

But he told me again that they have never experienced any problem like that with a YBR - but he did not tell how many people with a YBR drop in...

Greetings, Martin

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My YBR is 2007 same as yours.

Ups, my YBR is 2008. I guess it just feels like I have it for a longer time :-)

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Update: My YBR injection 2007 model would not start when left in the sun and the problem became so bad that it would not start at all and had to be looked at by the dealership; they replaced the cdi unit (£250.00) and all seemed well over the winter but this spring 2011 the problem returned as soon as the sun came out!

This time I adopted a more scientific approach to identify the root cause so one afternoon in strong sun it would not start; I could not hear the usual sound of the fuel pump priming. I then applied a cold compress to the tank (a wet towel with cold water poured over it whilst over the tank) to cool it as quickly as possible. This was done whilst still parked under a strong sun. 15 mins later the pump still would not prime, but after 30 mins it primed and engine started ok. I then removed the wet towel and let the tank heat up in the sun, and 30 mins later the pump would not prime and no start. Again I applied the wet towel over the tank and 30 mins later it starts fine.

My next move was to buy a salvaged fuel pump off ebay (£25.00) which was easy to install. Since then I have not had any problems starting in the sun. In my opinion the fuel pump was the root cause of the problem; the cdi unit failure was a symptom.

I hope this helps anyone else with the same problem - please reply if you agree or disagree with my analysis.

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Exact same problem , i have a 2008 ybr 125 always starts 1st time , today its really sunny wont start couldnt believe it , searched on google and found this forum, too the advice moved bike into shade and put a wet towel on the tank ...30 minutes later and amazigng started 1st time !!!!! come on yamaha this is obviously a design fault sort it out please !!!

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if the problem is pressurisation due to sunlight why not open the filler cap to release it? I know it isnt a cure but it may be a fix if you are in a fix!...better than a wet towel in your pocket lol.

come to think of it, perhaps you should be questioning your tank venting capabilities

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This is the bane of ybr owners everywhere.

I had been having identical problems that kept getting worse until it didnt matter what temperature it was. Finally gave in and took it to a garage of bike enthusiasts. Even took them a couple of weeks to decide but in the end I coughed up the £250 for a new fuel pump! (you can buy a new friggin engine for that, but I could not find the part ANYWHERE but the main dealer.

Touch wood, the problem seems to have gone, but I still worry. The pump had been ceasing up, and the heat was making it worse, so it didnt seem to be anything to do with tank pressure or anything like that. The guys who looked at the bike said they had no idea why injection would be fitted to a 125, let alone any other bike. Their opinion seemed to be avoid injection if you can, it's just an uneccessary thing to go wrong.

On top of that, they were speaking with a guy from the local yam dealer and judging by the frame number stamp they reckon the bike is made largely in china under license from yamaha!? Either I have one unlucky lemon (its a 2007 ybr ED by the way) or this is a dissapointing venture from yamaha. I went for the yam to avaoid cheap chinese parts!

Whatever, that's my two cents. The pump is a widespread problem that a lot of yam dealers aren't ready to admit if you ask them, although I concede that replacing it for Bane77 was good under warranty, my warranty is long past. It makes me wonder why they wouldnt acknowledge the problem though as it meant extra money for the dealers.

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Exactly the same problem here. Was in the (useless) Uno Motorcycles @ Shepherds Bush for 2 months , they thought it was a wiring loom problem and proceeded to change it!

Apparently this is a well known problem. It is something to do with the fuel additives in UK fuel that degrades the internal seals in the fuel pump. The main symptom is not starting at all after being left outside, however mine did not do that it was simply having fuel starvation problems (flatspotting, running rough). Took it to a Yahama dealer (Slocombes in Neasden, there are few dealers about these days even in London!). Said £400 repair but Yamaha are making a contribution as the bike has <4000 miles on it. Bike is 4 years old. Fingers crossed they will pay at least half!

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