tudor

Having checked and cleaned the carbs on both bikes several times over the last few months I'm now thinking it's an intermittent electrical issue. Although there is a spark present it doesn't seem to be a strong spark so is there any way of checking out the electrics? any known potential electrical failure points on gassers such as stator issues, CDI unit? Both bikes used to start fine so there can't be anything wrong with the carb jetting and set up. Any advice much appreciated.

Hi, I have an 08 125 PRO and an 04 125 PRO and both can be difficult to start. I say can be because sometimes they start ok but most of the time they don't and from cold they eventually gurgle (not fire) into life without choke and the throttle wide open. I've checked all the usual stuff, carb, aircleaner, plug. It's not just cold starting that's problem, if you leave the bike for about 10 mins and especially on a cold windy day when the engine cools down quickly, it can be very difficult to start and the only way to get them going is to bump start in 4th gear. It's really strange that both bikes should have the same symptoms and they both started playing up at the same time which was September last year. I'm using Yamalube semi-synthetic, 75ml to 5L of fuel. Both bikes seem to run fine whey they are going, it's just the starting that's the problem. Anyone any ideas?

I know its a long time since you started this thread but I'm just wondering if you managed to resolve the problem as I have an 04 125 PRO with exactly the same starting issues. Look forward to your reply

Hi Arnoux, I am from the UK and I know the person who had the bike before me had the flywheel machined (expert rider), the outer overhang has been removed plus an additional 6 or 7mm has been milled away so I'm very interested if you sell 'weight rings' that can be fitted without welding. What are the weight options and how much are these? Please e-mail any details to my e-mail address which is tudor@semicom.co.uk I'll take a picture of my flywheel tomorrow and e-mail it to you. I'll also weigh it when I've got it off the bike to see how much weight is required to get it to around 3.1kg. Many thanks for your help Tudor.

Hi, I would be very grateful if anyone could post a picture or a drawing of a standard SY250 flywheel, ideally with the dimension of the outer width of the flywheel. Mine has been machined to make it lighter, the overhang has been removed plus an additional 6 or 7mm milled away so I'm planning to spot weld a 14mm wide ring to end up with a total flywheel weight of 3.1kg. It would be very useful to see what the flywheel looked like before being machined. Many thanks for your help.

Hi, the flywheel on my 06 SY250 has been machined to make it lighter, this is how it was when I bought the bike and I would prefer to use a standard (heavier) flywheel. It seems impossible to get hold of second hand standard flywheels so I'm thinking of getting my local engineering workshop to weld an outer ring onto the flywheel. Has anybody tried this and been successful? If so I would appreciate any advice that I could pass onto the workshop. Cheers

It's probably the CDI unit that's faulty. I had the same symptoms with my Beta 200 and was told it was either the CDI or the stator. I got the stator rewound first but no joy, then fitted a new CDI and it was fine. Call Lampkins, I'm pretty sure they will sell you a CDI unit on a sale or return so you can see if it solves the problem.

I had a similar problem when I replaced the rear brake pads on my daughter's Beta 80 (03 model), the pistons would not budge at all. The problem with mine and I think you'll find the same is that the plunger is too long for the master cylinder. In other words when the plunger is resting on the circlip it is still not back far enough to either let fluid in or out of the cylinder. I got round it by taking out the circlip to allow the plunger to drop down just past the little hole. Hope this helps