Power issue! Fuel or mechanical?

My ludix was running okay for a while but has developed a power issue. If I am stopped at a junction it revs cleanly and we'll but when I throttle up to pull away the engine nearly dies. The bike drags itself slowly up then after ten secs or so will seem to clear and fly off. This is much worse if I start at the base of a hill as it struggles all the way until a flat road where it picks up. I have noticed that I can sit at a junction, put my feet on the ground and put on full revs but can hold the bike in place. Bike will rev then start dying. The struggle is less on a slight decline or flat and worse on slight incline or if I throttle while turning eg roundabout. When slowly dragging itself along, if I go WOT it actually gets worse and starts dying so I need to hold it at 25% until it clears. Carb has been cleaned so I don't know if it could be clutch, reed valve, inlet manifold , compressionor . It's a gurtner py12 so no air screw and no adjustable needle. Please help , I need to pull away faster than 5mph!!

 

as simple as it sounds when is the last time you changed the spark plug ? and have you checked the air filter for dirt and oil etc ? .

 

Thanks for replying. The plug was my first thought and was replaced a few days ago so not the issue. The air filter was a sealed unit so I cut the seal and fully cleaned and dried it before resealing with glue and hot weld. I dropped the main jet back down to 58 as I thought that it may be a slightly rich mix with a new 60jet in. Stock is 56 I believe. The jet change made no difference to this issue, just has less overall power but now idles properly which it doesn't do on a 60jet. I have a new inline fuel filter which the ludix don't usually have, but that shouldn't make a difference. It seems to be a power / load issue. Under load the bike just struggles until it gets momentum and feels like a fuel thing but I am a total novice. I did see signs of fuel pooling at the airbox to carb joint and the carb to inlet point but not sure if that's just normal. No water in carb, drained it to be sure. Any help is appreciated.

 

With fuel "pooling" as you say it could be that it's flooding slightly. May be down to a simple air/fuel mixture setting.
Have you changed the belt and rollers yet?

 

Hi, I put a new basic silentpro stock exhaust on about 6months back, the cheap rubbish thing dropped its restrictor cone into the main body so, having removed the restrictor I now run on an unrestricted cheap exhaust. In doing that I dropped the rollers from 9gm stock to 8.5gm so total 3gm lighter. This was about 5% so made sense at the time. I have stock variator, still restricted, and stock clutch. Belt is clean and unworn so may have been replaced on service 8months back. Everything on the ludix is stock except for the silentpro, unrestricted exhaust so how light could I go on the rollers? I tried up jetting but was flooding or not ticking over so jets are stock again. Could the clutch itself be the problem? Not slipping but what are the symptoms of worn or knackered springs? It's 2005 year with 25000km on the clock and I have had it 3yrs but never touched the clutch parts. To confirm the symptoms, I flew out of work today, good power no probs at first two junctions, WOT at 45mph to a roundabout, slowed to 15mph or so to get round it then, stutter, struggle, long slow hill, won't climb over 20mph, bogs with increased throttle, hit top of hill, bam! Flew as soon as I hit the flat. Every junction thereafter it felt stutters and struggled for a bit until momentum seemed to clear it up and bam! Off again. Weird. Would a sticky clutch spring cause that? Thanks for listening!!

 

Possibly, from the sound of it, the auto choke mechanism sticking on making it too rich

 

Thank you, I hadn't thought of that one, Ill strip the carb and clean the choke . Would the choke area need oiling or coating with fuel, wd40 etc or leave it dry? It also has a strange metal gasket where it screws into the top of the carb, would that need a good seal or perhaps replacing or won't it matter.

 

cant be repaired, just replaced

 

Ok, thanks, I'll give it a shot.

 

Replaced autochoke and problem sorted. Thanks, hadn't ever considered it might be that.

 

Great to hear your problem is fixed. Happy scootering and tell your mates where you got the help from. The more the merrier.

 

I had same problem replaced the auto choke n seems ok atm