kingkay7

Hi Guys, Got some more time on the bike yesterday. I flicked the choke off and tried to start which didnt work then when I flicked it on it started and didnt die. But it was revving high ( not adjusted idle screw yet ) but after a minute it started revving very high to the point I had to cut it off incase any damage was caused. Does it sound like I have an air leak or is this just the engine has warmed and is running more efficiently now? Daft question I know but I don't want to assume I know something, rather have it from you guys as you all know a hell of a lot more than I do. Cheers, GK

Hi Guys, Spark seems good when I put it to the frame. So when it revs high like that is that it running to Lean? Just changed the piston and rings so don't want to damage them! I tried increasing the mixture but couldn't see any noticeable difference. I will try putting the old carb in and see what that's like. I was just worried this accelerator pump could be causing issues, what is the benefit of this especially when you have a choke? GK

Hi Guys, I have a lexmoto XTRs 125cc and I have had various issues. Which I have gone through and fixed, but one issue persists and I am not sure how to fix it. Firstly I was getting a bit of white smoke and when I took out the spark and covered it with my finger I was getting oil pushed out. So I changed the piston and rings and that seems better now. While I was doing the piston I changed all the gaskets, oil and the crank case seals. I also did the valve clearance, the only figures I could find online were 0.08 for intake and 0.15 for exhaust. Secondly, when I was doing this, there was a lot of excess fuel in the rocker head. I got a new carb ( Mikuni VM26 ) as the crappy Sheng Wey had a acc pump which I heard caused quite a Few issues. However it also has smaller jets ( I believe the stock sheng wey had 125 Main Jet and 40 Pilot, Mikuni has 100 Main and 20 Pilot ) I think it may be too much of a step down. I also had to get a different air filter as the stock wouldn't fit on the Mikuni Now it still does the Revs to about 4-5k on start up ( requires a bit of throttle to get started so may be pilot needs increased? ), after this 5 second burst it stalls. I have a brand new tank as I had rust in the old one and it has new fuel ( disgarded the old fuel ). Any help would be greatly appreciated. I am not sure if its the carb or what, just dont know. GK

Yeah there is a small washer on the pilot screw

Hi Lumor, I stripped them, the left goes to the pilot and the right to the main, I suspect its the right one that's causing the problem, either extra air coming in, or losing air making an extra rich mixture. If when I find out what it does, I am tempted to block it if the bike runs well without it. Would you agree? I know its part of the design and must serve a purpose but for the lift of me I can't find it, I have searched google for 2 hours and nothing! Both carbs, 1 new and 1 old have not been correctly assembled in the first place ( I have no idea why ) but both did not have the acc pump correctly put together, not sure why its needed tbh but anyway. Cheers, GK

Hi Guys, Managed to get to run again however its gone back to the whole any throttle and it stalls. It appears that its something to do with the two small pipes at the bottom of the air intake side ( not sure if they are intakes or not ). I have added a picture with the two pipes. When I cover them, the bike runs and revs fine. When they are uncovered, it sounds as if when the throttle is used or choke is off that air is escaping from them making the bike run rich. I have two carbs for the same bike and both are running the exact same way. I can't see anyway of adjusting what happens with these, I guess it wouldn't be advisable to permanently cover these up? Or certainly the problematic one. Cheers again guys.

Thanks Tango / Lumor, You are correct Lumor, no filter. In my ignorance, I didn't even think about it. I have been in and put an order on the inlet manifold and a fuel filter. The manifold won't be here until Monday so will need to wait I am also going to give it an oil change incase any fuel has got into the sump when it has not been starting.

Thanks Tango, I have ordered a new one. If the tank has rust in it should I order a new one? Could anything else discolour the fuel to a golden colour? GK

Hi Guys, I had an issue recently with a lexmoto XTR s 125 where it wouldn't allow me to go above 3000 rpm when using throttle. The issue has got worse and the bike won't start at all. I have noticed the following which I believe could be the problem but would like a second opinion: Inlet: Split at engine side, only a small crack in the metal, rubber is still intact Tank: Found rust in the tank, flushed it out but I don't think it's helped Petrol: Coming out a golden colour Spark: After cleaning carb, it will ignite and rev but die quickly. Took spark plug out and put it against the frame and was getting a blue spark. Plug: Wet with fuel - adjusted fuel screw but still a bit wet ( not igniting so I guess it would be ) Root Cause: Combination of the above possibly? Split in inlet losing air, dirty fuel ( could it be that bad it won't ignite? ) Would really appreciate some advice, or if anyone in the edinburgh area cares to have a look?

Hi Guys, Put the other carb back in yesterday after giving both a very good clean. Currently its not starting and I didnt want to play around late last night and annoy the neighbours. It seemed both carbs were adjusted almost exactly the same, where this one wont start which I see as a good thing??? As it could have pointed to something bad on the original ( or could point to something bad here )

I did some testing just there, if I adjust idle screw it will reach 4-5k RPM, possibly higher but I just wanted to check. Would this mean it has something to do with: Needle Jet Main Jet Throttle Slide .... As I said I am going to try the other carb out see if that improves anything tomorrow / Wednesday.

Thanks Strange, I have another carb inc float at my parents house. I will try that on, hopefully it won't have the same problem. I tried another spark plug - clean, and it still does it. Would it be wise to reset the carb? Knock it up to 3k revs and start adjusting the fuel screw? Now it doesn't sound like its running correctly

Thanks Tango, I did originally have a problem with that but got a new airbox and carb boot. Both still in tact. Took it out there and again it happened, but when in neutral I revved it a bit more. At 3k revs it stalls, in gear or not.

Hi Rennie, Went back and checked as you said again, fuel is clean and fresh, starts when choke is off but not when it is on. Guys, I have however found a tiny hole in the petrol pipe to the carb, after taping this up it is allowing me to run around in 1st and 2nd ( only tried it in the yard ). However the engine was extremely warm, took the spark plug out and it was carbon black,does this point to being to rich? The fuel screw is out about 4 turns, but if I put it in any further I either get a really rough idle ( both cold and warm ) or it doesnt start, this is will adjusting the idle screw to compensate for idle RPM Thanks guys again, you are all helping me learn and get this death trap running! Yes a black plug is usually a sign of an engine running too rich.....but checking after tick over can also do that....an engine needs to be warm and run at higher revs than tick over before removing and checking plug. The screw that makes it run rough...get the engine warm...make sure the choke is fully off...the screw it in until in runs rough then back it out 3/4 turn... Thanks acting strange, I will try do this now, its a pain to get to. Whoever designed these really didnt have their thinking hat on. Its a screw on the bottom of the carb at engine side with only 20mm access. I don't have the special screw driver to turn it so have to use my hand, when doing this though it obviously burns me haha. I'll come up with a plan but many thanks for your advice, maybe get to take it out tonight. I guess if its running rich that is why it was so hot? This bike was designed so bad, to get the spark plug out you need to use a spanner ( socket won't fit in due to frame ) so I will pick up another plug tomorrow and try it after making this adjustment.

Hi Rennie, Went back and checked as you said again, fuel is clean and fresh, starts when choke is off but not when it is on. Guys, I have however found a tiny hole in the petrol pipe to the carb, after taping this up it is allowing me to run around in 1st and 2nd ( only tried it in the yard ). However the engine was extremely warm, took the spark plug out and it was carbon black,does this point to being to rich? The fuel screw is out about 4 turns, but if I put it in any further I either get a really rough idle ( both cold and warm ) or it doesnt start, this is will adjusting the idle screw to compensate for idle RPM Thanks guys again, you are all helping me learn and get this death trap running!