zedhead

If you read the previous post you will see that the problem has been resolved. It was the carb afterall ,with a rebuild with new jets and gaskets.Yes i did clean the carb each time i took it apart,but the fault lay with the components being worn.

Hopefully this is the final update . Got the Carb rebuild kit, fitted the new jets 'O' rings springs and gaskets. Lo and behold the beast works and keeps on working .It seems it may have been a Carb problem all along,but at the very least the rest of the bike has been adjusted and checked within an inch of it's life !. We only did a small journry today so tomorrow we will push it further [hopefully not literally!!] I am pretty confident it is all good now . The bike starts idles and runs smoothly as long as it is necessary. Many thanks for all the ideas tips and comments much appreciated. zedhead

According to the manual the jet that is missing is the pilot jet it is on the bottom of the carb exiting out of the float bowl. Also i don't think this has anything to do with the initial problem it's just a problem that has occured whilst testing the bike after the last attempt to solve the issue. It could have come loose at the end of the test and fallen away.

Quick update . Whipped the seat off and checked for any misbehaving electrics. Found a couple of wires that could have been shorting out under the weight of a rider,so i sorted them.Took the carb off to strip down and check over again and found that the pilot jet had come loose under vibration and disapeared along with it's spring and 'O' ring. Can only think it was whilst we were testing the bike out on the road,because it was there last time i looked. Will have to wait for a rebuild kit to arrive and then i can try again. Such fun

No the handbrake is definatley off it's my sons bike and i think his just ate too many pies Good advice with the carb that is my next job. Iv'e done it three times already [ooh err] but you can never clean a carb too much. No known split diaghrams or sticky plungers.Knowing me i have probably missed something really obvious and stupid!!

Somone asked that a few posts ago . There is a breather pipe coming out of the fuel cap which has been checked and is clear.There appears to be no problem with fuel flow from the tank to the carb,and the bike will idle forever and rev freely -until someone gets on the bike and tries to pull away. And if starting from cold the bike will run fine whilst being ridden for a few minutes and then act as if there is no power until the bike will not even pull away from standstill.Weird is not the word for it!!

No it has a gravity feed tap, simple on- off- reserve,one pipe to the carb.

I keep coming back to the carb whenever i think about this problem. I don't know much about the inner workings.I can take one apart and put it back together,but as to what each bit does im a numpty.The idea that the high speed jetting could be the problem sounds feasable . I will look into it thanks. There are some electrics under the seat might be worth a look.thanks for the idea.

Should add that to the list fuel cap breather checked for blockages all aok.

Hi after many unforseen and unavoidable distractions i am back!. Still got the same problem The bike from cold pulls away and runs fine.After a couple of minutes riding [maybe 5-10 min at times], the bike will run as if it is running out of petrol .Thing to note is that the bike will run for ever if just left to idle.This problem only appears when riding bike. Things i have done. 1/ Cleaned carb and petrol tap several times. 2/ Replaced spark plug with a new one.nice healthy spark. 3/ Checked coil 4/ Checked clutch plates, all still have friction material on them within specs 5/ Adjusted clutch cable 6/ Adjusted valves. 7/ Checked rear wheel/brake for any binding. Current thinking is could the cdi unit be cutting in and out as the bike warms up under load.? I welcome any ideas. I have the goat and chicken handy for ritual sacrifice if all else fails.

Hi again thanks for all the comments on this ongoing problem. As i have been trying to sort this a few things have come to light. 1/ The bike from cold pulls away and runs fine.After a couple of minutes riding [maybe 5-10 min at times]. The bike will lose power.When i originally found the problem the bike had already been running, hence the title. 2/ The power loss can happen when pulling away or when riding at speed 30mph etc. 3/ I have jacked the bike up and ran the bike through the gears up to speed for 5 minutes and no loss of power.! It only appears when the bike is ridden. 4/ Spark is good, nice and healthy,there is plenty of petrol. The gearchange is smooth and the cable works fine. Battery is charging and holding charge.There is required amount of oil in the sump. 5/ After running the bike and the problem appears i leave it to cool for an hour. When i try again the bike works fine for a few minutes and then the problem is back. 6/ The side stand switch suggestion made me think, as this bike has wiring leading from the clutch lever into the loom. I do not know where it goes. I have never had to pull the clutch in to start the bike. I should weather permitting get back to the bike on Wednesday to try again. Thanks again for all the suggestions i will sort this b@**er out! zedhead

Ok first off apologies for the sporadic nature of these posts,other commitments mean i cant always get to the bike . Took it out for a test worked fine did about three miles got bike nice and warmed up. That's when it started again!!!. Bike revs freely throught the range in neutral ,but pop it into gear and it struggles to pull away. All you can do is pull clutch in and try againand again with the same result, no power to pull away. I have done an internet search for this problem and most of the answers lie in one of two camps..Carbs or Sparkplug. I have cleaned the former twice and the latter is in good condition [only done 10-20 miles on it since new] and gives a decent spark.On the subject of spark the battery does seem to lose charge easily if the bike is not used much. Not being used to a 125 for a long time could the battery condition affect the performance of a small cc bike?. I may be clutching at straws but ... zedhead

Ok finally got back to the bike. I checked the plug again getting good spark,checked fuel tank breather pipe,checked everything i could ,associated with things i had changed ie:sprockets to the functioning of the choke and throttle cables after removing and cleaning the carbs...phew!!. Started bike ,runs perfectly throught rev range on idle,pulled away and it ran smooth with only a couple of dips which quickly disappeared. Bike now runs smooth as ever!!!!!! and i have no idea how it got fixed . Will test run it more over the weekend and fingers crossed it's sorted. Thanks to everyone who suggested ideas much appreciated. zedhead

I didnt think the sprockets had anything to do with it but it helps to list the things youve done prior to the problem arising. The only screw i have moved when cleaning the carbs was the pilot screw,and i put it back in the same number of turns that came out.Also i only cleaned the carbs after this problem arose. Petrol tank full fuel petcock working fine and carb bowl always has petrol. Checked spark plug-fine Both front and rear wheels turning freely neither brake binding. Bike revs throughout the range smoothly and flawlesly. Sit on the bike release clutch and advance throttle bl**@y thing stalls.

Hi Weird one here. My sons 125cc ebnduro bike will stall when you try to pull away. If the bike is standing still you can rev the nuts of it so i am thinking the carb is getting enough fuel,but drop it into first and release the clutch blurrgh no power and it stalls. This started after replacing the sprockets [same amount of teeth as old sprockets] and cush drive. I have stripped and cleaned the carb twice but that made no difference. If i had hair it would be out now. zedhead

Sucess!! after being sidetracked by getting my kids bikes through there MOT's i finally got to strip the carbs down. Both main jets were blocked .Gave it a good clean put them back in and voila! took 10 minutes to start [vacuum petrol tap] then vooom caught and ran perfectly . Took it down the road this afternoon and it ran sweet. Thanks for all the suggestions, kept me going.

My evil plan is to follow the b+*@ers everywhere!

Within the last two weeks both my kids a son and daughter have passed their CBT's. They did it with Bike Smart and both had a good day with them. Get the bikes Moted this weekend and then let them loose Aaargh!!

If it helps the flexible pipe coming out of the diaphgram housing connecter tube is in fact a Carb breather pipe. So should have no bearing on the no power pulling away problem. as seen here http://www.ex-500.com/wiki/index.php/Wh ... oses_go%3F the green pipe though this knowledge still doesn't get the power coming on again cheers

RoadTorque I checked the diagphrams both are in perfect condition.But if as i mentioned this tube which appears to exit from a metal tube linking the two diagphram housings that may be affecting the running. On the same note what causes the slides which are attached to the diagphrams to move is it a vacuum? if it is then this wayward pipe i have should go somewhere.

Fozzie the bowls have drain points on the bottom like most carbs the pipe to nowhere i mentioned is at the top coming of the diaghram housings.But thanks for the thoughts on the fuelling,stripping the carbs may be the way to go. The bike has been stood for a while but has been regulaly and ran perfect at all revs until this problem appeared. Tango thanks for that idea something i will investigate. I cant help but think this problem is simple [like me] and staring me in the face.

Hi this is probably a real obvious problem [hopefully]...but here goes. I have a 1995 GPz500s it will start and idle but when i go to pull away the revs rise to about 2.5k and then all power just dies off. The choke is off and the bike is running smoothly at idle. I am thinking it's got to be fuel.So i have checked,it has a good supply from the tank. The choke is shutting off correctly and there has been no signs of misfires or anything before this point. One thing i did notice on the carbs is that they are joined together with two metal tubes one on the bottom to the floats which has the flexible pipe from the tank connected and supplying the fuel. The other is at the top and seems to connect the two diaghram housings,this also has a flexible pipe which goes nowhere and seems to be a vent is this right ? Or is this a total red herring? I have also cleaned and checked the plugs. This problem just surfaced with no warning out of the blue. Anyone got any ideas? Cheers Zedhead

Cheers No the old seal appears in good nick [ other than it was leaking]

SUCESS !! After soaking the seal in brake fluid for 48 hours, i put the fork in a vice used the slidehammer technique about 10 times voila! and it popped out. Now to install the new oil seal ,put the fork back together and then do the other one. Thanks for the tips and intrest.

If only it was that easy! Yes i have removed the circlip. The only thing holding the legs together [ooh err] is the oil seal. As i am reluctant to use the slidehammer method for fear of damaging the bushes iam trying something suggested on another forum.....Brake fluid to disintegrate the seal,no luck yet. I will post the result when i finally get it apart.