wizzer

Alright guys, think i'v found the problem, today i managed to start the bike so i tested it with the WD40 again couldn't identify any leaks in the gaskets, i was bored so i decided to start stripping it down, when i took the bost bottle thing off (YEIS) i noticed the rubber connector had a split and there was like a 5mm hole in it. Not 100% sure this is the problem but it's worth a try.

Ok just went out there to test the bike and couldn't get it to start. It let off a loud bang from the exhuast when i was kicking it over even though the bike was cold. I'm sure it isn't the head gasket because i replaced it in the summer when it blew and you could see where the leak was because of the bubbles however this time it seems ok. I'l try start the bike tommorow and check with the WD40 around the base gasket Thanks guys

Ok thanks XJ6, I thought about that myself but thought i would be able to see any air leaking from around the base gasket i checked the nuts around the head aswell and they all seem fine also checked around the carb area with WD40 and couldn't find any problems.

Ok think i'l probably just replace the seal because it seems to be the most likely problem at the moment. I'l order a flywheel puler from ebay. So I will need a Left hand seal for the flywheel side? Thanks

1: I checked under the magneto cover and it's quite clean, doesn't appear to be any petrol/oil in that area. The bike now will barely idle, it revs up high without the choke then bogs down if you don't apply a little throttle 2: Tried spraying WD40 around this area, nothing seemed to happpen imedateatly but after a minute it started to hiss and pop from the exhuast which it's never done before. Is it possible to replace the crank seal without splitting the case?

Hi guys, haven't posted in a while. I have a dt125lc which i use offroad where I live, My problem started recently when i tried to start the bike up after lying in the shed for about a month. It was difficult to start then as it warmed up it started to rev higher and the only way i found to bring it back down was pulling the chocke out; Therefore I suspect it's running lean? From what i'v read it sounds like an air leak somewhere but how do i check for an air leak? My suspicion is that itcould be the crank seal. How do I check for a worn crankshaft seals? Thanks once again

Got it sorted, it was either the coil or ht lead. First thing to do now is go a wee run i think Thanks for all the help AGAIN!!!

hi zircon I'm having a similar problem to you. But i just wanted to say that my bike ran well with a resistor plug and a resistor cap 5k ohm without a problem. From what i read your bettter off running a bike with a resistor cap rather than a resistor plug because sometimes the resistor in the plug can breakdown very easily then damage your ignition system. hope this helps

Anyway little update took the ignition coil out and discovered the ht lead just about fell off it was that perished ordered a new coil and plug cap. Should there be any resistance through the plug cap even if its a non supresed type? The cap on mine gave k7.1ohms, to me this seems like alot of strain on a small ignition system.

Awright cheers for that Blackhat i'v already replaced the plug and i think i'l replace the cap as it's cheap Do you think with the low resistace in the primary it could be a short circuit

Hi i'v got a dt125lc3 and i am having some running problems. Firstly the bike was working fine then it gradually became like this. It is almost impossible to start i have to repeatedly bump start it down a hill to get it going, when it does run it miss fires consantly and wont rev. As it warms up it gets a little better but not by much when i try to rev the bike it just stops firing then cuts back in when the revs drop. What i have done: Cleaned out the carb twice with commpressed air Inspected the reads (thought they might be broken) Checked all conections visually Possible problem: I checked the secondary ignition coil resistance and it was spot on what the book says K5.9 ohm but the primary measured at 0.23ohm and in the book it says it should be 10ohm. There is a spark but it looks a little weak When the bike was working when i washed it i would have similar symtoms but after the bike warmed up they would go away. Thanks for the help.

Managed to free the piston, vez you were correct i had trapped the seal when trying to insert the piston. I'm now going to order up a new set of seals and maybe piston however it doesn't look to badly damaged so might reuse it baring in mind my bike is only used off road. Thanks vez for the help

Thanks vez i found a piston and seals kit on bitz for bikes so i'm just going to try and force the piston out. do you think those calipers you listed will fit my bike? I will take some pics and post them

I tried to bleed the brakes and remove the piston by hydralic pressure but it didn't seem to work. When i sqeezed the lever fluid flows down the brake line a little then when i release the lever flows back up into the master cylinder. I also tried to remove the piston with mole grips but it just damaged the soft metal. I'm starting to think i should try and find a new caliper.

Ok thanks for replying vez. In my manual it metions removing the piston using hydralic pressure from the brake but how would i do this once i connect it up how do i bleed the system?

Hi guys I have a dt125lc3 (disc)and im having problems with the brake caliper piston.My Problem is that when i replaced the pads i decided to remove the piston, when i tried to refit it it wouldn,t go back in so i used a C clamp (i think this was a bad mistake)now the caliper piston is kind of halfway in and it won't come out or go in any more. What do you guys sugest, do you think i should try to find a new caliper. In the manual it describes it as if the piston should just like slide in but mine doesn't I feel a bit stupid that i have probobly broken something now but i am a teenager and still learning. Thanks

Firstly i would check for loose valves if they are in check then it could be piston slap I would say it's the valves though

I found this one on wemoto do you think this would be a beter option.

Alright guys, I'm looking for a new chain and sproket set for my dt125lc3, i have noticed this site that sells the sprockets and chain seperatly but it's for a DT125LC MK3 My question is if the LC3 and the LC MK3 are the same model and so would it fit on my bike. Also I'm not to sure if my bike has the original standard sprokets on it so do any of you know how many teeth they have. On my bike I counted 16 on the front and 49 on the rear. Thanks for the help guys.

I Don't know what type of pump is on this model of bike but there should be a mark on the pump body that lines up with a mark on the pulley when the throtle is closed. Use the cable adjuster to line up these two marks once you have done this start the bike and watch for the pump moving in and out, when its at its outermost measure the gap between the pulley and a projection on the pump.I think it should be between 0.2 and 0.3mm.To adjust this take off the nut at the end of the pump and add or subtract the shims untill the gap is correct.

I had the same problem with my Dt125, make sure when you put the carb back together the throttle cable isn't snaged anywhere; like at the tank causeing the bike to rev up

When its stationary on the side stand it will tick over and run, but not rev freely. But when i try to ride it it revs to about 4k and misfires and after a few seconds it will cut out completely. [/code] Just a thought but is the carb on vertically, if its at an angle it would efect fuel level in the bowl, as you said it runs on the side stand

The bike was running fine then i ran the tank dry by accident. Filled it back up after that it started bogging down and stalled couldn,t start it. i took the carb off beacuse i thought maybe it had pulled crap into the carb cleaned the bowl put it back together still diddn,t work. Replaced the spark plug, Bingo!! It fired up first kick but reved all the way to 8000rpm. I checked the carb slide it wasn,t in the right way so i turned it round didn,t make a difference. i tried adjusting the idle speed no difference.

Hi, I have a dt125lc when i start it it revs up way to high i tried to adjust the idle speed but it didn,t make any difference. I read somewhere that this problem could be an air leak but it ran fine before i took the carb off and i checked the inlet and it seems sealed. Could someone point me in the right dirrection as in what could be the problem.

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