125sx won't kick start. please help me!

Motor is freshly rebuilt from bottom to top with all new parts. So we can probably eliminate that it needs new rings. Here is a little back story. Motor was rebuilt and the bike fired up every single time on the 1st or 2nd kick. I put maybe 15-25hrs on it over the summer/fall. Parked it in my basement when the weather got cold outside. About 3 weeks ago it was semi nice out so I figured I would get it out and fire it up because it had been sitting for around 2 months. Bike started up just fine and ran great. I put it away and lets fast forward to 12-27-08 Saturday. It was mid 60's outside and friends wanted to go ride. I get my bike out and it starts up with no problems. I ride it for about 15 minutes and shut it down because we were meeting people. I go to start it back up and nothing. The bike will start every time when it's push started but nothing at all when I use the kick starter. I feel no loss in power or anything like that. Today I pulled the carb. off and cleaned it plus checked the float. When holding it upside down the tab just barely pushes on the little spring loaded thing. Is this correct? Any suggestions would be great. Thanks,Adam

did you clean out the pilot jet? Including all the little side holes in it? Try a NEW plug?

I drained out all the gas and put in fresh 93 octane gas and a new plug. I just sprayed the carb out with some carb cleaner and blew some compressed air into all the jets to make sure they were clean. So any other ideas? What about my float setting? Does it sound close enough? Thanks,Adam

Anyone gonna try and help me?

I'm thinking it's an ignition issue becaue when I kick the bike over by hand I don't see a strong spark coming off the plug.

So lets eliminate possible culprits. Remember the bike runs when it's push started. So let's go from there...

1-If the coil was bad would the bike even run?

2-If the cdi unit was bad would the bike even run?

3-If the stator was bad would the bike even run?

4-If the plug wire was bad would the bike even run?

I would check the reeds. Other things to check:open up the ignition cover,clean with electronic cleaner. Clean up where the coil connects to the frame. Look at the wires-Any spots rubbed through? Check the compression-is it about 90-100psi?or more? CHeck the fluids. Oil look milky? Low on coolant? Check oil- right amount? Is it burning oil?

Start going over everything, inspecting it. Clean and tighten bolts. Make sure the fluids are right. Have fun with fixing the problem-ask a friend to help check over stuff-sometimes, you just overlook things and a second set of eyes helps.

Good Luck!

It's not the reeds. They are brand new. Bought them when I did the rebuild. Fluids are not going to keep the bike from kick starting. I already sanded the frame where the coil meets. I'm getting a very weak spark when I ground the plug out and kick it over. Sometimes none at all. Thanks for your response though.

I think spark should be all or nothing (not weak).

Anyhting weird happen when push-started?

Fluids are not going to keep the bike from kick starting. I already sanded the frame where the coil meets. I'm getting a very weak spark when I ground the plug out and kick it over. Sometimes none at all.

I didn't mean the fluids would stop it from starting, rather as indicatation of something wrong-by color,loss or smell. Did you take the flywheel off and clean stator/rotor? How about taking your yz coil and trying it on the bike-just to see if it will fire up.I doudbt cdi unit. I would disconnect the kill switch,just to see if there is something grounding out. How about new plug. What plug are you using? Inspect the spark plug cap-tight fit? I had a rm80 with a bad coil-it started,bat as it heat up would start to miss. If you bump start it-it runs completely normal? From low rpm to high rpm?

So you got:

1. weak spark

2. fuel? wet plug?


4 air? filter clean?

When push started the bike runs 100% normal. I have not tried the yz coil cause it looks way bigger then the ktm one. I don't think it will mount up to the frame. Kill switch is in working order cause that what I use to turn the bike off after I push start it. Brand new br8es ngk plug. I pulled the plug cap and trimmed off about a 1/4" of the wire and put the cap back on. I pulled the ignition cover off but haven't done anything with the stator yet. I will try that next.

air filter is clean,weak/no spark,compression is good,plug is wet.

I have a good used coil I could send to you.

Yeah man that sounds great. I can paypal some money for it. I'm figuring if not the coil it's the stator. I found one on ebay from a 05 in the Uk for about 65 us dollars.

I think it might be the stator but I need other opinions because I have no other ktm to compare this to. Here is a picture of my stator and the little black box that mounts to it. You can see where there used to be like a small metal strip but now it's worn down to nothing. It's flush with the black box. It doesn't even stick up at all.

I mean heck it could of come like that from the factory but I don't know so that's why I'm asking TT.


thats the "pickup" for the magnets in the flywheel as it spins around. It has an "air gap" that is supposed to be a certain size. The button that sticks out is almost flush when new.

That sucks. I really thought I found the problem. You say it almost flush when new though. This is flush if not beyond that.

if it has wear marks like it rubbed, then yes, that could be why it doesnt kickstart, but runs fine once it spins fast enuf and creates a better magnetic field. Does it have any adjustment to tighten up the gap? If so then try that. I will hold off on shipping the coil til later today until I hear from you. I will also get out my DVD and check the instrustions for this gap.

Ok, looked at it. This may be called the "pulse generator" in KTM speak. No instructions for adjusting the gap so it may be fixed, I cant remember and dont have a 125-200 anymore. It does give values to test the igntion tho, so if you have a dealer nearby they should be able to do it for you.

Im leaving the house for now and will check back this afternoon about shipping the coil.

Yes it looks like it has rub marks on it. It just mounts in a fixed position with no adjustment. I have no Ktm dealer anywhere close to me. 1hr drive is the best I got. Just go ahead and ship it out. I'm gonna hopefully pick up a stator from ebay but the auction does not end for another 6 days. I found a cdi from a 99 125sx on there also that I hope nobody bids on so I can get it cheap. I'm not on here much anymore cause I'm in the process of rebuilding the bottom end of my yz250. At the garage a good bit after work.

OK, ship today

one more thot, if it rubbed where did it get its ability to move? It shouldnt do that. Are the crank bearings worn, did it have a rock crush the ignition cover and bend it??

Yeah you have a good point. The bottom end has all new bearings and seals in it along with a rod. Never broke the ignition cover since I owned the bike but maybe by a previous owner/rider. I found someone on ebay who has both the cdi and stator from a 99 125sx. I'm trying to get them to end the auction and just send me the parts. we are working on price right now. Any ideas what those 2 parts are worth used?

Well I picked up a used stator/flywheel and cdi with coil off a ebay for 100 dollars shipped. It's from a 99 200mxc but Dan at Munn Racing told me they would work.

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