Advice if you can, if not oh well...

[morbidphil0622]

I have a 1993 rm 125 that I have had for about 6 months. When I first bought the bike it would start on the first kick every time, I mean every time.. Well my buddy and I were out of gas and really really wanted to go riding so we siphoned some gas from a buddys quad and mixed it up to ride on. as soon as we both started up our bikes the carbs on both clogged. We cleaned the heck out of both carbs and they ran fine for the rest of the day. now all of the sudden my bike has become impossible to start. I have pulled the carbs and cleaned them about 10 times now, I checked the float levels today and everything checks out. I have cleaned the power valve and inspected the reeds. the only thing questionable was my reeds because I dont know how old they are but they sit flush with the reed body.
I am lost and really dont know what to do. The bike has spark and the stator appears to be correct. I would say that the compression could be bad but I am able to bump start it, and when I do it runs better than it has ever ran before. I assume that is beacuse ov everything I have cleaned. I have tried hotter plugs and different gas/oil ratios but nothing seems to work, it just kicks and kicks and if you kick it a few times with no throttle at all it will sometimes backfire a bit.
Sorry to make this post so long but I am trying to give all the info that I can give. If you have had this problem or can think of anything else that I can try please respond to this. Like I said the bike will bump start but will not kick, not even after it is warmed up... Thank you, Jason

 

[Zenith]

I don't see where the gas from the quad would fit in with this, but for what it's worth we had a 1994 CR125 with very similar symptoms a while back. It was impossible to start with the kickstart but would eventually start when bump started. The spark LOOKED ok when you kicked it but there was obviously something wrong. It ran pretty good when it was going but once it warmed up a bit the engine sounded a bit rough. I went through the bike cleaning and checking everything. Eventually we just bought a new stator and voila the problem was gone! The stator was only about $140 so you might want to consider trying that after you're sure you've gone through everything else... I would put in a new topend first though, low compression does make an engine harder to start...

 

[morbidphil0622]

Wouldnt a broken stator cause the bike to not run at all? I would think that would be the case. I am starting to really wonder if it might be the reeds. they dont seem to look perfect, I found a set for dirt cheap so I will buy them tomorrow and see what happens. If that doesnt help I will do a compression test and go the ignition system with an ohms meter..

 

[Andy428]

had an 87 yz 250 that had spark but wouldnt start, checked stator with an ohm meter and was ok after a coil and cdi unit turned out to be the stator fired first kick

 

[morbidphil0622]

ok, I just figured something weird out. I parked the bike in my driveway to do something to the garage and so the bike would not rool downhill I put it in first gear. Even after I did this the bike would roll, catch a little bit, and roll some more. This is not normal is it? This is the first dirt bike that I have ever owned but my streetbikes never did this.. Does this mean that I have compression issues?

 

[Zenith]

Well I'm just telling you what happened with this bike. It certainly ran, though it wasn't running perfectly.
We did all the eletrical tests as well (my father is an electrician so we had the tools and know-how to do it right), these all showed the stator to be within limits. When I finally emailed a stator place giving the symptoms the guy was almost certain this was the problem, and so it was!

Yes that rolling you describe is perfectly normal from a two stroke 125. The compression is quite low and the ring seal comparitively quite poor on 125s.

 

[morbidphil0622]

ok cool, thats good to know.. I guess I will check out my stator then. I just got a flywheel puller so we will see what happens

 

[ZeCatfish]

replace the piston and ring. I gauge my bike by if I can push the kickstart lever down with my hand (normal is practically impossible) its time for a top end.
No your bike shouldn't roll with it in gear.

 

[morbidphil0622]

that is what the mechanic just told me. no bike should roll with it in gear and if you can push the kickstart down with your hand (I can by the way) then it is time for a top end... I have been meaning to do one anyhow. The idea of the stator being messed up is still a possibility but I think for compression reasons I am going to go with my top end first..

 

[Zenith]

ZeCatfish - this is a 125 he's talking about, they're a different animal. One of the BIG differences being the single piston ring.

morbidphil0622 - I'm afraid your mechanic is wrong. I'd definitely put a new topend in the bike if it has a lot of hours on it, but it is perfectly normal to be able to push the kickstarter down with your hand on a 125. There should be a very hard spot but you should be able to push through it. It is also normal for a 125 to be able to roll a bit, then stop (as the piston reaches TDC), then push through the compression and roll a bit more if the bike is on any sort of hill. I've been riding and working on 125s for 7 years now and this has been the behaviour of every one, be it on a new or old topend. This is not the case on a 250 say because they have much better ring seal and are FAR harder to kick over. Anyway, it's not a big deal if you want to agree to disagree it's fine by me :).

 

[morbidphil0622]

well now I dont know what to do so screw it.. does anybody want to buy a bike?

 

[ZeCatfish]

morbid do the top end, you have no compression, thats the reason it will only start bumping it. First sign of doing a top end is hard to start. I bet you a coke it will start first kick after you do it. Don't give up on it. I know I'm right and so is the mechanic. :bang:

 

[Chili]

morbid do the top end, you have no compression, thats the reason it will only start bumping it. First sign of doing a top end is hard to start. I bet you a coke it will start first kick after you do it. Don't give up on it. I know I'm right and so is the mechanic. :bang:

It may in fact need a top end but stating you and the mechanic are right simply because you can push the kickstarter down with your hand is a joke. I can walk into any showroom and push the kickstarter of any 125 through it's stroke by hand.

 

[morbidphil0622]

In all honesty, the both of you have a point and both are very possible. I will start with the cheapest and go fron there. I have ordered a piston kit and cometic gasket kit, my reeds will be here on tuesday and if That doesnt work I will move on to the nexy step.. Eventually I will end up fixing it one way or another.. I just need to remember 3 important things. Fuel, compression, and spark. Thanks guys I will keep you popsted. Jason

 

[rohleder149]

good luck with it morbid! but everything zenith has stated is right. when i broke my leg, i use to start my 125's with my hand.....it's very possible. i can push through the stroke on a 250 2 stroke, as well as any auto decompression 4 stroke. as far as your bike rolling; again, listen to zenith. very normal. it sounds like a top-end and reeds would be a good idea for your bike anyway, but it doesn't sound like that's what is keeping the bike from starting. STATOR baybee!!!!!!!!

 

[morbidphil0622]

Well I disassembled my top end today and what do you know, the piston is pretty messed up. It has a small peice missing right between the top and the ring. it isnt a very pretty thing. I ordered a new piston kit on thursday so we are good to go. However, I am a bit worried that I might have to replace my cylinder because the part of the piston that is broken appears to have nicked a small spot on the inside of the cylinder. It is not a very big spot bit it is in the cylinder, right on the corner where the exhaust port is at. Does anybody think that this will be a problem? I am wondering if I should hold off on this new piston until I get it figured out.. Does anybody know how much it costs to have this repaired at a machine shop?? Thanks in advance, Jason

 

[morbidphil0622]

put in new piston kit and reeds. Bike kicked up on the first try and now runs better than I have ever known it to...

 

[Moose]

I believe you owe ZeCatFish a coke. :)

 

[RocketRaccoon]

I believe you owe ZeCatFish a coke. :)

Too sweet...get him a Pepsi. :)

 

[morbidphil0622]

how about some budweiser...

 

[OldTimer]

Yeah, but can you still kick it over by hand? Does it still roll in gear?

 

[Zenith]

Do you reckon you have the cause of the problem sorted out though? Pistons don't snag ports for no reason.

 

[morbidphil0622]

that is what I am trying to figure out right now... I belive the exhaust valve somehow hit it. How it happened is what I need to figure out. It might just be out of spec.. I need to pull it apart and check it out every once in a while to see if the same thing is happening.

to answer the other question yes the kickstart will still move by hand but not fast enough to start it, and no the bike no longer rolls while in gear..

Thanks guys for all of your help I really do appreciate it more than most people will ever know. My stress level is now at a minimum and I am able to blaze up the trails and jump my ramps again... Im so freakin happy!!! Time to go build some more ramps...