SAPPERS Posted March 18, 2010 This 125 is killin me. For those who have them (03-05), do you have any type of sputtering when not in the powerband? We've got a bad one. We finally jetted and got alot of it out but it still has it. BUt when it's on the pipe, it rips and doesn't miss a beat. It's driving me absolutely nuts. Anyone have any ideas. I AM going to go ahead and do topend gaskets, crank seals, waterpump shaft seal just to be safe. What do you guys think about maybe an ignition problem? Were these prone? I'm about to lay it to rest with the .44 Mag or some C4. I got home too late from work tonite but will have a vid tomorrow. Share this post Link to post Share on other sites
crider400 Posted March 18, 2010 The cr125s do this if your not on the pipe. Jetting is a issue if its not spot on, also a dirty carb can contribute to the problem. Sinse your going to take the jug off, clean the powervalve. when i first got my cr125, i hated it because it was a lot harder to stay on the pipe unlike my yz250. Eventully i was emune on the 125 and i got used to being on the pipe. Also check the rc valve tension in the wires, if the left one hits the wall, its way to loose. Share this post Link to post Share on other sites
minimotos95 Posted March 18, 2010 if it still does it after the rebuild, might as well try a reed spacer on it. http://shop.thumpertalk.com/ProductDetails.asp?ProductCode=PU_10080001 Share this post Link to post Share on other sites
SAPPERS Posted March 18, 2010 Also check the rc valve tension in the wires, if the left one hits the wall, its way to loose. You lost me here. Either I'm drawing a blank and not realizing what you mean (been a long day) or you're referring to something that I don't refer to as "rc valve" Share this post Link to post Share on other sites
dmm698 Posted March 18, 2010 he's referring to a honda. The rc valve is on the cr's and its an electrical servo type motor thats prone to failure by either just plain sucking and failing or the cables backing themselves out all the time. the kx has no RC valve. Share this post Link to post Share on other sites
minimotos95 Posted March 18, 2010 You lost me here. Either I'm drawing a blank and not realizing what you mean (been a long day) or you're referring to something that I don't refer to as "rc valve" sounds like a honda thing.... Share this post Link to post Share on other sites
SAPPERS Posted March 18, 2010 HONDA???? ahhh why's he cussing at me??? No red here Share this post Link to post Share on other sites
Superjetrider Posted March 18, 2010 My 03 does the same thing if it is at low rpm and you go from small throttle opening to WFO. I want to work on the jetting to see if I can iron it out. I just try to stay on the pipe, and that's fixing it for now haha. Share this post Link to post Share on other sites
crider400 Posted March 18, 2010 sh**, been a long day for me, thought i was in the honda forum, Share this post Link to post Share on other sites
SAPPERS Posted March 19, 2010 My 03 does the same thing if it is at low rpm and you go from small throttle opening to WFO. I want to work on the jetting to see if I can iron it out. I just try to stay on the pipe, and that's fixing it for now haha. I'm wandering if this is an issue for the 03's and they fixed the problem for 04-05 or all of them. But now he rode it out on the track for about 2 hrs. We did the jetting thing and it helped a minor bit but it's still there. NOW, I found out the motor had, in fact, been into. I'm seriously thinking it's in the KIPS. Time for a partial teardown and cleaning. Guess it's time to master the 125 engine. Share this post Link to post Share on other sites
The Spanky My Ride Posted March 19, 2010 It sounds to me like you may have a worn needle jet (not the jet needle, but the jet itself). Share this post Link to post Share on other sites
Superjetrider Posted March 19, 2010 I'm wandering if this is an issue for the 03's and they fixed the problem for 04-05 or all of them. But now he rode it out on the track for about 2 hrs. We did the jetting thing and it helped a minor bit but it's still there. NOW, I found out the motor had, in fact, been into. I'm seriously thinking it's in the KIPS. Time for a partial teardown and cleaning. Guess it's time to master the 125 engine. Mine just seems like its a little lean on the bottom (gasps). It is frustrating. I'm anxious to see if you find anything. I'll be tearing mine down to inspect it once summer comes. I know mine has been apart before too. What kind of gas are you running with 210psi compression? Also tonight I noticed that my stator was rotated to maximum retard. I set it to the middle mark and I'm going to give it a shot this weekend to see if it helps. Share this post Link to post Share on other sites
SAPPERS Posted March 19, 2010 Chokey, I was told something about that. Something to do with these Mikunis that were bad for that. The shop he works for has them in stock. Might have to pick one up. Super, 93 pump. It's apparently a fresh topend. I usually get 190 -210 on a good, new topend. Share this post Link to post Share on other sites
The Spanky My Ride Posted March 19, 2010 Sappers, if you have a Mikuni, is it the model that uses the choke knob to adjust the idle? If so, before you go any farther making jetting changes, check the seal on the end of the choke plunger. It's common for that seal to begin leaking, making the jetting too rich and giving you jetting nightmares. Share this post Link to post Share on other sites
SAPPERS Posted March 20, 2010 Chokey, No thank God. I had an old RM that was like that. This is the TMX 38mm. He's been riding it for 2 days now and finally I tried a timing change. I tried advance ( got 10x worse) then retarded and it got better. The KIPS moves but not real smooth. It kinda jumps up in 3 steps then back down in 3 steps. But when it's on the pipe, it rips. It's killing him out of the turns. Share this post Link to post Share on other sites
SAPPERS Posted March 21, 2010 Well, new update... IT LET GO!!!! Something bad happened. He was riding his normal and something just let go. Started rattling real bad. So, looks like I'm getting into this sooner than expected. Oh well, at least it will have a new top/bottom end before racing starts. Share this post Link to post Share on other sites
SAPPERS Posted March 21, 2010 Well, new update... IT LET GO!!!! Something bad happened. He was riding his normal and something just let go. Started rattling real bad. So, looks like I'm getting into this sooner than expected. Oh well, at least it will have a new top/bottom end before racing starts. Share this post Link to post Share on other sites
2strokecrazy Posted March 21, 2010 Well, new update... IT LET GO!!!! Something bad happened. He was riding his normal and something just let go. Started rattling real bad. So, looks like I'm getting into this sooner than expected. Oh well, at least it will have a new top/bottom end before racing starts. sry to hear man ...i am in same boat ...both my and my daughters bikes are not currently running:banghead: rebuilding daughters rm 80 now and my kx 125 wont shift:foul: i too will be diving in to check things out ....thank god its still crappy weather so i have time to fix problem ...hopefully not bent shift forks 👍 hope all works out .....its a blast to ride with the kids ...right? Share this post Link to post Share on other sites
Superjetrider Posted March 22, 2010 Chokey, No thank God. I had an old RM that was like that. This is the TMX 38mm. He's been riding it for 2 days now and finally I tried a timing change. I tried advance ( got 10x worse) then retarded and it got better. The KIPS moves but not real smooth. It kinda jumps up in 3 steps then back down in 3 steps. But when it's on the pipe, it rips. It's killing him out of the turns. The timing advance really helped my bike. It rips now. The bottom end is 10x better. I still to have a little carb hesitation, but the timing really did it for me. Good luck with the rebuild. It'll be worth it when you're done! Share this post Link to post Share on other sites
