alrite here we go..got the bike about 6 mths ago (orion 21) . it's copped a hell ov i hiding and just took it on the chest untill third gear started jolting on me like the clutch was getting pulled in and out. Then it started making wicked grinding and snaping sounds, kinda like it was getting hit wth a hammer, so i puled it down and stip'd the box expecting a handfull of teath but there was zilch. everything was perfect inside visualy. so i put it back together and took it for a blast ..it was the same at first but on the ride home it was lockin up in first, slipping out of 4th, lost 3rd completely, making all sorts of noise in all the gears and jolting in every gear but 1st...but engine braking is fine...clutch engaged is fine and if i keep at a steady pace (say 50k's in 4th) it just tik's...how the f*%^ does that all add up? any suggestions? i heard there is a external gearbox adjuster, is this true?
strangest gearbox problem ever..real brain buster
- Thread starter mrsteve
- Start date
Help Support Mini Dirt Bikes & Pit Bikes Forum:
Divy
Well-Known Member
- Joined
- Oct 12, 2006
- Messages
- 1,206
- Reaction score
- 0
man thats wierd i would of thought too that the teeth or something would have broke
i dont think these is a exturnal gearbox adjuster, there is a clutch adjuster but for whats happening i doupt very much its got anything to do with the clutch adjustment
i have no idea! but wait for more replies im sure some one will think of something im waiting to see what other ppl say too cause its got me interested in whats wrong
good luck mate
i dont think these is a exturnal gearbox adjuster, there is a clutch adjuster but for whats happening i doupt very much its got anything to do with the clutch adjustment
i have no idea! but wait for more replies im sure some one will think of something im waiting to see what other ppl say too cause its got me interested in whats wrong
good luck mate
had exactly that same problem with my first engine!! gave her a flogging and id put it into 3rd and it would just slip and then snatch and the same with 4th and it also felt like i was loosing power so i just took it out and put it under the workbench and bought a new 125 Race engine. I think the only fix to this problem is to get a new gear box fitted or just go the whole hog and upgrade your complete engine! After a few weeks i though id inspect the problem so i cracked open my engine not quiet being able to get to the gearbox but a tooth off something fell out when i drained the oil... defiantly a new gearbox needed!
born2slide1980
Well-Known Member
I had a similar problem with my old 125cc, it kept making the grinding noise in 3rd gear "only" and also kept jerking as if the sprocket was slipping, like yours seems to be doing. At first thing I though it may have been the chain slipping off one of the sprockets, but soon realised that it was a little bit more serious than that.
I also bought a new engine to solve the problems a 140cc (which really does go hard for a stocker), but it only took me a month to kill that gearbox too. I did find 2 meshing tabs floating around in there, off 3rd gear, which eventually found there way into the other gears and seized the box, while is was doing about 50k's. I have new internals in there at the moment and I am about to rip them out and get them back cut and heat treated for extra strength.
Hoping that the problem might have been as simple to fix, I pulled apart my 125, but could not find any broken parts and did not know what was going on for a while either. After look at how it all operated for a while, I soon realised that it was not moving the shifter fork, up far enough on the drum to mesh third gear propel. when I had a closer look at the meshing tabs (technical name) on those two gears they both were polished like they had been rubbing. also after taking the drum out, I could clearly see that one of the shift forks was bent and had worn down the small tab on the end.
I ended up heating the fork (in a vice) and then gave it a few hit with a big hammer until it was kind of straight, I Then welded on a new tab and file it all down to specs. I deliberately bent it back past square to help get rid of the problem, but when it was all back sitting in the case it still didn't mesh as well as it should have, so I then ground down the brass washer in between them to improve the problem and then dished the outer washer a bit more to get rid of play on the shaft.
Anyway I hope this helps, I might not be the same problem, but It does sound very similar to what yous is doing. If it is it may be a lot easier, to try and purchase a new shift fork, instead on trying to repairing the old one.
My motor used to pop out of gear all the time (wont be now) and I used to get the shits with it and try to kick it back in, so that is how I probably bent it in the first place. But I have a feeling that a lot of these boxes don't mesh 3rd as well as they could...So it doesn't take much to trigger the problem. I could be very wrong though.
Cheers Matt
I also bought a new engine to solve the problems a 140cc (which really does go hard for a stocker), but it only took me a month to kill that gearbox too. I did find 2 meshing tabs floating around in there, off 3rd gear, which eventually found there way into the other gears and seized the box, while is was doing about 50k's. I have new internals in there at the moment and I am about to rip them out and get them back cut and heat treated for extra strength.
Hoping that the problem might have been as simple to fix, I pulled apart my 125, but could not find any broken parts and did not know what was going on for a while either. After look at how it all operated for a while, I soon realised that it was not moving the shifter fork, up far enough on the drum to mesh third gear propel. when I had a closer look at the meshing tabs (technical name) on those two gears they both were polished like they had been rubbing. also after taking the drum out, I could clearly see that one of the shift forks was bent and had worn down the small tab on the end.
I ended up heating the fork (in a vice) and then gave it a few hit with a big hammer until it was kind of straight, I Then welded on a new tab and file it all down to specs. I deliberately bent it back past square to help get rid of the problem, but when it was all back sitting in the case it still didn't mesh as well as it should have, so I then ground down the brass washer in between them to improve the problem and then dished the outer washer a bit more to get rid of play on the shaft.
Anyway I hope this helps, I might not be the same problem, but It does sound very similar to what yous is doing. If it is it may be a lot easier, to try and purchase a new shift fork, instead on trying to repairing the old one.
My motor used to pop out of gear all the time (wont be now) and I used to get the shits with it and try to kick it back in, so that is how I probably bent it in the first place. But I have a feeling that a lot of these boxes don't mesh 3rd as well as they could...So it doesn't take much to trigger the problem. I could be very wrong though.
Cheers Matt
oi your a ledge matt. cheers for your time...i'm gonna rip him apart again and have a closer look now cause it sounds like the same problem. I'm to anctious to wait for new motors and i like fiddlen with them so hopefully you advise does the trick..i'll let ya know how i go!!
steve's here
steve's here
born2slide1980
Well-Known Member
Hey no worries steve,
let us know how you go and what you find in there.
Cheers
let us know how you go and what you find in there.
Cheers
50s BRotherhood #1
Well-Known Member
im very curious too please let us know how it goes
