problem with gears, help...

[lvn]

i have a 150cc loncin engine and its been running fine up until now, for some reason it doesnt change from first to second smoothly, it always ends up in neutral and then jamms in there so i have to keep playing with it to get it into second, all other gears are fine, anyone had this problem before?

 

[Scottys140]

its like that one a mates when he uses a certain type of oil. Maybe due for a change?

 

[Shing]

Or the gear teeth have chipped or there is a piece of scrap metal floating around.

 

[lvn]

rs

the oil theory maybe right, i put some of my friends oil when i drained my old oil and thats when it started, so ill be changing it, and if the gear teeth were chipped wouldnt i be feeling it while its running in gear? changin is the only screwed up part.

cheers guys

 

[Cactus Jack]

It's a known to be common problem with chinese trannies that have neutral between 1st and 2nd ... the dogs get damaged if you cop neutral then quickly whack it into second or don't use the clutch properly ... Dirtbikesonline explained it to me when all 4UP trannies first started to appear on the scene (in horizontal engines) .. in fact ... that's WHY they went to the all up shift pattern in the first place ... Before that they were selling only 1D3UP shifting engines ... and copping heaps of complaints ...

As far as I know the vertical engines are supposed to have reliable trannies ... If you change the oil back and it still has the problem ... try adjusting all of the free play out of the clutch cable to see if that improves things ... If it doesn't , then you have a damaged tranny which can only be repaired by complete engine tear down and replacement of the affected parts ...

 

[lvn]

rsg

my engine is vertical, dont know how i managed to damage it, i changed the oil and same deal, still gets stuck in neutral.

 

[lvn]

what part of my transmission would be sutffed? gears would be fine i would imagine, it would just be the components like the hubs or the selectors yes?

 

[Cactus Jack]

The dogs do all the engaging and disengaging ... The gear teeth are always constantly in mesh ... The shift forks ride in the dog-ring sliders ...

If you're lucky it'll be something to do with the selector or shift star ... If you've ever dropped the bike and dug the shift lever into the ground or bent it , then it could simply be bent inside (selector fork or worse ... shift forks) or the detent spring stretched ... sometimes the bolt can vibrate out of the selector drum and allow the shift star to come loose ...

The selector fork rotates the shift drum which makes the shift forks slide the gears across the shafts ... the dogs pull out of one gear and engage in another ... if the forks get bent or wear thin the tranny can try to engage two gears at the same time which damages the dogs ... or the dogs don't get pushed far enough into second gear so they catch on the edges of the slots and get damaged ...

Shifting without the clutch pulled right in or a dragging clutch can do the same damage ... so can rough treatment of the shift lever ... or riding with pressure on the lever ...

If you can feel a pulsing feeling when you push the shift lever then I'd say the dogs are damaged ... pulsing tells me that they're all different lengths instead of the same ...

If the lever isn't sloppy (as in has play) and springs back to the centre position then your detent spring is OK ...

In a nutshell , the only way to find out is to get the clutch cover off and take a look ... Hopefully it'll be something minor ...

 

[lvn]

i really hope so, its not easy to get parts for my engine. the spring should be okay, the stick isnt sloppy

 

[lvn]

hahah bike fixed itself, love it when that happens