Crank Case Compatibility

[agabay]

hi

i have a 2011 TXT pro (125) with the magnesium case

i checked the engine today and found that the lower motor mounts (on the case side) has a crack

the engine is allrady out of the bike and i will take it to a magnesium expert welder next week, but i also take into account the eventually i will need to replace the cases

do you know if older or newer models (with aluminium cases) will fit? i saw a post of someone replacing a 2011 pro 300 case with a 2012 model, but the 125 cases are different

thanks 

[lowbrow]

I don't know the answer to your question, but would have expected your bike to have the same crankcases as the larger capacity bikes.  Have you tried comparing part numbers from different years?  You can find a link to the parts books on Shirty's site or here http://www.gasgasmotos.es/en/manuals.html

[copemech]

I believe 125 cases are different from the larger bikes(except 200), just find new ali cases now and save yourself! All years Pro motor should work I would think..

 

Check for frame cracking as well, which may have caused this.

Edited September 27, 2015 by copemech

[baldilocks]

Its usually caused by the sump guard becoming bent by repeated impacts and the rubber block getting split. There is a thread on the issue.

[arnoux]

Yes loose or worn bash plate and/or engine bolts and/or bushes are the culprit. As the bash plate is an integral part of the frame forming a structural "hoop" around the engine. Break the strength of that "hoop" by having a loose section and the frame flexes, and that load is transferred elsewhere, and the bottom engine mount gets loaded badly especially on big suspension compressions.

I have seen a few of these over the years in our workshop and everyone had loose or worn bolts, or missing bash plate bushes with just a nylock nut or something else in its place.

Seems a little thing, but it can have big consequences.

[aussiechris]

According to the 2011 parts book for the standard (non-raga) models the part numbers for the 125 is different to the bigger bikes.

 

Left crankcase MT280310001RA for the 125 vs MT110002811 for the 250,280,300.

Right crankcase MT280310000RA for the 125 vs MT100002811for the bigger bikes.

 

However, the later parts books suggest they are the same.

 

I didn't see where you hail from but Paul (above) is our Aussie dealer and he would be able to help with part numbers.  I don't envy you trying to get parts right now so you might have to shop around.

 

And yes, if possible get the 2012 or later cases because you can replace the gear shift shaft without splitting the cases.

 

Chris (been down this road before )

 

 

[agabay]

thanks guys

the problem in my bike could have resulted from all 3 reasons, as my skid plate was bent, the rubber inserts were torn, and one of the engine screws (the one hooking to the connector above the carb) was loose

since the crack is only partial and only on the left case i will take it tomorrow to someone that specialize in magnesium welding, and if this wont work i'll order the cases (i see that 2012 has same partnumber - so i'll go for 2013).

i also saw a post where someone switched internals of 2008 with 2011 (280), so i guess that differences were minor over the years

thanks