Camshafts and big bore kits, 140cc

[rosco]

hay guy an gals

i have dmx 140cc mini bike .I have done a bit of work to it (CRF MILD CAM ,port an polished manifold). I am thinking of adding a big bore kit to the list of stuff ive done has anyone done this sort mods to a mini bike ? the kit i am looking at is the 178cc big bore kit by takegawa 178cc + R. if any one has any ideas or other brand kits thay know off on the market could u let me know. an any info on crankcase boring for this kit. Also if my cam would be anygood for this mod.

thank heaps rosco

 

[wogtaz ryder]

not sure that will work , pretty sure that kit is designed for the YX 150 engines.

 

[150man]

try TBparts or classichonda50saustralia or ebay!

 

[reco750]

try TBparts or classichonda50saustralia or ebay!

you can get 160 big bores for 124cc-140cc not to sure about 178cc thought thats only for 150cc-160cc

 

[rosco]

ill try find out more bout 178cc bigbore kits on a 140cc outlaw motor

i know a guy that has been helping me with my proformace mod to dmx 140cc
he is a mechnic at my local motorvert dealer he has been telling me bout this kit he is puting on his son 140cc as far as he has told me it is a 178cc big bore kit with a 4 valve head an he thinks i will be able to fit this kit on my 140cc i will find out cos im shore some of u other guy will be interested to see how i go
thanks for all the post guy an keep up the good work
i did find a 160cc bb kit for a 140cc if all else fails i will prob go for that
rosco

 

[wogtaz ryder]

yer they make 160bbk biggest ive seen to fit the 140's , but im around 90% sure 178 with the new 4valve wont! work on it dont even think its out yet....

instead of spending several hundred just buy a yx160cc engine and you will be happy for a while till you want more power , and you can get EASY power out of a yx motor..... much easier then out of a 140.

 

[Cactus Jack]

^^^^^ Yeah , what he's saying is spot on ... the Takegawa 178 S-cut (short cut piston skirt) kits are for KLX type engines (YX 150/160) which have a wider cylinder stud spacing than Lifan BVH engines , GPX , YX140 etc ... so they won't fit Honda type engines ...

The piston skirt is shortened to allow the bore to be increased without the need for case boring but it can also create oil control problems thru poor drain back and windage if the cylinder bore is bigger than the stock case bore ... Shortened pistons also tilt more at TDC and BDC rockover and that can allow the rings to not seal as good as possible ... the tilting can also be heard as a rattling sound ... Long skirt pistons run much quieter and give superior ring seal ...