too bad you can't buy just the piston assembly from Drow yet.
This is a discussion on FYI DrowSport 181-4v piston works great on a Takegawa 181 cylinder/4v head setup within the Grom Talk forums, part of the Honda Grom Forums category; So one of my Takegawa grom's piston took a shit so I opened up the engine and noticed that the Takegawa piston and piston rings ...
So one of my Takegawa grom's piston took a shit so I opened up the engine and noticed that the Takegawa piston and piston rings were fused together causing reduced compression. This grom would start if I bump start it but would not start via the starter. So replacing the piston was a must.
The DrowSport 4v-181 piston/rings/piston pin worked great on the Takegawa cylinder that already had over a 1K miles break in. I was more worried about the DrowSport piston rod pin since I already had one fail where the rod pin crumpled.
FYI if you try to use a Takegawa piston rod pin it is a couple hair longer and will not work with a DrowSport piston, you'll have to shave off a couple of hairs off on both ends to make it work and the reason why is because if you don't the circular clip will not sit correctly in the piston groove.
DrowSport 4v-181 pistons/cylinder are the replacement parts for the Koso 170-4v kit.
Last edited by CiscoSanJose; Yesterday at 01:00 PM.