What caused this

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the 72nd goon

Vital MX member the 72nd goon
57376 the 72nd goon http://p.vitalmx.com/photos/users/57376/avatar/c50_Screenshot_2016_09_26_15_13_54_1494040598.jpg?1494040403 http://www.vitalmx.com/community/the-72nd-goon,57376/all 04/23/17 11 14

Posts: 25

Joined: 4/23/2017

Location: Yacolt, WA USA

9/16/2017 6:35 PM

Kx 144 piston after 4 hrs. The tip of the spark plug is fused into the top.

H4L

Vital MX member H4L
51473 H4L http://p.vitalmx.com/photos/users/51473/avatar/c50_H4L_photo_96848_1458328084.jpg?1458327318 http://www.vitalmx.com/community/H4L,51473/all 03/18/16 2 346

Posts: 348

Joined: 3/18/2016

Location: CA, USA

9/16/2017 9:13 PM

It looks like a lean jetting cond. or higher octane fuel needed or a combination of both. If your running higher comp. in the engine you need to run higher octane fuel. A 2 stroke engine will melt a cast piston if the jetting is lean & using a lower octane than what the motor was set up for.

Speak softly and carry a big stick.

the 72nd goon

Vital MX member the 72nd goon
57376 the 72nd goon http://p.vitalmx.com/photos/users/57376/avatar/c50_Screenshot_2016_09_26_15_13_54_1494040598.jpg?1494040403 http://www.vitalmx.com/community/the-72nd-goon,57376/all 04/23/17 11 14

Posts: 25

Joined: 4/23/2017

Location: Yacolt, WA USA

9/17/2017 4:20 PM

H4L wrote:

It looks like a lean jetting cond. or higher octane fuel needed or a combination of both. If your running higher comp. in the engine you need to run higher octane fuel. A 2 stroke engine will melt a cast piston if the jetting is lean & using a lower octane than what the motor was set up for.

Thank you

Dusin791

Vital MX member Dusin791
58900 Dusin791 http://p.vitalmx.com/photos/users/58900/avatar/c50_IMG_3549_1505848385.jpg?1505848231 http://www.vitalmx.com/community/Dusin791,58900/all 07/31/17 http://www.vitalmx.com/community/Dusin791,58900/setup 1 11

Posts: 12

Joined: 7/31/2017

Location: Templeton, CA USA

9/17/2017 8:55 PM
Edited Date/Time: 9/17/2017 8:57 PM

Could be using the cheaper spark plug?

Kyle220

Vital MX member Kyle220
55008 Kyle220 http://p.vitalmx.com/photos/users/55008/avatar/c50_IMG_20170520_105215683_1496182353.jpg?1496182115 http://www.vitalmx.com/community/Kyle220,55008/all 11/24/16 6 http://www.vitalmx.com/community/Kyle220,55008/setup 4 113

Posts: 117

Joined: 11/24/2016

Location: USA

9/17/2017 9:25 PM

The crank seal behind the stator can cause that too, could be sucking air in somewhere.

Bhack711

Vital MX member Bhack711
59572 Bhack711 /images/default/avatar/c50.png http://www.vitalmx.com/community/Bhack711,59572/all 09/14/17 1 8

Posts: 9

Joined: 9/14/2017

Location: Watertown, CT USA

9/18/2017 8:05 AM

How many hours on the crank? A friends bike had this problem. It turned out that the crank bearings were worn cause it to be a big "longer" than spec, and the piston hit the head.