I bought a namura top end kit and sent it to get rebuilt Well here s where my...

I bought a namura top end kit and sent it to get rebuilt. Well here's where my hard earned money went. Guy never even used my parts and kept the ones I gave him. Has anyone ever had a piston melt.like this.

16 comments
  • Idk how and I don't have the tools to do it.

  • If I had to guess. I'd say you didn't jet it, started up a fresh motor, didn't let it warm up very long and ripped through the gears until you pegged in 6th down a long ass straight away.

    But I'm not a professional or anything. Just my blind guess.

  • No actually when I got it back I let it run for a week before I took it for an actual ride but I didn't ripp it untill my third ride. I ALWAYS let my motor warm up for almost ten min before I get on and ride. The guy who did my rebuild never mentioned jetting. So I didn't know it needed jetted. Another thing about jetting I don't get is. Everyone on here says you need to rejett. You get e new pipe -rejett, you get a new piston- rejett, buy a new set of reeds-rejett. How can you always be sure you have the right jetting for all of that?

  • It blew half way through 4th gear on my way home from the field I ride in.

  • A plug chop will confirm proper jetting. Not needed for a new piston. Port work, aftermarket pipe, Airbox modification etc. Basically anything that effects your AFR including weather and altitude.

    I said riding it without warming it up because of all the scratches on the side. That's normally a symptom. I think a lean condition will cause that too but don't quote me on that. Considering the edges of the piston are melted I'd say you were definitely lean.

    What mods are done to it and what size main jet?

    Did you perform a leak test after putting it together and retorque the head after initial heat cycles?

  • Idk what size jet it is. I don't know how to tell. I'm kinda new to rebuilding and I'm very serious on learning how these motors work and trouble shooting. So plz be nice to me for now.lol it has a full FMF gold series exhaust that's the only mod on the motor.

  • Lol no worries. I probably knew less than you when I started and I'm still learning. There are alot of helpful members here. Listen to them and you'll learn alot, save money and get full potential out of your machine.

    Would be easier to show you with pics. I can do that later when I'm home unless someone else has some handy.

  • Thank you man it means alot.

  • Air leak or jetting is off

    That's detonation that did that...

  • That is possibly what the little ticking sound was when it was ridden.

    The 2 strokes arch enemy, detonation......

  • The jets should have a number engraved into them

  • So that means I was running lean? Right.

  • Thinking I heard sounded like a dull one like my rod that is also moves like a gear shifter in your car now. It was nice and tight before it went in. I rode all day for twenty to thirty minutes each ride. Four rides over the course of the day. My last ride I was heading out of the field and once I got to third gear I could hear a sharp tick the would progressively get louder if I kept raising rpms. I let off the gas and stayed at a low rpm and the tic stopped. I got.to the street and made it to.fourth gear and it blew.

  • If you look close you'll see a number on it. Stock is 230.

  • Damn this sucks!

  • Yup