BlksnshN Posted August 3, 2013 Report Share Posted August 3, 2013 I've only owned my Banshee for a little over a month and have only ridden it around my yard and a couple of blasts down the road. I bought it as a 4mm stroker with no port work. It was running great but I just felt like I was leaving too many HP on the table by not having it ported. So, I decided to tear the engine down and send the cylinders out to have a dune port and this is what I found, Multi-point seizure caused by only having about .001 clearance between the cylinders and the pistons. I went back in forth on if I wanted to tear it down now or wait til the winter to do the port work. I'm really glad I caved in to the pressure of more HP. While I'm not super happy about having to buy new pistons, If I would have rode that much longer, I could have wiped out the crank too. Quote Link to comment Share on other sites More sharing options...
dave5.0 Posted August 3, 2013 Report Share Posted August 3, 2013 Prob would have had to get it bored after the porting anyway. Quote Link to comment Share on other sites More sharing options...
Wildcardracing Posted August 3, 2013 Report Share Posted August 3, 2013 I port around fresh bores all the time. Probably plenty of meat in the cylinders to do a good hone on and correct the piston clearance. Good thing you caught it before any more damage. 1 Quote Link to comment Share on other sites More sharing options...
BlksnshN Posted August 3, 2013 Author Report Share Posted August 3, 2013 I port around fresh bores all the time. Probably plenty of meat in the cylinders to do a good hone on and correct the piston clearance. Good thing you caught it before any more damage. Yeah, there should be plenty of room for a good hone. I'm half tempted to just re ring these pistons as all the damage is cosmetic. Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted August 3, 2013 Report Share Posted August 3, 2013 I'm half tempted to just re ring these pistons as all the damage is cosmetic. Hell if your going to go that cheap I would just throw them back in as is and let them wear their own clearance. Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted August 3, 2013 Report Share Posted August 3, 2013 Hell if your going to go that cheap I would just throw them back in as is and let them wear their own clearance.YEAH!! Just add a little extra premix in, you'll be good on that! Saving money. Quote Link to comment Share on other sites More sharing options...
blowit Posted August 4, 2013 Report Share Posted August 4, 2013 Impressed you see you actually measured your engine to determine what was going on. However, that level of scuffing was leading me to look for "4 corners damage" or a tight engine which causes cold seizure. It is possible someone bored for stock cast pistons but Seizecos were installed. Forged pistons get funky with heat. You could possibly go back with good WSM or Namura pistons or hone a bit and run Seizecos. Nice job finding the cause before a rebuild! URCH: Hell no on reusing those pistons. One of the big things with pistons running on cast iron bores is oil retention. No oil grooves, no run. You WILL overheat them again and lose them. Start over on pistons, touch up the bores, and be happy. Brandon Mull Engineering Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted August 4, 2013 Report Share Posted August 4, 2013 Seizecos, huh....... That's funny Quote Link to comment Share on other sites More sharing options...
Zillaguy Posted August 4, 2013 Report Share Posted August 4, 2013 I have run Weisco's in every 2 stroke motor i have ever had, and not one problem since the mid 80's.... With the exception of My Maico engines which you can only get Mahle pistons for... The bore needs to be clearanced properly for a forged piston... They swell much more than a cast piston, i have always gone by the .0035 per inch of bore rule of thumb for clearance on a forged piston in a free air cylinder, or a little tighter on a liquid cooled cylinder... Quote Link to comment Share on other sites More sharing options...
98_shee Posted August 4, 2013 Report Share Posted August 4, 2013 What bore is it on? I have a set of pistons for a mill (795 series). Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
BlksnshN Posted August 4, 2013 Author Report Share Posted August 4, 2013 What bore is it on? I have a set of pistons for a mill (795 series). Sent from my iPhone using Tapatalk 65mm Quote Link to comment Share on other sites More sharing options...
98_shee Posted August 4, 2013 Report Share Posted August 4, 2013 I think mine are 64.50 Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
BlksnshN Posted August 4, 2013 Author Report Share Posted August 4, 2013 I think mine are 64.50 Sent from my iPhone using Tapatalk Too bad. Quote Link to comment Share on other sites More sharing options...
blowit Posted August 6, 2013 Report Share Posted August 6, 2013 I have run Weisco's in every 2 stroke motor i have ever had, and not one problem since the mid 80's.... With the exception of My Maico engines which you can only get Mahle pistons for... The bore needs to be clearanced properly for a forged piston... They swell much more than a cast piston, i have always gone by the .0035 per inch of bore rule of thumb for clearance on a forged piston in a free air cylinder, or a little tighter on a liquid cooled cylinder... Are you sure you are not confusing the ring clearance? Probably a small error but I did not want someone thinking of using 8-10 thou for clearance on a Banshee. She might slap a bit. Quote Link to comment Share on other sites More sharing options...
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