any ideas on why this piston failed catastrophically?

[N8tsNastyBlasty]

the main windows have been raised lowered and widened not sure how much? I just worked on it until i was sick of it.Im not really into safe, im into fast. We all know you can push somethings' beyond they're designed limits for awhile.I just like to stay on that edge of disaster and bad ass!! my last build would stand up in every gear sometimes! i currently have less than $300 in this one.

 

[N8tsNastyBlasty]

I never knew the luxury of this forum and im getting a crash course on do and dont's this is way better than trial and error. I have 2 more jugs to work on and another quad to assemble. port timing of the exhaust / triple ports has been determined to be 192.5-194* at the most (by myself with a printed degree wheel) transfer between 128-130* the intake windows im not sure of but it was like a light switch powerband. on or off

 

[N8tsNastyBlasty]

don't know the clearance but its gettin dropped of tomorrow to the mid america powersports for the fresh bore/ piston. wich im fighting the urge to modify slightly...

 

[brandoz28]

i would back down that exhaust timing and it should broaden that out a bit

 

[hudack]

if you widen and raised the ports to much couldnt you hurt the power???? and i would just leave the pistion alone theres a reason noone realy has them modified

 

[N8tsNastyBlasty]

when i ported it i did it at 192*exhaust and 126* transfers but that was with vito super thin metal base gasket. when i double checked port timing on my mock up /bench motor it was with a paper gasket which raised my ports ever so slightly. i did a leak down test with the metal base gasket glued in and it held pressure and didnt bubble with soapy water at the seems. everyone on here says vito's gaskets suck balls and i noticed that my high comp p.o.s. head gasket had oil out side the bolt hole but only after i disassembled it.

 

[hudack]

i used one of them super thin vitos bases gaskets and awk as my whitness it leaked the hole way around the base of the cylinder thats why i dont use vitos gaskets....

 

[N8tsNastyBlasty]

ive read that an intake with too much area will lack velocity and impare bottom end torque and even be rev lazy. this engine ran pretty quick and it would lug around in the bottom of the gears fine but when i cracked the throttle it went wild! I have know idea on how much area is the sweetest for a 200cc ported blaster but if u want bigger hp i know it will be at the top of the rpm band. 125c dirt bikes have always had bigger hp and lower torque than a blaster something tells me the difference is in port work induction and exhaust not displacement. i ride dunes and drag race buddies. i want it to rev to 9-10k if i can. i wont ever ride it all out for more than 20mins without sittm on top a dune and chillin.

 

[N8tsNastyBlasty]

that's what i heard after spending $50 on 2 sets of high comp head and base gaskets. . . . .FML!!!!!!!!!!!!!

 

[StrokedTater244]

you have the right idea thats for sure... the intake windows i wouldnt widen alot but can be both raised and lowered about 2mm.. you can open that upper/center port a good deal also. what are you doing with the heads on these setups? your going to loose a great deal of power with stock heads on these ported jugs. also timing, pipe and carb choice are playing huge factors. are considering the ex port shape and transfer angle at all?

 

[Larry's Shee]

Going to the edge is ok if you are willing to pay the price. You're lucky you didn't destroy more than the piston. The higher the desired output, the tighter the tolerances need to be kept. IE, if spec says bore at .05 , an all out motor might need a piston at .04 (just random example numbers). Gotta pay to play. Aparently the light switch powerband is ok for how and where you ride.

 

[Blaner]

I ordered a new piston as soon as i had low comp.I wouldn't call it half assing it by using a brand new piston and doing all of my own work. the bore still looks really good or i wouldn't have ran it. i picked all of this up in a packaged deal for next to nothing. On the second note Ive ran 2 others with great success that where ported piston motors and ive seen other builds that had them opened up. I agree i went a lil too far. I'll be the first to admit in a novice but ,at least im not scared to try.

Well at least you know not to use holesaws on your piston skirt again!

 

[N8tsNastyBlasty]

well Ive acquired a set of bore gauges and am going to check the bores on the three jugs i have. they a coincidentally much cheaper than blowing up pistons on a regular basis and now i can check all kinds of i.d.'s lol.

 

[sicivicdude]

Tools to keep it together usually are cheaper than blowing it to pieces repeatedly.

Good call on the bore guages, they'll come in handy for bunches of engine related projects.