possible lead on optiosn for 250sx/es hi comp pistons.

[oscarmayer]

I have access to a friend's piston wharehouse and i will be going there sometime in the enxt 2 weeks and taking the 250sx piston with me to match up. He's a weisco WD. yea! and he has nearly every honda engine piston made. He also can cross-reference by size to see if something will fit and work correctly. I'm hoping that one of the honda civic motor pistons will work. the d15 was 74mm and the D16 was 75mm. stock for the 250sx/es was 74mm, so if the 75mm demsions fit and will work, then we can use that and they have all the way up to 15:1 comp pistons!

anyway, I'll post up what i find out.

[oscarmayer]

update!!!!:
ok so far it looks like "MAYBE" the 88 honda TRX300 2Valve piston will work! it's 74mm. the piston measurements appear to be nearly identical and weisco has them in anything from std to 2mm over bore sizes! it's 10.25:1 compression (thin cometic HG will bump it to 10.65-10.75:1 compression)

this may be the best bet! I'm considering ordering one and testing it out. if it works, we are in good shape!!!!!

my only concern is the piston pin size. the 300 has a 17mm pin. what size does the 250sx have? I need to measure it to be certain it will it. Also i suspect one coudl get a 300trx rod, piston, jug and make a stroked 250sx by the looks of it.

[oscarmayer]

I'm needing someone who knows about these but i'm seriously considering a trx300 rod and piston and jug setup for my 250sx. if i swap out I not only get a 300cc setup, but I also have access to tons of parts!!!!!! not to mention it will be WAY cheaper than trying to get a trx300 engine ($600+ on egay right now)

[honda250sx]

Wont work!

Been there done that.

Bore is the same. Stroke is different.

[honda250sx]

I have three original rocky atv high comp piston kits forsale. a 2mm over bore is in the classifieds.

[oscarmayer]

i wants! gotta try to find that post.

[oscarmayer]

ok good news!!!! here;s what I found. I ordered a 300trx 2v piston. its 65mm as well. the piston will fit and work for the 250es/sx, but it iwll be much lower compression. the distance from the piston pin to the top of the piston is shorter than the stocker 250sx/ex, now good news is, we can alwaus look at the weiso 12:1 pistons and probelby get around 10:1 out of it. there's roughtly about 1-2mm heigth difference. wait! hrmmm turbo, nirtrous setup anyone? :lol: