replacing pistons

[mrdude1400]

alright ... i bought a used 2002 honda 400ex and i had it about 3 weeks and then i realized the pistons and rings were burnt up so i am replacing them. i want to bore it over about 16 but my uncle said it is a waste of money and will make it less reliable...
can i bore it over 16 and have it still be just as reliable as before or is it a waste of money?
and will it actually make it any faster if i bore it?.... thanks!

[quadkrazy400ex]

i bored out my 400ex to a 416 w/ hotcam stage 2, other mods in signature...and ill tell you what it made a huge difference. i used to not be able to beat a raptor and now its no problem. boring it over and making sure you do everything right will help you alot.

as far as reliability, ive been told that going with a 416 kit is a pretty reliable thing to do, ive had no problems since i did it except for a little more engine heat.

i say go for it, just make sure to have a good manual and to do everything right.

[440exnacsracer]

i would reccomend just getting a je high compression piston. wiseco's arent worth the money, but a je 12:1 should be good. youll get alot of torque. you will also want to get the cylinder honed if you keep the stock bore.
Ben

[TRXRacer1]

Originally posted by 440exnacsracer
i would reccomend just getting a je high compression piston. wiseco's arent worth the money, but a je 12:1 should be good. youll get alot of torque. you will also want to get the cylinder honed if you keep the stock bore.
Ben
12:1 is okay but not as reliable as stock and your most likely not going to just be able to hone a burnt cylinder and put a piston back in it. The 416 is a great motor. You won't have to worry about reliability.

[Pappy]

Originally posted by 440exnacsracer
wiseco's arent worth the money, but a je 12:1 should be good.

i was under the impression that these companies were merged awhile back and that for all intensive purposes they are the same pistons now?

[DaleJrFan]

if you are going to have it bored, go all the way with the 426, that way if the sleeve cracks later,you still have room to go with the 440. but as i say that, i know several people that have 416 or 426 bores and both are very reliable. yes, there is some more heat, but these guys have had these mods for over 2 years and their original bores are still going strong. that is my winter project is a 426 mod with a stg 2.

[mrdude1400]

alright thanks everybody.
i almost have the entire top end apart now... just gotta take the pistons out and get it all fixed... thanks again!

[440exnacsracer]

i was under the impression that these companies were merged awhile back and that for all intensive purposes they are the same pistons now?


havent heard about that one pappy...not sure. i just know that all the je pistons ive had experience with produced alot more hp. for example, i had a wiseco in my 440ex and it was ok, but i replaced it with a je piston (same 12:1 compression) and got alot more power and torque, though the JE had a much larger dome. same thing happened with a friends warrior on stock bore. just my experience, but you could be right pappy:confused:

[foleyit]

Originally posted by Pappy
i was under the impression that these companies were merged awhile back and that for all intensive purposes they are the same pistons now?

In addition to what 400exsnacsrace said in the previous reply, I've heard that the rings themselves are different. Which may contribute to the overall performance between the two. I'm not sure about the 2 merging so you might be right there Pappy.

[cals400ex]

yeah, i think je and wiseco are still different but maybe owned by the same company. something like that. the pistons are still different. the wiseco's are flat tops. the wiseco's piston + piston pin weighs less than the je's too. however, the je's are a domed piston. the both have their advantages and disadvantages. with the flat tops, the flame travel accross the top of the piston is supposed to be better from what i hear. i still think the wiseco's compression ratios are wrong though. for this reason, i would go with the je. some builders recommend the wiseco still though. others recommend je and others say ross. i have a ross and i won't change unless i have a problem. by comparing the ross to je, they are very very similar in looks. i simply went with the ross because it is the lightest of the 3.

[mrdude1400]

ok i was takin the motor apart and i have the top half of the cylinder off and i got to the bottom half of it and there is one bolt that is stuck, the other three came out fine, but this one is stuck, and me and my dad have broke 3 sockets tryin to get it out and we cant think of anything else to do to get it out,... what can you do to get somethin like that out?

[quadkrazy400ex]

1 of the 4 bolts holding the jug on the case?

[dirtmomma]

Originally posted by cals400ex
yeah, i think je and wiseco are still different but maybe owned by the same company. something like that. the pistons are still different. the wiseco's are flat tops. the wiseco's piston + piston pin weighs less than the je's too. however, the je's are a domed piston. the both have their advantages and disadvantages. with the flat tops, the flame travel accross the top of the piston is supposed to be better from what i hear. i still think the wiseco's compression ratios are wrong though. for this reason, i would go with the je. some builders recommend the wiseco still though. others recommend je and others say ross. i have a ross and i won't change unless i have a problem. by comparing the ross to je, they are very very similar in looks. i simply went with the ross because it is the lightest of the 3.

WE have Wiseco high dome(high comp) pistons in all our quads??? Just wanted to mention that ;) not trying to start anything w/ ya Cal :)

[Johnny B]

.
ok i was takin the motor apart and i have the top half of the cylinder off and i got to the bottom half of it and there is one bolt that is stuck, the other three came out fine, but this one is stuck, and me and my dad have broke 3 sockets tryin to get it out and we cant think of anything else to do to get it out,... what can you do to get somethin like that out?

Heat it up with a torch it will come out then.

[cals400ex]

Originally posted by dirtmomma
WE have Wiseco high dome(high comp) pistons in all our quads??? Just wanted to mention that ;) not trying to start anything w/ ya Cal :)


thanks for the info. i have seen 406 and 440 pistons from wiseco and they were all flat tops. i have even read this before from other members. maybe i am wrong once again. :eek:

[mrdude1400]

the part of the cylinder still on the motor is the part with the piston actually in it... i am goin to try a different type of socket and if it doesn't work then i will try the torch thing. thanks