Piston Compression Question.

[jasonanderson1]

if i got a 14:1 compression race piston around what cc would it be at about? Like if i get one thats that big seem them around.

[Miami_Vice454]

well they can be at alot of different sizes. compression will not change CCs.

[400exrider707]

Are you talking physical engine size in CC's or actual dome size?

Motor size doesn't change.

You have a 400ex I'm guessing... dont think I've seen anyting in 14:1 range for a 400ex. You'd need a lot of supporting mods for higher compression on a 400ex.

[jasonanderson1]

Originally posted by 400exrider707
Are you talking physical engine size in CC's or actual dome size?

Motor size doesn't change.

You have a 400ex I'm guessing... dont think I've seen anyting in 14:1 range for a 400ex. You'd need a lot of supporting mods for higher compression on a 400ex.

the actual done, and what kinda of power gains would i see from a 14:1 piston?

[Miami_Vice454]

well you would see a noticeable gain but i wouldnt buy that becasue you would have to run 100% race gas and you would also need to install HD studs and probably a HD rod. i wouldnt do that. just bore it out and you will see more gains. 87mm

[bkelley]

14:1? That's ridiculous for a little 400EX motor.

[jasonanderson1]

Originally posted by bkelley
14:1? That's ridiculous for a little 400EX motor.

They sell it so im jsut wondering how much more power it would be kinda sick.

[honda400ex2003]

unfortunately the highest i found was 13:1 and that would require 110 race gas and possibly a better crank, for sure hd studs. It would rip though with a nice stage 2 in it no matter the bore size. i only found 13:1 JE with a 426cc bore also so this would be your only option for 13:1. 12:1 is available in85, 87, and 89 though so you could get a stock bore piston with 12:1 run 93/110 mix about 30/70 %. this would be a very nice addition to the hundy. you may have some heat issues but it should be minimal on a 85mm piston. you would have to give it a hone and you could put it in with little effort. need a top end gasket kit, stage 2 cam is recommended and a piston. steve

[F-16Guy]

I think you're probably confusing it with a 450R piston. If you could install a 14:1 piston in the EX, it would snap the stock connecting rod in pretty short order. Back in the day, people were breaking conrods with 12.5:1 CRs. Now if you did HD studs and installed a Carrillo rod, you could potentially run 14:1, but it would be on straight race fuel, and I'm guessing you'd have cooling issues. You might be able to do it, but it won't be anywhere close to a simple piston swap if you want it to live.

[jasonanderson1]

Originally posted by F-16Guy
I think you're probably confusing it with a 450R piston. If you could install a 14:1 piston in the EX, it would snap the stock connecting rod in pretty short order. Back in the day, people were breaking conrods with 12.5:1 CRs. Now if you did HD studs and installed a Carrillo rod, you could potentially run 14:1, but it would be on straight race fuel, and I'm guessing you'd have cooling issues. You might be able to do it, but it won't be anywhere close to a simple piston swap if you want it to live.

Thats true im just wondering, because i have an 01 400ex motor in my garage that needs a rebuild and im either guna rebuild it or sell it? So im trying to see if i rebuild it how sick i could make it and how much power i could get out of it.

[honda400ex2003]

high comp 440 stroker with 12.5:1 piston, carillo rod or hot rods rod for the stroker, stage 3 hotcam 110 octane. it would rip really nicely with that in it in my opinion. if i was going to go all out that is what it would be. or i suppose maybe a 460 would be nice too. lol steve

[jasonanderson1]

Originally posted by honda400ex2003
high comp 440 stroker with 12.5:1 piston, carillo rod or hot rods rod for the stroker, stage 3 hotcam 110 octane. it would rip really nicely with that in it in my opinion. if i was going to go all out that is what it would be. or i suppose maybe a 460 would be nice too. lol steve

Ok thanx il look into that. IM just looking for w.e will get me the most power possible idc if i have to run 100% race fuel and get a larger oil cooler or a SPAL.

[honda400ex2003]

all three would be really nice to have for cooling and such, but 110 is a neccessity for 12.5:1. I would do a spal fan first then go with a bigger cooler next, if those dont work then do a bigger tank also. steve

[jasonanderson1]

Originally posted by honda400ex2003
all three would be really nice to have for cooling and such, but 110 is a neccessity for 12.5:1. I would do a spal fan first then go with a bigger cooler next, if those dont work then do a bigger tank also. steve

Ok yea i just gota figure all this out i just have to see howmuch its guna be and everything.

[honda400ex2003]

piston is right around 180 for most kits (426), the rod is another couple of hundred at least depending on the rod you get you have to get the matching piston to go with it(i am not sure off hand which but believe it is the hotrods one) (+4 stroke to get to 440), cam is 180 (stage 3), bore 50-70, port and polish is about 100-150 depending, install of the rod and such can be done by you if you are pretty mechanical. the top is easy but the bottom can be a bit tougher, gaskets are around 70 for a full kit of cometic, new cam chain is about 50, valve seals can be included in the right gasket kit, i would suggest a hinson clutch for the added power delivery around 150, jets are around 30 for most of the ones you could possibly need, also the GT thunder studs 150 for everything with install and such, otherwise you can get a 450r carb for right around 150 for everything. I would suggest a full exhaust to go with the stroker to let it breath the best it can and match the port and polish 400 depending. With all of that you would have a very nice machine that would run great. some of the prices may be a bit off but will get you in the ball park for the setup you would need. steve

[jasonanderson1]

Originally posted by honda400ex2003
piston is right around 180 for most kits (426), the rod is another couple of hundred at least depending on the rod you get you have to get the matching piston to go with it(i am not sure off hand which but believe it is the hotrods one) (+4 stroke to get to 440), cam is 180 (stage 3), bore 50-70, port and polish is about 100-150 depending, install of the rod and such can be done by you if you are pretty mechanical. the top is easy but the bottom can be a bit tougher, gaskets are around 70 for a full kit of cometic, new cam chain is about 50, valve seals can be included in the right gasket kit, i would suggest a hinson clutch for the added power delivery around 150, jets are around 30 for most of the ones you could possibly need, also the GT thunder studs 150 for everything with install and such, otherwise you can get a 450r carb for right around 150 for everything. I would suggest a full exhaust to go with the stroker to let it breath the best it can and match the port and polish 400 depending. With all of that you would have a very nice machine that would run great. some of the prices may be a bit off but will get you in the ball park for the setup you would need. steve

thanx alot bro. il look further into it, where could i have the [port and polish done and what exactly do they do?

[honda400ex2003]

any motor shop could do it, some do more than others depending on what you want done. you can get different types of port and polishes also for mx drag and such. they take parts of the ports out and clean them up then smooth the exhaust side out a bit. this helps to make the head flow better. this is a pretty low end explanation but gets the point across i guess. i had mine done by the same shop that did my bore for me, they also did my valve seals and did a valve lap too while it was apart to make sure the head was good to go for sure. steve

[honda400ex2003]

also you should try to get that sig shortened up a bit lol. it is getting pretty long with all of the wish list stuff. you gotta start buying stuff for the 400 lol. steve

[jasonanderson1]

Originally posted by honda400ex2003
also you should try to get that sig shortened up a bit lol. it is getting pretty long with all of the wish list stuff. you gotta start buying stuff for the 400 lol. steve

ea i no what yu meanil shorten that right now...maybe il get a port and polish for my current 400 too il ahve to see. thanks tho.

[honda400ex2003]

i was just kidding lol. but if you want to shorten it that is good too. lol. steve

[jasonanderson1]

Originally posted by honda400ex2003
i was just kidding lol. but if you want to shorten it that is good too. lol. steve

yea maybe i dont feel like it tho, what is a port and polish exactly?

[jasonanderson1]

Originally posted by honda400ex2003
i was just kidding lol. but if you want to shorten it that is good too. lol. steve

yea maybe i dont feel like it tho, what is a port and polish exactly?

[honda400ex2003]

any motor shop could do it, some do more than others depending on what you want done. you can get different types of port and polishes also for mx drag and such. they take parts of the ports out and clean them up then smooth the exhaust side out a bit. this helps to make the head flow better. this is a pretty low end explanation but gets the point across i guess. i had mine done by the same shop that did my bore for me, they also did my valve seals and did a valve lap too while it was apart to make sure the head was good to go for sure.

steve

[jasonanderson1]

Originally posted by honda400ex2003
any motor shop could do it, some do more than others depending on what you want done. you can get different types of port and polishes also for mx drag and such. they take parts of the ports out and clean them up then smooth the exhaust side out a bit. this helps to make the head flow better. this is a pretty low end explanation but gets the point across i guess. i had mine done by the same shop that did my bore for me, they also did my valve seals and did a valve lap too while it was apart to make sure the head was good to go for sure.

steve

oh thanks, wat kinda power would i get from this?

[honda400ex2003]

I am not too sure, it depends on what else you do to the machine. i would guess maybe a couple of horse on the machine without a full exhaust or something. maybe 3 or 4 on a fully built motor. steve