compression ? i searched

[tnine416]

I did a search and could not find any answers to this question...
I plan on running some xc races this year and I want my engine to run cool and be reliable without any worries. Will sparks JE 12:5:1 piston(416) run to hot, or should I just run 11:1(416) and mix race gas and 93? also, how much hp will the 12:5:1 piston yeild over the 11:1?

[chad502ex]

Originally posted by tnine416
I did a search and could not find any answers to this question...
I plan on running some xc races this year and I want my engine to run cool and be reliable without any worries. Will sparks JE 12:5:1 piston(416) run to hot, or should I just run 11:1(416) and mix race gas and 93? also, how much hp will the 12:5:1 piston yeild over the 11:1?

If I were you I would run 11:1 to keep the motor temp down; unless, you plan to run an external oil cooler.

11:1 to 12:1 is a 3% gain in hp

you can read all about it at,...

http://www.chad502ex.com/measuring_head.htm

hope this helps

chad502ex.com

[cals400ex]

Originally posted by chad502ex
If I were you I would run 11:1 to keep the motor temp down; unless, you plan to run an external oil cooler.

11:1 to 12:1 is a 3% gain in hp

you can read all about it at,...

http://www.chad502ex.com/measuring_head.htm

hope this helps

chad502ex.com


how much power do you gain by for example boring a bike .080 over? well, lets say if i was to run the same compression, 11:1 on a stock bore vs .080 over. how much will that add?

[chad502ex]

Originally posted by cals400ex
how much power do you gain by for example boring a bike .080 over? well, lets say if i was to run the same compression, 11:1 on a stock bore vs .080 over. how much will that add?

no replacement for displacement.

I've built an 0.080 over that dyno'd 42hp!

3% gain from stock 27 is about only 28

hmmm, 42 vs. 28

understand?

hope this helps.

chad502ex.com

[cals400ex]

Originally posted by chad502ex
no replacement for displacement.

I've built an 0.080 over that dyno'd 42hp!

3% gain from stock 27 is about only 28

hmmm, 42 vs. 28

understand?

hope this helps.

chad502ex.com


i am assuming everything else on the bike is the same besides the stock bore vs the .080 over like cam, jetting, etc?

Originally posted by cals400ex
i am assuming everything else on the bike is the same besides the stock bore vs the .080 over like cam, jetting, etc?

uh...are you kidding lol...42 hp out of a 416 and all u think he has done to that is boring and a piston?...no way...he will have porting, carb, cam, and many other things to get that much hp out of a 416...if boring really made that much of a difference i think i would be running a 502 with chad :D ...now as for stroking...that is a totally different story

[cals400ex]

sorry i didn't explain myself. it is only common sense that there is not that much difference in the two bikes if they were identical. i meant to ask how much difference would there be in the two bikes if everything was identical besides the two pistons sizes?

[Martin Blair]

to get 42 out of a 416 you ahve to have some extra extra parts. I imagine it had more done then the stock one with a hi compresion pisont if you where to compltly build the stock motor with 11:1 you could probably get some good hp #s

[muff]

you also have to realize when you run 12:1 compression and up you have to worry about the stock rod holding :(

if i were you i'd go with the 11:1 416cc bore and a hotcam stage 2, then pick up a fcr39mm carb and a good exhaust and you'll have some noticably different power there :cool:

[tnine416]

Originally posted by muff
you also have to realize when you run 12:1 compression and up you have to worry about the stock rod holding :(

if i were you i'd go with the 11:1 416cc bore and a hotcam stage 2, then pick up a fcr39mm carb and a good exhaust and you'll have some noticably different power there :cool:

good point, never even thought about the rod...if I got 3 angle valve job done, would that make a noticable difference.

So what kind of hp are we lookin at here with 11:1 JE piston, .80 over, 3angle valve job ,hotcams stage 2, sparks exhaust, 39mm fcr?

[chad502ex]

Originally posted by tnine416
good point, never even thought about the rod...if I got 3 angle valve job done, would that make a noticable difference.

So what kind of hp are we lookin at here with 11:1 JE piston, .80 over, 3angle valve job ,hotcams stage 2, sparks exhaust, 39mm fcr?

I'd say with the setup mentioned above you should hit 42hp or so, but definitely low 40's. I've seen many 416's kick 440 up and down the track because the 416 piston mass is alot lighter than the heavy arse 440 slug (piston). If I were building a new 400ex motor, I'd be building a 416 all the way. Like, a 80 over 11:1 JE with heavy port/flow 3 or 5 angle valve job, cam, X-4, and 41mm fcr.

cal, stock bore 9.1:1 piston vs 10:1 stock piston would give you a 3% gain in power, with every other mod same too!!

Hope this helps.

Chad502ex.com

[tnine416]

lol..the slug:p

thats a informative website you got there chad502

will I need an oil cooler?

[chad502ex]

Originally posted by tnine416
lol..the slug:p

thats a informative website you got there chad502

will I need an oil cooler?

Thanks tnine416, I appreciate your comments good about my website. I plan to really improve it spring time shortly after my next 550R project like boring/stroking, port/flow, cfm, calculate compression, and other topics will be posted to help others get a sense of building a thumper from start to finish.

As far as needing a oil cooler, I recommend it. There are a lot of threads here on exriders.com that talk about oil coolers. HEH, some are even closed cause of the heated debating that took place about the topic. But these coolers do help reduce the top end temperature about 30-50 degrees- and that prevent fade.

Chad502EX.com

Originally posted by chad502ex
Thanks tnine416, I appreciate your comments good about my website. I plan to really improve it spring time shortly after my next 550R project like boring/stroking, port/flow, cfm, calculate compression, and other topics will be posted to help others get a sense of building a thumper from start to finish.

As far as needing a oil cooler, I recommend it. There are a lot of threads here on exriders.com that talk about oil coolers. HEH, some are even closed cause of the heated debating that took place about the topic. But these coolers do help reduce the top end temperature about 30-50 degrees- and that prevent fade.

Chad502EX.com

yep...i made 1 of the ones that is now closed...and i am still undecided

[cals400ex]

Originally posted by chad502ex
I'd say with the setup mentioned above you should hit 42hp or so, but definitely low 40's. I've seen many 416's kick 440 up and down the track because the 416 piston mass is alot lighter than the heavy arse 440 slug (piston). If I were building a new 400ex motor, I'd be building a 416 all the way. Like, a 80 over 11:1 JE with heavy port/flow 3 or 5 angle valve job, cam, X-4, and 41mm fcr.

cal, stock bore 9.1:1 piston vs 10:1 stock piston would give you a 3% gain in power, with every other mod same too!!

Hope this helps.

Chad502ex.com


why would you run an x-4 on that kind of motor with an fcr 41?

[chad502ex]

Originally posted by cals400ex
why would you run an x-4 on that kind of motor with an fcr 41?

x-4 provides bottom end power, fcr41 gives lots of fuel for top end.

If you get over 440, then go with x6 with reverse megaphone and fcr for top end, and the mere bore for bottom end grunt.

chad

[tnine416]

what about a 39mm? get an x6?

[chad502ex]

If I were to buy a carb I'd make sure its over 40mm. I mean,... a 39mm fcr almost has the same bore as a stock carb, same accelerator pump. Only diff, in my opinion is slide,... bfd. If you paying all that money you might as well get a 40mm or bigger carb.

this is just my opinion, and everyone has them,...


The X6 is for BIG BORES/STROKER MOTORS and really dont perform as good as a x4 on a 440 or less.

chad502ex.com

[tnine416]

I thought stock was 36mm? I am not 100% tho...

Originally posted by tnine416
I thought stock was 36mm? I am not 100% tho...

ya its 35.5...and if the 2 carbs are so similar chad...y does a 38mm stock carb only flow like a 36?:huh

[chad502ex]

flow bench them and find out why!

All I'm saying is that I would get a 41mm FCR if I had anything over 440cc

chad

Originally posted by chad502ex
flow bench them and find out why!

All I'm saying is that I would get a 41mm FCR if I had anything over 440cc

chad

ooooo...i thought u meant if u had any 400 and u were gonna buy a carb it would be a fcr 41...in that case...i agree with u 100% nething over a 440cc should have a 41 fcr carb if you were buyin a carb

[tnine416]

so a 39mm would be ideal for a 416? or is the 41mm

Originally posted by tnine416
so a 39mm would be ideal for a 416? or is the 41mm

39 for the 416 unless u want a drag racing 416 with only top end power