how to gain power?

[Andrew170-440ex]

I have a 1999 400ex with the following mods to the engine;
440 big bore
hot rod crank
namura piston
hot cam stage 2
valve and head work
head studs
outerwears pre-filter cover
k and n filter
t4 exhuast
im runnin a 195 jet on regular gas with klotz octane booster... how do i gain more power?
remind me if you need to know anything else i probably forgot something...

[crownandmonster]

Buy a bigger bike. 400ex's are a blast to ride and can be quite a handful when you grab the throttle, but lets be honest the little air cooled engine can only give you so much. Buy a 450 if you want more.

[togup]

you didnt mention your piston comp ratio so the best bang for your buck is a high comp piston

[gasguzzler]

What carb do you have?

[atvrider13]

A bigger carb, if you have the stocker on there. A 04 05 trx450r carb gives a tremendous gain over stock and a fcr makes even more power!!! I would suggest running at least half race gas in with your regular even if you have 11 to 1 compression.

[slightlybent47]

You shouldn’t be concentrating on how fast your bike is!
You should be concentrating on how well you can ride it!

If you ride fast tracks then get a 450.
If the tracks are technical then just keep er’ pined!

[Andrew170-440ex]

half race gas? wouldnt i have to jet it to those specs then..?i mean i got power untill 4th 0r 5th then i lose it and it takes a while to get up to those higher rpms..i shift up to 5th and its just boggy..and after i let off the accelerator and press it all the way down it just boggs down..i have the regular carb and lower compression cuz i had trouble with head gaskets..

[Andrew170-440ex]

its probably what the normal compression is for a 440...idk i had it all done professionaly.

[atvrider13]

Originally posted by Andrew170-440ex
half race gas? wouldnt i have to jet it to those specs then..?i mean i got power untill 4th 0r 5th then i lose it and it takes a while to get up to those higher rpms..i shift up to 5th and its just boggy..and after i let off the accelerator and press it all the way down it just boggs down..i have the regular carb and lower compression cuz i had trouble with head gaskets.. Yes if you run race gas you can run it a lil leaner because the race gas helps keep it cool. If you got a bigger carb it wouldnt be boggy on the top end at all.

[crownandmonster]

The lead in race gas has some lubricating properties and helps it run slightly cooler, however you shouldn't change jet sizes if you switch to race gas. Race gas might make it run a tad cooler, but its not going to stop it from burning a hole in the top of the piston from being too lean.

If you are getting a boggy condition under full load it leads me to believe your jetting is probably the culprit. Jet it correctly and you will probably free up a little HP.

[Andrew170-440ex]

its jetted correctly..it just bogs in low end when you hit it in low end it bogs..in top end i can climb the highest dune in 4th with out losing any power.top end is good. so should i try race gas with the jet i have in it?

[crownandmonster]

There should be no bog anywhere in the rpm range. Your jetting is either slightly off or the carb could be slightly plugged somewhere. If you aren't running high compression there is no reason to run race gas. Race gas won't give you any more power.

[CJM]

Well for starters im sorry to say but namura pistons are trash, you could be losing compression-Ive seen them literally melt. Its b/c they are cast, not forged.

As for why you have a bog, your to rich, drop down to a 190 and see what happens.

[Andrew170-440ex]

i tried a 180 and a 190 and both were that same way.....it only does it at like a certain temp. right when the engine is cold it doesnt do it then when it gets warmed up it does it agian..than after a while it goes away..like when it is super hot it runs better...its wierd.

[CJM]

And your checking the plug after the jetting changes as well-it was golden brownish or chocolate colored? your bog is jet related, what size pilot do you have?

What grade of fuel are you running?

[hondarider421]

i agree its deff jett related id say check fuel screw also but depends where bogging is and i advies with that work getting a bigger carb would increase power and rev limits but u still have to jet it correctly too and keep in mind the spark plug check is mainly good after running wide open in gears then killing instantly or thats wat i understand

[400exshop]

that junk pistion can be letting compression by when it get's hot........change pistion then go from there ( . ) i put one in a xr100 and with in 3 day's it was out of there put a wiseco in and did not change a thing and ran great just from that ( pos ) pistion.

[Thumpin440ex]

Originally posted by 400exshop
that junk pistion can be letting compression by when it get's hot........change pistion then go from there ( . ) i put one in a xr100 and with in 3 day's it was out of there put a wiseco in and did not change a thing and ran great just from that ( pos ) pistion.

This is bogus.. No need to swap pistons out before you check to see that jetting is correct.. If anything the piston will grow under heat. If it is not smoking or blowing oil out the pipe then rings and gap would seem to be fine hense eliminating a bad piston.. Get the jetting down, before you route to something like swapping the piston out... Seems like the pilot, poss AF screw might need to be tweaked some..

John

[slightlybent47]

Originally posted by crownandmonster
The lead in race gas has some lubricating properties and helps it run slightly cooler, however you shouldn't change jet sizes if you switch to race gas. Race gas might make it run a tad cooler, but its not going to stop it from burning a hole in the top of the piston from being too lean.

If you are getting a boggy condition under full load it leads me to believe your jetting is probably the culprit. Jet it correctly and you will probably free up a little HP.

Not all race gas is leaded!

[SandRiper]

you can buy a new igniton too, dynateck do a good one, unlock your rpm and increase sparks

[crownandmonster]

Originally posted by slightlybent47
Not all race gas is leaded!



Which brands aren't?

I live in a pretty rural area and the only thing sold around here above the usual 91-93 pump gas is 112 sunoco and its leaded. You gotta go to the track to get it though.

[hondarider421]

I run vp 110 in my race bike and c12 in my drag bike both are leaded

[powerbomb400]

They make a unleaded race gas. I don't think its as good myself. You could mix 50% 93 and 50% 112 and it would run good. The octane prevents predenoatnation. We run it in all our quads. The problem is in your jetting. We built a 250ex and it took awhile to get the jetting right after putting a 26mm carb. on it. It did the same thing but it was at idle to 1/3 throttle and I dropped needle one notch and it solved the problem. It was getting to much gas and it was taking a second to get the air in. Getting the jetting right is alittle hit and miss. Almost make you pull your hair out. The thing you have to watch is not to get too lean.

[400exrip]

Running a good synthetic oil can also make a difference on the 400ex, I mean you are not going to notice it that much as far as HP, but it will make the motor last longer and run better. and longer lasting compression out of your piston because of the good seal in between the piston rings.

[Thumpin440ex]

Originally posted by 400exrip
Running a good synthetic oil can also make a difference on the 400ex, I mean you are not going to notice it that much as far as HP, but it will make the motor last longer and run better. and longer lasting compression out of your piston because of the good seal in between the piston rings.


You change the oil when it is supposed to be changed, it will last just as long


John

[CJM]

Never had an issue with shell rotella ever, its a conventional oil btw.

I change it every 20-30 hours so for me thats like 3-5 rides.

[hondarider421]

I run klotz but thats in my race bike

[slightlybent47]

Originally posted by 400exrip
Running a good synthetic oil can also make a difference on the 400ex, I mean you are not going to notice it that much as far as HP, but it will make the motor last longer and run better. and longer lasting compression out of your piston because of the good seal in between the piston rings.

CJM I’m surprised you didn’t catch this one!lol
Running synthetic oil in an ex is a no….no!
Synthetic oil will make the clutch slip.

And there’s no one on the planet that is a good enough rider to feel the deference in power with changing or using any oil.lol Thanks that made my day!!!

[CJM]

Originally posted by slightlybent47
CJM I’m surprised you didn’t catch this one!lol
Running synthetic oil in an ex is a no….no!
Synthetic oil will make the clutch slip.

And there’s no one on the planet that is a good enough rider to feel the deference in power with changing or using any oil.lol Thanks that made my day!!!

Hey I dont see EVERYTHING lol bent.

The only syn oil I know that you can run in these things thats off the shelf is mobil 1 15w-50, its safe for wet clutches. Im almost positive nothing off the shelf besides honda oil is otherwise.

[hondarider421]

I run klotz but its made for raceing engines iv never had a prob with my clutches on either bike my 460ex or my 450r and i dispise honda oil ir rather run knock off car oil its cheaper and the same thing

[CJM]

Originally posted by hondarider421
I run klotz but its made for raceing engines iv never had a prob with my clutches on either bike my 460ex or my 450r and i dispise honda oil ir rather run knock off car oil its cheaper and the same thing

Thats the difference, its made for wet clutches. But like I said-most off the shelf stuff is not.

[hondarider421]

I see guess thats y the **** is 10 bucks too lol my bad man

[CJM]

Originally posted by hondarider421
I see guess thats y the **** is 10 bucks too lol my bad man

Bingo.

Honestly the only thing I would ever run an oil that $$$ in is a 2 stroke that was worked. klotz makes EXCELLENT 2 stroke oil. If the EX didnt have a wet clutch system Id run mobil 1 as its only 6/qt at walmart. Hell with paying 10/qt or more.