Honda Bros 400 Muffler and air Filter upgrade?

**bros400** · 16th December 2003, 21:23

Hey, i just got a honda bros 400 (also knowen as a honda nt 400). And its all stock standard. Im wondering what i can do to bosted its power output.

To start with i was thinking of puting a new muffler and air filter on it. What are your guys sudgestestions, and what kind of air filter / mufffler would you sugested?

Any other sugestions as to what i should do?

Any one elce had this bike and what have you done to it?

Thanks Daniel

**Redstar** · 16th December 2003, 22:27

Hey Mate I have no idea what you could do but all the hype about K&N filters and modified exhausts will do nothing if the 400 has a rev limiter fitted the first test is does it have a limiter?
if not chuck it on a dyno and find the start point PS (what is PS) A knats dick under a BHP then maybe if it has a restrictive can you can gain 5 ps with a new can and without major reporting thats it.
actually I no nothing I just wanted to have 200 posts

**Redstar** · 16th December 2003, 22:37

seriously now.. who know what PS means?
Pascals per second? he was some french dude who converted BHP to metric perhaps? any takers?

**Motu** · 17th December 2003, 07:37

PS is metric horsepower - they needed something to equate to the old HP,so they came up with that.Actualy with SI we are supposed to think in watts,but until everyone uses it,watts is what?

To get more ponies out of a 400? pipe,filter,one size up in jets and lift the needles a notch should allow it to achieve what little potential it has.It's the same bike as the Bros600,so finding a 600cc motor would be the best way to go.I have the same problem with my XT400...the supertrapp has helped,well,it sounds really fast now,but looking for an XT600 engine will boost power best.

**bros400** · 17th December 2003, 08:49

I have done some reading on the net and it sounds like the exsorsted is quite restrictive. They say just changeing the exsorsted can improve how frealy the engon revs and also mid range tourque.

BTW for those not familuer with the bros 400 its a v twin.

**merv** · 17th December 2003, 17:15

I've ridden with this guy a bit who has had a 400 Bros for a long time and it is no slug. I'm not sure if he ever had to modify it or derestrict it but the speed it goes he doesn't need to. If you want to talk about it give Motorcycle City a call in Lower Hutt at (04) 566 0729 and ask for Richard as he works there.

If you want to check out more photos have a browse around my website at http://bikemerv.topcities.com and follow the links through "Photos", "Road Rides" and then look through the pages.

**Hitcher** · 17th December 2003, 21:43

Originally Posted by Motu

PS is metric horsepower - they needed something to equate to the old HP,so they came up with that.Actualy with SI we are supposed to think in watts,but until everyone uses it,watts is what?

To get more ponies out of a 400? pipe,filter,one size up in jets and lift the needles a notch should allow it to achieve what little potential it has.It's the same bike as the Bros600,so finding a 600cc motor would be the best way to go.I have the same problem with my XT400...the supertrapp has helped,well,it sounds really fast now,but looking for an XT600 engine will boost power best.

I can swear by my Kerker (Supertrapp). I don't know how much power it adds but it sounds f'n gorgeous!!

**kiwibros** · 12th March 2009, 09:34

hey mate ive got a bros 650, and ive got k&n pods with stock carb and exhaust, it has made a small difference just by letting it breathe better, so id say that if you were to re-jet and free up the exhaust side you would be seeing a 5-10% power increase, im planning on it.

**bungbung** · 12th March 2009, 10:39

5 year old thread dredge!

**puddytat** · 12th March 2009, 10:54

Lift the needles......Bore lots of holes thru the top of the airbox, or cut the whole top of leaving the rim with the scewholes......get rid of snorkles on front of airbox.....if you want to save money on an exhaaust take a 12mm drill bit & drill about 8 evenly spaced holes thru the end of the pipe.....throw away rear shock & replace with an early '90s CBR 900 shock(using the original Bros spring tho for the correct rate), cut the tight 3 coils off the bottom of the fork springs & put in a piece of pvc plumbing pipe to get the right preload, go up to 15 weight oil in forks....try & get a 650 motor as it'll bolt straight in....sorted!! These are the cheap mods I did to my 650 & she flew!!!Such a shame they never kept developing them as they handle awesomely when sorted & way cooler than a SV.

www.hawkgt.com is da bible