Go Back   Horizons Unlimited - The HUBB > Technical, Bike forums > Honda Tech

Honda Tech Honda Tech Forum - For Questions specific and of interest to Honda riders only. Questions comparing which bike is best etc go in the "Which Bike" forum.
Contact Overland Solutions for all your custom modifications and setup for overland travel.

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 28 Feb 2008
Registered Users
Veteran HUBBer
 
Join Date: Sep 2005
Location: Wasatch Mnts, UT, USA
Posts: 245
Suggestions for improving performance

Hello,

I am trying to get better performance from my recently purchaced Honda nx 400 Falcon that I purchased in Santiago, Chile.

It seems to be lacking in power. I have a difficult time maintaining 100 kph except for on the flattest of terrain and it is a real pig when climbing (me 90 kilos, load 30-35 kilos). It feels more like a the 1978 xl 250I owned when I was a kid. The 1979 400 cc Kawasaki LTD I had would easily cruise at 75mph with two people


I am considering lowering the gearing by getting a smaller (1 tooth) front sprocket and am wondering what differnce I can expect this to make as far as overall performance. I am sorry to say that I do not know the size of the front-rear sprockets now so I hoping to get an idea ¨in general.¨ The bike is at the mechanics now, so I can´t run out and count the sproket size. I am having the valves and carb adjusted, but am assuming this will not make too much of a difference. Right now she is at about 5000 rpm at 60 kph. Fifth is only useable on the flats and I am down shifting on the slightest of inclines. She is also a little tall in the first gear for negotiating technical terrain with a load. Can anyone venture an educated guess at how much differnce a smaler front sproket might make? Should I consider two teeth lower?


What else I can do to get a reasonable performance level for a modern 400cc. Possibly K/N filter?

Sorry to be so vage but any info would be appreciated.

BTW, I have found out it´s sprokecks are 15t & 40t.
__________________
India Himal, 3mo,2x; Kazak/Krygyz/Tajik, 3 mo; Kashi-Lhasa, China 219! 6 wk; Nepal, 4 days/trekked 55; Santiago-Ushuia-Cusco, 7 mo; Peru, 3 mo; Chile-Medellin 3 mo; Medillin-Arica, 3 mo
Reply With Quote
  #2  
Old 28 Feb 2008
Guest2
Guest
 
Posts: n/a
Hi Neal,

I am not real familar witht he 400, I did have a 650 so I thought I would have a stab at the problem.

It looks to me that the gearing you have is wrong, 5000 rpm at 60 kph is about 12 KPH per 1000rpm and you shoud be nearer 18 KPH per 1000 rpm. I think the peak power is around 6500 rpm. At 5000 rpm you should be pulling around 90 kph.

The ratio you are running now 15 / 40 is 2.66 to 1.

1 tooth less is 2.86 to 1 about 7 % increase, 64.2KPH at 5000 rpm

Can you find out what the standard sprockets should be?

I maybe completly wrong about this.

Steve
Reply With Quote
  #3  
Old 28 Feb 2008
Registered Users
Veteran HUBBer
 
Join Date: Sep 2005
Location: Wasatch Mnts, UT, USA
Posts: 245
I could be wrong about the revs versus speed, but I am sure the stock sprokets are 15-40 and I am considering 14-40. It is also speced at 29 hp at honda chile.
__________________
India Himal, 3mo,2x; Kazak/Krygyz/Tajik, 3 mo; Kashi-Lhasa, China 219! 6 wk; Nepal, 4 days/trekked 55; Santiago-Ushuia-Cusco, 7 mo; Peru, 3 mo; Chile-Medellin 3 mo; Medillin-Arica, 3 mo
Reply With Quote
  #4  
Old 28 Feb 2008
mollydog's Avatar
Registered Users
Veteran HUBBer
 
Join Date: Aug 2003
Location: california
Posts: 2,261
It could climb any trail .... in 3rd gear! A ton of power.

Good luck,

Last edited by mollydog; 24 Mar 2009 at 20:28.
Reply With Quote
  #5  
Old 28 Feb 2008
Registered Users
Veteran HUBBer
 
Join Date: Apr 2006
Location: Staffordshire. uk
Posts: 776
Has it suddenly got worse? Maybe some crap fuel or damage to the exhaust. You don't say what altitude you're riding at, that will have an effect too. What happens if you pull the choke out a bit does it get better? Also check the rubber between the carb and the inlet manifold. If it's cracked there could be air getting in and making it run lean. I'm sorry if you've tried all of these already but I'm thinking aloud. Good luck, nothing worse than a lack of power!
Reply With Quote
  #6  
Old 28 Feb 2008
mollydog's Avatar
Registered Users
Veteran HUBBer
 
Join Date: Aug 2003
Location: california
Posts: 2,261
I like the idea of an air leak.

Last edited by mollydog; 24 Mar 2009 at 20:28.
Reply With Quote
  #7  
Old 29 Feb 2008
Guest2
Guest
 
Posts: n/a
Quote:
Originally Posted by glasswave View Post
I could be wrong about the revs versus speed, but I am sure the stock sprokets are 15-40 and I am considering 14-40. It is also speced at 29 hp at honda chile.
If the sprockets are correct and I guess it red lines at 8500 or so, it will have a top speed of around 100 KPH.
if it will not red line in 5th will it in 3rd or 4th if so the smaller sprocket may help but you could end working the engine harder.

Patrick may have a point about the timing not advancing.

But even with all the Bolt on tuning goodies you will strugle to add more than a few extra BHP.

if it is remains the same after the service, you may have to accept it is what it is.

What sort of fuel consumption are you getting?

Steve
Reply With Quote
  #8  
Old 29 Feb 2008
Registered Users
Veteran HUBBer
 
Join Date: Sep 2005
Location: Wasatch Mnts, UT, USA
Posts: 245
Quote:
Originally Posted by mollydog View Post
I don't believe gearing is the main problem. This bike is not right from the sound of it. Is the NX a Single or a Twin.
The nx4 falcon is based on the xr400 motor. The specs are here¨--

Honda

After a valve and carb adjustment, the bike feels much stronger, though I haven´t had it out of the city yet. I will go for a test ride (loaded) today, but still think I may want to lower the front sproket tooth. It seems a little tall in first gear for riding techincal terrain and I will likely gain access to more up the upper powerband when loaded.

I will check out what I can do with the airbox.

Thanks
__________________
India Himal, 3mo,2x; Kazak/Krygyz/Tajik, 3 mo; Kashi-Lhasa, China 219! 6 wk; Nepal, 4 days/trekked 55; Santiago-Ushuia-Cusco, 7 mo; Peru, 3 mo; Chile-Medellin 3 mo; Medillin-Arica, 3 mo
Reply With Quote
  #9  
Old 29 Feb 2008
mollydog's Avatar
Registered Users
Veteran HUBBer
 
Join Date: Aug 2003
Location: california
Posts: 2,261
Removing the snorkle in most cases will be only getting HALF THROTTLE.

Last edited by mollydog; 24 Mar 2009 at 20:29.
Reply With Quote
  #10  
Old 29 Feb 2008
Registered Users
Veteran HUBBer
 
Join Date: Sep 2005
Location: Wasatch Mnts, UT, USA
Posts: 245
I got her out on the open road for a while today. It´s a little stronger, but still rather "uninspiring." I openend the airbox and tried that way for a while, no0t much more power, but lots more noise.I think the trick will be a single tooth smaller sprocket, I´m only at 5600 rpm at 100 kph and a 7% boost in revs should´t hurt. Also first is a little long legged for tackling technical terrain with a load. Unfortunately, I have been unable to locate a sproket and must be going. Hopefully in Bariloche.
__________________
India Himal, 3mo,2x; Kazak/Krygyz/Tajik, 3 mo; Kashi-Lhasa, China 219! 6 wk; Nepal, 4 days/trekked 55; Santiago-Ushuia-Cusco, 7 mo; Peru, 3 mo; Chile-Medellin 3 mo; Medillin-Arica, 3 mo
Reply With Quote
  #11  
Old 1 Mar 2008
Contributing Vendor
Veteran HUBBer
 
Join Date: Apr 2006
Location: Tallinn, Estonia
Posts: 973
Quote:
Originally Posted by glasswave View Post
The nx4 falcon is based on the xr400 motor. The specs are here¨--

Honda

After a valve and carb adjustment, the bike feels much stronger, though I haven´t had it out of the city yet. I will go for a test ride (loaded) today, but still think I may want to lower the front sproket tooth. It seems a little tall in first gear for riding techincal terrain and I will likely gain access to more up the upper powerband when loaded.

I will check out what I can do with the airbox.

Thanks

I must say, valves and the like is the first place I look, when a bike is not pulling well. Was the air filter dirty? Is the spark plug looking healthy?

As for the uninspiring ride, the NX400 may be based on the XR, but that is where the similarity ends, i suspect. The NX650 (Dominator) pulled well, but was a more sedate motor than a trail bike equivalent. The NXs are road bikes with off-road styling, so do not expect your engine to pull like an XR: it was not made that way, IMO.

Also there is probably far more body work that it must pull along...
I'm sure it will get you to all the places you want to go though. Only, perhaps not on the back wheel!!
__________________
Adventure: it's an experience, not a style!
(so ride what you like, but ride it somewhere new!)
Reply With Quote
  #12  
Old 1 Mar 2008
Guest2
Guest
 
Posts: n/a
Quote:
Originally Posted by glasswave View Post
I got her out on the open road for a while today. It´s a little stronger, but still rather "uninspiring." I openend the airbox and tried that way for a while, no0t much more power, but lots more noise.I think the trick will be a single tooth smaller sprocket, I´m only at 5600 rpm at 100 kph and a 7% boost in revs should´t hurt. Also first is a little long legged for tackling technical terrain with a load. Unfortunately, I have been unable to locate a sproket and must be going. Hopefully in Bariloche.
Hi Neal,

5600 rmpm at 100 kph is as expected, I think this motor is made for the South American market tuned to cope with the low grade fuels.

Tipo Monocilíndrico de 4 tiempos, SOHC, Refrigerado por Agua
Cilindrada (cc) 397,2
Diámetro x Carrera (mm) 85,5 x 70,0
Relación de Compresión 8,8:1
Potencia Máxima 21,6 Kw @ 6.500 rpm
Torque Máximo 33,0 Nm @ 6.000 rpm

Quote:
It seems to be lacking in power. I have a difficult time maintaining 100 kph except for on the flattest of terrain and it is a real pig when climbing (me 90 kilos, load 30-35 kilos).
The differece between a 14 tooth and 15 tooth sprocket is easy to check for your self. I think the 4 th gear ratio and 5 th gear will be under 10 %. if you know what the ratios are you can work it out.

With a 14 tooth sprocket your speed at 5600 rpm will be 107 kph.
ride in 4 gear and see what the speed is at 5600 rpm and my guess is it will be around the 107 area. See how it rides in forth.
Can you reduce some weight, 35 kilos sounds a lot, that will help.

Steve
Reply With Quote
  #13  
Old 2 Mar 2008
Gold Member
Veteran HUBBer
 
Join Date: May 2007
Location: Buenos Aires, Argentina
Posts: 663
Honda NX400 Falcon rider repot

My Falcon is now 3 years old, around 15,000 K on it. Yes, the Falcons NX400 and Tornados XR250 manufactured by Honda in Brazil are carbed for low grade fuel, very low, and we both find our bikes perform better on lower grade fuel, very weird.

Like the Transalp, designed for the Alps, the Falcon was designed for South America. It is, in my humble opinion, all the bike anyone would need to tour anywhere in Mexico, Central or South America.

We had an experienced rack man "Pato" a friend of Mariano at Motocare in Buenos Aires, do our custom racks and he even built me a not so small metal pannier for my tools, etc.it fits very nicely below the rack for my soft saddle bags.

The only problem experienced through 5 South American countries and more than 12,000 K, much of it on gravel, was power loss under stress at around 4000 meters altitude and above. And, a needed clutch replacement.

Elisa rides a Honda XR250 Tornado and we both pulled our air filters and were able to lug up the steep grades at Paso de Hama fine. It was just too damn cold to change carb jets.

The NX400 is air cooled NOT water cooled (NO Refrigerado por Agua), I have a top end, one up, fully loaded with gear of 130 K/ hour plus and more without gear.

How is your clutch? About 1000 K ago I replaced mine after noticing loss of get up and go. With the new clutch it just jumps. I didn't start noticing the clutch slipping as I have on other bikes. But, my Faclon was acting a bit like your Falcon. I also replaced spark plugs - there are a variety of plugs available for the Falcon, make sure the ones you have are designed and gapped for your needs...

The NX400 has a quirky little way to check oil, it is in the manual and to check oil requires a warm up and "holding the bike level" for several minutes, until oil drips down, having too much oil, apparently can damage the engine.

I have no complaints with my NX400, nor does Elisa have any complaints with her XR250. She has yet to replace anything except air and oil filters. Both were manufactured in Brazil and purchased new in Buenos Aires.

For those interested, we both cruise, fully loaded between 100 k per hour and 110 k per hour, no problem. We have pleanty left to pass trucks etc...

We have almost exactly the same fuel range just under 300 k Falcon with 15.5 liters and Tornado with 11.5 or so. We each carry a 3.9 liter spare fuel tank for over landing.

Hope checking clutch helps. I am not a mechanic, but rather intuitive. xfiltrate

Last edited by xfiltrate; 2 Mar 2008 at 12:37.
Reply With Quote
  #14  
Old 2 Mar 2008
Registered Users
Veteran HUBBer
 
Join Date: May 2002
Location: London, UK
Posts: 638
your bike sounds like its below average. I'd hold fire on changing gearing till you've solved the problem.

has the problem started recently or got worse and worse?

have you checked the spark plug colour? check it before riding, then do a high speed run for a few kilometres. while at high speed, cut the ignition, pull in the clutch and stop the bike to see if the colour is black/white etc. if black, its too rich. if white, be grateful that you haven't seized the engine - yet! from what you said about opening up the airbox, I'd suspect its either very rich (too big main jet) or the timing is retarded. is the ignitor hot at the end of your high speed run?
Reply With Quote
  #15  
Old 3 Mar 2008
Registered Users
Veteran HUBBer
 
Join Date: Sep 2005
Location: Wasatch Mnts, UT, USA
Posts: 245
Thumbs up

Benos Dias from Cos Mala, AR. Problem solved, basically.

As I mentioned, I adjusted the vavles and carb as well as a new plug. Air filter was OK, (I will change it in Ushia). I also had the clutch changed as it was exasperating to hit nuetral when the bike was running. How the previous owner finished a clutch in 7000 km of pavement leaves me bewildered. This resulted in a small increase in power.

The key was changing the 15t front sproket for a 14t. This was just enough to get me some access to higher revs in 5th. Now, instead of always shifting between 4th & 5th for barely perceptable inclines while cruising the flats, I can cruise in 5th and even pull 5th gear up a reasonable little hill. The lower 1st gear is very nice as well for technical terrain when loaded. I haven´t seemed to loose any top speed, and the economy seems to be the same, if not better.

She is perfoming as expected now, if still a little unispiring.

Thanks for all the help.
n
__________________
India Himal, 3mo,2x; Kazak/Krygyz/Tajik, 3 mo; Kashi-Lhasa, China 219! 6 wk; Nepal, 4 days/trekked 55; Santiago-Ushuia-Cusco, 7 mo; Peru, 3 mo; Chile-Medellin 3 mo; Medillin-Arica, 3 mo
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 Registered Users and/or Members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
KLE 500 Performance modifications needed. sparkie Kawasaki 30 16 Aug 2009 18:45
Route Suggestions in Marmara and Aegean Regions of Turkey ducatigirl Europe 5 17 Jul 2009 09:27
Suggestions for route fron Santiago to Ushia glasswave South America 2 19 Feb 2008 15:11
XT600 Performance Juey Yamaha Tech 1 28 Jul 2003 22:25

 
 
 

NEW! HU 2015 Motorcycle Adventure Travel Calendar is now available! Get your copy now for some terrific travel inspiration!

HUGE, 11.5 x 16.5 inches, beautifully printed in Germany on top quality stock! Photos are the winning images from over 600 entries in the 9th Annual HU Photo Contest!

Horizons Unlimited 2015 Motorcycle Adventure Travel Calendar.

"The calendar is magnificent!"

"I just wanted to say how much I'm loving the new, larger calendar!"

We share the profit with the winning photographers. YOU could be in the HU Calendar too - enter here!


HU DVD Autumn Special!

Take 40% off Road Heroes Part 1 until October 31 only!

Road Heroes features tales of adventure, joy and sheer terror by veteran travellers Peter and Kay Forwood (193 countries two-up on a Harley); Dr. Greg Frazier (5 times RTW); Tiffany Coates (RTW solo female); and Rene Cormier (University of Gravel Roads).

The first in an exciting new series, Road Heroes features tales of adventure, joy and sheer terror by veteran travellers."Inspiring and hilarious!"

"I loved watching this DVD!"

"Lots of amazing stories and even more amazing photographs, it's great fun and very inspirational."

"Wonderful entertainment!"

Check it out at the HU Store! Remember to use Coupon Code 'HEROES' on your order when you checkout.



Scottoiler automatic chain oilers. The most important accessory for your next motorcycle adventure!


Renedian Adventures


Renedian Adventures

What others say about HU...

"I just wanted to say thanks for doing this and sharing so much with the rest of us." Dave, USA

"Your website is a mecca of valuable information and the DVD series is informative, entertaining, and inspiring! The new look of the website is very impressive, updated and catchy. Thank you so very much!" Jennifer, Canada

"...Great site. Keep up the good work." Murray and Carmen, Australia

"We just finished a 7 month 22,000+ mile scouting trip from Alaska to the bottom of Chile and I can't tell you how many times we referred to your site for help. From how to adjust your valves, to where to stay in the back country of Peru. Horizons Unlimited was a key player in our success. Motorcycle enthusiasts from around the world are in debt to your services." Alaska Riders

contest pic

10th Annual HU Travellers Photo Contest is on now! This is an opportunity for YOU to show us your best photos and win prizes!

NEW! HU 2014 Adventure Travel T-shirts! are now available in several colors! Be the first kid on your block to have them! New lower prices on synths!

HU 2014 T-shirts now in!

Check out the new Gildan Performance cotton-feel t-shirt - 100% poly, feels like soft cotton!


What turns you on to motorcycle travel?


Global Rescue, WORLDwide evacuation services for EVERYONE

Global Rescue is the premier provider of medical, security and evacuation services worldwide and is the only company that will come to you, wherever you are, and evacuate you to your home hospital of choice. Additionally, Global Rescue places no restrictions on country of citizenship - all nationalities are eligible to sign-up!


New to Horizons Unlimited?

New to motorcycle travelling? New to the HU site? Confused? Too many options? It's really very simple - just 4 easy steps!

Horizons Unlimited was founded in 1997 by Grant and Susan Johnson following their journey around the world on a BMW R80 G/S motorcycle.

Susan and Grant Johnson Read more about Grant & Susan's story

Membership - help keep us going!

Horizons Unlimited is not a big multi-national company, just two people who love motorcycle travel and have grown what started as a hobby in 1997 into a full time job (usually 8-10 hours per day and 7 days a week) and a labour of love. To keep it going and a roof over our heads, we run events (22 this year!); we sell inspirational and informative DVDs; we have a few selected advertisers; and we make a small amount from memberships.

You don't have to be a Member to come to an HU meeting, access the website, the HUBB or to receive the e-zine. What you get for your membership contribution is our sincere gratitude, good karma and knowing that you're helping to keep the motorcycle travel dream alive. Contributing Members and Gold Members do get additional features on the HUBB. Here's a list of all the Member benefits on the HUBB.


Books & DVDs

amazon

All the best travel books and videos listed and often reviewed on HU's famous Books page. Check it out and get great travel books from all over the world.


Motorcycle Express for shipping and insurance!

Motorcycle Express

MC Air Shipping, (uncrated) USA / Canada / Europe and other areas. Be sure to say "Horizons Unlimited" to get your $25 discount on Shipping!
Insurance - see: For foreigners traveling in US and Canada and for Americans and Canadians traveling in other countries, then mail it to MC Express and get your HU $15 discount!




All times are GMT +1. The time now is 17:48.