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-   -   Will it improve fuel economy by changing the main jet ? honda nx650 dominator 88 (https://ecomodder.com/forum/showthread.php/will-improve-fuel-economy-changing-main-jet-honda-30654.html)

herberpower 12-08-2014 09:12 AM

Will it improve fuel economy by changing the main jet ? honda nx650 dominator 88
 
I 've ruined my bike engine , a clove of distribution was shifted and an splattered two exhaust valves .

take and change the engine.

my bike is 88 and the motor 89 mounted .

it is said by the " xrfanatics " forum that the NX650 88 and 89 are the most powerful , then change and are less .

I've been researching and found some differences according to the year.

Year 88 89 have kickstart , the year 90 onwards have not.

years 88 89 90 91 motorcycles are equal changed hands and the color of the plastic and stickers. 92 changes from the plastic, larger tank , exhaust pipe and each year 92 93 94 changing colors .

year 88 89 carburetor is the same and ends at A, year 90 91 92 93 94 the carburetor is the same and ends B.

Year 90 using ethanol- gasoline blends , with a maximum of 10% is approved.

used here gasoline with 10 % ethanol .

The supplier references idle jet, needle and other parts are all equal in the years 88 89 90 91 92 93 94 , except the main jet , in the year 88 , 89, 90, it is 155 , in the year 91 92 93 94 is 148 .(the years were poorly)

In 1991, must meet the new standard antipollution EURO 1. Throughout the european union .

This explains the size of the smaller main jet .


I am comparing the NX650 models sold in Spain .

88 89 90 91 92 93 94 is the model made in Japan.

95 onwards is the model made in Italy.


Will it improve fuel economy by installing the main jet of 148 ?

more than six months ago, and rebuilt the carburetor, bringing the main jet 148 and 155 , install the 155 to be the same carburetor .

NX650 was replacement of 88 to 94 years

more than six months , change the jet needle , so that it falls more within two millimeters , so is the poorest part of media , the needle is not adjustable, but can return to the origuinal settings .

always talk about the NX650 japan , there is also the model NX650 EEUU, and not know the settings. want to think they are the same .

There is also the NX650 Italy 95 96 97 98 99 00 01 02 carries bigger carburetor jet idle , different needle and main jet 145

the bike works well for 0-1000 meters from sea level. where I use normally.

In mountains over 1000 meters from the sea the engine seems less potent and somewhat maladjusted and sometimes appear jerks. It may be that the carburetion is too rich .

is difficult to exceed 1700 meters (1056 miles) from the sea.

herberpower 12-09-2014 09:25 PM

install the 148 main jet .

it is very cold to ride a motorcycle.

I hope to one day better .

roosterk0031 12-09-2014 09:38 PM

Like the nx650, had a 80's xr600 dual carb version. Good luck turning it, I'll get another KLR650 someday(maybe xr650l), put 19,000 miles on a 2000 KLR and thought I needed more bike, 5-6 bikes later I was wrong, KLR was the perfect bike for me.

Bike fuel economy is a small part of the cost of ownership, running lean may gain a few mpg or km/l but engine repair is way more expensive.

Not even sure the Nx650 ever came to the states, I think the 250 did for just a few year.

adam728 12-10-2014 06:48 AM

You say it's down on power and seems to run rich at altitude. Where do you ride the most? I'd jet to be safe at the lowest elevation you'll see, but also concentrate on making the jetting ideal for the elevation you'll ride at most often. The downside of a carbureted bike is that they don't deal well with elevation/temperature changes. When I was racing I had different jetting settings for every 800 m or so of elevation change. Not in one race mind you, but depending where we were going to be riding I had a jetting setup to go to for that. What runs great at 600 m is awful at 2100 m.


Also keep in mind that the different jetting for different countries could be due to other changes. And I don't just mean possible bike differences (like muffler, cam, etc), but fuel as well. Different blends of fuel act differently and can require different jetting, even if from the outside they appear "the same", as in same octane, reed vapor pressure, etc.

user removed 12-10-2014 07:51 AM

If possible you might try to pick up some heat from the engine to preheat the air going into the carburetor. The early Nissan-Datsun 240Zs with the Mikuni (SU type) carbs had a preheat tube connecting the air cleaner to the exhaust manifold heat shield. The manually adjustable flap was marked "winter" and "summer".

With everything properly tuned and mixture adjusted properly, the variable venturi carbs
are notorious for severe hesitation and driveability issues. Set the flap to winter position=problem solved. You could feel the air filter housing get almost too hot to touch when it was working.

More heat better fuel atomization, more efficient, better driveability.

regards
mech

herberpower 12-10-2014 08:59 PM

Quote:

Originally Posted by roosterk0031 (Post 459043)
Like the nx650, had a 80's xr600 dual carb version. Good luck turning it, I'll get another KLR650 someday(maybe xr650l), put 19,000 miles on a 2000 KLR and thought I needed more bike, 5-6 bikes later I was wrong, KLR was the perfect bike for me.

Bike fuel economy is a small part of the cost of ownership, running lean may gain a few mpg or km/l but engine repair is way more expensive.

Not even sure the Nx650 ever came to the states, I think the 250 did for just a few year.


change to the NX650 after having a XR250R 2001.

The XR250R is enduro . the road used just with mixed tires, long trasmision .

The geometry was inappropriate . to go 120km/h, 74 MPH (permitted maximum speed ) worked many revolutions, and lacked a little power. not to damage the engine did not exceed 100 km/h, 62 MPH.

with the NX650 works well, and you have a little extra power .
A 400 or 500cc motorbike think would serve me , but before buying I thought that I would stay small.

klr650 is a great bike that fits all , as the NX650 . A motorcycle with larger engine usually heavier , not suitable for mountain trails and more tiring to use .

I hope not to destroy the engine , I do not want to open it again.

herberpower 12-10-2014 09:26 PM

Quote:

Originally Posted by adam728 (Post 459074)
You say it's down on power and seems to run rich at altitude. Where do you ride the most? I'd jet to be safe at the lowest elevation you'll see, but also concentrate on making the jetting ideal for the elevation you'll ride at most often. The downside of a carbureted bike is that they don't deal well with elevation/temperature changes. When I was racing I had different jetting settings for every 800 m or so of elevation change. Not in one race mind you, but depending where we were going to be riding I had a jetting setup to go to for that. What runs great at 600 m is awful at 2100 m.


Also keep in mind that the different jetting for different countries could be due to other changes. And I don't just mean possible bike differences (like muffler, cam, etc), but fuel as well. Different blends of fuel act differently and can require different jetting, even if from the outside they appear "the same", as in same octane, reed vapor pressure, etc.


I normally motorcycle being 0 and 700 meters. routes sometimes reaching 1700 meters .

have different configurations according to the height or the temperature is not an option , I do not run races. must be a setup for winter / summer 0-700 meters. in winter I hardly use it , very cold does.

What is the correct settings ?

a slightly richer mixture to lose some power . safer .

a mixture to get the maximum power .

A slightly more lean lose some power . less certain. greater fuel economy.

I changed the first page , I'm talking about all the NX650 models sold in Spain .

herberpower 12-10-2014 10:38 PM

Quote:

Originally Posted by Old Mechanic (Post 459082)
If possible you might try to pick up some heat from the engine to preheat the air going into the carburetor. The early Nissan-Datsun 240Zs with the Mikuni (SU type) carbs had a preheat tube connecting the air cleaner to the exhaust manifold heat shield. The manually adjustable flap was marked "winter" and "summer".

With everything properly tuned and mixture adjusted properly, the variable venturi carbs
are notorious for severe hesitation and driveability issues. Set the flap to winter position=problem solved. You could feel the air filter housing get almost too hot to touch when it was working.

More heat better fuel atomization, more efficient, better driveability.

regards
mech


already knew what hot air . I did not know what was best for that.


the first car I had, peugeot 205 GTX 1988 , powered Talbot, llebaba this system with a three-position lever, with cold air , intermediate position , or hot air, other cars and Opel Corsa B 1994 or seat ibiza 2000, both with single mono point injection , this system is regulated by thermostatic valve. Over time the valve is damaged, and remains open in hot air .

by the shape of the air filter box can only get air through the top. The top is connected to the air filter . the air filter box there clean air and oil vapors .


on top of the air filter box is the seat and there is little space , is not whether some small cave Tuveri .

there is very little room to pass a pipeline from the front of the engine where are the collectors to the air filter.


my motorcycle



http://i58.tinypic.com/2mopet3.jpg

another motorcycle without air filter box .

http://thebikeshed.cc/wp-content/upl...D25-Engine.jpg

herberpower 12-11-2014 11:12 PM

hot air pipe 17 mm inner diameter .

http://i60.tinypic.com/282hkps.jpg
http://i58.tinypic.com/qrzpxy.jpg
http://i59.tinypic.com/5a5hrb.jpg

Is it useful ? Is it too small?

My father says I'm nuts . that to work better air must be as cold as possible . there is more power. other sport bikes have front air intakes for between cold and pressure.

Frank Lee 12-11-2014 11:56 PM

If power is the priority then yes, use cold air.


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