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Cool Motorcycle Pictures & Stuff Other motorcycle related stuff and some pictures.

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  #16  
Unread 12-02-2008, 01:21 AM
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Upper Screw Adjustment (after engine warm up):
Once it's nice and warm after some riding around you can adjust the idle down when you come to a stop by turning the upper screw out (counter clockwise) a little at a time while listening to how the engine responds by slowing down. Don't let the engine idle too slow because then it will take forever for the RPMS to build up for the bike to take off from a stop sign. I like mine kind of high because you don't want to be caught with your pants down out in the streets with soccer moms breathing down your neck!


Lower Screw Adjustment (after engine warm up):
Now that the bike is burning oil properly with a nice hot spark plug you can judge how well the mixture of oil and fuel is. The factory recommends 2 and 1/8 turns out but I found this to be too lean (not enough oil mixing). How can I tell? Well the top speed was only pulling up to 20mpg and then the engine would sputter and run really rough. The fuel was burning off too quickly and not pushing the complete stroke of the combustion cycle... just take my work for this if you aren't up on your combustion engine science.

So with my trusty screwdriver on a country road I backed out the screw a half a turn and hit the straightaway again! This time it ran better but STILL sputtered and spit. It sounds like the difference between a little weed wacker running at half speed compared to full throttle. You know, the wacker is sounding funky and sputtering like it wants to be given full throttle to take off. Well that's just how the 50 was running. Then I adjusted out the screw another half of a turn and the top speed increase by a few MPH as the engine sang it's note to full RPMs. I rode the Honda Express around some more roads and hills listening to the engine and making sure it sounded and ran like a good little 2 stroke. The air mixture screw is now out to around 3 turns out and it pulls 25 MPH consistantly.
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  #17  
Unread 12-02-2008, 01:23 AM
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Here is a TOP SPEED run on the Honda Express-SR 50. This is one mean little bike! Notice the throttle technique needed to get the engine RPMs right where I needed them in order to set the Honda 50cc world record. The wind was brutal at this speed.

http://www.youtube.com/watch?v=oG2gIganWYw

It's a good thing we had the roads shut down by the local law enforcement for this event.

THE HONDA WILL possible run a little more rich with oil once the air filter is placed back on the carburetor. For this top speed timed run the bike in the video was running an illegal unrestricted air configuration. Your adjustments might vary from the setup on this bike once you install your own air filter. I recommend a UNI foam filter that you can guy at just about any motorcycle shop. They make displays with universal filters hanging on them for sale and you should be able to find one to fit your carb without any problem.

Have fun and watch out for John Law and his radar gun.
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  #18  
Unread 04-14-2010, 09:51 AM
Dobber
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Hello, I am wondering if you can send me more pictures of how the carb. is supposed to be hooked up. I just bought a nx50 and the guy who had it before me had it all messed up and I am having a little trouble figuring out what goes where. Any Pictures or info. would be greatly appreciated!
Thanks, Chris

you can e-mail me if it is easier
[email protected]
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  #19  
Unread 04-14-2010, 01:10 PM
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I'll be visiting my friends place who has the bike this week. I'll do my best to get a couple good pictures of the carb and the hoses.
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  #20  
Unread 04-15-2010, 04:37 AM
Dobber
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Hey Thanks I appreciate it, but after I replied on here I actually got it figured out from the pics. on here! Thanks!
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  #21  
Unread 11-08-2010, 07:21 PM
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I just bought a used 82 nx50 and cant seem to get any help anywhere.

thanks for the picture showing the vacuum bypass, mine was also missing the airbox

I have no idea why mine isnt starting though. I tried every thing you've said and even sprayed some ether in the carb with no luck.

I know I'm getting compression as the starter is strained and turns over easier when the spark plug is removed. I also verified spark.

the only thing I can figure is I didnt disassemble and clean the choke

I'm out of ideas...
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  #22  
Unread 11-08-2010, 10:37 PM
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Hmm that's a bummer. I'm wondering HOW much compression it's getting though. How many miles does it have on it? The rings could be bad even though it feels like it has compression. :-\ And you're trying to start it without an airbox right? That would make sure that it's getting air. Basically the carb controls everything. You really have to be thorough when cleaning them out and disassemble every single thing.

I've seen TONS of bikes thrown away simply because of a dirty carb. It costs big bucks to have a mechanic get them going again! I'm working on some really complicated carbs at the moment. The bike was basically trash simply cause the carbs were completely neglected and in really bad shape. I'm just wondering how many miles are on your cylinder. 2 strokes don't last all that long.. but then again it's a Honda and they are the highest quality 2 stroke mopeds out there.
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  #23  
Unread 11-09-2010, 02:29 AM
electrohacker
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it is rather high mileage (part of why it was so cheap) over 2000 miles. but I'm not afraid of re ringing the cylinder, infact I might just save up and upgrade the cylinder at the same time
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  #24  
Unread 11-09-2010, 02:30 PM
electrohacker
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I'm going to check the head gasket tonight as I saw fuel leaking from the forward part of the engine. a head leak would explain the fuel leak and the low compression issue. I can also check the cylinder walls and rings while im there
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  #25  
Unread 11-09-2010, 02:52 PM
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Very good. That would be great if it was just a leaking head gasket. Here is a place to order parts that has been recommended to me by a good friend. He insists that they offer the best prices/quick shipping. http://servicehonda.com/

My local dealer really goes out of his way to give me the best prices on OEM parts so I haven't tried Service Honda yet but I'm sure I will in the near future. I've known the owner of my dealership since I was a kid so I support his business. With times being hard supporting local shops and businesses that do a good job is important. The only problem is that the dealership is an hour away so yesterday I just called in some tiny carb parts to have them sent to me from a place that only sells carb parts. I just needed some simple o-rings sent to me so I ordered them from a carb part specialty business http://carbparts.com/

I looked at a few carb parts websites for the tiny little parts that I needed for my friends ZX-7R carbs and I just couldn't tell exactly what I would need to order. So I just called them up and literally within a minute I told them exactly which part it was and they knew exactly what to send me. The only thing they asked me was how many and what type of card will I be using. The parts were cheap and they are on the way.

Let me know what you find when you get into the engine some more.
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  #26  
Unread 01-16-2011, 09:13 AM
electrohacker
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sorry I havent posted updates, I found that the rings and piston were just plain wore out. it was going to cost me over $110 to have it hones and get a new piston and rings so I opted to get a 70cc big bore kit from 1977 mopeds. parts just dropped on and other than a vacuum choke issue I had she started right up and I;ve been running it around in the snow covered detroit like a fool (got it regestered and all the lighting repaired) now I just have to track down a fuel leak, when I fill the tank I come back the next day to an empty tank...

I added an inline petcock like your previous owner did and this revealed that my leak is at the stock vacuum petcock, probably where it joins the tank. I'll tear down the tank and figure it out.
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  #27  
Unread 01-16-2011, 09:14 AM
electrohacker
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oh and so far I'm 1/4 or so through my break in, and I'm up to 33mph, not bad considering I'm running stock exhaust with no porting and stock intake with an aftermarket filter
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  #28  
Unread 01-16-2011, 09:26 AM
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videos
http://www.youtube.com/watch?v=H9bpDJekuzw first start up
http://www.youtube.com/watch?v=KgvpdhYZJE0 first drive
http://www.youtube.com/watch?v=Nv_yP2rC8D8 top speed run around the veledrome
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  #29  
Unread 02-21-2011, 08:26 AM
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What the heck? Are you getting your bike ready for the scooter races there or something? I was looking at other vids of that park and it seems like they have some pretty sweet races there. Ah that looks like so much fun. Wow almost 35 mph out of that thing is a substantial improvement. It sounds like it has some balls now. I bet you can't wait for the weather to warm up!

Last edited by Smithers; 02-21-2011 at 08:28 AM.
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  #30  
Unread 07-09-2011, 02:10 PM
aidynphenix aidynphenix is offline
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hello guys, this is my first post here at 4wforum, and im excited, i got one of these little honda scooters the other day from sombody on craigslist..
it works pretty good and on a level surface i reach about 28mph.

there is a few things i still need to get working before i can drive it legally like i need to.
first my tail light and headlight are blown, and i think its because i have no battery.
im going to see if i can find a 12v battery for farm/lawn use today that will fit.
i am going to replace the taillight, but dont have the replacement headlight for the front, so i think i will have to improvise for now., planning on cutting the back of of the light off with a dremil and puting my own light in the houseing..

i also, have a problem with they keys. i cant take the key out and have it turn off. it doesent work, it can even be started and driven without the key, and i dont like that.
i can no longer lock the handlebars in place with the key, i cant push it in and turn to the left at all.

and lastly, i dont know what kind of oil i should be putting in it, and also where i can buy it, the guy i bought mine from said he put, Honda GN-2 auto oil in it..

if these questions can be answered in the user manual or some troubbleshooting guide could you guys point me in the right direction, i would really like a pdf manual on the bike to help me get these problems worked out.

im needing this bike for my transpotation at the moment, i will be putting about 15 miles on it per day on my way to and from work.
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