Wednesday, May 26, 2010

Honda Express nc 50 Transmission Oil - What Should I Use?


As printed in the 1980 Honda NC50 ('77-'82) Express NA50 Express II ('79-'81) Shop Manual by American Honda Motor Co. Page 26-1, you should use 10W-40 Motor Oil.

The Honda Scooter nc 50 has a Transmission Oil Capacity of 0.75 lit. (0.79 U.S. qt.) (25.28 U.S. oz.) that should be filled with 10W-40 Motor Oil.

Do NOT use 2 stroke oil and do not use 10w-40 lubrication oil in your Honda Moped Oil Tank.

What brand is the best for your honda ped? Well, Synthetic is all the Rage. During my internet research another brand of oil that people love and stand by is Royal Purple which happens to be easily located at many auto parts stores near you. I have seen it stocked at my local Pep Boys and Advanced Auto Parts store.

15 noped comments:

Robert said...

i read somewhere(maybe this blog) about someone who changed their transmission oil(using these specifications) and their ped actually performed worse than before the oil change. well, i just did the oil change to these specs(except i used mobile 1, full synthetic, 10w-40 oil)) and got the same result. prior to the oil change, my ped would do approx. 28mph on the flat. now im running at least 2mph slower. any suggestions? link to post i mentioned earlier? thanks

jfk said...

Robert,

Don't know what to tell ya. I have read 10W-40 and that's what is in the manual. Have you read something else you can try?

Robert said...

no, i havent heard any other info regarding this. im just lost on why its doing this. coincidence, perhaps? i dont know what to do to get my ped going 30mph. every time i take a step forward(removing air filter, triming to make air pass through more efficiently), it seems like i take one step back(changing oil).

jfk said...

Robert,

I have had the same problem in the past. I was running 30mph easy... then one day in early summer... I lost 2-3 mph. For me it seemed like it had to do with the humidity in my area. It ran faster when it was dryer. Now that's just my opinion, might have been something else entirely.

Don't give up!!!

I would say... meet the specs on all the oils and moped conditions, then do a couple performance upgrades.

Best suggestion I would say is... save $125.. purchase a 70cc engine kit upgrade and make your honda express go 35+ mph.

I have a video I am splicing together where I did just that. Kit worked wonders and I don't really care about speed anymore. I coast around 33mph and I am perfectly happy. :)

Let me know if you have more questions, I will try my best to help.

-=JFK=-

Robert said...

i do have one question ive had a hard time getting answered... what do you do about a carb upgrade? are there any carbs out there that have an oil injection intake like the stock express one? ive had my eye on the honda DR kit, and a lot of the things ive read about them strongly suggest a larger carb. is there a larger carb that has the oil intake? what have you done with your kit's carb? stock? thanks for the help jfk

sshizzle said...

Is it possible that you put too much oil in the crankcase? I ask because I just change the crankcase oil on my 1983 Honda Express (NC50I), and it's going about 3mph slower than before the change. I drained about .6L out (just as expected based on service manual), then refilled "to brim" as stated in service manual...doing the math on the volumes: I took ~.6L out, theoretically leaving ~.15L in the crankcase, then put in a whole 1L because of the directions in the service manual...seems like I just have way too much oil in the crankcase, and this is slowing the drive-train down. I will attempt draining a bit out, and I'll repost the results.

sshizzle said...

Two days ago I drained and refilled the crankcase on my 1983 NC50I. I followed the service manual instructions, but this seemed to result in adding far more crankcase oil than what is called for in the specs. Immediately after the oil change, the express's max speed was 3mph slower. At first I suspected that the old oil was so broken down that it was really thin and the increased viscosity of the new oil, possibly in combination with the overfilling was slowing the bike down. Today I drained my overfilled crankcase and refilled it to the service manual specs. This did not change the top speed, so it seems it was the change in oil viscosity alone...unless anyone has any other ideas.

steve said...

these do use a centrifugal clutch maybe the lubricity of the new oil is making the clutch slip?

241febfa-8180-11e1-afd8-000bcdcb2996 said...

they have special oil for small engines such as lawn mowers mopeds etc.

David O said...

I have a few questions about the oils to use. My first question is why have the Honda Oils have not been recommended? It looks like Honda makes a GN2 (regular) and HP2 (synthetic) injector oil. Which of these would be best? It appears the GN2 is a 20:1 oil (which I believe the original Honda Pro oil back in the early '80s was also) and the HP2 is a 32:1 oil. My thought is the bike was designed around the 'older' non synthetic oils so it might not be a good idea to use the newer synthetics?.? (looking for comments on this). The same applies for the transmission oil - should I use my usual Castrol 10w40 motor oil or go synthetic such as Royal Purple or Mobile 1?

David O said...

I have a few questions about the oils to use. My first question is why have the Honda Oils have not been recommended? It looks like Honda makes a GN2 (regular) and HP2 (synthetic) injector oil. Which of these would be best? It appears the GN2 is a 20:1 oil (which I believe the original Honda Pro oil back in the early '80s was also) and the HP2 is a 32:1 oil. My thought is the bike was designed around the 'older' non synthetic oils so it might not be a good idea to use the newer synthetics?.? (looking for comments on this). The same applies for the transmission oil - should I use my usual Castrol 10w40 motor oil or go synthetic such as Royal Purple or Mobile 1?

David O said...

An update to my own questions (as per the local Honda Dealer rep) ... The rep said GN2 is the recommended/preferred engine oil to be used with an injector pump for the Honda Express (separate tank for the oil). The HP2 is an oil that is primarily used in motorcycles that use a gas/oil premix in one tank. Also, he told me, with regard to the transmission oil, that the 10w40 honda motorcycle oil had an additive package designed around motorcycles and is slightly different than the 'normal' car motor oil. Not sure how much difference it makes using one vs another. I finally decided to purchased the 10W40 motor oil and the GN2 injector oil from Honda. One thing I did notice is the GN2 is clear and the old Honda injector oil I drained was the usual bluish/green color I'm used to seeing for 2 cycle oil. Additional information is gladly accepted.

Phillip Greene said...

I have a Honda 50cc Moped, Urban Express which I purchased along with my home in Arizona, from the previous owner. He never had any oil leakage. I have a spot or more on the garage floor, once in a while, not every day but often.

The bike has 2,470 miles on it and I'm having a hard time finding where to drain the old transmission oil and where to pour in the new oil. Where is the filler hole? On the back left side of the bike is a circular chrome housing with a 9/16" screw. I unscrewed it and a grayish oil started to drain out. I was told, when the transmission oil gets old, often when living in a hot, dry climate, then the oil gets thin and leaks could occur. Would you agree with that statement? In your diagram, online, you show the drain plug screw, on the lower left side of the transmission housing behind the kick starter lever. The only screw on the bottom of my transmission looks like the other screws holding the cover on the transmission, is that probably it? And, where and how do you pour in the new 10W- 40W Motor Oil?

Any and all help would be appreciated. Thank you for taking your time to read this.

Phillip

Phillip Greene said...

When I purchased my home in Arizona, I also bought the previous owner's Honda 50 Urban Express, 82 model. It's been great for short trips around home, but recently it's starting to leak oil from around the cylinder housing, or the front half of the engine. Since it's a 2 cycle engine, I assume the leak must be coming from the transmission housing, right? It's not a steady leak, often a drop here or there, but not everyday. The speedometer is at 2,760 miles. Not sure if the oil was ever changed. When I called a local motorbike shop, they said in a dry, hot climate, when the oil gets old, it thins out and sometimes leaks. I found a 9/16" screw in the circular, chrome housing on the left side of the rear wheel. When I unscrewed it a grayish oil started to ooze out. It sure didn't look like 10W-40W motor oil, or is that the color it changes to when heated over a long period of time? I downloaded you manual but can't find any info on how to fill the transmission. Where is the hole to pour in the new motor oil? And, I saw you picture on the location of the drain plug, under the transmission housing, behind the kick-starter. However, I'm not sure, that's the drain screw, because it looks like all the other screws holding the transmission cover in place.

Could you help me by answering my questions pertaining to changing the transmission oil? Location of the - filler hole and drain plug?

Any help will be received with much appreciation.

Phillip

Pasquale Dale Quale said...

good evening! what oil should I put in the engine; 10w-40;

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