78 Honda Express(NC50) 70cc DR kit

Richard Hicks /

Hey, I just purchased a 1978 Honda Express and I am having a hard time getting up hills without losing a ton of power/speed. I also recently had it shut down on me(seemed like it fouled out) after riding it a couple miles...? Either way, I just purchased a 70cc DR Kit from treatland.tv and cant wait to get it this week! I know I'll have to cut a fin to make it fit which is no biggie, but I have a few questions... 1st, I was planning on taking the carb off and cleaning the hell outta it b4 I put the DR Kit on, but will I need to do anything else to the carb for the new 70cc Kit? I've heard I'll need to Jet it or something, but I'm not familiar with this process. I've heard that you can't buy different jet screws for the NC50 carb...? 2nd, Should I purchase a new head or will the stock one work fine as is, or would I need certain gaskets if I use the stock head? 3rd, my 78 Express has been altered so that the oil pump system is plugged off and the oil section of my tank has been formed to be part of the gas tank which I like, but my question is, what is the gas/oil ratio for this new DR Kit that I'm putting on? Will it be different because of the size or the newness of the engine...? Please hlep! Can't wait to get this beast back on the road!!! Thanks!

-Rich

Re: 78 Honda Express(NC50) 70cc DR kit

I have a '78 with a70cc kit. I also put on a mikuni vm20 carb, boysen dual stage reeds, a treats intake and a hack and weld jammy pipe. It will run up a little over 40mph.

The stock carb on the NC50 didn't have interchangeable jets as far as I can tell. That's why I went with the bigger carb. Also check your compression that could be where you are losing some power. It might be time for new piston rings.

Make sure your points are set correctly too. That made a 10mph difference when I was tuning mine.

The stock head works great with my 70cc kit, not saying that a high comp head wouldn't be better, but I'm saving money this way. Standard gaskets should work fine.

Hope that helps!

DH

Re: 78 Honda Express(NC50) 70cc DR kit

Rollo Tomassi /

I would get a new carb for sure. Other stuff can wait, but you won't see the potential of that kit with the stock exhaust.

Re: 78 Honda Express(NC50) 70cc DR kit

Richard Hicks /

Daniel, thanks a lot for the advice! I already purchased the DR Kit(Picture is below) and I don't want to put it on until I have EVERYTHING that I need to make this worth while.

#1 I found out that my 78 Express has a hobbit carb on it, but I'm still in the right mind to get a "Mikuni vm 18mm clamp style carburetor"

- Should I get a bigger Mikuni carb? and if so why, and what would that intel?

#2 Are the "Boysen dual stage reeds" necessary(will I have problems if I don't add them)?

#3 There are multiple intake pipes to choose from, all around the same price($60) what's the best? My goal is to have 0 problems with install and having a reliable bike that requires very little maintenance.

#4 There aren't many, if any options on Treats website for exhaust pipes... any tips or links?

Thanks for the info! Look forward to hearing back so I can get this thing on the road!!!

Honda Hobbit DR-70cc-kit-2.jpg

Re: 78 Honda Express(NC50) 70cc DR kit

On the exhaust buy a used pipe and cut the expansion chamber off and weld it to the oem header. Ive got a leo vince hack and weld on my qt50. Bike goes 50 with that pipe using stock header with a malossi kit

Re: 78 Honda Express(NC50) 70cc DR kit

Also I think the vm18 would be more than enough, wouldnt go bigger

Re: 78 Honda Express(NC50) 70cc DR kit

VM 18 should be fine. The boysen dual stage reeds probably aren't necessary, but it helped performance a little bit. I bought my intake from treatland. it was the only one available at the time. Make sure it has the arm for the rear brake cable. Mine is fantastic! The hardest part for me was finding someone to do the welding on my pipe. I was turned away by several shops because they didn't work on such thin metal. I finally found a little shop the did anything. But if you already know how you will get the welding done....you've got no worries. Hope this helps!

DH

Re: 78 Honda Express(NC50) 70cc DR kit

Richard Hicks /

JP,

I looked up Leo Vince on ebay and the picture below is what comes up....? is this correct, bc if you ask me that looks like a dirtbike pipe which I am familiar with... is there one that is made for smaller bikes like my 78 Exp. or do I buy one that fits a dirtbike and have it welded to my bike? JW because I'm not sure how one like this would even fit or if it would really get in the way...?

Daniel,

I put a pic of the intake I'm looking at below, I'm trying not to waste my time buying the wrong shit so let me know if this looks right or if I need to find a different one.

THANKS A LOT GUYS!!!

Leo Vinci Exhaust.JPG
Weak-Ends-Express Intake-2.jpg

Re: 78 Honda Express(NC50) 70cc DR kit

Richard Hicks /

Ok, I found some Leo Vince mufflers for scooters... but is there a particular one? If you could send a pic of what I should be looking for that'd be ballaa

Re: 78 Honda Express(NC50) 70cc DR kit

That's the intake that I bought. It works really well for me. It was very well put together. Hope that is helpful.

Re: 78 Honda Express(NC50) 70cc DR kit

Richard Hicks /

Right on, I put a pic of everything I'm going to order from Treats below(I'm shooting in the dark with the jets so if you know which ones would work best with what you see plus my 70cc DR Kit feel free to let me know). And I'm going to skip out on the muffler and just cut mine open and do some fab work so I can avoid the $$ & complicated welding issues.

My Express List.png

Re: 78 Honda Express(NC50) 70cc DR kit

Shouldve specified sorry.

Thats a leo vince hack and weld on my qt50

Re: 78 Honda Express(NC50) 70cc DR kit

Re: 78 Honda Express(NC50) 70cc DR kit

https://www.treatland.tv/bing-air-filter-p/puch-bing-black-foam-filter.htm

That works real good on the vm18, cheaper too. Use the extra money saved to go towards an exhaust. Youll be happy you did, stock even unrestricted (which i did to my 78 express didnt do much but make it louder) doesnt add much mph

Re: 78 Honda Express(NC50) 70cc DR kit

Re: 78 Honda Express(NC50) 70cc DR kit

https://www.treatland.tv/exhaust-chamber-p/chamber-black-28mm.htm

or contact week ends for a direct bolt on pipe(last attached pic)

polly 002.JPG
polly 001.JPG
week ends pipe.jpg

Re: 78 Honda Express(NC50) 70cc DR kit

puch techno boss

dual chamber (on qt50)

Proma

all must be modified/welded

techno boss pipe 009.JPG
dual chamber.jpg
scrapper.JPG

Re: 78 Honda Express(NC50) 70cc DR kit

Richard Hicks /

Thanks a lot! Here's my official list of stuff(Picture is below)... I decided to go with the Mikuni VM20 Carb since there aren't any intakes that are made specifically for the VM 18(let me know if you disagree on the VM20 idea)... Now I'm just wondering what main jet and what idle jet to get for the BEST results, remember, I'm putting a 70cc DR Kit on it. I read around and haven't found a direct answer, but from the looks of it I'm guessing I'll do a 155 main jet and just use the 22.5 idle jet that comes with it. It comes with 180 main and 22.5 idle.

PARTS LIST.png

Re: 78 Honda Express(NC50) 70cc DR kit

you need the mb5 intake also?I have the same bike with similar wish list so update when your finished.

Re: 78 Honda Express(NC50) 70cc DR kit

Moby Express /

I have an 82 NC50 and in the same boat as you.. confused about the carb as

I have a cut/weld bi-turbo, ported stock intake and deleted oil pump. goes 38 now.

I don't see mounting options for a vm18 carb to any of those weak-ends intakes. How are you guys running vm18

Re: 78 Honda Express(NC50) 70cc DR kit

Richard Hicks /

Eric, are you asking me about the mb5 or confirming that I "DO" need it?

Mike, Ya, I've decided fu*k the VM18 and I'm just going to get the VM20 bc apparently everything is compatible with it. I also deleted oil pump as well, wk'd out great!

Re: 78 Honda Express(NC50) 70cc DR kit

I dont think you need the mb5 intake.

Re: 78 Honda Express(NC50) 70cc DR kit

Richard Hicks /

Eric, I just spoke with Treatland and confirmed that "the mb5 is NOT necessary/required"

The guy also said that I should get several different Jets so I don't burn up the engine... why the Fu*k can't there be 1 answer!?! or at least a round-about answer so I don't have to buy 5 of each(main & idle), I wouldn't mind buying 2 of each... Please let me know if you find any accurate info/place that will lead me to the answer I'm looking for on what jets to purchase for my Mikuni VM20 carb that will be paired with a "Honda Hobbit 70cc DR Bore Kit" & "0.4mm boyesen carbon tech reeds" & an aftermarket pipe, all of which is going on my 1978 Express.

P.S. Any suggestions for sparkplugs to use? I read/heard I may need a cooler one but of course haven't got a direct answer, maybe someone on here may know

P.P.S. I also had to bump the intake up from a 32mm(fits VM18) to a 43mm(fits VM20) since I've decided to roll with the Mikuni VM20 Carb. Picture of new list is below(notice there is no mb5)

I REALLY appreciate your help guys! And if there's anything I can look into or answer, please let me know

EXPRESS LIST.png

Re: 78 Honda Express(NC50) 70cc DR kit

ngk bp7hs

Re: 78 Honda Express(NC50) 70cc DR kit

WEAK-ENDS honda express NC50 NA50 mikuni VM intake - no fender bracket version, OKO 10 pack box of main jets - small range, big large gigantor gladiator robuust chamber for all uncoated, 44mm metal screen air filter for mikuni carburetors, mikuni vm 20mm, 70cc dr kit is what i am putting on my 77 express. Im looking to hit upper fourties..

Re: 78 Honda Express(NC50) 70cc DR kit

briny briny /

The reason they tell you to buy a few jets intially is that the jetting process is a trial and error process. There's a big chance you might not get it right the first time. You should also buy a few spark plugs intially so you can "read" them to tell if your jetting is correct. It takes some effort, but in the end it's worth the time and the hassle. Your Express will run better and most importantly it won't seize and ruin your brand new DR kit. Consult the Wiki for more tuning help.

Re: 78 Honda Express(NC50) 70cc DR kit

Sounds about right for the jetting 150-160 maybe a fatter jet for break in. 22.5 idle works too

Re: 78 Honda Express(NC50) 70cc DR kit

Hey Richard, I have all the mods on my 78 Express that you are describing (DR70 kit, Jammy pipe,VM20, Weak-ends intake).

Don't stress over the jetting. It's just a process you have to go through. Your final choice will depend on the idiosyncrasies of your bike and your setup, like your choice of exhaust and air filter. Even the altitude will have a bearing on your jet choice. The idle jet that comes with the VM20 is a 22.5, and works for most people. It's probably fine. I went with a 17.5 idle jet because I am at really high altitude (4,500 feet), where the thin atmosphere makes my bike run rich. For your main, I would start out with something around 160, then after the new rings are broke in a bit, work your way down gradually till you find the jet that works best for your bike. It's also nice to have a range of jets on hand for other conditions... like winter riding or, say you decide to take your bike on a vacation trip to Denver...

Back to your original question about fuel mix. General consensus is to start out with an oilier mix with a new kit to help ease the break in. About 30:1 or 40:1 on your first tank of gas. Some people run 50:1 all the time. I run 40:1 all the time in my bike because I think it will extend the life of my new kit.

By the way, it would be a real good idea to take your wheels off and check your brakes. Now that you're gonna have all this speed, it'll be nice to be able to stop! Brake shoes are pretty easy to replace.

I had someone available to weld my pipe onto the stock manifold, but if you can't do that, I'd suggest you try to find one of the Weak-ends pipes made for the Express. They were pretty pricey, last time I checked, and since I wasn't wanting to do competitive racing or anything like that, I just went with a cheep solution.

Feel free to send me a PM if you need details on any of this stuff. Good luck with your new bike, man! Arrive alive.

Re: 78 Honda Express(NC50) 70cc DR kit

briny briny /

Excellent answer!

Re: 78 Honda Express(NC50) 70cc DR kit

Kyle Strand /

Hey guys,

I just jumped into the same boat with a 1979 honda express.

I think i've figured out what parts i need, except the header.

If i get the DR kit, what will work? I dont have the stock head.

I think a spree will work, i read that somewhere.

I dont completely understand the jets, but if i get a mikuni 20; like you all recomend, it doesnt need modifying. Is that correct?

And treatland seems to be out of the carb i need. I could try other sites, are there any you reccomend? Or do they get parts in regularly?

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