To all you guys who have done some express tuneing

So I have come to the point where I just don't think I can get much more out of my stock 78 motor, and I have found a guy that has the goods to hook me up with just about whatever parts I need to build an Express Omega, the penultimate express, as there can always be one better. I have been reading through posts for a couple days here, props to Jax184, Derek, Hawkster, and I.R.A. rick for the valuable info left through the years. At this point, I am going one of two directions and I can't choose which.

1. Get a two speed engine from 80 on, bolt it on, get the hp CDI and combined with all my other express shit rip it up, or on the more ambitious side,

2. Get an urban engine off of an NU50 and swap it on there. I know this one has more potential, but it also seems like a lot more possibilities for complications.

I just want some advice from guys who have done either or both of these swaps. I already have the carb worked out I think, but I hear that the newer express engines have a throttle cable that splits into three different cables? What the hell is that about? I should clarify that since it will be kitted from the get go, the oil injector/pump, auto choke, top end and any issues arising from any of those parts will be a non issue.

I am super pumped, I already love the looks of people seeing a screaming express on the road, I can't wait to see the reaction to a screaming express passing them!

One last thing, anyone know how compatible sr/nx parts are with nu/urban parts?

Thanks, again.

Re: To all you guys who have done some express tun

Go with option 2.

The 2 speed engines have the same final gear ratio as the 1 speeds; unless you weigh like 250 lbs. it's not worth it. Plus the 2 speeds are more fragile then the 1 speeds.

Passing on an NC is awesome.

Re: To all you guys who have done some express tun

How hard is it to swap out? Pretty much what I am trying to ask is what do I need to make it happen? Engine of course, wiring harness, what else? Bulbs, ummm, rear wheel/rim, anything I am missing? Problem is I looking at a 4 1/2 hour round trip plus part finding/scavenging/shooting the shit time, so I can't just run back over when I need the whatsit for the whoosimit.

Re: To all you guys who have done some express tun

Not easy.

You'll need all the wiring for the NU; the longer rear brake cable; throttle; carb and choke; battery; and the rear wheel.

You'll need to figure out a longer rear shock and you'll need to switch to 12V bulbs.

That's about all I can think of. Jax was doing this like 2 years ago but never finished and won't give any updates, maybe try e-mailing him.

Re: To all you guys who have done some express tun

Ok, well what does a post 80 to pre 80 swap take? I might just build an urban later, it sounds like a lot of work just to eliminate that johny 5 lookin frame. I am still going to find out if sr gears fit into an urban engine.

Re: To all you guys who have done some express tun

If you come to Whiskey business all of your questions will be answered.

Re: To all you guys who have done some express tun

I'll be there and can't wait to see it.

Re: To all you guys who have done some express tun

johnny 5 is alive!

Re: To all you guys who have done some express tun

I've had both a 1982 Express (2-speed) and now I run the 1983 Extreme Express. I still have the stock NC50. I swapped because of the limited performance capability of the two-speed. With the Urban you can tune the trans/clutch for your specific purpose (ie: weight, hills, drags) although, I had to make custom bushing for the variator

Having built both, the Urban is considerably different as described above, wheels, 12v, wiring, cables. It's just a bigger, heavier bike which is one of the things I wanted.

Hondas just don't have many options for performance other than kits, some pipes and DYI, which is what I did for carburation/intake/reeds. I've been playing with this stuff for some years and I'm now running a Mikuni 24mm with no problems on my 70cc kitted bike. I have a 26mm on the bench and a new CT 4-petal block in the works.

Also, Urban parts are much harder to find and thus more costly. If you decide to build an Urban, try to buy the BEST, most complete starter bike you can. I built mine one-piece-at-a-time off of Ebay and it took a few years to get everything together for the build.

Check out specs on the MA performance tuning spec sheet for the 20mm version.

Check out You Tube for the Extreme Urban Express Tour and Clutch Operation videos.

Check out this addy for a gent in Australia who premiered my 1982 NC50 on his NC50 tuning website. The last pics is the Extreme Urban under construction. Be sure to read his Bio, a very interesting and educated guy.

Whichever chassis you choose, I'm sure that you'll have fun doing it.


Re: To all you guys who have done some express tun

Rick, how do you like that Proma Lowboy? Have you tried any other exhausts?

So looking at this picture

It looks like you have the support bar for your exhaust mounted to the frame instead of the engine. Bet that worked out well with the engine pivoting an all, haha.

Re: To all you guys who have done some express tun

Ha!, good catch in that pic. No, I was just anxious to get some pics taken and hung a dummy brkt on it at that time. The "working" brkt I used for a few years ran almost horizontaly from the case boss behind the stator cover. It wasn't ideal, but it worked fine by tightening the shit out of it with 5/16" bolts and nylok nuts.

On the Extreme Urban you'll notice that I cut that lame mid-pipe brkt off and re-welded another one on back by the silencer to catch the fender support. That has worked out very well to hold up both the right side of the fender and the pipe. Also, I made a custom, HD, rear fender/front case mount brkt because I couldn't use the stock one with the carb mods.

As far as pipes goes, this is the only one that I've tried. I salvaged some larger pipe sections from work to modify the header pipe for the larger carbs and reed setups I have in the works. The 24mm carb seems a bit "exhaust choked" to get optimal flow with the stock smallish Proma header pipe.

Got any recomendations for a better, higher flowing pipe?

I weld & fab so I can adapt just about anything that would work with the motor mods.


Re: To all you guys who have done some express tun

Best pipe I've found, other then the LeoVince and Proma Circuits is the one in the attached pic. It comes from the pocket bike section of ebay for like $50; but I have yet to try the Lowboy yet though.


Re: To all you guys who have done some express tun

I shouldn't reply to this thread. It's too great to just lurk in, though.

There are lessons to be learned from the... um, let's just say "work" that I do.

For example, I made the pipe in the attached image based on a model I found in On Beyond Zebra and some parts from IKEA trash.

In the process of doing so, I learned that the Express exhaust header is absurdly easy to duplicate (unlike the tortured nightmare that is a header for a 103 or a Grande).

Make your own header, and then use whatever pipe you can find!


Re: To all you guys who have done some express tun

Gah! Yeah, you sort of have to be prepared for it.

Also, yes, the license plate bracket was hitting, so I just turned the whole assembly on its side.


Anyway, I also learned to not rely on the stock exhaust bracket.

Derek showed one solution with his pocket bike exhaust support bar. Another way - the way that's too obvious to actually do, really - is to carefully use a 180-degree-bend support bar to undo all of the hard work that Honda put in to making the single-sided rear swingarm.


Re: To all you guys who have done some express tun

Last one. I used stainless steel table knife handles as brackets to

anchor a bar wrapped around the rear wheel (in green) that

supports the significant weight of my absurd exhaust.

This exhaust works great, by the way. I don't know how well my

speedometer works, but it pins now. It didn't do that before...


P.S. - Thank you Derek and Rick for taking Expresses seriously. I

aim to not crap in your sandbox.

Re: To all you guys who have done some express tun

Are you sure that you didn't install the silencer on the wrong end? Looks like the pipe os on backwards. HaHa.

Hey, whatever works for you. I'm a salvage whore too. I always keep my eyes open on trash days and behind business' for stuff that I might be able to use for another application.

Re: To all you guys who have done some express tun

Keep it up, innovation is the Mother of invention! Don't take me too seriously. But I do love what you've done with what you have available.

For so many, for so long, with so little...

Re: To all you guys who have done some express tun

OMG! Reversible pipe!

"Sure, you call your pipe a bi-turbo, but does it bolt on both ways?"

Re: To all you guys who have done some express tun

i just re-did my mount this past weekend it's super solid now, I'll post pics tomorrow.

The attached pic a pipe i just made this past weekend for a guys NU50.


Re: To all you guys who have done some express tun

I have tried that pocket bike pipe, and for a time it was good, but I think my header has kind of fatigued because the flange lip busted off after a hundred miles or so. I think the increased vibrations had something to do with it. I wish I had pictures of it mounted on my bike, but I took off the engine to prepare for the kit'n'swap. They mount up almost perfect, all you need is a little piece of bracket to reach the last inch from the pipe to the fender bracket, or wherever else you want to bracket it to.

If you notice the dimensions are quite similar. I think the inner diameter of the jamiriqui pipe is like a couple mils bigger, and the flange lip at the end is way more substantial, which was a major selling point for me. I think ifn I remember correctly, the pocket bike pipe had a tiny bit more speed on the top, but the jammy more than made up for it on acceleration. I am going to get my new engine tamary and I think I am going to make it the two speed, then down the line somewhere just go ahead and build an urban as an urban, just too much hassle.

I have been kind of mocking this one up and think I might have figures out how to mount it up with a little modification. From the looks of it though it seems like a lower end pipe designed for take off and mid range, and with a kitted two speed engine I reckin acceleration is going to be one thing I am not short on.

Re: To all you guys who have done some express tun

These darn bikes just don't have an easy place to mount a pipe and we have to get creative. That's where I ended up putting mine on the NC50, very similar mounting to about mid-pipe.

It looks like this guy did an epoxy manifold conversion to mount a Dellorto. I've never tried the epoxy for anything structural where I tapped it for a screw. I have used it for some other support or repair type stuff though.

Re: To all you guys who have done some express tun

Also, I was wondering your guys opinion on my carb set up. I have a 16mm mikuni clone on there right now, and it mounted up really well. I am wondering if thats going to be enough carb for the 65cc Dr. kit, or if I should start looking for a way to slap on a counterfit 19 phbg I have laying around.

P.S. sorry for the crappy pics, but my walgreens 20 dollar camera is doing its best.

Re: To all you guys who have done some express tun

Is the snail a Proma Circuit pipe? How well do they fit an Express?

As a rule, the smaller the stinger at the end of the pipe the more top end power and higher RPM's it usually produces. Larger stingers are better for low end torque and less revs. Sometimes it's hard to see in a pic when there's a silencer covering it. Of course, there are many other factors to consider to make this a completely true statement.

Re: To all you guys who have done some express tun

Definitely go for the 19mm if possible, but you'll probably need to be doing some jetting. If you can't afford them or don't have them available, better stick to the smaller, more forgiving carb. Also, it looks like your running the stock manifold. Do you have the large Express reeds or smaller ones? There are two available with one being about 20% larger. Not sure which one is which (Iowa, non-Iowa, Urban?) but I have both in my spare parts box that I've acquired over the years. I'm going to put the larger one on my stock NC50.

Re: To all you guys who have done some express tun

Click here for details of my bike...

I'm running a 15 SHA on a 70cc Parma kit.

The epoxy isn't supporting anything, I just used it to form a smooth passage though the intake.

That black and gold pipe is OK, kinda heavy, sounds kind of moto-x'ish, the bike I used it on had a bad belt at the time so I can't say much about it's performance other then it seemed to work right.

Re: To all you guys who have done some express tun

I have [like three sets of performance reeds for the express. I was running a set of carbon fiber ones I cut down myself, but for this build I got both the stock and mod dual stage boyesin reeds. Express stock reeds are crop I think, thats why you see all of the old air filter boxes with stains where gas mixture has been puked on them over the years.

Re: To all you guys who have done some express tun

Nice read Derek. Pretty much my experience with the Metrakit. I had to go around and check the gaskets and match ports. I did not have to cut away any fins though, I don't think mine had that plug(?). I'm at work and can't check right now.

The manifold looks good too. I think that you got as good of an angle as you could get to get around the stock 90* bend . Hope the putty holds up for you, watch out for vacuum leaks and running lean. Although I'm happy with what I did/have now, I'm already working on another one for a different reed block so I can mount my Miki VM26mm

I didn't take that much time to break mine in. It's just a toy for me and I don't ride far. If I seize it I'll just call the wife to come pick me up in my truck. I also don't have a problem taking it apart, up and down. So far, so good though after 4 tanks of fuel. I just run Honda pre-mix at 28-1 w/ premium gas and hardly get any color other than the good brownish tip I'm looking for.

Again, nice pics and "white paper" documenting your kitting experience and I look forward to seeing more on your project bike.

Re: To all you guys who have done some express tun


that snail is not the proma circuit, there is one in the big urban pic on the floor behind the bike, or check here for better view


Re: To all you guys who have done some express tun


copy & paste, (without the quotes), im too lazy to redo it.

mine bolted right on to a spare bolt hole on the alternator cover, my friend who had a hobbit, the bike its made for, had to cut & re-weld his mounting brackets. i did have to remove my center stand, working on a side kickstand.

Re: To all you guys who have done some express tun

anyone thought of puting the pipe on the other side? you could have to bed it diff... but you would have lots of things to mount shit to.

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account