Re: Honda Motocompo NCZ50 - The build log!

Toby B Wrote:

-------------------------------------------------------

> @ Graham Motzing, I just ordered a 46mm Puch

> Airsal head, which will need to have the holes

> slotted to suit the Honda stud pattern. To that

> end, I have been attempting to bring myself up to

> speed on the best way to achieve this and have

> read a couple of references to a bushing kit that

> you are repeatedly credited with. I don't suppose

> you'd be able to point me in the right direction

> as to how I might lay my hands on one?

I think the bushing kit was for derbi heads though.

Re: Honda Motocompo NCZ50 - The build log!

Thanks Will. It was definitely a Derbi head conversion that I read about, though I thought it might have the same bolt spacing as the Puch (haven't gone looking to confirm).

Re: Honda Motocompo NCZ50 - The build log!

This thread just keeps getting better! Nice work! Keep it up!

Re: Honda Motocompo NCZ50 - The build log!

This thing is so cool, and I love the car too!!

Re: Honda Motocompo NCZ50 - The build log!

holy shit you have the car too. i love this

Re: Honda Motocompo NCZ50 - The build log!

I'm in love. So much. With all of it.

Re: Honda Motocompo NCZ50 - The build log!

Hey fellas,

Not too much to update on since pre-weekend. I did however manage to take the 'compo for an additional run since putting the Boyesen dual stage reeds in. I can confirm that whilst they make the throttle seem a little more crisp in the mid-range, there is in fact no change to top end performance. I took the bike along the same stretch of road that I recorded 48.4km/h on last time, and amazingly hit the exact same number with the Boyesen reeds.

The plan was to then fit the 21mm Dellorto to this 50cc setup, but rather than having to tune the carby twice for two different setups, I will instead just move straight onto the 70cc setup and tube the carb for that. I've ordered a few extra bits from Treats, so once they're in hand i'll start updating a bit more!

Re: Honda Motocompo NCZ50 - The build log!

ᴛᴇʀʀʏ ᴅᴇᴀɴ /

the 2 stage reeds shouldn't really give you much of a top end boost, assuming your stock metal reeds were working well, since at full blast they will be opening up about the same as the stock reeds.

that said, you could cut the divider bridge between the two reed holes out your reed block now that you don't need it, this would get you more air in when the big reed opens up all the way.

Re: Honda Motocompo NCZ50 - The build log!

Yeah, it absolutely makes sense that the size of the openings in the reed block are the limiting factor, and so there shouldn't be any difference in top end performance. I was actually planning to enlarge the reed windows, which I might have an attempt at during this week.

Re: Honda Motocompo NCZ50 - The build log!

ᴛᴇʀʀʏ ᴅᴇᴀɴ /

cutting that bridge out will help a bunch! i wouldn't go too huge until you've got your carb situation worked out tho, bringing in more air but not more fuel can make a 2 stroke unhappy

Re: Honda Motocompo NCZ50 - The build log!

Toby B Wrote:

-------------------------------------------------------

> Yeah, it absolutely makes sense that the size of t

> he openings in the reed block are the limiting fac

> tor, and so there shouldn't be any difference in t

> op end performance. I was actually planning to enl

> arge the reed windows, which I might have an attem

> pt at during this week.

Definitely worth a try there is a good thread on it somewhere. Those aftermarket reeds make for a more safe cylinder as the metal reeds fail especially when they got old and they can make a mess out of your piston.

Re: Honda Motocompo NCZ50 - The build log!

Re: Honda Motocompo NCZ50 - The build log!

Thanks Will !

Re: Honda Motocompo NCZ50 - The build log!

Brandon Weiss (Detective brandon to you) /

Loving this thread....

Re: Honda Motocompo NCZ50 - The build log!

Toby B Wrote:

-------------------------------------------------------

> Thanks Will. It was definitely a Derbi head conver

> sion that I read about, though I thought it might

> have the same bolt spacing as the Puch (haven't go

> ne looking to confirm).

derbi and puch heads are not directly interchangeable unfortunately.

Re: Honda Motocompo NCZ50 - The build log!

Thanks for the confirmation Dave.

I've ordered a big 'ole Puch head from Treats, so will size it up once it arrives.

Re: Honda Motocompo NCZ50 - The build log!

Nobody likes a bully. * /

i love motocompos but paired with the unobtanium (in the US at least) City 2... hnggggg...

Re: Honda Motocompo NCZ50 - The build log!

Yeah, the City Turbo's are pretty damn thin on the ground here too. I wouldn't think there would be any more than a dozen registered ones in the country.

Re: Honda Motocompo NCZ50 - The build log!

Not much to update on.

I've received another parcel from Treats so am slowly piecing things together and plan to start pulling the Motocompo apart to put the 70cc drive-train in place.

I did however notice a horrible casting transition in the Malossi intake manifold, so it was out with the dremel to tidy it up. During this week i'll also take to the reed cage with a grinding bit, to allow the 70cc to breathe as much as possible.

I also noticed that the Dellorto PHBG as delivered had the needle set on the highest (leanest) notch, so i've stepped it down one position, to avoid some catastrophic seizure straight out of the box. From memory the needle has four notches, so i am contemplating whether I should actually raise the needle even more, to the 3rd or 4th position. Thoughts?

IMG_0067.JPG
IMG_0064.JPG

Re: Honda Motocompo NCZ50 - The build log!

This thread is gold! I have a Motocompo as well and been researching ways to get more speed out of this NCZ50. Looking forward to see improvements!

Re: Honda Motocompo NCZ50 - The build log!

There was an episode of Mighty Car Mods about these bikes!

Re: Honda Motocompo NCZ50 - The build log!

Hey sorry i didn't see this, pm or email always best.

I haven't made any of those for awhile, sorry, and yes derbi heads only. Folks get away with just hogging out slots and using a couple big washers but given how much load those tiny M6 studs (bolts on the hobbit/express, even worse) are under that really freaks me out.

The bushings i made were kind of a top hat shape with a hole drilled off-center. There is a writeup in the wiki on them. If you have access to a machine shop they shouldn't be too hard or expensive to make or get made.

> Toby B Wrote:

> -------------------------------------------------------

> @ Graham Motzing, I just ordered a 46mm Puch Airsal head, which will

> need to have the holes slotted to suit the Honda stud pattern. To that

> end, I have been attempting to bring myself up to speed on the best way

> to achieve this and have read a couple of references to a bushing kit

> that you are repeatedly credited with. I don't suppose you'd be able to

> point me in the right direction as to how I might lay my hands on one?

Re: Honda Motocompo NCZ50 - The build log!

Downhill Harvey (OFMC) /

so i am contemplating whether I should actually raise the needle even more, to the 3rd or 4th position. Thoughts?

That's what the trailtech temp gauge, that Ken mentioned, is for. It is indispensable when tuning. A temp gauge, and plug chops, determine carb settings.

Did you Upjet/make jetting changes when you put on the performance pipe? seems like you should've got a lot more performance, are you running a performance mesh filter ? If you change the exhaust output you got to change the input of the carburetor/air filter to match.

I am however surprised that you feel going from 24mph to 30mph (25% bump) is not as much as you'd imagine. What do other mopeds typically see with just a change of pipe?

What Ken means is that all pipes require a re-jet of the carb. On most mopeds, with a pipe, re-jet, and opening up the airbox, (and maybe a little messing with the vario) will yeild 10mph over stock.

Could you snap a pic of the engine with the belt cover off, I wanna see what's in there.

Re: Honda Motocompo NCZ50 - The build log!

Thanks Downhill H.

I might have mentioned in a previous post that I did not change any carb settings once I put the expansion chamber on, because the Motocompo comes with a pissy 12mm Keihin carb with a pressed in main jet. As I never intended to persist with that carb, I wasn't inclined to run a drill through my original, incase I ever wanted to revert back to standard some day. But I completely agree that it would have gone better still with some more fuelling.

Anyhow, I actually got this beast fired up over the weekend with the 70cc Polini and 21mm Dellorto in place.

Unfortunately (or fortunately actually) my jetting was well on the conservative side, with the bike 4 stroking crazily at around 6,000rpm. Even so, it surged to 25mph quite quickly, and should do a lot better once I can access those final 3,000+rpms. For reference, I started with a 98 main jet.

However, I have not pulled it apart just yet to downjet, as my idle jet is also too high (carb supplied with a size 50). I just ordered a 42, 45 and 48 to play with, so once they arrive I will also downjet the main and try again!

Re: Honda Motocompo NCZ50 - The build log!

Loving this thread!

Re: Honda Motocompo NCZ50 - The build log!

Hello guys,

Been doing some more mucking around with the new 70cc/Dellorto setup. I originally started with a very rich 98 main jet, and stuck with the 50 idle jet which came fitted to the Dellorto. I was actually having a lot of trouble to get the idle to crack cleanly in the 1-8-1/4 throttle range, so downsized to a 45 idle jet which seems a bit better. I realised after ringing the throttle harder, that the 1/4 throttle cleaned up a lot more, so i don't think it was a case of the original 50 idle being bad, so much as the plug was just fouling up at low rpm's.

Anyhow, first run on the 98 main jet was waaay too rich. I could barely get past 7,000rpm without it 4 stroking quite heavily. I then dropped right back to a 92 main, and went for a ride today. It rides much nicer, though it still hesitates in the upper rpm's unless you wind up the throttle very gradually. Essentially, it is still too rich but i'm getting results. Even with the 4 stroking in the upper rpm's, it's picked up a few more mph, up to 55.8kmh / 34.6mph. The temperature is slightly concerning, so I will be looking to use the Puch gigantor head, which can only make things better. In the mean time, i'll drop to a 90 main and do a plug chop.

IMG_0118 (002).JPG

Re: Honda Motocompo NCZ50 - The build log!

Downhill Harvey (OFMC) /

There's two motocompo drag bikes in this video,

https://www.facebook.com/LubeStar89Official/videos/659322077589059/

Re: Honda Motocompo NCZ50 - The build log!

Alright moped friends... I seek your valued input.

The 70cc Polini and 21mm Dellorto are up and going, but i'm having some WOT issues. A summary of my setup as follows;

70cc Polini kit

OEM custom cut head to 46mm. Basically this: https://www.treatland.tv/honda-nu50-46mm-custom-cut-head-p/46mm-cut-head-urban.htm

Dual stage Boyessen reeds with slightly enlarged reed windows

Malossi intake manifold

Malossi air filter with metal screen

Standard BP5HS plug

Custom expansion chamber

Dellorto PHBG 21mm carb kit: https://www.treatland.tv/honda-hobbit-malossi-PHBG-carburetor-kit-p/honda-malossi-phbg-kit-1610944.htm

As delivered settings on carb as follows;

* 90 main jet, 50 idle jet, W7 needle with clip on leanest setting, AU262 atomizer

Now. First thing I did was upjet to a 98 and change the needle setting to the 2nd richest. However, this setup just ran super boggy and struggled to manage any speed beyond half throttle, with heavy 4 stroking. I could not get a crisp 1/8 throttle either, so downjetted the idle to a 45, and dropped the main right down to a 92.

With the 45 idle, it was definitely better on the 1/8 throttle, however, I think my plug was just fouled when i was testing the 50. Either way, i'm pretty happy that the 45 is suitable.

Now, with the 92 main, I was still struggling to get that last 20% of the throttle before it started chugging again.

Against my own better judgement, I then fitted the 90 main which came with the carb, but my WOT problems remained. At 80% throttle it rides nicely, but if you ramp up the throttle too fast or go from 80% throttle to 100%, it just chugs and drops speed. I did a plug chop, and to me, it looks lean. Image below.

90main.JPG

I then reverted back to the 92 main, and changed the needle setting one notch higher (now 3rd from the bottom), but to be honest, didn't notice much difference, with the top end still being inaccessible, but riding nicely at about 80% throttle. I did another plug chop, with it looking a little darker, but still on the lean side of an ideal looking plug (in my opinion).

92mainmiddlenotch.JPG

So.... what next? I'm thinking I should check for air leaks, but to be honest, it seems to idle fine and work smoothly at 0-80% throttle, so not sure if that's the problem. I feel it is just the tuning that is not right. Should I work my way back up and try a 94 jet? Should I try a colder plug? I have 6's and 7's here, but just haven't tried one yet. I am also thinking of putting my un-dremeled reed block in with the standard window sizes, in case it's getting too much air... if that's even possible?

Also, my engine temp escalates way too quickly. I was seeing 430F after 5 minutes of riding, so I will be slotting some holes in the Puch gigantor head and fitting that ASAP.

I welcome any and all input!

Re: Honda Motocompo NCZ50 - The build log!

Don't put holes in the head. More mass dissipates more heat!

Re: Honda Motocompo NCZ50 - The build log!

Will, to clarify, i will be slotting the holes in the monster Puch head, to fit the Honda stud pattern.

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