Hyosung Morini Big Bore and Exhaust Dilemma

[Greg]

Those are decent prices on reliable parts.
Here is the SD pipe / Flange: SD Old Style pipe
As far as I can tell the SF always had the flat mount flange. It looks like the SD had the weird flange then switched to the flat style.
It could be a year thing too. My Son's Sense is a 2005 with the old style flange.
Any ideas on where I can get a jet kit and what is a good range to start tuning a 70cc kit with Next R exhaust?
Also, I'd love to hear about CVT mods too. (rollers and contra, just rollers, what works on your bbk Morini, etc.).

[ThomasTPFL]

On the TGB using the Malossi cast iron kit and a 17mm Chinese clone Mikuni carb I was running a 95 main jet I think? With a very opened up air box.

Scooterpartsco also have a Malossi pipe for the Morini in the same price range as the Next R. I don't know what kind of power curve it has but it's got a better designed muffler, lol. The seized TGB I may be buying has one. It looks really nice.

scooterpartsco.com/malossi/01-malossi-master-part-list/malossi-racing-exhaust-for-tgb-50cc-scooters?zenid=4fc31619f06f431b74547bcaa865ef3e

[pinkscoot]

I would call Jorge at Scooterpartsco, he is a great guy and very scooter smart. He has a few personal Italjet morini scoots including 2 Velociferos. He also has good pricing on Malossi parts and flat rate shipping. His ship times to the SE are either very fast or about a week. He has an Italjet Dragster 180 that is a daily rider.

[Greg]

I have an email in to him for a jet kit.
Does the Morini use the same roller weights, contra and clutch springs as the Minarelli?

[Greg]

Nosey kid.
He knew exactly what was in the big box that arrived Saturday.
The big bore and pipe are a birthday gift from my wife and I.
My son will be buying the jets and transmission parts unless he can scrounge through my Mina transmission tuning parts.

[pinkscoot]

My memory is they are different sized rollers. I used a minarelli contra spring but it was tight. Up grade to a Multivar and they use the 16X13 rolers found on QMB139 4 poke's. Otherwise my stock ones are 17X12. Scooterpartsco and Partsforscooters has that size.

[Greg]

I ended up buying a Stage 6 17 x 12 rollers set with varying weights with 4.1, 4.5, 5.0 and 5.4 sizes. We are still waiting on those. In the meantime, I got the Malossi cast iron big bore kit and the Technigas Next R pipe. I also got the red and yellow contra springs.
I got the BBkit an pipe installed. There was some fitment issues, but we got past those.
I got it fired up on an 86 Main jet to start.
It is cold here, probably about 50 for a high.
It is running, but I had to go down to an 82 for decent results. It wasn't running good on the 86, so I went to a 90 and it was way worse!
So 82 is close. There is more tuning to do, but I am making HP with the 82 for now.
This is a 2005 Sense. It has become very apparent that there is a CDI rev limiter.
The scoot is getting to 30 MPH very easily but will not go past it.
I looked at the CDI and the blue wire was cut.
I connected the blue wire and now the scoot cannot got faster than 25MpH!
Wow, it looks like I have a restricted CDI.
Time to go shopping some more!

[pinkscoot]

Have you been to the Korider forum. They are an all Hyosung forum? You might get some info there.

[Greg]

Thanks. I did not know that. I have seen posts from there when doing Google searches but didn't know for sure.
I'm pretty close on my own.
I have figured out the sense wiring so now I can wire in any 5 or 6 pin CDI as I also built a 5 to 6 pin converter.

The CDI wiring is unlike most scooters. For starters, generic 5 pin CDIs do not use the top middle pin (pin 2).
This Sense uses all 6 pins.
The service manual doesn't even show the 6th blue wire. Since the scoot goes 5 MpH faster with the blue wire cut and its not shown in the service manual, I didn't use it in figuring out the 5 pin configuration.
The blue wire is not on pin 2 of the CDI, so I think there are very few CDIs out there that are plug and play.
I'm very close on this. I got it to run good on a spare marginal 6 pin CDI (a CDI known to not want to run in conjunction with a starter engaged) , but then when getting to test ride, my marginal CDI would fire but not stay running. Hooking up the original CDI and the scoot starts right up. So I have a 5 pin and 6 pin CDI on order. Gonna try a couple different ones.

[ThomasTPFL]

The TGB harness is weird. It has wires going to all six pins but the CDI is only five pin. If I remember correctly when I studied it it looked like it was set up to run either a AC or DC unit. I replaced the restricted CDI I had with one from a Buddy 50 ndnit worked great. Don't know if your Hyosung is similar.

[Greg]

It probably is the same.
That 6th blue restrictor wire was really throwing me off.
I now have an adapter harness so I can use a 5 pin or a 6 pin CDI.
The only two wires I am unsure of are the two from the stator.
The red/black and black/yellow I thought R/B was stator power and B/Y was pulse.
When testing it only fired here and there.
When I reversed the two, the scooter ran on a 6 pin (4 and 2 connectors) CDI.
I ordered a "CDI AC 5 Pin Racing No Rev Honda DIO Honda Elite Honda Spree Daelim 2 Stroke TGB".
Unfortunately this was damaged in shipping and another is on the way. But even this "TGB CDI" I can tell will need to be rewired because it is not using the top middle pin (like most 5 pin CDI setups). The Hyosung harness has the middle wire going to the coil.
I'm getting a great refresher on ignition wiring!

[benjiescoots]

Can you please give an update? I own a 2001 Sense and believe my CDI is broken. I have ordered a new one but its is one of the 5 pin kind. Did you ever find the right wire config for one of these "blue box" CDIs? I am also looking to buy a BBK for this bike, due to the fact I'm sure the piston and cylinder could use a replacement (why not BBK it right?). How did your tuning go end up?

[Greg]

May 13, 2019 1:32:50 GMT -5 benjiescoots said:

Can you please give an update? I own a 2001 Sense and believe my CDI is broken. I have ordered a new one but its is one of the 5 pin kind. Did you ever find the right wire config for one of these "blue box" CDIs? I am also looking to buy a BBK for this bike, due to the fact I'm sure the piston and cylinder could use a replacement (why not BBK it right?). How did your tuning go end up?

I ended up buying 2 blue boxes 1 black box and 2 orange boxes.
I think I got the wiring right. The scooter would run on them, for a little while.
I spent a lot of time and research trying to get it right. The last straw was when the bike was running on the replacement 5 wire black box. A little while of run time, I inspected the CDI and there was a bulge about the size of a dime. The capacitor inside the CDi was getting so hot it was melting the plastic.
Our CDI had always worked. I thought it had a restriction. Months later the restriction was found in how I fabb'd the intake. We bought the scoot with no airbox. When fabbing a Uni to a heater hose which goes to the carb, I used too much silicone and really restricted air intake and causing us to jet down to 82. With restriction cleared we are at an 86 or 88 jet.
So we are still back to the original CDI and I threw out about 3 CDI failed experiments.
I would suggest getting a replacement CDI here:
www.koreanbikeparts.com/hyosung-scooters/sd50.html?p=3

I have bought some cool OEM parts from them like a Hyosung key blank, oil and gas caps.
Get it running, then I can tell about fun surprises I had going BBK.

[pinkscoot]

My experience with the SF50 engine you needed an OEM CDI.

[benjiescoots]

Oh god do I even want to know about these "surprises". I'm just trying to get this darn thing running so I can get to work a bit easier. Do you remember if you ended up ordering the origanal CDI or the after market one from the site you provided? The "origanal" is out of stock, dont imagine they will get more.