New Member: Just bought a Flywing MX 100 and a little confused.

T Bear · 12-02-2019, 05:42 PM

So I paid 50 bucks for what I knew was a basket case and planned to rebuild it.... Thinking I may have to swap the motor. It seems to be an electric start. on a bike that doesn't have a place to mount a battery...

I read some where on this forum (by the way THANK YOU to all who have been sharing info!!!) that a 125 will mount right up to this bike. So I was thinking about buying: Engine Assembly - 125cc 4-Speed Kick Start for Dirt Bike - Version 15
Will this work?

I should say that thought I have ridden street bikes my whole life I have never ridden dirt.

I bought 2 dirt bikes for a youth group and as a group we are going to revive them.

Weldangrind · 12-03-2019, 11:19 AM

Welcome! That's a bike I have some experience with. It's loosely based on the Yamaha PW80, with engine mounts for a horizontal Honda clone; the 125 is likely a bolt-in deal. When it's dialed it, it'll go like a scared rabbit.

That exhaust is awful and needs to go. It's also based on the PW80, which is a two-stroke. You can see how there is an expansion chamber that is not helpful and the pipe necks down after the chamber, just before the muffler. A generic pit bike pipe and muffler will do the trick (they're cheap and plentiful).

You might have trouble getting a pod filter to fit, since there is little room between the carb inlet and the frame. I solved that with a 45 degree intake and a foam pod on my son's first bike. You can also get a cheap carb rotator if necessary, to tilt the carb as necessary.

T Bear · 12-03-2019, 01:04 PM

Thanx Weldangrind. I have read a lot of your post and gained a lot from them. I have some VERY noob questions.

I have tried like hell to find a manual in English with no luck. I've also seen many on this forum doing the same SO... I am kind of piece together information where I can.

Wiring - should I be using a PW80 wiring diagram/harness or something from Honda? or does it really matter since I'm starting from scratch? If I'm correct all I need is a CDI, Coil, Kill switch, and the stator (which I think comes with the motor) since its a kick start only.

Fuel - in a street bike I run 93 octane. Should I be running the same in a dirt bike?

45 degree intake - any chance you can show me what you did exactly and where I can get it?

dirtbkr188 · 12-03-2019, 02:39 PM

My suggestion would be to buy the 125 you've linked above, and then go to TBoltUSA.com and get a complete electrical system from the Flywheel/stator to the kill switch for $99.00. The kit is complete so you know everything is compatible, you'll need a flywheel puller tool to swap the flywheel and stator on the 125 you buy.
You can also pick up a reasonably priced exhaust system that will work on your bike, and yes, you can run 93 octane in the bike.

full electrical system

flywheel puller

exhaust system

dirtbkr188 · 12-03-2019, 02:54 PM

I worked on a Panterra 12+ years ago, it has a similar frame configuration. I used a UNI pod filter with the 15° angled boot to fit under the twin-ribbed frame, and it worked well. You can see it in the photos below.

franque · 12-03-2019, 04:57 PM

Just run whatever's cheapest, it isn't exactly a high performance motor, high octane is just sending money out of the tailpipe.

Weldangrind · 12-03-2019, 10:19 PM

Quote:

Originally Posted by T Bear

Thanx Weldangrind. I have read a lot of your post and gained a lot from them. I have some VERY noob questions.

I have tried like hell to find a manual in English with no luck. I've also seen many on this forum doing the same SO... I am kind of piece together information where I can.

Wiring - should I be using a PW80 wiring diagram/harness or something from Honda? or does it really matter since I'm starting from scratch? If I'm correct all I need is a CDI, Coil, Kill switch, and the stator (which I think comes with the motor) since its a kick start only.

Fuel - in a street bike I run 93 octane. Should I be running the same in a dirt bike?

45 degree intake - any chance you can show me what you did exactly and where I can get it?

Nothing noob about your questions.

Despite that engine being a good deal, perhaps you'd care to shop for one that includes a complete wiring harness. It'd be nice to know that it's a matched system.

I use regular fuel, unless it's a high compression engine. High octane will only make a low compression engine harder to start.

Here's what I had in mind for the intake:

https://www.ebay.com/itm/Black-26mm-...YAAOSw-0xYbofx

Here's a cool option:

https://www.ebay.com/itm/Manifold-In...oAAOSwYmZXG0WR

EricE · 04-24-2022, 09:27 PM

Just curious, did you ever put the 125cc. Motor in? Thanks!

12-03-2019, 11:19 AM	#2
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Welcome! That's a bike I have some experience with. It's loosely based on the Yamaha PW80, with engine mounts for a horizontal Honda clone; the 125 is likely a bolt-in deal. When it's dialed it, it'll go like a scared rabbit. That exhaust is awful and needs to go. It's also based on the PW80, which is a two-stroke. You can see how there is an expansion chamber that is not helpful and the pipe necks down after the chamber, just before the muffler. A generic pit bike pipe and muffler will do the trick (they're cheap and plentiful). You might have trouble getting a pod filter to fit, since there is little room between the carb inlet and the frame. I solved that with a 45 degree intake and a foam pod on my son's first bike. You can also get a cheap carb rotator if necessary, to tilt the carb as necessary. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	1

12-03-2019, 01:04 PM	#3
T Bear Join Date: Dec 2019 Posts: 2	Thanx Weldangrind. I have read a lot of your post and gained a lot from them. I have some VERY noob questions. I have tried like hell to find a manual in English with no luck. I've also seen many on this forum doing the same SO... I am kind of piece together information where I can. Wiring - should I be using a PW80 wiring diagram/harness or something from Honda? or does it really matter since I'm starting from scratch? If I'm correct all I need is a CDI, Coil, Kill switch, and the stator (which I think comes with the motor) since its a kick start only. Fuel - in a street bike I run 93 octane. Should I be running the same in a dirt bike? 45 degree intake - any chance you can show me what you did exactly and where I can get it? __________________ T Bear early to mid 1970's Kawasaki F11 250 2003 Harley Wide Glide 2004 Jianshe Flywing MX 100 2007 Yamaha VStar Proof of motorcycles in biblical times: "David's Triumph was heard throughout the land."
	1

12-03-2019, 02:39 PM	#4
dirtbkr188 Join Date: Aug 2009 Posts: 507	My suggestion would be to buy the 125 you've linked above, and then go to TBoltUSA.com and get a complete electrical system from the Flywheel/stator to the kill switch for $99.00. The kit is complete so you know everything is compatible, you'll need a flywheel puller tool to swap the flywheel and stator on the 125 you buy. You can also pick up a reasonably priced exhaust system that will work on your bike, and yes, you can run 93 octane in the bike. full electrical system flywheel puller exhaust system
	1

12-03-2019, 02:54 PM	#5
dirtbkr188 Join Date: Aug 2009 Posts: 507	I worked on a Panterra 12+ years ago, it has a similar frame configuration. I used a UNI pod filter with the 15° angled boot to fit under the twin-ribbed frame, and it worked well. You can see it in the photos below.
	2

12-03-2019, 04:57 PM	#6
franque Join Date: Nov 2017 Location: Marseille, France -> Conakry, Guinea Posts: 1,481	Just run whatever's cheapest, it isn't exactly a high performance motor, high octane is just sending money out of the tailpipe.
	2

04-24-2022, 09:27 PM	#8
EricE Join Date: Apr 2022 Posts: 2	Just curious, did you ever put the 125cc. Motor in? Thanks!
	0