Suzuki FA50 Moped - "The Bumblebee," or, my first two stroke

adventurco

Nick Ol' Eye
DTT BOTM WINNER
After romping around the neighborhood on one of these the other day, we decided we wanted to snag one to tool around on. This came up about an hour away for $80, seemed like a decent deal so we hopped in the truck and scooped it up. It was put away by the PO after it got "hard to start," may need a set of rings but we'll see.



Not sure if the kicker is installed correctly, I think they're usually parallel to the ground and kick down to about 6:00, and it marred the hell out of the case and Suzuki logo.



The footpeg support plates are both broken, looks like they were both JB welded and only one made it. No big deal I'll just weld a chunk of scrap on the missing one and run a bead over the JB.



First things first, a cold compression test showed 90 PSI. Seems low, but I'm not sure. I couldn't find a value in the service manual, only the compression ratio which is 6.5:1. I'm sure I can find spec range somewhere.



Yanked out the little baby carb. Clean as a whistle. The float bowl gasket even came off in one piece. That never happens. Throttle cable was a bit sticky so I'll have to address that later. Pretty sure the PO drained all the fuel before putting it away, which is a damn good surprise. Even the jets were clean. Quick soak for peace of mind and then I'll slap it back together.





And a tiny little container to stick all the tiny carb parts in ;)



Tomorrow I'll see if we can get spark. It has a PEI ignition which I've never heard of but has got to be some type of electronic ignition dealio. It's got a magneto so I think I can just complete the circuit where the battery would be and it should get spark. To be continued!




Sent from my iPhone using DO THE TON
 

adventurco

Nick Ol' Eye
DTT BOTM WINNER
After a bit of searching it seems like 90 PSI is right on for these little scoots. So that's good news, I shouldn't have to pull the cylinder off. Standard piston kit with rings is only $20 shipped from japan, so I may pick one up later to stick in the shop just in case.

I'm unfamiliar with 2-strokes, but I know crankshaft oil seals can cause hard starting and general problems. Would a bad crank seal cause low compression in the cylinder or would that show itself some other way? I'm thinking it can't hurt to replace it, only cost about $7 on eBay.
 

hillsy

Active Member
Bad crank seals won't affect compression, but they will make the bike run lean as it will suck air in through the worn seal instead of fuel / air through the carb.


On one of these engines the crank seals should be pretty easy to replace (as opposed to a triple), so if I was you......
 

adventurco

Nick Ol' Eye
DTT BOTM WINNER
Only explosions I want should be inside the cylinder ;D

Crank seal on the way. Worth buying one of those pullers or should I just use a screw?
 

VonYinzer

Active Member
Posted this in the "Latest Purchase" thread, but I'll post here as well so I can follow along. I have two of these plus some in the garage. Let me know if you need parts...
 

adventurco

Nick Ol' Eye
DTT BOTM WINNER
VonYinzer said:
Posted this in the "Latest Purchase" thread, but I'll post here as well so I can follow along. I have two of these plus some in the garage. Let me know if you need parts...
Sweet!...I'd not be opposed to a headlight and fenders, luggage rack, if you've got any extras. Once I get it moving, that is.
 

VonYinzer

Active Member
adventurco said:
Sweet!...I'd not be opposed to a headlight and fenders, luggage rack, if you've got any extras. Once I get it moving, that is.
Shoot me a PM with the stuff you're looking for and I'll do some digging in the garage.
 

adventurco

Nick Ol' Eye
DTT BOTM WINNER
Re: Suzuki FA50 Moped - "The Bumblebee," or, my first two stroke

I started out today with spark, not great but definitely there. Cut the end off the plug wire and got a new bite with the cap and ended up with a nice fat blue spark. The exhaust was caked up with carbon and misc junk from being stored, so I ended up hacking off the tip of the muffler to clean it out. I'll run it like that temporarily until the welder is set up.

The carb was cleaned and reinstalled, even though it hardly needed it. The needle is set to the middle.



The petcock was a little sticky but a squirt of WD and it freed right up. I've got fuel to the cylinder, after cranking it a few times the plug is wet, but it's not sounding like it wants to start. I kick it over, but it's not firing. Somewhere between then and now I lost spark, so one of the dang ignition switches must have shorted out. Another project for another day.

I was originally thinking the timing was off, but in order to change it I need to pull the flywheel, with a tool that I don't have. Could also be something stuck in the reed valve, or the crankshaft oil seal if it's real bad. Not sure where to look next.




Sent from my iPhone using DO THE TON
 

adventurco

Nick Ol' Eye
DTT BOTM WINNER
Re: Suzuki FA50 Moped - "The Bumblebee," or, my first two stroke

Got sick of looking at this thing on the bench so I decided to get into it. About 20 minutes later we had this:

Trans case clean, as expected. The kicker shaft is indeed bent about 1/8" out at the very end. I chucked it up in the drill press to get an eyeball on it.

Cylinder and piston all good. Rings moving freely. Inside of the case looks clean as a whistle.


When I pulled the carb for tear down, the bowl was empty. Since compression above the piston was 90psi, I'm leaning towards a leak in the crankcase. I'm thinking it's one of these few things causing the problem: the 2 crank seals, the reed valve sealing to the top of case, or where the carburetor bolts onto the intake.


Sent from my iPhone using DO THE TON
 

DesmoBro

Busted Nut
You gonna go full out crank up rebuild with a kit and bigg carb and pipe? ......PppppppPlease...........do more reasearch ! What if a motobecane race crank fits right in ? What then?
 

adventurco

Nick Ol' Eye
DTT BOTM WINNER
Re: Suzuki FA50 Moped - "The Bumblebee," or, my first two stroke

Oh damn. Turbo scooter!!!

I'm trying to get to the crank seal over here, but this centrifugal clutch thingamjig is in my way. Manual says I need a clutch holder tool, but it's discontinued everywhere and I can't even find a good picture to make one. Any ideas?






Sent from my iPhone using DO THE TON
 

DesmoBro

Busted Nut
Search Moped Army repair section ****hint *****search all dates not just last month...but i think motion pro has one that could work
There may also be stuff in the moped wiki
There is also a tuning spreadsheet so you can see what kit pipe jet speed etc....others used & got
And if you search in the performance section youll see all sorts of tricks
 

Attachments

stroker crazy

crazy as a fox
DesmoBro said:
There is also a tuning spreadsheet so you can see what kit pipe jet speed etc....others used & got
And if you search in the performance section you'll see all sorts of tricks
This may be gathering momentum!

Crazy
 

adventurco

Nick Ol' Eye
DTT BOTM WINNER
DesmoBro said:
Search Moped Army repair section ****hint *****search all dates not just last month...but i think motion pro has one that could work
There may also be stuff in the moped wiki
There is also a tuning spreadsheet so you can see what kit pipe jet speed etc....others used & got
And if you search in the performance section youll see all sorts of tricks
I actually have read through there. The formatting on that forum makes it a pain in the ass to read though. I guess a popular mod on the FA50 is to shave the mating surface of the head, I think you can take about 1mm off to make the fins sit even with the cylinder. I'm not set up for it, all I have is a belt sander


Sent from my iPhone using DO THE TON
 

Nj732port

New Member
adventurco said:
I actually have read through there. The formatting on that forum makes it a pain in the ass to read though. I guess a popular mod on the FA50 is to shave the mating surface of the head, I think you can take about 1mm off to make the fins sit even with the cylinder. I'm not set up for it, all I have is a belt sander


Sent from my iPhone using DO THE TON
more has been done with less 8)

inspiration?
 
Top Bottom