The goal of this article is to get people looking at the basics before getting all crazy and ordering a bunch of parts. Don't worry, we'll get to top speeds and making it faster. SO KEEP READING
We started with a Met that "runs good, and goes 35-40mph" claimed the seller "It only needs a carb cleaning", I'm guessing her hack mechanic told her that. Not sure about the 35-40mph either but who am I to doubt it, the girl was half my size. After listening to it run it sounded like someone let loose marbles under the drive cover, I said, "what's that noise?" She said, "I think I ran over something and it's stuck on the wheel." No, I think it's in there (pointing).
She was quick to haggle after that, it's OK I was looking for this type of bike. For some reason Met owners seem to think if it's still moving it's all good. The problem is next they usually want to buy a bunch of parts and get mad when things don't work out. I'm not slamming Met owners here, I think it's just that more Mets are on the road so the issue is more common. Anyway we wrapped up the deal and I had a Met, no test ride, perfect Met for me, neglected and handed from hack to hack and into my waiting arms (^_^)
After removing the drive cover, then variator and clutch assembly it became crystal clear what all the racket was. I should have test ridden it, may have gotten a better deal. the point is 50% clutch each shoe was just dust and parts floating in the drive unit, and the girl was riding it like that (^_^) Add a CDI or anything to this and... Don't expect much.
So I always remove the drive cover and inspect all the parts inside for damage and wear when a bike comes to me with a performance issue or even to make it faster.
Needless to say, the clutch shoes and springs had to be replaced. I did the pulley spring and torque driver mod as described in the variator install article as well.
When the cover is off it's always a good time to grease the shaft on the starter pawl. They get stuck from belt muck and in this case a bunch of parts were sitting behind the gear.
Nope, didn't put them there. I took off the gear and low and behold a bunch of parts just sitting in there, waiting to ruin any repairs and new parts I'm installing. MMMm, I wondered where the old springs ran off to.
After taking care of that stuff and making sure all the metal bits were in the trash where they belong I moved along to something else I noticed.
More proof some half wit was mucking about the engine. The intake boot was not installed correctly. This is basic, just do it right. If this type of thing happens you can get an air leak which will cause all sorts of problems.
The entire airbox system from the intake inlet of the box through to the carb needs to be sealed. Leave one screw out or misalign something and fight jetting issues until you go mad.
I did get in there and make sure the jets weren't blocked since I was half way home. Just check that type of stuff if you are holding the part. I found some stuff in the float bowl, clutch pieces?? Nah.
While you have the carb off it's a good idea to look down the intake manifold on your Met. The MetII has a restrictor plate with a tiny hole for the air to pass through. If someone didn't remove it go ahead and do that now! The mid Year MetIs don't have a restrictor but the newer Mets do have a "restrictor" plate. I'm under the impression it's to better atomize the fuel in the intake. It doesn't restrict much. It's also possible the plate was added to slow the Met down a little. Mets have a tendency to always be bouncing off the rev limiter, more so than the Ruckus. Since the engine is just dumping raw fuel in the engine at that point things will ware out faster. It's also the reason CDI bike will get better MPG as well as the FI bikes. The newer FI bikes bounce off the limiter but they have a fuel cut too so no harm, no foul.
The air filter, Oh ya! A paper filter in there taking on water for nine years. Looks clean eh? Who cares, replace it. I couldn't blow through this thing to save my life.
When you replace the filter make sure you use the metal frame from the old one, otherwise just leave the filter out all together. The metal frame holds the filter in place and seals the box. This is the main reason the K&N for the Briggs doesn't work. Make sure if you use a K&N filter the part# is HA-0502. If someone sells you another part# from K&N pick up the phone and start yelling! Run those people out of town on a rail.
You went this far, time to check the valve clearances and change the plug.
The intake valve is almost always tight after 1000mi. and the plug needs to be changed. This one actually looked like the plug was newer. I'm guessing the "mechanic" thought a new plug would fix the clutch.
I'm not being mean to the owner here, she paid somebody posing as a tech to work on it. Whoever that guy is, he should be ashamed of himself.
Since I had all the plastic off to look things over I installed a CDI as well. It's a tight fit but you can stick it on top of the ECM, it makes for shorter wires and a cleaner install. I made four solder joints rather than the two required if you run the coil wires down to the coil. I prefer to do the coil wires right at the ECM.
This is a 2003 so the rev limit is LOW. The CDI helps even the higher limited 2006 and newer and Japanese 9.5k limited bikes. I rather have no limit and listen to make sure the engine is happy. It's called self control, I'm sure most of you have it (^_^)
Keep in mind these four push clips that hold the rear plastic on are very easy to use and break. Be gentle, the picture shows what one looks like when it's ready to be inserted. Push flat and it's locked. The coolest part is push again so it's in a little and the clip is ready to be pulled out. Don't force these things, if it's not coming out keep practicing. Sometimes a tiny rock can get stuck in the clip and keep it from unlocking but that's usually on sport bikes on the belly of the fairing.
This is our cutie all running good and feeling fine. Still breaking in the clutch, variator, belt and springs but I was able to 40mph on the first run out with my 200lb body on it. It's pretty cold out as we speak so I'm guessing with a little break in and warmer air she'll be jamming.
If you have a MetII you have a couple holdups. Some differences in years and versions are listed below.
2005 and older has 7900rpm limit
2006 and newer has 8900rpm limit
New design airbox, atomizer intake plate (not really a restrictor) and needle.
Restrictive catalyzer exhaust.
Older models only.
Stock 25mph. Though just because your Met does 25 doesn't mean it's a Met II.
Restrictor Plate - Remove the restrictor plate located between the intake manifold and head.
*Interesting fact. I've heard of dealers installing these plates on the Met I and Ruckus so they will meet the local moped laws. Since these bikes are so fast they actually exceed the maxium allowed speed for 50cc "mopeds" in most places.
Camshaft - Doesn't seem to effect too much.
Final Drive Gearing - Same as the Ruckus gearing but doesn't seem to effect too much.
Longer Carburetor Diaphragm Spring - Replace with a Met I or Ruckus spring.
ECM - Even lower limit can be overcome with an aftermarket CDI.
Variator - Replace with a Met I or Ruckus moveable drive face and weights. Aftermarket is better. Keep in mind the higher geared variators are better on the Met II with it's low final drive gears.