Owner's Manual/Service Manual part numbers
Yes, you can still get quite a few manuals direct from Yamaha! The Owner's Manuals are $30 and the Service Manuals are $60.

Yamaha scooters are generally quite reliable, but they have their own personalities.

Starting problems with the Riva 180/200

Here, I’m speaking mostly of the Riva 180, manufactured from 1983 – 1985. This scooter is famous (or infamous) for the “starting problem”. It has an incredibly complex carburetor/starting system. Maybe this system worked ok when the scooter was new, but nowadays after more than 15 years, it tends to have problems. The best way I can describe it is to say that I’ve had about 11 Honda Elite scooters, and 7 or 8 Riva 180/200 scooters. None of the Hondas every had starting problems, and all of the Yamahas have had starting problems or some sort…

Aside from the usual setup (carb, coil, etc), the Riva 180 has two solenoids, something called a bi-metal control valve, a mixture control valve, a thermo sensor, and a black box control unit for the solenoids. There are something like 9 hoses going to the carb. As you can imagine, it’s quite a job to remove the carb for cleaning, and then to try and reinstall it. All of these parts have to work together to get the scooter to hot and cold start.

Riva 180/200 engine removal procedure

With practice the engine can be removed in less than 15 minutes. When working on the carb, I find it way easier to remove the engine than to try and work on it in place.

Fan run-on problems with the Riva 180

The Riva 180 (but not the 200) uses an electric fan in the engine area to cool the engine. There is a thermo switch attached to the bottom of the carb, which is supposed to control whether the fan is on or not. On most 180’s this switch seems to have worn out, and now the fan stays on all the time, even with the ignition off. This will wear out your battery in a short amount of time. You have at least three choices: 1) Do away with the fan entirely. Assuming you don't ride you scooter on many 100 degree days in stop-and-go traffic, I would think that the built in fan would be adequate for cooling the scooter. 2) Get the specs of the thermo switch (I have them if you want them) and source a replacement part at your local electronics shop. 3) Wire a switch in-line with the fan, and just turn off the switch when you part your scooter.

The Riva 180 single sided fork

The Riva 180 uses a single sided fork. It generally holds up well, but in an accident it can be bent without too much effort. It can usually be straightened. You have to remove the fork and heat up the base of the steering head with a welding torch. Then just straighten it out. This is harder than you might think because you have to remove the fork, and mount it in a large vise, heat it, and straighten it by eye. The Riva 200 has a convential two sided fork, which is much stronger.

Riva 125/180/200 front shieve weights

These weights go inside the front pulley (AKA variator) in the transmission case. The weights are made of plastic with a brass center. After a number of years, the weights will wear out. They become flat on one or more sides (they are supposed to be round). The wear occurs because these weights slide up and down small ramps within the shieve. They side up the ramps at higher engine RPM's, which moves the variator halves and forces them together. As the halves are forced together, the drive belt rides up higher between the halves, resulting in taller gearing. In any event, these weights are really expensive new from Yamaha (dealer cost is around $17 each and you need 8 of them!) I'm currently trying to source some custom weights for a much lower cost.

Riva 125/180/200 headlight bulbs

The stock replacement bulb can be hard to get. WIth a little manipulation you can replace the stock bulb with a type H4 bulb, usually available at your local auto store. But the headlight beam pattern is not very good.

Riva 180/200 engine oil changes

These Riva's use an oil filter, located under the engine. To change it you need to remove three 5mm allen screws holding the oil filter cover. This cover is underneath the scooter, on the right hand side. The oil drain bolt is on the lower right hand side of the engine. Engine oil will drain best if you remove the filler cap and warm up the engine first. The oil filler cap is on the right side. I use the best synthetic oil I can find - Mobil 1 or Castrol Synthetic. Change the engine oil every 1000 miles. The total cost is only about $10 ($5 filter and $5 1.4 quarts of synthetic oil) - your engine will appreciate it.

Jog air boot

I once cracked the air boot on my Jog when I hit a pothole in the road. At first, I didn't know what happened. The scooter would barely run. Then I found the problem and taped it up with duct tape until I got home. The boot design and boot material lead to the failure.