| Exhaust restriction - All Vinos ship from the factory
with a restricting washer in the exhaust pipe where it bolts to the exhaust port on the
cylinder. Some dealers remove it. If your scooter goes 30mph top speed, you need to remove this
annoying piece of metal, believe me, you will never look back!
Removal - Remove the exhaust pipe by loosening the bolts
on the right side of the scoot (the ones that secure the pipe to the crankcase
[Figure 14 & 15]).
After they are loose (do not remove them) you can then remove the bolts
on the actual exhaust manifold (under the scooter [Figure
16]). Be careful when you do this, these bolts are made of a very
soft alloy to protect the cylinder head and will break if you have to
force them. After you remove the manifold bolts you can then remove the
bolts that secure it to the crankcase and subsequently remove the entire
pipe. When you look down the motor end of the pipe you will see a washer
limiting the diameter of the pipe. How you remove this is up to you. I
have heard several ways that are effective, from using a grinder/dremel
tool to just plain taking a screwdriver/hammer to it, cave man style.
Just be careful to not damage the bottom of the pipe, if you flatten out
the tube it will be kind of a waste that you are even doing anything to
it, since this will restrict it again. [Figure
13]
Reassembly - Once the washer is removed you need to put
the pipe back on the scooter. This is the tricky part. The end of the
stock pipe has slots as opposed to holes and this makes it a little tricky
to reattach. First place the pipe in position and put in the top bolt
to the crankcase about halfway, so the pipe is free to move back and forth.
Then go to the manifold and hand tighten the bolts to the manifold making
sure that you have the threads on straight and that it is not hard to
turn the bolts, that they go in easily. If you have to force them or feel
like it takes too much force to screw them in, chances are you are cross-threading
them. If you do this you may break them off in the head and that is bad
news. It is recoverable but you just added about 1-3 hours to your work.
Once you have the bolts in the manifold pretty much all the way in (but
leave enough room to slightly shift it around if the main crankcase bolts
don't fit) then go to the crankcase bolts and replace the bottom bolt
and hand-tighten both crankcase bolts. Then you can move to the manifold
again and tighten them with a 10mm socket. I don't have the correct torque
setting but just past the point where it is flush should be adequate,
if you run it a while and get some oil leakage or popping sound from under
your scoot, you may need to tighten it up a little. A Yamaha dealer or
the official service manual would have the toprque settings if you want
to be sure.
If you break it - If you happen to break one of the manifold
bolts (don't feel bad, I did it), then you have a couple options according
to your situation. If you still have quite a bit of bolt above the surface
of the manifold you can use a pair of vice grips to take out the bolt.
If you broke it off flush or near flush with the manifold then you will
need a drill that has forward and reverse settings and a drill/reverse
drill bit set (for removeing broken bolts) from your local hardware store.
Follow the directions that come with the drill bit set to drill out the
center of the bolt and then use the reverse bit at reverse spin to remove
it. You will also have to get a new bolt (I would suggest getting a few)
at a Yamaha Dealership. When this happened to me The dealer didn't have
these in stock so I just went to the local hardware store and got some
normal metric bolts. With these however you have to be extra careful not
to cross thread the bolts in the manifold since they are now the same
strength you could damage the manifold threads. |
Figure 13
Figure 14
|
