Motorcycle Safety & Driveability: Exhoust on Yamaha Zeal, scooter, rattle

Question
Hey,

I have Yamaha Zeal 250cc. I have had it for a while, it has just enough power to get me from A - B and it is pleasurable to ride. Recently however, my exhaust started to get rattly at 5-6k rpm. I have inspected it and there is no rust outside. What I found though is the a hole at the bottom of the exhaust. I'm not sure if it is normal (ie. drainage) since I'm sure some water might get in while I'm raiding in rain, or is it rusting from inside out!

The exhaust is not slip on it is all welded together. Do you think it would be a good idea to take it to a welder and get the exhaust open to see how bad it is and just get rid of the rust inside? Or should I get new exhaust and get welder to fit it in.

From my research I found out that I can get whole exhaust system of other bikes (bigger cc ratings) much cheaper than exhaust for my bike. Would I have to get my bike tuned up after putting big exhaust on?

Cheers,
Luke

Answer
I suspect the hole in the exhaust is supposed to be there, like you said: for drainage of condensation, and rain--which enters through the tailpipe opening, not the little hole. I doubt you have much rust to deal with.

As motorcycles and scooters break in, they can get a little buzzy. Parts go loose. Before you go after your exhaust with a cutting torch, do a head to toe screw-and-fastener tightening of every screw and fastener you have access too. (It's a good idea, in general, to do this with a shop manual and a torque wrench.) Retorque all your bolts and tighten all your fasteners. You'll probably find a couple of loose ones that are causing the rattling. If the problem comes back, use a little thread locker (such as Loc-Tite) on those fasteners.

I just had this happen to me on my little moped. The metal plate that guards the muffler was held on by screws that came a little loose and were buzzing at various rpms. Tightening the screws solved the problem.

Doing this head-to-toe tightening regularly, once a year or so, is also a good way to keep abreast of any mechanical issues that might come up. If you're looking over your bike closely like this, you spot things that might go unnoticed, and you can get them fixed before they cause major problems.

It could also be that part of the insides of the exhaust, such as a baffle, has broken or come loose. Not much you can do to fix it other than replace it.

If you do end up putting a bigger exhaust on the bike, it should be re-tuned for the greater flow, but it is probably not absolutely necessary.

Pat