Hi,
I just finished porting my stock manifold, amongst other mods(BAK, AIS gone, Stage III exhaust) Been reading a lot of posts about these types of mods and some associated issues such as popping on decel. When I will be dialing it in, I wanted to check for any possible intake and/or exhaust leaks.

Intake:
I wanted to know when re-installing my stock manifold (brand new 03 with 600 miles) can I simply put the manifold back on without replacing the O-rings given that the O-rings looked real good, very flexible and a little oiled, do I need to add any additional sealant?

Exhaust:
I had the mufflers off the stock pipes to do the Stage III. I put them back on firmly and tightened up the clamps, I tightened all the other connections. Does this seem sufficient or is there any additional muffler gaskets to replace? (Note: I did not remove the header pipes from the engine)

I am being patient with the final tuning of the bike as I understand it can take some trial and error. I'm close to running smooth now, I took the R* out for a test drive with the mods listed above and wow it is a different beast, I mean bike.

Thanks,
Mike in San Jose, CA

I was going to suggest lapping the manifold but it sounds like you already have it back together. Check for any air leaks where the manifold bolts to the motor just to be sure.

If the O-rings are not nicked and perfectly round, not compressed then you can re-use them. You can also go to the hardware store and pick up a set rather than paying Yamaha prices. Don't use sealant; the O-ring seals the manifold.

The muffler to header should be OK. If not you'll notice some carbon deposits where it leaks.

Doc

Hi Musky,

What is lapping the manifold, can you give me a description of that process?

Thanks,
Mike

What is lapping the manifold

It's a fancy term for flatting out the horrible finish Yami left on the mating surfaces of the manifold. Not complicated. No machinery needed. Get a sheet or 2 of 300 grit emery cloth at the hardware store. I used the thin double face tape and stuck the emery cloth to a piece of masonite. Some people use glass. What you want is a smooth bump free surface. Take your manifold, place one mating surface on the emery cloth, and go in a figure 8 pattern. You need some pressure but not alot. After you go about 5 or 6 laps look at the manifold. you'll see some shiney spots and some spots still dull. That will show you how uneven they leave the surface. Just keep going until it's all shiney and then do the other mating surface. It took me about 20 minutes total. Just take it slow and make sure you keep it flat.

Oh yeah, don't forget to take the O rings out before you begin this procedure <br><br>Post edited by: Musky, at: 2006/09/20 18:33

Excellent idea, I will definately give it a try next time I have the manifold off. Hopefully after leak testing I wont have to.

Thanks,
Mike

Lots of guys seem to do the 'lapping' but I question whether it's really needed.

If you have metal to metal contact and use some type of liquid gasket material then I believe that lapping would provide some benefit.

On the other hand, for the manifold to head seal it's the rubber gasket that seals the two parts. Even if the two surfaces are slightly uneven (which they are), unless they are warped (in which case 'lapping' would be useless) what benefit is there in this process?

Doc

Hey Doc

The stock O rings didn't seem to me to stick out very far past the surface. If you tighten down to a rought spot then the the O ring isn't making as solid contact as it could. I can see it possibly causing a leak. Just cheap insurance IMHO.