Mike Trains WR400 turned down exhaust tip instructions

Mike Train recently posted instructions of how to build a cheap but effective turned down end cap that goes on the stock WR400 exhaust.

I've modified my Vortip exhaust tip by basically cutting out all of the internals. But, the diameter is quite a bit smaller than the stock opening. Mikes design is the same diameter as the stock opening so I think it will work much better and is definately cheaper.

I know from running my modified Vortip exhaust that the sound level is nice. At idle it is a LOT quieter than stock. When opening the throttle it is loud, but it takes the harsh edge off the exhaust note. I'm guessing Mikes design will work great and I'm going to try it.

Here are Mikes instructions again on how to build the turned down tip followed by a picture he sent. To see a bigger view of the picture, go to my technical section and I have the picture there too (I'll also post this info on the tech section in the next day or two).



I did a modification to my stock WR muffler that worked well with WR or YZ valve timing. Here is what I did for a cost of $5.00:

1. Buy an automotive 1 3/4"-90 degree exhaust bend. The size is important; it fits perfectly over a sleeve inside the end cap.

2. With the muffler and end cap on the bike, slip the female end into the muffler end cap until it stops, angling the bend down.

3. Through the original insert screw hole in the end cap, drill a small hole into the extension Install a short self tapping sheet metal screw.

4. Using a hacksaw, cut off the new extension to suit your preference of down angle. Cut square to the pipe centerline at the cutting plane. Debur the cut with a file and emery paper. My turndown extended about 3" from the end cap.

5. Seal the extension outer diameter to the muffler cap with black silicone.

6. Raddle-can paint the extension and sealer black. Not required to be heat rated.

This install looked good and did the following for my bike:

A. Provided water protection to the upturned stock cap opening.

B. Significantly lowered the sound level at low throttle.

C. Preserved all the power characteristics of the open WR end cap. This is true for all the "dial in" combinations discussed in this forum.

D. Leaves the spark arrester screen in place.



Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now