How To - WPS Pipe Fix
Topic: Fixing old rusted-out WPS Pipes
Expertise Required: Intermediate and above
Estimated Time: About 2 hours
- 180 degree bend from Summit Racingn
- Bandsaw or hacksaw
- Cutoff Wheel
- 4 Inch Grinder or 90 degree pneumatic die grinder
Be aware that there were several steel pipe designs and only 1 aluminum one that I know of. This tech article is limited to the steel pipes.
Deep Inspection: Ok - you need to get the pipe off the bike and on the workbench. The first thing you wanna do is give it a good visual. If you see rust-through on the water-jacked area, you can probably stop here. There's probably not enough left to start with.
If things look ok - except for the 180 degree bend, then you are ready for step 1.
Old Style Pipes - Put the air gun onto one of the water intake nipples and put your finger over the other. If you can pressure it up without hearing any air escaping through the pipe (either end) - then that's spectacular. Jump to step 2.
If you hear air escaping, then you probably have pinholes in the exhaust pipe under the water jacket. Game over really. If there's one or two holes, there'll be a hundred once it gets up to temperature.
New Style Pipe - This is almost impossible to do properly since the water enters the exhaust pipe "inside" the water jacket. So, it's impossible to isolate one from the other - unless you cut the 180 degree bend off first. Here's a new style pipe.
Step 2: Take a minute and find a plug and seal up one of the water nipples (if your pipe has 3, then seal up 2). Then increase the air pressure on your water hose and run it up to about 60 psi and check again. If no air is escaping, goto step 4.
If you now hear air escaping you need to make a decision. You'll need to cut the water jacket off and fix any holes. That usually involves welding on patch panels - then welding the water jacket back on. Decide - is it really worth it?
Step 4: Take about 30 pictures of the pipe, the angle of the 180 deg. bend, the length of the ends on the bend, etc. Then take a sawzall or 4 inch cutoff wheel and lop off the 180 deg. bend about 1/2 below the weld where the water jacket is welded on.
If you have an old style pipe, you'l need to be careful not to damage the two lower water nipples (water bypass hose).
New Style Pipe - Now is the time to try to pressure-up the water jacket to see if it's leaking. You can either pressure up the exhaust pipe or the water jacket. The easiest way is to use an adjustable/expandable freeze plug with smaller washers. Shove that dude up into the pipe on the end you just cut off - and above the water holes. Tighten it down and pressure it up. You shouldn't hear air escaping through the water jacket.
New Bend Fitment: Take your time and lay the cutoff piece of pipe onto the new pipe bend. Leave about 1/8" of extra on the ends of the pipe so that you have a little bit of metal for final fitment. That is, you will probably need to file the pipe down a little to get the angle right.
Also - if you have the old style, you'll need to transfer the water nipple to the new pipe too. It takes a bit of time, but you can do it.
Weld the new bend in place and do a pressure test. This time, use a rubber stopper to seal up one end and a donut with the air hose in the middle on the other. Summit Racing has these too - or you might find them at your local radiator repair shop. Use a little soapy water to check for leaks.
When you're done, it's time to mount the pipe back on bike.
Once clean, put a liberal dab of 5200 in the groove (about 1/2 way full) and mount pipe back in there.
Now, unless you like the smell of burning Vinyl (on 60hp bikes) or burning fiberglass, you need to be sure you get your pipe installed correctly. Put the fastener through the upper mount (rubber mount) but don't tighten it down yet. Take a screwdriver or wooden wedge and put some pressure on the pipe to move it forward away from the hull and seat. Tighten down the upper mount now. Here's a pic of the upper mount:
Put the springs back on - 2 is plenty.
Put the intermediate exhaust hose, 180 degree hose, and lower pipe back in as well. Hint: Lean the last pipe back a bit before tightening down the hose clamps and it won't hit the head bolts (and leak).
Copyright 2011 Capt'n Obveeus