Other PVC pipe in place of waterbox on VXR

OtherDonnieGuy

OtherDonnieGuy

Location
Illinois
Hi everyone, Newbie to the forum here! My problem is I blew apart the waterbox on my 1991 waverunner vxr 650, the engine back fired and chunks went flying. My question is can I just use a piece of PVC pipe to replace the waterbox? I already cut a piece and have it bolted in. The ski has been sitting for 7-8 years and I now have it running, i'd like to drop it in the water and see if it's going to run fine, but I dont want to hurt the engine.

My Dad said he thought if it got hot enough it may possibly melt it, and I read where the waterbox keeps water from pushing back up in the exhaust when the ski sits in the water. Did some searching but could't find anything where anyone had done this.
 
chad

chad

I pretty much love beer
Site Supporter
Location
Cheney lake Kansas
I have personally seen pvc pipe melted from a ski after the water box. I wouldn't do it. At least run aluminum ,till you get another waterbox
 
Waternut

Waternut

Customizing addict
Location
Macon, GA
The waterbox does help prevent water from flowing back into the engine. It also acts as your muffler so you will piss off a lot of people if run a straight pipe because it will be really loud. If you plan to run it once or twice to check the jetski's functionalilty, I say go for it. Just please don't continue running without a waterbox. In a stock ski, the pvc will be fine. I've run them just past the waterbox for over a year and never noticed even a slight problem.

As an FYI...PVC pipe is rated to 140°F and your waterbox shouldn't be seeing that if all is working properly. A metal waterbox will be warm to the touch even when excessively dried with a flow control valve but will not burn you. From my experience it's much cooler than the average exhaust pipe or cylinder under normal conditions. Temperatures around 130-140 will burn your skin. On a really hot summer day and a hard ride, my exhaust pipe has come close to burning me but only leaves a red mark that goes away quickly.
 
AZRIDER

AZRIDER

stupid desert
Location
TUCSON ARIZONA
I'm sure you could find another one of those water boxes pretty easily
just ask the question "what othe ski's use the same water box" and then you can end up with a pretty broad shopping list find a used one cheap
 
OtherDonnieGuy

OtherDonnieGuy

Location
Illinois
Here's the whole story...picked up a pair of vxr's that have been siting for years (registration tags say '04). Last summer I got the Pro vxr running since it was the better of the 2). The '93 pro vxr backfired and blew the waterbox apart right after I cleaned the carb. And since it was near running I salvaged the water box from the '91 waverunner vxr so I would have a ski to ride last summer (near the end of the year). Now I'm working on getting the '91,had no spark and i thought the carb was shot, I literally dumped out white powder from oxidization from inside the carb. Every bolt/screw is rusted bad. Almost traded it to a guy for parts for a 750sx, figured I'd give it a whirl... got spark and cleaned the carb best I could, put PVC in place of the water box and now she runs great on the trailer!

Sounds like I'll give it a whirl, I usually ride in the local river where sound isn't an issue, but I am going to get it replaced just to keep ensuring sound isn't an issue lol. (I almost lost the motocross track behind my house due to noise).

And thanks for the replies!!! much appreciated!!!
 
swapmeet

swapmeet

Brotastic
Location
Arlington TX
I dealt with this Sat. I made a adapter out of PVC to hook up 1.75 ID exhaust tube to 2.5 ID tube that is in the bulk head. The adatper melted, my exhaust was dumping into my engine compartment and damn near sunk my ski.

Just get a piece of steel pipe like fence pipe or flexible exhaust hose from the auto parts store. If its truely temporary than it won't rust. Its gonna be loud, and not in a good way FYI.
 
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