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Discussion Starter · #1 ·
I have a 98 powder special EFI that I got in 2013, rode once, and then the motor siezed. I ordered a whole new top end and got the cylinders replated but never put it back together. Finally I want to get it fixed and sell it. Fortunately before throwing all the new parts on, I decided to look into the oil injection system and discovered:

1) The intake spacers where the oil is injected prior to the reeds were upside down(?) the barbs that the tubes attach to were on the bottom, not the top as seems to be correct in the service manual.

2) More alarming was the bottom banjo fitting was just GONE. Considering there is supposed to be a check valve in it, I suspect it was just sucking air in and not pumping any oil at all. The barb on the crank case banjo was busted off too...

3) Seemingly yet more alarming there was no spacer/ input shaft retainer, AND even despite that being gone, the water pump/ oil pump shaft doesn't seem to be long enough to engage the oil pump at all. In other words I can clock the pump and shaft 90 degrees out of phase and still install the oil pump. Was there maybe another year shaft that was shorter that mistakenly got put in? Maybe it wasn't installed correctly or has the wrong water pump assembly? I haven't Disassembled the water pump yet.

Bottom line, for several reasons it seems there was ZERO oil getting to the motor which explains why it locked up.

Now considering the current situation, it seems it would be easiest to simply delete the oil pump, cap the ports on the engine and intake, and run premix. Or would that be a terrible idea? I am not really sure how to diagnose the shaft/pump problem, the manual doesn't go into it much, and I don't think I want to waste that much time trying to figure it out if doing a delete and mixing is a good option. Option 2 would be to spend the about $50 to get a new oil pump with banjos, a new retainer and figure out why the shaft seems to be too short. Maybe just get a new shaft too and replace it.

Thoughts?
Thanks!
 

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Discussion Starter · #3 ·
Far as I can tell the crank bearings are all good.

I pulled the rest of the motor so I could take off the water pump cover and was glad I put in the effort. Because of that weird spring seal thing, it had pushed the shaft and impeller forward, so the impeller was all scuffed up from rubbing on the inside of the cover. Seals were obviously shot as well. Also explains why the shaft wasn't reaching the oil pump, because it had been pushed that far forward! Turns out the retaining spacer for the oil shaft/pump actually was there, it was just grimed up and stuck to the case so I couldn't tell.

My question now is what keeps the shaft from moving too far forward? Obviously there is a spring that pushes on it towards the water pump side, but what holds it in place?
 

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Discussion Starter · #5 ·
The shaft goes in from the oil pump side. It has a shim that I believe acts as a thrust bearing on the input shaft retainer. However, I DONT see a similar shim on the water pump side of the shaft and I find it harmed to believe the shaft is supposed to rotate directly on the aluminum engine case, there should be a steel surface for it to spin on... that second shim doesn't appear to be in place and the shaft has eroded into the engine case.

Current theory, the idiot that worked on the engine forgot the shim and without any oil lubricating the pump shaft, it just started digging into the case until it got far enough in to disengage the oil pump and the top end siezed.

I am going to spin up am extra thick steel "shim"/ thrust bearing surface on the lathe and it should keep the shaft in its proper place. "New" shaft, water pump, oil pump and seals on the way. Gotta love eBay!
 

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I put that shaft in a zrt once, and a F7, both long ago though….apparently I’m shot. Sounds like a fun mystery sled project. I had two of those new in ‘98. Huge over achievers if that era. They just didn’t get respect much, due to all the three cyl hype of the time
 
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