97 GTX Sheared Oip Pump Drive Shaft

[jengberg]

97 GTX Sheared Oil Pump Drive Shaft

I am new to the forum and I have a question concerning my 97 GTX. Last summer I dropped in an SBT rebuild. I ran premix plus the oil injection for the first tank break in. On second tank without premix the engine died as a result of the plastic oil pump drive shaft shearing. I finally got around to putting another SBT engine in along with a new oil pump. I have worked on this ski for years so am fairly knowledgeable on the thing. I bled the pump and made sure it was properly adjusted. Was very careful when installing drive shaft and pump. I torqued mag cover and oil pump to specs. Being paranoid I kept a very close eye on the oil injection system. On initial startup I manually advanced oil pump and watched oil flow thru both supply lines. I again ran premix plus the oil pump for the breakin and all seemed OK. On second tank of gas I was still running premix as a precaution. I put it away one day and noticed air bubbles in oil supply lines. Started engine and manually advanced oil pump and nothing happened. I knew engine was OK because of the premix but couldn't believe that I had sheared a second shaft. I called SBT and they acted like this was all new to them. I pulled the mag cover and sure as heck the shaft was again sheared. Seemed to work fine for about 4 hours and then gone. I gave up and installed block off kit. These shafts are a redesign from the original ones and I am wondering if they are maybe slightly too long and running under a bind causing them to shear. Anybody have any info. on this. Thanks

 

[LouDoo]

Honestly I've not heard of this as being a problem, lets see if we can get opinions from experts. [MENTION=41828]Minnetonka4me[/MENTION], [MENTION=57920]racerxxx[/MENTION], [MENTION=49142]griz400[/MENTION], [MENTION=16022]Dr Honda[/MENTION]

Lou

 

[racerxxx]

I'll assume you have the black ones that capture the flywheel nut. The original ones went into the square of the crank.

Personally I have never seen/heard of one snap. They do look cheap. Was the first one that snapped the OEM one or one from SBT?

 

[Minnetonka4me]

Actually yes if you go to pwc today there is a bunch of people it's happened to. Sbt claims it's a oem part but it's been proven they are lying.

Sent from my HTC6525LVW using Tapatalk

 

[jengberg]

Yes, they are the black ones that have fingers that ride on flywheel nut and both were OEM. They do look cheap but I have never had problem before. I still have the original drive shaft but there is no key way on end of crank to engage it. Never wanted to have to pre mix but I have lost confidence in the system have a brand new oil pump that don't need anymore. Any market for them?

 

[Dr Honda]

Over the years... I've heard of a few oil drives breaking on the 800. BUT... it's generally caused by other issues. (Either running the pump dry, or damaged the drive during assembly) The pump itself should put no stress on the plastic drive.

Personally... I would get an actual OEM part... and use the pump. There are a lot of 800's out there, running hundreds of hours on the plastic drive parts.

 

[jengberg]

Hey guys, thanks for all the replies. I have always been a fan of the oil injection system and resisted SBT's recommendation to install block off kit until I sheared my second OEM shaft. I realize there is always a reason something fails but am still perplexed. This shaft and pump assembly were assembled on a bench where it is a very simple process. If the shaft is carefully placed over flywheel nut and then pump drive paddle is carefully inserted into the driveshaft keyway I can't for the life of me see how the drive shaft could get damaged. I torqued to specs, bled and adjusted pump and verified it was pumping oil on initial startup. All that leads me to believe that the shaft is slightly too long, or SBT's crankshaft is slightly longer than specs and shaft is being squeezed between oil pump and flywheel resulting in failure. Doesn't matter anymore because I gave up and reluctantly removed oil pump. Just thought some of you very knowledgeable folks would be interested. SBT seems to be a common denominator in all the shaft failures I have read about..........just saying. Thanks again