I just got done removing the oil pump and installing the block off plate on my son's pred 90... and when I went to reinstall the flywheel I noticed the crank shaft would not turn! Duh, the plate is less than half as thick as the oil pump housing it replaces... and I used the OE bolts to install the plate. Well somehow the outer bolt just barely bottoms out against the crankshaft as it becomes snug, and wouldn't allow it to turn. Can i now just install shorter bolts??? It appears that the holes are both tapped all the way through, but I'm not sure if they were that way before I ran the bolts all the way in... the cavity is full of grease for the oil pump drive, and I didn't look at them that close before I insta;;ed the block-off plate. My worry is I broke the bottoms of the bolt holes out and forced small chunks of aluminum into the pump opening. Is this cavity seperate from the engine crankcase? I lightly blew air into the outer bolt hole, and it only seemed to come out of the bottom bolt hole. Thanks, Dan.

 

Looking at the parts diagram on the polaris website, it looks like I bottomed the screw out against the oil pump drive gear... shouldn't be a proble then, but I'm still curious if the holes are supposed to be blind holes. And if their is a seal between the oil pump drive gear and the rh crank bearing... I only see one crank seal on each side. Thanks, Dan.

 

Update! Called Lakes motorsports where I got all the goodies to hop this thing up... turns out the holes are tapped all the way through, and the cavity containing the oil pump drive gear is seperated from the crankcase... so no danger of contamination either way. Usually when they build a race engine, they will just remove the drive gear all togather. I installed shorter screws and everything is okey now. Can't wait to get this thing done! It's getting a complete Aluminum race cylinder kit, Billet high compression head, reed cage and reeds, intake, 24mm kehin, oil injection deleted, LMS chromed race exhaust pipe, Race variater, clutch kit, adjustible no rev limit cdi box, works shocks, 1" rear wheel spacers, and I'm building a 3 1/2 inch extended swing-arm and widening the front control arms each by 2". I've already welded gussets and extra braces into the frame and had it powder coated red. This is a lot of fun, but my boy is getting even more anxious than me!