I just got done rebuilding my 600, replaced everything but the crankshaft, bought a used crankcase because mine was destroyed. I started it for the first time today and it idled fine, but as soon as I cracked the throttle it blew the seal on the oil filter. The first time I thought maybe I didn't have the filter tight enough, it was tight the 2nd time it blew, same scenario. I read the manual and checked all there was to check, tried pulling the plunger with a magnet (spring was missing when I took the plug out). The plunger won't move. I took the side cover back off and pulled the oil pump and I can't get the plunger to budge. Does anyone know if there is a good way to get one of these out or should I try to get a refund on these cases and start over again? I plan on buying a new plunger and spring if I can get this one out, thought about drilling it and trying to get a screw or something in it but I tested the drill method on the one in my junk case and it's super hard, couldn't scratch it with any drill bit I have here.

 

Manual doesn't get too involved on this,but does emphasize the valve(dowel rod end) needs to be installed tapered end first or priming and oil problems can happen.Could be what has happened. If it's lodged tight,it may be installed backwards.Only thing I can thing of is to use penetrating oil along with compressed air into the area(with a rag covering it) to see if you can work it loose and be able to remove it.

 

I'll try the penetrating oil when I get somewhere to pick up a new can. I did spray it down with carb cleaner to see if it was varnish or something holding it down. I never had the valve out, so I can't say if it's installed correctly or not, I honestly didn't know it was there until I had a problem with it. The plug wasn't included with the case so I used the one from my old cases....they were missing the spring too. I can't see the taper in the hole where the oil pump is, so it may be backward. The cases were really clean, like they had been hot tanked, so I'm wondering if it isn't corroded in place from the acid?

 

That's a good possibility it's corroded or dirt got down into the cavity if it was cleaned with the plug missing.Hopefully you can get it out with penetrating oil and air.Keep us updated.

 

Thanks for the help OPT I went out early this morning and soaked it down with carb cleaner again and a little bit ago I found an allen wrench that was small enough to fit in the orifice directly below the plunger and long enough to reach it, I got it broke loose and moving it up and down with a magnet and screwdriver underneath it I got it out. The new one is on order, hopefully I can ride this one of these days...been on the bench a long time

 

Just make sure the tapered end goes in first! Glad you got it out.

 

will do, it was in correctly, not sure why it stuck, wasn't rusty or anything...it was scorred some though. Maybe it picked up some FM that was left in the oil galleys or something? There was some copper flake in the oil and it had only run about 2 minutes on the bench at idle.