To me a 35 year old seal is begging for a Swedish train wreck. In comparison to the cost of the potential consequences, the cost of replacing crank seals is negligible. I started tearing down the 84 250WR right after I purchased it. I had to pull the engine because I could not get the cylinder to clear the cylinder studs in the frame. So the engine came out and found a worn piston with .008" clearance. So silly me think Ok, just need to bore to the next oversize and I will have a nice bike to restore. The bore was egged shaped and went from STD to 2nd oversize on the first bore in its then 24 year old life.
Seems easy enough, right? But wait, there's more...
Pulled the flywheel off the ignition and found the magnets rattling inside the flywheel.
Pulled the pristine clutch cover and found a knackered clutch hub so need to replace a couple posts on it.
Seeing I have everything I need to split the cases I figured I might as well just split the cases and replace the crank seals and centercase gasket because I could see the last person inside these cases assembled it before it went into a frame on the assembly line in Sweden.
Found that one of the POs had replaced a worn piston without boring and fitting an oversize piston. The piston removed had broken it's skirt and left an artifact embedded in the crankwell wall. Just the 250 reduction web but did not perf the 400/430 wall.
The point is that buying a vintage machine with a string of questionable POs comes with some risks. Especially since so few come with service records. We do not know anything for certain until you investigate. This may be about bragging rights for some but since the only mechanical failure I ever had was a stripped countershaft spline on my MR250 in a gully on a mountain about 7 miles from home. I had to pushed it uphill to get out the gully to pull it over rocks and med size boulders to get to the street at the bottom of the mountain. I got it to a friend's house and he gave me a ride home to get my car and my father's bike trailer. That was a 2 year old bike at that point. We are taking about machines that went out of production before the majority of the current riding stars were even born. My point is prep like you will run the ISDE and that is your best chance to finish any ride you set out on.
Seems easy enough, right? But wait, there's more...
Pulled the flywheel off the ignition and found the magnets rattling inside the flywheel.
Pulled the pristine clutch cover and found a knackered clutch hub so need to replace a couple posts on it.
Seeing I have everything I need to split the cases I figured I might as well just split the cases and replace the crank seals and centercase gasket because I could see the last person inside these cases assembled it before it went into a frame on the assembly line in Sweden.
Found that one of the POs had replaced a worn piston without boring and fitting an oversize piston. The piston removed had broken it's skirt and left an artifact embedded in the crankwell wall. Just the 250 reduction web but did not perf the 400/430 wall.
The point is that buying a vintage machine with a string of questionable POs comes with some risks. Especially since so few come with service records. We do not know anything for certain until you investigate. This may be about bragging rights for some but since the only mechanical failure I ever had was a stripped countershaft spline on my MR250 in a gully on a mountain about 7 miles from home. I had to pushed it uphill to get out the gully to pull it over rocks and med size boulders to get to the street at the bottom of the mountain. I got it to a friend's house and he gave me a ride home to get my car and my father's bike trailer. That was a 2 year old bike at that point. We are taking about machines that went out of production before the majority of the current riding stars were even born. My point is prep like you will run the ISDE and that is your best chance to finish any ride you set out on.
...if it was mine, it would fail catastrophically at the furthest point from the trailer
