380 Crankcase won't open.

[CowboyX]

I've stripped the top end of my 380 down after blowing a piston. I had intended to open the crankcase to be sure there was no debris left inside. (the piston kinda shattered a bit) However, after following the manual and removing the bolts in the proper pattern, the case refuses to separate. A small opening started and I tried to open it further buy driving a wood wedge in the crack but no real results. Am I missing something? Is this even worthwhile? It was only a few shards that came off of the piston and no damage was done. Most of the debris was recovered. Am I just making more work for myself opening an engine that is fine otherwise?

[Allan k]

100% sure you got all bolts out? Those on the underside are easely missed.

[titan performance]

Cowboy........I am a 500 man, and have never even owned a 380, so this comment may be worthless, but on the 500, there is a small crescent shaped strap behind the clutch which joins both halves of the cases. It's just a thought, but if you have left the clutch on, and the 380 is the same....then it could be your problem.

[CowboyX]

Been a long time since I replied to this. Project got backburnered during a move. I removed the clutch but cannot see anything holding the works together. Recently got a book on restoring bikes and the author suggests heating it with a torch and then a touch with a rubber mallet. Might try that.

On a related note. How do I get the oil pump out. I mean the plastic octopus part that the pump sits on. Is this holding me up? The manual I have is rather vague on this point.

[gt-keith]

Once the three screws holding the pump are removed the oil pump simply lifts out, be very careful not to lose the 3mm pin in the bottom of the pump shaft that provides the drive.
The remove the 6 banjo bolts that bolt to the top crankcase at the back of the cylinders that feed oil to the main bearings and inlet, the oil pipes will then lift off.

If you have removed "all" the crankcase bolts you should have something like this.




27 in total, there's one 6mm one missing in the photo that sheared off.

[celt_rock]

Again, another 500 guy, but the manual I was following for my 500 dismantle neglected to mention two bolts on the bottom towards the front of the engine. When in doubt, take 'em out. You're just gonna put them back in again!

[mike1161]

Double & triple check that all the bolts are out again, especially if the engine cases are full of dirt, grime, etc... - I say this from personal experience. On my T350, I was really sure that I'd gotten all the bolts out, & was tapping with a mallet, wood blocks, etc... & could see it starting to open on one side, but I was just going crazy trying to get the thing to finish opening up. Let it sit a day, and then took another close look, & guess what? Somehow I had missed seeing 2 bolts. When I loosened those, it practically fell apart. Felt pretty dumb for a while...

[CowboyX]

Thanks for all the feedback guys. I was looking for anything I could have missed. The halves are separating but refuse to let go. There is a small plate behind a cog I have yet to remove. Could be the plate all you 500 guys have been telling me about. High hopes. Just have to get some snap-ring pliers.

[gt-keith]

This will be the offending chap....

[ConnerVT]

Speaking of hidden bolts, an embarrassing story from my youth:

I was helping a friend (who was the one who sold me my first T500) replace the head gaskets on his Ford Galaxy 302 V8. We were in the process of taking off the intake manifold, which Ford secures with about 30 bolts. We (rightly so) figured that the manifold should easily pop off, but was being stubborn.

We worked our way through several ideas, until we reached the point where we had the hood removed, a come-along winch attached to a tree branch across the driveway, and the car hanging, front wheels nearly off the ground, from the intake manifold.

My friend's dad came out, saw us, and insisted we stop hanging the car and let him assist. He dug through the grunge on the intake manifold, and found two more bolts we had failed to remove. Once out, the manifold popped right off.

[mike1161]

Good story! I'm sure all of us have a few like that! Also, if the gear selector retainer plates are still on (as shown in the photo by gt-keith), those definitely have to come off 1st before the cases will split. And just a tip, those Phillips head screws are a bear to get out unless you have an impact screwdriver. Without the impact tool, you'll probably damage the cross points in the screws, they really torque them in there tight, and I think most of the time they are put in with locking compound, too. With the impact tool they loosen right up with no problem. It's definitely worth the $15 bucks or so for the impact screwdriver set.

[CowboyX]

Thanks to all you guys! It was indeed those two retainer plates in the way. As soon as those were off separation was achieved. Why does the manual not mention this detail? Who knows... Now off to secure a parts bike to help fill in the missing and broken bits. Like the piston. Thanks again to everyone. I hope that re-assembly goes as smooth. Undoubtedly I will have more questions later.