Do I need a lower end kit if I am pulling the crank case off?

[drake1]

I pulled out my 787 and found a large warp on the crank case on the rear jug, the feeler gage will go thru all the way on the carb side and it's a 4 thounds gage so it's a big warp over 6 inches. I already got a top end kit now I will need to remove the top of the crankcase so I can have it machined down, what gaskets or seals will I need to get if I am opening the crank so I can take it in have then make make it flat again, I am not replacing the crankshaft just need to bring the top in so there are no piston rods sticking thru it..basically just wondering what I will need to order in for parts, I already have removed the jugs. I know this may be a basic question but will the need to do a full disassemble or can I just remove the bolts holding on to the top half of the case and remove that half?

 

[racerxxx]

Technically you could get away with none, just buy a tube of threebond 1211 for between the cases. Now, if you have the pto off, id buy a rear crank seal, mag cover seal, and a counter balance cover O-ring, a mag housing gasket, you can probably reuse the cover O-ring. You'll need Loctite 515 for the case bolts and some grease for under the heads of the screws. Remember to check the squish gap since your machining the case. Do you know how many holes your current base gasket is? They are marked in between the jugs by a series of holes. Hope you saved them. You'll need a thicker gasket now. The manual denotes the holes into thickness. Any questions post up.

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[drake1]

Just seems like a large gap to seal up, I can get some hondabond and try that only thing that sucks is if it doesn't hold then water goes right into the crank. How much pressure is in the crank anyway?

 

[racerxxx]

My post was meant for after you had the case machined.

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[racerxxx]

Are you checking the gap with the jug sitting on the case bare? Also make sure the underside of the jugs are spotless. So you can fit a .004 feeler gauge in there( the thickness of printer paper), I originally thought you said 40 thousandths, not 4 thousandths--my bad. Come to think of it, that's not that bad. Plus you really need to check it with a precision straight edge and a feeler gauge, your jug could be out not the case or both a little. But regardless the base gasket should seal it up put a super thin coat of the hondabond on the case and the top of the gasket and seal it up. That is what the gasket is meant for, to make up for any imperfections, more than likely the case is high where the jugs bolt down due to the fact of torquing the cylinders and the repeatitive beating of 7K RPM for extended times:thumbsup: