First Rebuild

[DNChassis]

Hey all,

New to the forum. I picked up an 81 Heritage Special last spring for $300. It ran rough and the case was broke around the neutral detent threads. Instead of JB weld I decided to buy a case and swap the top halves. I wanted to create a thread so people could follow along an share their input. Any tips or hints would be great. So far I have gotten the engine torn down to the bottom half. I have the case split and am waiting on new crush washers before I start putting it back together. Everything looks really good in the engine. It has slightly over 16k on the motor. Before I tore it down I did some carb work to it and was able to get it to run better, it still backfired a bit, but when I got it it wouldn't run without choke. Here is where I'm at now. Let me know of anything I should look for. This is my very first motorcycle engine teardown. I have been doing everything using this site, YouTube, and the 650 Facebook pages. Thanks to all of you that have put so much of this information out there. You've made this an easy process SO FAR.

 

[5twins]

You may not be able to swap just top halves. The top and bottom case halves are a matched pair. They are clamped together at the factory and then the bearing holes are bored. This insures exact alignment of the ones located along the case seam. If you look on the right side of the cases, under the shifter, you'll see numbers stamped on each case half. They should match .....

 

[DNChassis]

I had considered that and would have used the entire case I bought off eBay, but Hercules that owned it before me tried making sure his drain plug wouldn't leak and stripped the drain plug threads in the case I bought.

 

[5twins]

Well, you might get away with it. I would fit the two halves together dry and empty to observe how well the bearing bores along the seam match up. You want them to be darn near perfect.

 

[DNChassis]

Went with 5twins and am going to use matching halves. Just blasted them and got them painted up. Will be replacing oil seals and putting it back together soon.

 

[DNChassis]

Well if it doesn't run it should still look nice

 

[XSLeo]

The head and rocker box are done the same way. Machined as a pair.
Just so you know, or anyone who reads this.
Leo

 

[DNChassis]

Thanks Leo. Fortunately I've got a match set there.

 

[DNChassis]

Hopefully try to fire it by the end of the week. Just needs to be put back in the bike, carbs, and exhaust put on.