How hard/expensive to fix cracked left case?
#1
How hard/expensive to fix cracked left case?
I found a nice clean 2000 12oo Sporty near me, but it has a pretty good crack in it. I have basic mechanic skills (did the pistons on my old BMW Airhead before) and a long winter to fix it, but I'm wondering even the costs to fix this myself- buying a new case half and putting it on. Ideas appreciated.
#2
The following users liked this post:
Rob Roy's Revenge (09-08-2024)
#3
Join Date: Sep 2021
Location: Under the affluence of incahol.
Posts: 759
Received 923 Likes
on
417 Posts
+1. I would not split the cases to fix that. Just don't over tighten the case screw that goes in there. It should not leak oil.
Possibly you could put something like a Timesert thread repair insert in there, very carefully, and glue it in place with high temp epoxy for some extra strength. But again, not worth messing with unless there is a problem.
Another solution might be instead of using a screw in that hole, is cut a piece of threaded rod or stud and epoxy it into that threaded hole with enough thread sticking out to run a nut down it. You might have clearance issues for a socket to get into there so nut may need a spacer behind it to move it out past the case a bit.
Carefully drilling a very small hole at the end of the crack should stop the crack getting any longer. You might have to put a bit of sealer on the screw to stop oil coming out past the threads in that case.
To fix it "properly" you can get such cracks welded up, very carefully, with the engine still assembled to minimize heat distortion. I had an aircraft welder to a similar job on my Ironhead Sportster cases this way. It was where the sprocket cover mounted on the other side. He said he set the engine up on its side on the bench and just put one dab of weld on it then walked off and did something else for 10 or 15 minutes then came back when it had cooled off and put another dab, and so on until the run was finished.
Buying a new left case and then line-lapping the bearing races to match the right hand case seems like overkill for a crack like this. Expensive and time consuming.
Possibly you could put something like a Timesert thread repair insert in there, very carefully, and glue it in place with high temp epoxy for some extra strength. But again, not worth messing with unless there is a problem.
Another solution might be instead of using a screw in that hole, is cut a piece of threaded rod or stud and epoxy it into that threaded hole with enough thread sticking out to run a nut down it. You might have clearance issues for a socket to get into there so nut may need a spacer behind it to move it out past the case a bit.
Carefully drilling a very small hole at the end of the crack should stop the crack getting any longer. You might have to put a bit of sealer on the screw to stop oil coming out past the threads in that case.
To fix it "properly" you can get such cracks welded up, very carefully, with the engine still assembled to minimize heat distortion. I had an aircraft welder to a similar job on my Ironhead Sportster cases this way. It was where the sprocket cover mounted on the other side. He said he set the engine up on its side on the bench and just put one dab of weld on it then walked off and did something else for 10 or 15 minutes then came back when it had cooled off and put another dab, and so on until the run was finished.
Buying a new left case and then line-lapping the bearing races to match the right hand case seems like overkill for a crack like this. Expensive and time consuming.
Last edited by PeterB; 09-07-2024 at 08:54 PM.
The following 3 users liked this post by PeterB:
#5
The following 2 users liked this post by Bubba Zanetti:
Architect (09-09-2024),
John Harper (09-08-2024)
#6
Join Date: Jan 2011
Location: Southeast Michigan 15 Minutes East Of Hell
Posts: 149,130
Received 49,832 Likes
on
19,326 Posts
#7
It looks like a previous owner has forced a longer bolt in there which has bottomed out and cracked the inside of the casting.
J-B Weld Extreme Heat will repair the crack without further issues.
Last edited by Rob Roy's Revenge; 09-08-2024 at 10:53 AM.
Trending Topics
#8
The following 2 users liked this post by blsexton1:
John Harper (09-09-2024),
Rob Roy's Revenge (09-09-2024)
Thread
Thread Starter
Forum
Replies
Last Post