Removing broken tacho housing

xs650brat

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Looks like the PO of my '78 XS650 Special broke (or cut?) the tacho housing (pictured below as #1 in the diagram). There's no tacho on my bike and I don't plan to add one, but the o-ring #2 is leaking so this needs addressing. I have parts on the way (replacement housing, threaded insert, o-ring) along with Mikes XS screw-on tacho cap to cap off the tacho housing.

I'm looking for insights and ideas as to how to get the remaining lower portion of the broken housing out of the crank case. I believe that removal of the housing can usually be be done without draining the oil or removing the crank case as long as you maintain downward pressure on the tacho drive gear #7 (so that the washer #8 at the base of it doesn't come loose and wander around in my crank case!), but have a couple of questions before I get at it:
  • Once the bolt #5 that retains the housing in the crank case is removed, how would you get the remains of the broken housing out? The highest point of the broken housing is inset within the crank case, leaving nothing to grab. Pick through the bolt hole and lift it up? Pick between the o-ring and the housing and pull it up? Any ideas or insights?
  • How tricky will it be to replace the housing while maintaining downward pressure on the tacho drive gear so as to not lose the washer at its base? Are we talking high risk, 'diffusing a bomb' levels of careful, or probably okay as long as I'm careful?
If this is going to be a simple, relatively low-risk job I'll tackle it now and take care of the leak...if the consensus is that it's more trouble than it's worth and likely to end in tears with washer #8 lost inside my crank case, I'll hold off until the next time I need to pull the crank case anyway. If I can take care of it now, I'd love to take care of that leak though!

Insights appreciated!
 

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Thank you. The plug from Lowbrow Customs would make sense if I ultimately decide to remove the drive gear entirely. For now I’m just looking to replace the seal, the housing and cap it off with the screw cap…but I’m stuck on how to remove the remains of the old housing (as pictured), hopefully without pulling the crank housing,
 
use some cardboard and a 5 gallon bucket lean the bike over, handle bar on the bucket, remove the cover. Tap it out from the inside. While in there open and inspect the oil pump. That's what I'd do anyways
 
At least if I absolutely have to pull the cover, a five gallon bucket gets to be part of the act!

I’d hoped to be able to do the job from the outside, but perhaps finagling the housing out of there just isn’t a possibility‽‽
 
Yes. Ordinarily with a (non-broken) housing you’d just unscrew that bolt and pull it out…but not so simple if someone has sheared of the only grab-able portion of it :/

When I got the bike the broken top half of the housing was just politely sat in place here…only noticed it was sheared once I inspected the leak.
 
You can pull up the shaft a bit to remove the collar. The washer "might" stay in place. It kinda sits in a recess in the cover. Then again someone else may have already lost it...............
On a new to you bike there's several things worth checking inside that cover anyways.
 
I had warm enough weather this morning to get out on the stoop and take care of the tacho cap-off job.

Ultimately having removed the housing retaining bolt (on the front of the case) I was able to insert a dental pick into the bolt-hole and lift the broken housing out from there, with the last little lift being done using a bent hair pin. I was super careful (AKA anxious and terrified) and kept downward pressure on the drive the whole time in order to prevent that washer from going on a stroll around the inside of the case. Ended up being a pretty quick and easy job.

The capped off drive looks much better (vs the remains of the old housing)...and next I'm gonna have to start polishing the case to match the lustre of the new tach housing and cap...which won't be a quick job 😅

Tacho Cap.jpg
 
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