cases are split, a little scary

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cases are split, a little scary

Postby K Daddy » Sun Jan 20, 2019 3:14 pm

I have split the cases of my '52 K. The bike is a real basket case and presents a new problem every day, mostly due to my ignorance of the K model.
The cases are split because it wouldn't shift. I could shift from 1st to neutral and back but that was all.
When actually opening the cases, needles fell out from the bearings of the clutch and right side main bearing. I have carefully gathered the needles up but I can imagine there is a trick to putting the needles in place and not knocking them loose when reassembling the cases. The last few inches of closing the cases won't allow me to see what is going on with the needles.
The only resource I have is a '59 sportster manual and maybe that is inadequate. I have the K model parts book with exploded views.
My plan is to clean up the light surface rust, replace the transmission springs and go back together.
I welcome any tips you might have to keep me out of trouble.
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Re: cases are split, a little scary

Postby strong56KH » Sun Jan 20, 2019 4:46 pm

Use some grease to hold the flywheel gear shaft (pinion shaft) bearings in the bearing cage. The 23 mainshaft bearings (9095 in parts book) can be put in after the cases are assembled. Read over section 4 (Transmission) of the Sportster service manual and inspect parts as noted there, e.g., shifter forks for any wear or damage (bent or cracked). If you get overwhelmed with trying to use the Sportster service manual and a parts book, you can always take the engine to a reputable builder e.g., Bill's Custom Cycles in Bloomsburg, PA.
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Re: cases are split, a little scary

Postby chuckthebeatertruck » Mon Jan 21, 2019 9:39 am

Yep, you're totally over thinking this one. Even with a trap door, you can't see the loose rollers.

The trick, as pointed out, is a good layer of grease. They won't shift unless you cock it up. No different, really from a big twin 4 speed, except k/sporty transmissions work far better.

While I haven't done a k model without a trap door, I've done far too many integral transmission cases across other makes, including aermacchi/hd. Assemble your trans first in the case half and measure your fork spacing. Keep in mind over and undersized forks didn't exist at the factory in 52.

Get that right, then assemble cases without flywheels. Snug it all up and measure end play. Correct as needed. Loose is better than tight, especially if you beat bikes.

Then plop in your lower end, seal her up, check end play one more time for trans and flywheels.

Three beers, a little music, and a few hours will sort you.

Last tip, ANDREWS, wherever possible in that trans. I've also become really a big fan of polishing gears in my tumbler. Talk about smooooth.
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Re: cases are split, a little scary

Postby Ferrous_Head » Mon Jan 21, 2019 5:33 pm

Lwt mw start by saying I'm not a K guy, I'm a Sportster guy. But these engines are very similar so I'll throw in my 2 cents.

HD made a lot of changes in the gearbox area from the first year and as I understand it they used better materials and better design BECAUSE they had breakages. I also have been told that the trap door was developed in response to dealers complaining about having to split cases when the gearbox failed under warranty.

I believe (think) all the newer parts retro fit. It's up to you whether or not you change out gears and shafts but if your ever going to now is the time to do it.
If you keep the original gears and shafts the end plays should stay the same. Unlikely you'll need to replace the shims. If you change parts be prepared to start juggling shims in there. Again, this isn't an impossible task it just takes time to get it right. It can be frustrating for anyone in a hurry.

I recently had to pull my gearbox twice in two days at a race meeting. The HD race teams did this often enough as well. But here's a tip that WILL save you time and frustration. (Here I presume the early K is built the same way as a Sportster)
The 23 crowded needle rollers on the gearbox main shaft are contained by a spring ring that fits into the bearing race on the right side. This spring ring is quite substantial ie it's hard to get out and hard to put back in.
If you have already removed this snap ring there is an easier way to re-install it as long as the rollers and shaft aren't in there. Turning it90 degrees sideways you can force it into the race and then just rotate it through 90 degrees again and it's quite easy to move it into the grove.
Putting your rollers in first is defiantly easier than trying to re-install the snap ring if you do it after the cases are together. The trick is in not knocking the rollers out while trying to maneuver the gearbox (or in your case the right case half) into place.
If you machine up a plug to fit inside those rollers that's just a tad (engineering term of measurement) smaller than the diameter of the main shaft bearing are it can hold the rollers in place while you do this. As the shaft comes through the bearing it will displace the plug and viola ! the job is a breeze.
I didn't have a plug at the track last time but just used a socket of suitable diameter. That's a race day kludge.
But without doing that there's no way I would have attempted to do this job at the track.

DO make sure you put the washer for the right side of the rollers in there. If you do remove that snap ring ALWAYS replace it with a hew one.
"I know only too well the evil that I propose, but my inclinations get the better of me."
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Re: cases are split, a little scary

Postby mikeslemmon » Mon Jan 21, 2019 8:29 pm

you can put the roller bearings and main shaft in the right case before you put the cases back together. see section 4D in your service manual, starting on pg. 13. while you have it apart, check, and, or change the rod and main bearings. easy now , hard later.section 3E in the service manual, starting on pg.11
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Re: cases are split, a little scary

Postby EKHKHK56 » Mon Jan 28, 2019 10:59 pm

I use a spoke to check check out some trans play through windows in cases if assembled.
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