View Full Version : Ironhead 73 XLCH Transmission Questions

11th October 2009, 02:58
Hi all. I have a 73 XLCH that I've had since 1987 when I got it at a swap meet. I've put tons of miles on it, but it has sat for the past couple of years. Took it our for a ride a few weeks ago after taking it out of hibernation. Changed fluids and all that good stuff. While riding it, the clutch acted funny, so I thought I'd remove the primary cover and make sure the primary chain was adjusted before running in circles with clutch adjustments.

Found three roller bearings in the primary case! So took everything apart and pulled the transmission. There is basically nothing left of the mainshaft bearing (on the right side case). I can't find a detailed picture of the right side case (looking out from inside the transmission housing). The FSM shows roller bearing washer, retainer ring, etc. I only have a few scant pieces and the case looks out of round. Anyone with some pics of this?

I can't figure out how to post the pics I took, so I apologize for the lack of detail.

11th October 2009, 03:20
Best way to post pics ...

open a photobucket account
upload pics there
copy/paste the IMG code [not HTML code] into message here

11th October 2009, 03:40
Thanks Mick!! Here are the pics. Any suggestions anyone can give would be great. Gears and dogs all look good. Just worried about the case.





72 Ironhead XLH
11th October 2009, 03:55
Sometimes a very tight chain will flatten a roller to start the process, no/very low oil might do the same thing. Either way, you need to replace the race first.

11th October 2009, 04:05
Ok. So what's involved in replacing the race? Is it pressed into the case? I have a variety of bearing pullers/installers. SOmething I can do myself I'm assuming??

11th October 2009, 10:19
You need to heat the case with a propane torch to about 212 degrees F, spit sizzlin hot, then knock out the old race and knock in the new one with a stepped drift made the right size to fit the race.

Depending on the brand of race you get, it will most likely need lapping or honing to final size, in line with the bearing in the trapdoor. That needs ether the original Harley lapping tool, or a machine shop with a Sunnen hone machine or similar.
Factory workshop manual has all the details.

Dont buy no-name Taiwan made race and rollers. Get Andrews or Jims, USA made etc.

And make sure it is assembled with the flat washer between the rollers and the spring circlip on the outer end, so the rollers dont catch in the gap in the circlip.

11th October 2009, 13:06
Wow! You're lucky something didn't get caught in the gears and blow up the trans. Hop pretty much gave you the lowdown. Repairable but you will need some machine shop help It is essential that the new race be line bored with the existing trans trapdoor bearing. Take a really close look at the mainshaft and make sure its not boogered. I believe the rollers are available in std., +.0004 and +.0008 sizes if that helps.

11th October 2009, 13:08
YOu're right, I did get really lucky! I'm searching for parts now. Thanks to everyone for the advice! I feel better now knowing I have a plan.

11th October 2009, 13:41
72 ironhead xlh makes a very valid point!! bearing overload from tight chain.

looking at the pic's, i believe you can salvage the cases. i do not think a line bore would be needed but machine work is definite.

1.leave old race in as a protection, have the inside case decked so it is flat again.
2.make sure the stop pin for the tab washer is reinstalled and long enough to catch the ear.
3.machine the mainshaft low gear shoulder back flat
4.the main shaft can be turned and a wear sleeve be installed to bring dimensions back to standard.(we do this on pump shafts all the time)
5.install new bearing race
6.install trans with new parts for that side. take an axial end play reading and add shims as needed between low gear and the tab washer.
7.very important that the opening (slot) for the mainshaft bearing on the case is restored so the bearing can get oil

old guy with kmodel
11th October 2009, 19:54
I have never seen that weird gear tooth profile on any type of geared power transfer box other then the old XLs. Terrible design that wants to push itself apart.
As far as I ever could tell, HD, through Kent Moore never did offer an XL trans bearing lapping tool, however Eastern Motorcycle does, seen here from this outfit. These attachments do not fit the HD- Kent Moore tool.

When I was doing these, I used Jims races, they were under size, I would first Sunnen hone them and then use the Eastern tool to finish them up, as the Sunnen hone will only follow the hole in the race, where the Eastern tool has the pilot for the tranny door to help bring the shaft true.
One thing I learned the hard way, when the trans is assembled, if there is any bind at all rolling the tranny by hand, find out why and fix it, dont hope it will work itself out when running.

11th October 2009, 21:24
old k dude:
i agree on the design in part largely due to the fact that xl trap doors are weak and the gear dogs are basically a hit/miss application. while the helictical cut gears are quiter and shift easier, the old straight cut gear has been around for decades. truck & auto world used a crack-pot of them. barring a mis-shift, the old xl trans was all in all a pretty good unit. judging by the varnish left in the cases, this machine lacked maintenance.
andrews really improved the hd tranny with their gears, especially in the ramp design. it did away with the clunk and mis-shift was reduce because it wasn't a roll till you fall design.
a bad thing about setting a machine up for long peroids with old oil is that parts have a tendancy to stick like roller bearings. the shaft will turn but not the rollers.
there is one possibility of trashing the right mainshaft bearing design and going to a unitized bearing like is now used and get rid of the 23 rollers, race and the need for the tab washer which is essential to the old design for oiling.

old guy with kmodel
11th October 2009, 21:54
One problem worth considering is, in 2nd and 3rd, those gears have only 50% contact! You can tell folks to be easy when in those gears, but, it doesnt seem to do any good.
I found back in the day, patching up those old XL trannys was a money loser, as something else would fail, and it would be all my fault.
Later on, I would only replace everything with new Andrews, that resulted in me doing far fewer XL work because of the cost, but, it always worked out with no come backs.

12th October 2009, 01:51
I don't know if you can tell by the pics, but the first gear thrust washer was fused to the mainshaft. I had to heat the hell out of it to pull it off. I ordered a bunch of new parts today based on my inspection. New mainshaft, first gear, bushings, bearings, etc. I will take it somewhere to be aligned bored and with the new parts, should last me many more years.

14th October 2009, 19:59
I looked up the tools for the align bore - $600.00! Wow. Anyway, still waiting on my parts but had a quick question. If I install everything (new bearings, mainshaft, bearing race, etc.), can't I check if its running true by taking a reading with a runout gauge? I can't find a decent shop around me that can do the work or even has the tools to do it right.