line reaming cam bushings

[silver65]

Has any one ever line reamed new bushings in cam cover with a different case half of similar year. (57-69 ironhead) Because they did not want to crack the case, I have read things saying it's ok and it's been done and others say no any one else have a opinion on this matter. I know There are others that have asked themselves the same question. Any help please

[T. Cotten]

Ideally, Silver65,..

You want the exact case, but frankly, HD's production control was quite remarkable.

Nonetheless, piloting off of needle bearings is naturally sloppy anyway. And so are many modern catalog bushings, leaving very little 'meat' in the bushing for any correction.

So I always took it to task to trial-fit the cams in order to detect any binds, observe any signatures within the bushing bores, and then hand-scrape accordingly.

LEVIT3.jpg

.....Cotten
PS: Doweling often puckers the bore anyway, and a scraper is best used even before a reamer or hone.

[silver65]

So I have some blue machinist layout dye after the new bushings are installed and dowel pined in cam cover and after the dry fit of cams in cover I will coat the inside of bushings with the layout dye then install cover and check if the cams favored one side of the bushing or the other or slide in straight and might have to scrape the location of the dowel pin first. Your thoughts on using another right side motor case and should I be looking for same year case. Knowing this should be done on the same motor that it will be run on.

[kitabel]

You should be looking for the next sequential VIN

[T. Cotten]

There's certainly a time and place for Prussian Blue, Silver65!

Especially when its already real real close, but felt-tip markers are great, and clean up easy. "Dry-erase" can be helpful, too, but my technique was to soft abrasive brush (ADALOX, NYLOX, etc.) the bores for a cross-hatch finish, that would then show shiny-spot interferences upon trials, giving an indication of tight spots or puckers in bushings, without ink.

Then I attacked them with the triangular scrapers, which I still use daily.

....Cotten

[chuckthebeatertruck]

Harley did not line ream at the factory. That is a field repair and unless you pull the Torrington and use a tapered pilot slug, you’ll never get the fit as close as you think. Therefore pretty much any cover for a 900 will fit another 900 if in oem trim. If messed with, that’s a different story.

if folks are telling you otherwise, they don’t have much hands on experience with this topic and likely haven’t done it recently.

generally pinion fit and generator idler fit are the issues. Pinion due to excessive runout at the end after years of abuse and generator idler due to wear. Both are easy to detect but harder to repair properly. During rebuilds, these issues disappear. Scraping for bias only works on a static motor. There’s a lot of backlash on these on the gears plus the sloppy fits at both ends. Sporty cams walk all,over as you wind up and down the rpm range. The more radical the cam, the more it tries to walk.

as such, your best bet is a nearly unmolested cover with around .0015 shaft clearance on each bush. If you have that, it will fit straight on without fuss unless something is wrong (again, generally pinion or generator).

if you want an example, pop over to the 67 build thread I did on my wife’s bike. I swapped an incorrect 1969 cover for an also incorrect 1964 cover. Both fit the 67 motor beautifully. Yes, I have reams, pilots, and my own sunnen honing station, but I rarely have to use them for anything other than pinion bush replacement.

the only thing that trips you up are the dowels. Make sure there are two and make sure they fit the cover snuggly. From there normal observation of rotation will show any issues.

[silver65]

Thanks for your wisdom everyone I do know that the pinion is important to get right due to the fact it carries the oil to crank pin bearings not to say the other bushings are not as important.I have also read and seen people putting the Torrington needle bearings in the cam covers of corse with some thick shims because the needle bearings don't have collars and I guess they would have to lock tight to hold them in place. Any thoughts or opinions on bushings verses bearings.

[chuckthebeatertruck]

All the bushes are important and need to be in the correct locale with correct clearance. Almost all bush problems in sporty are caused by short cuts, hope it will work, or band aids on bushes. No glues of any type should come anywhere near a cover. A lot and I mean a lot of hack work is done to sporties and posted on the net as a “solution.” Most will get a bike back up and running, but that’s a very different thing than a proper repair.

in reality, installing Torrington’s is considerably more work than a bush replacement and more expensive, with out offering any advantages. In fact, if you have worn cam journals and sloppy play it will amplify wear because both ends will be able to walk up to .002/.0025. This can cause all sorts of secondary issues and uneven wear. There’s a reason this wasn’t offered on street bikes.

doing a conversion involves cutting down bushes (not thick shims) so that you can install a Torrington behind them. They must be staked in bore to prevent walking out/spinning of race and the bush must also be retained from spinning. Dowel pins have a habit of distorting bore and affecting the needles, but you can’t correct it after the fact like a bush. so instead you install bush retention by tapping rim for 10/32 and using a set screw with the bush peened over the screw. You need to get the depth correct so the set screw is just below the bush outer rim. It’s a bit more precision work with delicate drills and taps than the average diy enthusiast can do well. Frankly, without a lathe and a mill or very good drill press, it’s a real pita to do a conversion and expect perfect results.

be forewarned a Torrington conversion is not fool proof and if a Torrington sheds needles you’ll have a much bigger mess on your hands than running a worn bush.

To be clear, I just finished a 1960, 76” stroker with a Torrington conversion. It went home with its owner in December after I personally broke it in. It’s really just a lot of work and $$ for no real gain.

[silver65]

I do know that at anything over .001 in.clearance on any of the bushing including the pinion is too much and needs to or should be replaced so yes the cam cover with bushings at .0015 in.would slide right on and the bushings also should be replaced.The roller bearing allow a little more clearance and should be replaced at anything over .0025 in. I don't know what every one else thinks but I think that unless your trying brake some land speed record stroking a older motor is just stupid.But I do agree if you dowel pin your bushings in correct you do not need lock tight.

[chuckthebeatertruck]

If you find it “stupid” to stroke motors you’d find it even stupider to know the bike was first done about 1965-67 with continuous improvement. The bike is totally tractable, will last 30-40k miles before it needs major work, and is stupid fun to ride.


Insulting folks trying to help you is plain silly.

Insulting them over topics you clearly do not have experience with is even more silly.

[silver65]

I thought AMCA sight was about preservation of antique motorcycles not modification.Call me silly but theres is nothing in any of my service manuals that tells you cut up a good case to modify or stroke the motor or reinvent the wheel. Knowing that sometimes you have to modify to preserve.I would much rather in joy the ride and be the silly tortoise, and sorry if you think I was insulting you. I started this topic about reaming bushings not stroking a motor and you.Have fun at the races.

[T. Cotten]

Let us hope, Folks,..

Anybody can play with their toys any way they wish.

The Club failed its mission of preservation with decades of mythical judging mandates, causing more destruction than conservation.

Now, the skills and resources to repair are becoming more scarce than the hardware. Vintage motorcycles last forever hanging in museums or posed by the fireplace; Vintage motorcycling is endangered, and doomed if we make it boring.

....Cotten