Ironhead connecting rod bearings

[Rodburner]

how often has anyone had to use undersize rollers ? doing the math i have -.00015 with a .001 clearance calculated in my gozintas . on the rear rod i had 1.6236 & 1.6237 ID of races, front race ID was 1.6245 . nos HD crankpin =1.2488. rollers are .1873. Am i doing my math right ?

[Chuckthebeatertruck]

Originally Posted by Rodburner

how often has anyone had to use undersize rollers ?

No.


Rather than fit undersized bearings -- you instead hone the races for clearance.

[Rodburner]

thanks for the reply....i saw undersized rollers and was wondering about that. bought this early '73 as a basket ,literally brought it home in the trunk of my car. been a very slow process being able to dedicate myself to it. don't know any history of the bike but have matching #'s .had found excessive play in crank bearings so i tore it all down planning to replace all bearings, bushings, seals and whatever else needed replaced. thrust washers were worn,1 was grooved pretty bad.it had steel roller cages with bronze washers,it was a little tricky getting the correct ones ,2 different ones listed in parts manual .

[brucstoudt]

which is the best route for you? honing the races requires a precision tool,lapping or rigid honing.undersize rollers could be done at home? accurately i can't say.

[kitabel]

Easiest: buy a rod & pin set outright, comes fitted with rollers and pin bushings

[needspeed]

Some questions.

Availability of undersize rod rollers? This is new to me. Where do you get them? I've heard of undersize plain bearings for a car but never harley roller bearings. They may exist, but never seen in Harley parts books. Just standard and over sizes.

Did the parts you measured in post 1 come from the engine you bought? If so and your measurements are accurate the rear rod was too tight, and yet you say there was excessive play in the crank bearings.

If you rebuild the rod bearings, the right way would be to lap or hone the races as mentioned in post 2 so they are true and round and fit new rollers.

Originally Posted by kitabel

Easiest: buy a rod & pin set outright, comes fitted with rollers and pin bushings

Agreed. If the quality is good this would be the easy way.

[ericfreeman]

Send the crank to Truett&Osborn for rebuilding.

[thefrenchowl]

Think about it a second and you'll know why undersized rollers don't exist..

They might (just might...) fit OK on the ID and OD with a thou or two play, but will certainly crowd themselves on the PCD and won't turn freely...

It's only with white bearings that one grounds the crank and not the rods...

Patrick

[Chuckthebeatertruck]

You don’t need to own a rigid hone or buy a rod set to solve this one.

Easiest and cheapest is to go to an automotive rebuild shop and give the machinist a $50 and your target measurements. About 10 minutes per rod maximum and you’re done.

Honing a Harley race is no different than honing split connecting rods for plain bearings and completely within the skill set of anyone with basic training on a honing station. They don’t have to be a Harley or motorcycle mechanic.

Or you can spend several hundred to solve it the other ways.

Buckdancers choice.

[Iron Mike]

Chuck is correct. A honing machine does not know it is sizing a HD rod. A well equipped hydraulic cylinder repair shop should have the equipment as well, if an auto shop is not convenient.

If you go for the second suggestion towards the few hundred dollar route, your almost to the cost of a used hone and mandrel for the job. Then you can do them yourself as well as your next project,.. and the next, ect ect.