Rod Bearings
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6th Gear
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Rod Bearings
Want to check connecting rod bearings if they need replacement.
Have two HD Manuals, but they do not agree on ammount of free play, more play for front rod less for rear, a bit confusing.
Cylinders, and pistons are removed for re-bore @+.040, and valve job, engine is not removed from frame.
How can I measure this short of total tear down? (which I dread doing), and how much play can I get away with?
BIKE= 1975 XLH Ironhead Sportster 1000cc. Oil=Valvoline 60wt.
Thank You much.
db.
Have two HD Manuals, but they do not agree on ammount of free play, more play for front rod less for rear, a bit confusing.
Cylinders, and pistons are removed for re-bore @+.040, and valve job, engine is not removed from frame.
How can I measure this short of total tear down? (which I dread doing), and how much play can I get away with?
BIKE= 1975 XLH Ironhead Sportster 1000cc. Oil=Valvoline 60wt.
Thank You much.
db.
Seasoned HDF Member
Joined: Dec 2004
Posts: 11,068
Likes: 1,477
From: Texas! Ya mean there's someplace else?
RE: Rod Bearings
Here's what my manual I bought back in '77 says. Checking for rod up-and-down play & side shake: Remove pistons. Refit when "appreciable" up and down play is found, or when 11/64" side shake on front rod & 3/64" on rear rod, measured at the top of the rod.
Lay a ruler across the crankcase deck with one end against the side of the piston pin hole of the rod being measured. Move the rod end from side-to-side and note the movement on the ruler. I always found that if you were at, or even close to, the side shake limits, you'd have that undefined "appreciable" up-and-down play.
The measurements are different for the front & rear rods due to the male-female construction at the crank pin end of them.
Lay a ruler across the crankcase deck with one end against the side of the piston pin hole of the rod being measured. Move the rod end from side-to-side and note the movement on the ruler. I always found that if you were at, or even close to, the side shake limits, you'd have that undefined "appreciable" up-and-down play.
The measurements are different for the front & rear rods due to the male-female construction at the crank pin end of them.
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6th Gear
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RE: Rod Bearings
Thanks for the reply;
Your specs. are alot more forgiving than my (1970-1978) HD Sportster service manual.
It says: 3/64" front, and 1/64" rear rod side shake, (pretty tight), also that these specs. are for 1976 and earlier XL's w/steel bearing retainers. 1977 on has aluminum.
CRAP!
WHAT THE HECK IS SIDE SHAKE? Do they mean side to side (slideing) movement across the rod journal, which is around (4mm),
OR.. if it is a rocking motion of the rod, like if you held it to either side of the journal and tried to tilt it.
I gota get this thing right the first time before I put the new top end together.
Thanks to you all for this forum, and any advise.
db.
Your specs. are alot more forgiving than my (1970-1978) HD Sportster service manual.
It says: 3/64" front, and 1/64" rear rod side shake, (pretty tight), also that these specs. are for 1976 and earlier XL's w/steel bearing retainers. 1977 on has aluminum.
CRAP!
WHAT THE HECK IS SIDE SHAKE? Do they mean side to side (slideing) movement across the rod journal, which is around (4mm),
OR.. if it is a rocking motion of the rod, like if you held it to either side of the journal and tried to tilt it.
I gota get this thing right the first time before I put the new top end together.
Thanks to you all for this forum, and any advise.
db.
Seasoned HDF Member
Joined: Dec 2004
Posts: 11,068
Likes: 1,477
From: Texas! Ya mean there's someplace else?
RE: Rod Bearings
Went back to my manual to check and see if I misread. '59 - '72 manual, '70 - '75 manual, & '70 - '77 manual all agree: 11/64" side shake on front rod & 3/64" on rear rod. Your specs are probably a misprint.
To measure side shake, push the rod down into crankcase until the bottom edge of the rod small end is even with the crankcase deck. Lay a ruler from the side of the engine to the edge of the small end. Move the rod small end from side to side, measuring the movement against the stationary ruler.
To measure side shake, push the rod down into crankcase until the bottom edge of the rod small end is even with the crankcase deck. Lay a ruler from the side of the engine to the edge of the small end. Move the rod small end from side to side, measuring the movement against the stationary ruler.
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6th Gear
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RE: Rod Bearings
Thanks for the correction. My 70-78 Sportster manuel was reprinted on 6/98 by H-D Inc.
I couldn't belive my book's specs. either, so I posted this quest in hope that others, like yourself, would catch it's error.
For that, I thank you for your time and trouble. Now I can put the new top end together. Wiseco +.040. and valve job.
Something must have gotten lost in the 20 years since the first version. Just think how many other vehicle service guides are mal-fungo. It's really the pits when you cannot count on the repair bible to tell the truth.
It's a good thing I lost my hair years ago, because this would have thinned it for sure!
LAST QUESTION: I know to oil coat all friction points, parts, etc. with motor oil upon assembly. My crankcase oil has been Valvoline 60 wt.
this seems too heavy for new parts, "should I use something else lighter"?
Can I use motor on NON metal gaskets of the top end too?
You should give yourself a $ raise, and take the week off.
Thanks again,
db.
I couldn't belive my book's specs. either, so I posted this quest in hope that others, like yourself, would catch it's error.
For that, I thank you for your time and trouble. Now I can put the new top end together. Wiseco +.040. and valve job.
Something must have gotten lost in the 20 years since the first version. Just think how many other vehicle service guides are mal-fungo. It's really the pits when you cannot count on the repair bible to tell the truth.
It's a good thing I lost my hair years ago, because this would have thinned it for sure!
LAST QUESTION: I know to oil coat all friction points, parts, etc. with motor oil upon assembly. My crankcase oil has been Valvoline 60 wt.
this seems too heavy for new parts, "should I use something else lighter"?
Can I use motor on NON metal gaskets of the top end too?
You should give yourself a $ raise, and take the week off.
Thanks again,
db.
Seasoned HDF Member
Joined: Dec 2004
Posts: 11,068
Likes: 1,477
From: Texas! Ya mean there's someplace else?
RE: Rod Bearings
I'm a convert to multi-vis oils in any HD if it's newly rebuilt. Swapping an older one over may cause a few leaks. I'd suggest going to a good 20w-50, and am pretty sold on Havoline 20w-50 for a non-synthetic oil.
I never oil up the gaskets, unless it specifically says to do so.
I often wonder why I kept most of my old manuals. Now I know, and can tell THE MAMA next time she wants me to clean 'em out!
I never oil up the gaskets, unless it specifically says to do so.
I often wonder why I kept most of my old manuals. Now I know, and can tell THE MAMA next time she wants me to clean 'em out!
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