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[ultrafxr]

Friend had his 110" built to a 113" and is having some problems.  For the record the builder was NOT one that is on this forum - perhaps it should have been, lol.  Anyway bike ran great with no problems for about 5k miles then it started puking oil out the air cleaner.  He tried all the usual remedies like keeping oil level below full, cleaning air cleaner element, etc.  But it continued and got worse and started showing up on the left side of the bike.

Took it back to the builder who diagnosed a problem in the rear cylinder by looking at the spark plugs and down the cylinder with a borescope.  He suspected  a broken ring letting oil up into the combustion chamber even though the bike was not smoking.

Upon teardown he says the cylinder is distorted - out of round.  Long story short he is replacing both cylinders and totally rebuilding them under his warranty.  So good for him.

But what in anyone's experience would cause this?   

[Para Bellum]

Jerry, What brand of cylinders did he use (if it wasn't a bore-out of the stockers)?  HD factory-fresh cylinders aren't that great sometimes.

[ultrafxr]

Jerry, What brand of cylinders did he use (if it wasn't a bore-out of the stockers)?  HD factory-fresh cylinders aren't that great sometimes.

He bored the stockers (which had about 35k miles on them) 0.060" over I think it is to make the displacement 113".  Pretty sure he used torque plates but would have to verify to be 100% sure.

[FlaHeatWave]

Improper breakin / bad tune (both heat related) are 2 things that would cause the distortion...

[hrdtail78]

Thin walled spigots can also cause it while tqing down the head.  So, you say out of round?  Is that at the top, middle, bottom?  If it is the spigot area and the builder is standing behind it.  I'd say you are at a good shop.

[ultrafxr]

Thin walled spigots can also cause it while tqing down the head.  So, you say out of round?  Is that at the top, middle, bottom?  If it is the spigot area and the builder is standing behind it.  I'd say you are at a good shop.

Don't know those details.  But when I go with him to the shop to pick up the bike we will find out.  Thanks for the info.   

[HD Street Performance]

But what in anyone's experience would cause this?

A bad tune and sustained running lean

[GMR-PERFORMANCE]

Many things can cause a cylinder to change shape.. Heat , like idling in traffic and getting too hot. Tune , ign timing .  OR just a cylinder that is flawed to start with..

This bike used oil and it was a stock 103 . Dealer did hone cylinders re ring it worked for a while and then started using oil again. Bike dropped off warranty customer wanted it fixed . I tossed these cylinders , they both looked like this. ( look at stud holes) now if this happens some where in the middle maybe you can see it maybe not. Think about how many 4.0 cylinders are made and no way you are not going to get a few bad cylinders. It may be fine in a region where the bike never gets really hot or stop and go traffic .. so region can play a role as well.. Funny how many customers claim that the bike never got hot. But you see a blue/ green viton valve seal that is now black .. Well something got hot as it did not change color on its own..  It happens air cooled engine..

[TorqueInc]

110 cylinders should not be bored .060   .030 would be best....  .040 the max that goes out of here

The cylinders from harley might just be fine....they may not be located properly when machined

chuck one up in a lathe off the ID of the cylinder and youll see what im talking about

[chicoman]

110 cylinders should not be bored .060   .030 would be best....  .040 the max that goes out of here

The cylinders from harley might just be fine....they may not be located properly when machined

chuck one up in a lathe off the ID of the cylinder and youll see what im talking about

Been running my 110 bored to 113 for over 20000 miles no problems. I had bob at razorback tune mine, that is why it runs so good.

[prodrag1320]

its pretty much on how they were bored & honed (was the proper equipment used?) lots of guys out there doing cylinders with machines not made for boring cylinders.find out before you have it done.if they say they bore in a mill or with a lathe,find a shop that uses the correct machines (we have van norman boring bars & sunnen honing equipment here)

[HD Street Performance]

.060 over working fine here
Kwik-Way boring / Van Norman power stroking Sunnen stones and brushes

[Texas 103]

Friend had his 110" built to a 113" and is having some problems.  For the record the builder was NOT one that is on this forum - perhaps it should have been, lol.  Anyway bike ran great with no problems for about 5k miles then it started puking oil out the air cleaner.  He tried all the usual remedies like keeping oil level below full, cleaning air cleaner element, etc.  But it continued and got worse and started showing up on the left side of the bike.

Took it back to the builder who diagnosed a problem in the rear cylinder by looking at the spark plugs and down the cylinder with a borescope.  He suspected  a broken ring letting oil up into the combustion chamber even though the bike was not smoking.

Upon teardown he says the cylinder is distorted - out of round.  Long story short he is replacing both cylinders and totally rebuilding them under his warranty.  So good for him.

But what in anyone's experience would cause this?   

Don't know how it was broken in. That's why it's critical to establish a  relationship with a good builder/tuner. Breaking it in on the dyno is the only way to go, you can monitor EVERYTHING and control it , heat , fuel etc:  You know for sure how it was broken in and eliminate that variable.  No substitute for quality builder/tuner     

[mike jesse]

Unless you have the parts in hand, how would you know?

[TorqueInc]

Then theres those that dont hold up

if you know where they are going to be tuned that is one thing

better to be cautious than not