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[Para Bellum]

A mechanic here said the cylinders on my 110 were 4.004 inches in diameter at the top, but were 3.998" at the bottom, and would need to be bored to correct that.  He also said the pistons skirts were scuffed because of the too-small diameter at the bottom.  Is this for real, or is should the BS flag be flying?

[timo482]

it sure can be real

its what happens when cylinders wear out - well and they start getting oval front and back too

to

[grc]

I'm not sure what Harley uses for a wear tolerance these days, since they've been changing a lot of tolerances in recent years to avoid paying warranty claims, but back in 2005 the limit for cylinder taper was .002".  Assuming your mechanic's measurements are correct, you would appear to have .006" taper, which is excessive.

How about a little more info, like why your guy had reason to pull your cylinders and measure them.  Is this a high mileage engine in need of an overhaul, or were you just doing some performance upgrades, or ??


Jerry

[HD Street Performance]

I would ask to see the dial bore and mike witnessed. Is this possible yes. I still have been fed BS from shops that measure bores with feeler gauges (circa 1950)  so I trust very few. Not in torque plates is no big deal but that will have a few tenths here and there off not thousandths. measure with gauging and the cylinders at room temperature.

[Para Bellum]

How about a little more info, like why your guy had reason to pull your cylinders and measure them.  Is this a high mileage engine in need of an overhaul, or were you just doing some performance upgrades, or ??

Jerry

15K miles.  Took it apart to install HC pistons, cams, lifters, port and polish,
etc.

[JCZ]

15K miles.  Took it apart to install HC pistons, cams, lifters, port and polish,
etc.

Only 15k miles and tapered that bad?  What was the crank run out (assuming he checked that also)?

What compression are you going up to?

[Para Bellum]

Only 15k miles and tapered that bad?  What was the crank run out (assuming he checked that also)?

What compression are you going up to?

Run out was .006.  IIRC the latest and greatest MoCo r/o limit is .012.

Had planned on 10.5:1 pistons.

[HILLSIDECYCLE.COM]

Bored/honed incorrectly from the MOCO.
We've seen the tapered bores on bikes that have as little as 1500 miles.
Always tighter at the spigot, usually by .0015-.0020".
Scott

[Skillet]

Looks like I better keep the wick turned up high on this motor till the warranty runs out next year. Just keep reading bits and pieces on this 110 but for now ''Went for a ride and nothing broke''. Sorry.

[grc]

OK, if the plan was to install new high compression pistons, I would expect a good mechanic to measure the cylinders (with torque plates, btw) and not just throw new pistons into used cylinders, no matter how many or few miles were on the engine.  A lot of Harley shops just take the crap out of the box and slap it together, so at least you've got someone working on your's who seems to understand the right way to do it.

As for the entire cylinder taper issue, if you go back and read some of the information on this and other sites concerning the 110 jugs from 2007 and 2008 you will find that they were coming right out of the factory with huge amounts of taper, and I also remember a tech posting information that his dealership sent back 7 sets of cylinders they checked right out of the box that were out of tolerance.  This was just one of the many quality screwups Harley inflicted on folks in those early years of the 110, along with the cylinder liner movement issue, crankshafts from hell issue, ACR issue, ad infinitum.

If you trust the guy working on it, let him get the jugs bored and honed to the next oversize and proceed with the work.  If you don't trust him, you probably should have found someone else to work on it from the git-go.  Just sayin'.  IMHO, the folks who deserve to have the BS flag waving at them can be found in Milwaukee.


Jerry

[Para Bellum]

IMHO, the folks who deserve to have the BS flag waving at them can be found in Milwaukee.

Yeah, another fine episode in the history of MoCo, quality control, and/or planned obsolescence.

Thanks to everyone for the info and advice.  We're going to press on with the upgrades, and as always, we can be glad we bought the best. 

[HILLSIDECYCLE.COM]

Good he caught it.
Scott 

[cvobiker]

 A lot of Harley shops just take the crap out of the box and slap it together, so at least you've got someone working on your's who seems to understand the right way to do it.


Jerry

Yup, I've seen this first hand, more than once and different shops......Exactly why I do my own work and double check tolerance's when I have to farm out machine work...