perfect..that clears it up for me. The first thing I noticed was how much more oil this bike uses per thousand miles than any other harley I own. I assume the valve stem seals are the culprit. That and the tensioners need to be addressed. I had so hoped that I would be able/willing to leave this completely stock as it is now...no that's not happening.

 

Are you going to wrench your own bike?

You should call hillside or visit our local engine shop R&R in Manchester.

Looks like a little head work, bore to 98" along with the right cam and a great tune will solve all of your engine needs.

 

The crappy guide seals are black; I think the replacements where orange but not sure. If oil consumption is high, very likely the seals are the cause.

 

 

You've accumulated a lot of miles on that bike, which implies to me you're happy running it with a stock amount of power.

When my dad bought an 04 Ultra with 88K miles in 2012 we did a full rebuild with a 95ci kit using CAST pistons, Andrews 21 cam (gear drive), mild headwork (I cleaned up the valve seat area and put new seals in), and had Darkhorse rebuild the crank and put some take-off HD rods on with a balance to the cast pistons as well as bore the OEM cylinders at .001" clearance. John himself said the HD rods are said to be good for 150K. That's NOT to say they'll immediately fail over 150K, but it does say their ability to perform under higher stress situations can be called into question. That bike still runs like a top, very streetable, doesn't require 91 octane, and smooth as silk. A great, mild, reliable bagger motor.

My point here is don't build the bike into something you're not going to enjoy and appreciate. I must honestly admit to over-building some motors only to regret going that route because even though the new motor rips, it's not as "streetable" anymore. Not to mention, they're cheaper to build.

 

It looks like Wiseco makes a 4.25" piston that is made for use with a 4" stroke (the std. 88 stroke), which will render just under 114 cubes at 10.5-1 comp. Of course the crank case would have to be bored out to make provision for the larger O.D. of the bottom end of these much larger sleeves. Does anyone know if such a critter has ever been built and was it a worthy exercise? On another note re. boring crank cases to allow for such large lungs, Have any of you all heard of anyone doing an "in fame" bore job on these crank cases. I'm an old automotive machinist and have looked over the shoulder of tool & die makers in my time and I think I may know how to create the tooling that would enable a machinist to do this task without an engine re & re and tearing down the engine, and therefore eliminating a lot of hours. Rather than a boring bar & tool bit, I believe I could create a rotabroach device that can straddle the con rod instead of removing it like the conventional method. If this hasn't been perfected yet,would it not be a breakthrough specially for those on a budget?
Bigger is better and more is never enough!

 

It's been done and generally not with good results.

 

Like rhuff says, it has been done but case boring to that diameter weakens the case at the stud bosses and the studs are prone to pulling out. Most looking for more displacement using the 4" stroke stop at 4.125" cylinders and case bore; referred to as an "all bore" 107" motor. These motors are very "torquey" and fun to ride. As for trying to develop a tool to bore the cases in place, forget it, not worth the cost or effort. Building a motor that is capable of making 110-115HP and 120-125TQ, the crank should come out to be trued, balanced and welded. Dropping the 4.125" or 4.250" pistons will require that the crank be balanced, otherwise, the motor will vibrate somewhere in the rpm range and will be unrideable; no need to reinvent the wheel.

 

Thanks for the reply, I guess I should have stuck to one question at a time. Are you referring to my question about putting 4.25 bore on the 88 or my notion of creating the tooling to machine the crank case in frame? If you're referring to the 4.25 bore,can you tell me what the negative results were that you heard? I did wonder if it would just be more than what that bottom end was engineered to endure,(all those cubes)-- but I just don't know.

 

Thanks for the comment on these points. This makes sense,you drew the picture in my minds eye that points out just such a thing that I thought may be the case and demise of going down that road I was looking at. So as I thought may be the situation, just too much top end for the bottom end to endure. Reminds me of my rifle re- loading hobby, "If you want to make a 30 caliber 160 grain bullet reach high velocity (say--3400 feet per second), don't overload your little 3030 winchester rifle cartage with powder, go get a 300 win magnum that's designed to withstand this big powder charge and pressure".
Nice chatting with you who speak the same language, knowledge really IS power!