2004 88ci Rebuild advice
Grand HDF Member
Joined: Nov 2009
Posts: 4,315
Likes: 1,663
From: Tampa
I didn't say anything about a big inch motor being unreliable. All I said was "streetability" was compromised, which is entirely a subjective measurement by the operator. In my case, the engines felt too high strung and weren't really that fun to just cruise around on. And with the 106" Evo taking out pistons, I believe that's because the Evo block doesn't have piston oilers like the TC and S&S SA blocks do to keep the pistons cool.
No offense to all our forum builders, but I'm tired of being suggested to go as big as possible "while you're in there..." I get a lot more satisfaction from a mild build than I do out of a really hot big bore. Something a little under or around 1hp/ci with torque peaking around 1/2 the rev range is a good recipe for success in a street motor.
No offense to all our forum builders, but I'm tired of being suggested to go as big as possible "while you're in there..." I get a lot more satisfaction from a mild build than I do out of a really hot big bore. Something a little under or around 1hp/ci with torque peaking around 1/2 the rev range is a good recipe for success in a street motor.
Road Captain
Joined: Oct 2018
Posts: 539
Likes: 284
From: Coldstream B.C. CA.
Question. I'm thinking of putting a 4.375 stroker in my TC 88 as well and perhaps going bigger bore sooner or later and that will require crankcase boring. Can anyone tell me where I can get a couple of teck questions answered re this exercise. First, what is the recommended clearance between the crankcase bore and the cylinder spigot? I've heard measurements that differ more than .020,--thats a huge spread in this game! And if this actually is such a forgiving spread in tolerance, this kind of answers my second question which is "I hear that you can actually oversise the crankcase spigot bore to make accommodation for the larger bore jug spigots and still use stock 88 jugs". I assume this would be for those who are anticipating going big bore jugs at a later date. Sure this means the cost of lower deck height pistons for my original 3.75 bore jugs if I just do the stroke part of this project, and I realize it would be great to just do drop the cash and do it all while I'm ***** deep in the bottom end (hmmm I meant that from harley engine stand point), but I have a curious mind as well as limited budget. Doing the stroker alone would make my TC a 96, add the 4" jugs and then it's a 110, go 4.125 bore and it's a 117. It would really suck to do any scope of this project then find out I should have done some of it different. Any advice?
Grand HDF Member
Joined: Nov 2009
Posts: 4,315
Likes: 1,663
From: Tampa
Question. I'm thinking of putting a 4.375 stroker in my TC 88 as well and perhaps going bigger bore sooner or later and that will require crankcase boring. Can anyone tell me where I can get a couple of teck questions answered re this exercise. First, what is the recommended clearance between the crankcase bore and the cylinder spigot? I've heard measurements that differ more than .020,--thats a huge spread in this game! And if this actually is such a forgiving spread in tolerance, this kind of answers my second question which is "I hear that you can actually oversise the crankcase spigot bore to make accommodation for the larger bore jug spigots and still use stock 88 jugs". I assume this would be for those who are anticipating going big bore jugs at a later date. Sure this means the cost of lower deck height pistons for my original 3.75 bore jugs if I just do the stroke part of this project, and I realize it would be great to just do drop the cash and do it all while I'm ***** deep in the bottom end (hmmm I meant that from harley engine stand point), but I have a curious mind as well as limited budget. Doing the stroker alone would make my TC a 96, add the 4" jugs and then it's a 110, go 4.125 bore and it's a 117. It would really suck to do any scope of this project then find out I should have done some of it different. Any advice?
Having said that, Axtell recommends 5 to 10 thousandths clearance between the cylinder spigot and crankcase. I would recommend maintaining this, especially if your spigot is thin. OEM cylinders have a slightly larger gap based on how it feels installing them compared to Axtell but I've never actually measured them. That being said, when I took my 88" Sportster back down to an 883cc to sell it I did not do anything special to the crankcase. I just plopped them 883 cylinders right onto the huge crankcase hole with the almost 1/8" of clearance and sold the bike. Granted the 883 cylinders have a 1/4" thick sleeve down there so I doubt there would have been any issues even way down the road.
I would not screw with deck height by milling the case. Go with thinner gaskets, or mill the cylinder. There's no way to know where you need to be in the deck at time of machining so leave that adjustment to the top end of the engine.
I know exactly where you're coming from when it comes to options. "In for a penny, in for a pound" is a common philosophy when it comes to building engines. Since you're having the case bored, why not just go 117"... or if you're buying a crank just get the 4 5/8" stroke and go 124"..., etc... I'm assuming your limited budget combined with your original comment of using the 4 3/8" stroker crank that you're referring to the cheap Screamin Eagle stroker crank for the TC88. I put that crank in an 04 Ultra with Wiseco pistons for a 103" conversion with the S&S 551 EZ cams and it's a ripper for minimal dollars.
My last suggestion, don't overdo it. For some reason it's fun to rip the throttle on a hot engine but it gets old after many miles on the highway. Focus on your end game for the bike and build backwards from there.
HDF Community Team
Joined: Jun 2006
Posts: 12,776
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From: san antonio
Late to this thread but wanted to add my own experience related to some of the questions that have been asked in this thread.
I have not found any issues related to streetability WRT bigger build motors since streetability has nothing to do with displacement and more to do with compression and generally pushing the envelope on build parameters; Kirby said it best.
I had a bad experience with an Axtell Mountain Motor kit for an "all bore" 107 and eventually had to junk the Axtell cylinders that would not maintain a true bore. Cases were bored to fit the Axtell cylinders but a short term solution to get the bike (one of mine) back on the road was to use a set of HD OEM 4.060" cylinders to rebuild the top end. The spigot diameter of those cylinders was .0525" smaller than the case bore, i.e., .026" gap between spigot and case bore. I ran those cylinders with no issues while I sorted out a final solution to restore the top end to 107" configuration. I cannot speak to longevity because the motor was only run in that configuration for less than 3K miles but I think it would have held up just fine.
Having been down the "stroke" vs "no stroke" a couple of times with my own bikes, I subscribe to the "go as big as you can while in there" position. I built two of my own bikes without stroking, an all bore 107" (124TQ/110HP) for my '02 FLHT and a 98" (115TQ/114HP) for my '05 FXSTD and both were excellent running bikes, if I did it again, I would pay what is a marginal cost increase to the build for the additional displacement.
I have not found any issues related to streetability WRT bigger build motors since streetability has nothing to do with displacement and more to do with compression and generally pushing the envelope on build parameters; Kirby said it best.
I had a bad experience with an Axtell Mountain Motor kit for an "all bore" 107 and eventually had to junk the Axtell cylinders that would not maintain a true bore. Cases were bored to fit the Axtell cylinders but a short term solution to get the bike (one of mine) back on the road was to use a set of HD OEM 4.060" cylinders to rebuild the top end. The spigot diameter of those cylinders was .0525" smaller than the case bore, i.e., .026" gap between spigot and case bore. I ran those cylinders with no issues while I sorted out a final solution to restore the top end to 107" configuration. I cannot speak to longevity because the motor was only run in that configuration for less than 3K miles but I think it would have held up just fine.
Having been down the "stroke" vs "no stroke" a couple of times with my own bikes, I subscribe to the "go as big as you can while in there" position. I built two of my own bikes without stroking, an all bore 107" (124TQ/110HP) for my '02 FLHT and a 98" (115TQ/114HP) for my '05 FXSTD and both were excellent running bikes, if I did it again, I would pay what is a marginal cost increase to the build for the additional displacement.
Road Captain
Joined: Oct 2018
Posts: 539
Likes: 284
From: Coldstream B.C. CA.
Thanks for the heads up on the dead thread, I'm still learning the in's and out's, I'm not much of a net head.
I guess I wasn't clear on my comment about "Deck height", I was referring to wrist pin to piston deck height which would be a lessened distance (which would mean different pistons) if I went longer stroke while using my original jugs and bore size. Thanks too for your comments re "don't over do it". I currently have a commander 5 fuel syst, slip on's and 551 S&S gear drive cams and it works great for me. What ever I do in the future, I want to focus mainly on torque rather than hp. but it looks like the 551's have there limits when it comes to cubes. S&S says 106 is about it for the 551,'s so -- maybe that's as far as I should go unless there's something else out there that has a similar power band with the larger cube engines. I love my "Tractor Sickle" as I call it. I think 114, maybe 117 is a far as I'd go with the cubes if I do go through with this. Nice to connect with someone who speaks the same language, I was just at dealership again speaking to a cocky counter guy babbling on in response to my questions until he realizes I see through his evasive answers about how technical this topic is an that he don't know his own *** from fat meat when it comes right down this stuff, specially when I point out that I'm an automotive machinist that spent decades rebuilding engines. But I'll be the first to point out that I'm not very familiar with the Harley scene and there just ain't much room left in my head (or time in my life) to learn another whole world of this cool stuff. Thanks again mate, we'll see where this goes!
I guess I wasn't clear on my comment about "Deck height", I was referring to wrist pin to piston deck height which would be a lessened distance (which would mean different pistons) if I went longer stroke while using my original jugs and bore size. Thanks too for your comments re "don't over do it". I currently have a commander 5 fuel syst, slip on's and 551 S&S gear drive cams and it works great for me. What ever I do in the future, I want to focus mainly on torque rather than hp. but it looks like the 551's have there limits when it comes to cubes. S&S says 106 is about it for the 551,'s so -- maybe that's as far as I should go unless there's something else out there that has a similar power band with the larger cube engines. I love my "Tractor Sickle" as I call it. I think 114, maybe 117 is a far as I'd go with the cubes if I do go through with this. Nice to connect with someone who speaks the same language, I was just at dealership again speaking to a cocky counter guy babbling on in response to my questions until he realizes I see through his evasive answers about how technical this topic is an that he don't know his own *** from fat meat when it comes right down this stuff, specially when I point out that I'm an automotive machinist that spent decades rebuilding engines. But I'll be the first to point out that I'm not very familiar with the Harley scene and there just ain't much room left in my head (or time in my life) to learn another whole world of this cool stuff. Thanks again mate, we'll see where this goes!
Outstanding HDF Member
Joined: May 2014
Posts: 2,400
Likes: 284
From: Fort Worth, TX
I took the 88' in my '05 FLSTN to 117" when I did the engine and am happy I didn't go smaller. I was already going to buy pistons and have the cylinders bored when I decided to go with the 4.375" S&S crank (was planing on a 107" build at the time) so the difference in cost was buying cylinders instead of boring and having the cases bored for the 4.125" cylinders, short money at that point for the ten extra cubes. All said and done I have a very well mannered bike that is happy slow cruising on back roads or having the **** flogged out of it. Build it as big as you want now and don't second guess yourself down the road...
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