Unless you buy new cylinders from Axtel, Rev Performance or S&S, stock cylinders/liners are bored to accomplish the 107 upgrade. I don't know of anyone installing new "thinner" liners.

 

There is a great article on Rosa's Cycles 107" kit in the October issue of Baggers Magazine. It's well worth the read is you are thinking of making that upgrade. The kit costs about $2500.
I'm guessing but You may be able buy a new Harley 110" motor for a few bucks more.

 

You have a point.

The issue with boring cylinders has to do with the ability of the cylinder to: 1.) Absorb the heat from the combustion process (which isn't a constant value), and then 2.) To dissipate this heat fast enough to prevent distortion of the cylinder. The less metal there is (due to boring the cylinder), the less time will be available to absorb extremes of heat production. Then also the speed that this heat will need to be dissipated must either be increased or taken into account.

Within the context of the amount of boring that it takes to obtain a 107" displacement: If the cylinders are not able to handle to temperatures that they reach due to the over-bore; one of two problems will show up: 1.) Head Gasket compression leaks and/or Cylinder Base Gasket oil leaks due primarily to cylinder distortion, 2.) A gradual increase in cylinder leak down as the cylinder bore and the piston rings wear out at a faster than normal rate; due to the elevated temperatures for increased time spans that they are subjected to. Unless a cylinder leak-down test is being done on a regular basis (such as s done on a real race engine application) an owner will typically report this as an increase in oil consumption/burning over time.

Since no one on this thread seems to be experiencing head gasket or cylinder base gasket leaks, it would appear to me that a 107" Bore does not generate these sorts of failures. As for increased cylinder and piston ring wear? That almost certainly is happening, even when going from a 96" to a 103" bore. The question is: How many miles before the increased wear, increases oil consumption to an unacceptable level . . . or actually of more importance; given the reason for boring the cylinder in the first place (increased power) . . . how long before the increased wear on the cylinders and the piston rings causes an increase in cylinder leak-down that cancels out the increase in performance that the original displacement increase got you? On a race engine, a fresh set of zero gap piston rings are almost a requirement after just a few hours or running . . . . if you want to remain competitive . . . and while you can't feel it in the seat of your pants . . . the stop watch and/or the competition will let you know directly!

 

If you are going to have the crank straightened, welded, and balanced, the Timken left hand bearings are a must do. Also, if you are going to do all of that, you might as well bore the cases and go to a 117" kit. I regret not doing that when I had mine apart. If you check your crank runout and it is less than .003" then I would say you can go with the 107 without doing the crank. You can run a 107 with stock heads and get acceptable performance, if you go to 117" you will absolutely need to have the heads done. By the way, I have about 18,000 miles on an overbore 107", no known problems, good compression.

 

5000 miles on mine and that includes half in over 104 degree heat here in Oklahoma.
Not a problem at all.

 

K. If your using the 88 crank did you get the cases machined to accept that massive piston?
If you bought 107 pistons it would make an 88 a 98(iirc).
Just wondering.
And those are some great numbers.
My 96 sucked so I went 106 and tw6-6 cams. Got 12000 on it now and not even a hiccup

 

22'000 km. on my GMR Perf. 107. Make sure the cyclinders to be bored are bored dead centre from the factory. Mine were off-centre so much that Gmr wouldn't bore them to 107 because there wouldn't be much material left on one side. Got a better set off E-Bay for $80.00.

 

If 106 build counts I got 11 k on it. No leaks. No weird stuff. All good.

 

Yes, the cases had to be bored to accept the thicker Axtell cylinders.

 

On my 2009 Classic, I am chasing an annoying vibration in the 2500 to 3000 rpm range which I am now convinced is comming from the crank. So, as a winter project, I intend to split the case and have the crank shipped to Revolution for a full service (plug, weld, true and balance...).

Naturally, while I am there.... might as well put it back together with a few goodies... As I am mostly a long distance rider and comfort/reliability is my first concern, I thought the Revolution 107 kit with its new (not re-bored) cylinders were the best choice out there. I like the idea of plated cylinders for better heat control...darn, all other motorcycle mfrgs have gone to that...the MoCo is probably one of the last ones still sleeving cylinders...

Thinking of simple build, TW555 cam, stock heads. With the welded and balance crank, this should yeald a pretty good long distance set-up I think...

Any thoughts? And I too am wondering about long term reliability of those juggs....