103 Ci : V-Twin Forum: Harley Davidson Forums

03 Roadking · 08-24-2007, 09:01 PM

I'm thinking of taking my 96 up to 103. I looked and haven't had any luck so far finding the bore of the "Big Bore" kit. Since the outside of the cylinders are the same I'm thinking, why not have a machine shop bore them out and buy a set of pistons. Its gotta be cheaper than buying the SE BB Kit with the same out come.

stix68 · 08-24-2007, 09:10 PM

If you are going to do that, why not go to 107. Worth a thought.
On the other hand, had a mate bore his stock cylinders to 103 not long ago, no problems either.
good luck. 103ci= 3 7/8" 107 = 3 15/16"
Stix.

TXCHOP · 08-24-2007, 09:11 PM

Quote:

Originally Posted by 03 Roadking

I'm thinking of taking my 96 up to 103. I looked and haven't had any luck so far finding the bore of the "Big Bore" kit. Since the outside of the cylinders are the same I'm thinking, why not have a machine shop bore them out and buy a set of pistons. Its gotta be cheaper than buying the SE BB Kit with the same out come.

It is definitely cheaper to go that way and better off as you have control of the piston type and what size the cyl is bored to. Contact one of the site sponsors here if no one local is qualified to do so for you. Are you just thinking of going to 103 or are you thinking about heads and cams as well?

03 Roadking · 08-24-2007, 09:30 PM

Quote:

Originally Posted by TXCHOP

It is definitely cheaper to go that way and better off as you have control of the piston type and what size the cyl is bored to. Contact one of the site sponsors here if no one local is qualified to do so for you. Are you just thinking of going to 103 or are you thinking about heads and cams as well?

Yea I'm going to do the heads and cams. I'm not looking to go too radical, don't want to loose dependability.

nw_guy4_fun · 08-25-2007, 01:24 PM

I would go 107. I am very happy with mine but if I did it over would bore the stock barrels to that size and use the CP pistons from GMR

route66paul · 08-25-2007, 01:40 PM

I would go with one of our sponsors and get the whole package from him. Talk to him, I would suggest a chain driven cam set, the new 525 looks interesting or else a 37. Pick out a full flowing a/f and some efficient pipes(2in1s are best).Get a good port and replace the valve guides, you might want to go with larger intake valves. Buy your pistons from him, buy cast(kBs are nice), forged if you are going radical. Have you cylinders bored to the pistons, and buy all the gaskets and other goodies at the same time. This is the way to get your best deal, unless you are dealing with a HD dealer. If you can do the work fine, if not, get a good indy to do it for you. Don't go to too high of a c/r and if over 10:1, get comp releases installed in the heads at the same time as the port job.
It's not rocket science, but the details are what determines a good build.

mtnmotorrider · 08-28-2007, 06:01 PM

I keep looking at KB's web site and can't find any listing for pistons for the 103. Am I missing something? Anyway, most go the bore out route and that's all HD does is bore out stock 88 cylinders. You don't need new ones. As far as 107, the cost increases significantly. The pistons alone are more than the whole 103 conversion. If you can aford it, it is a stronger build. Need to be careful about chamber volume and cam choice too, as CR goes up with cubes.