would love some help identifying exactly what this motor setup is.

I just bought very clean looking 2005 deluxe and was told it had a "screamin eagle cnc ported 103" I assumed it was a common bolt on big bore and didn't think much of it for a few days. seller says he isn't sure just that he was told its a 103 when he bought it from the original owner.

I cant seem to find any bolt on tc88 to 103 kit. From what I understand it would have either needed to have the bottom end machined for a stroker crank or could possibly be a whole motor swap from a 2005 CVO.

seems to run fine maybe a little weaker than I expected but without issue and I didn't get any bad vibes from the seller and he definitely wasn't in a big hurry to sell or negotiate.

 

Probably a Stage III kit in a 95" motor (bigger cylinder/pistons)? I ran a Stage I 95" in my '99 TC.

 

I'm not sure where to even begin looking to figure it out. I don't really have any reason to worry at the moment but I don't really want to wait until something breaks to have to have a mechanic try to rip it apart just to see what it is before I can even order any parts.

I doubt its anything dodgy, everything added go the bike looks quality and it looks like new even though its 16 years old.

my only dislike what's the performance is it seems kind of weak down low whether it is or not I don't know but I expected a little more from it. It really wakes up as the RPMs clime though. not sure if that's the build in general or just a cam or tune holding it back.

I could live with it as is without any regrets though as long as I know what exactly it is so when it comes time to buy parts or troubleshoot an issue I'm not completely screwed

 

Really doesn't matter how the motor grew to 103" since there are limited possibilities and that really doesn't need to be known until ready for a major repair and pulling the heads and measuring the bore will tell the tale.

If the sluggish performance is an issue, replace the true duals with a good 2:1 pipe, pull the cam cover and you will likely find an HD cam that is profiled for higher rpm performance and should be replaced with a good aftermarket cam. Knowing the existing cam profile and checking static compression will help with cam selection; I did notice compression releases which would indicate a higher compression setup, so checking compression would be worthwhile data. The heads will have a PN and/or a casting number on them and running down that number is another data point to run to ground. If there is no fuel management system, the addition of the Power Vision tuner and a dyno tune once everything else is sorted is necessary to pull everything together.

One more thing to check. If the work was done by a dealership, the work should be in the mothership system and can be tracked with the VIN; might try running that down as well.

I am sure you can wake that 103" motor up without spending a lot of money and make it a runner.

 

You can get an idea on the stroke by putting a welding rod in the spark plug hole, mark the rod at TDC and BDC and measure the distance. The 95" TC would be around 4", the 103" crank would be about 4.375"

 

I think a wooden dowel might be in order. Wouldn't want any flux to break off in the cyl?

 

How would I do that? Is that something you can run online or do you have to have a friend at the Harley shop?

 

Any dealer should be able to input the VIN into the system and whatever work was done by a dealership should be in the system.

 

A stock 88 big bore will be a 95. Using the basic HD big bore cylinders & pistons yields a 10.5:1 cr & makes decent bottom end torque w/o cam/heads. My 95, even w/o compression releases, started just fine at 10.5:1 cr.

With the heads & comments @ bottom end torque indicates a HP cam upgrade, hence weak bottom end torque. Stage II would be big bore & cam. Changing heads suggests Stage III.

Despite being advertised as a 103, unless the crank was swapped out, my money's on it being a 95.

 

The advertised 103 could very well be a 95" motor but a compression test will tell us a lot.

Not sure how you come up with 10.5:1 static with "basic HD big bore cylinders and pistons"; it's actually about 9:1. OEM head gasket is .045", deck height is -.003" to -'005", chamber volume is +/-85cc and piston dome volume is -1.5". If your 95" motor makes 10.5 static, the pistons must have domes and/or the heads have been decked; if they haven't your 95" isn't making 10.5:1. Let's do this. Run a compression test on your 95 and have a compression test run of the 103" motor and let's compare.