Hi, I have SE-204 cams installed on my stock 96" motor. The bike changed personality night and day, for the better. I like a hard hitting mid range and this one delivers! I am considering installing 103" cylinders and flat top pistons with SE 110 heads. This combo keeping my compression ratio at 9:1. Not looking for max hp/tq numbers at top end but keeping it healthy in the midrange which is where these cams shine. I love the cams I have and was wondering if they will still work well keeping the compression the same with the new big bore set up?

 

SE110 heads are better suited for 110's or larger. They have fairly large valves and ports. I think you would be disappointed with them on a 96". Besides they have a larger combustion chamber, which would drop your C/R, unless you went with a domed piston.

 

I am no expert, and there are a lot of people that contribute to this tech forum regularly that know a lot more than I do, but I did a 107" low compression build and had my existing heads custom machined to my riding style for the same money as buying new HD 103 heads from the dealer. IMO, I think if you check around you'll be much happier getting your existing heads custom made to your specs for the same or less money, and your bike will run just the way you want it to.

 

Rework your stock heads (mild port job), and ask your porter to shave them down for 9.5:1 compression. That cam likes 9.5 better than 9.0:1. Use a .030 head gasket to maximize squish (helps avoid ping).

 

Cometic head gasket.

 

A 30T pulley will also wake it up.

 

Any 110 heads you would be likely to buy would be MOCO program heads and you would regret buying those and not having them reworked. So, for the price or working those heads you could rework the stockers and have a way better performing bike.

Bigger is NOT always better.

 

I agree - stick with the stock heads, have them reworked and stay in the 9.5:1 range.

 

A 103" with flatops and squish tightened as it should be will require the head chambers increased to get to 9.5/1

 

Depends what his heads cc out to.
My stock heads cc'd to 84 cc's. Would have put him at 9.6:1.
Portwork would take a tad out as would relieving his valve pockets.
His might cc bigger (or smaller).
If he has 85cc (realistically possible), he'll be right at 9.5:1

He might get lucky, but I think I'd plan on carving a little out.
It shouldn't be much at all.

I'd do that before I did the thicker head gasket.
Especially with all the built in advance on that cam.



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