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[wnogood]

On my 2006 SEUC will standard flat top pistons work with these heads or does the SE head require a special piston design?

TIA!

[hd-dude]

Flat tops are standard in these.

[wnogood]

Flat tops are standard in these.

Exellent! Thanks for the info!

[HD Street Performance]

It is very low actual compression.
There are special domes available should yo want to add compression and give the 103 legs, or the heads can be milled for smaller compression jumps

[wnogood]

It is very low actual compression.
There are special domes available should yo want to add compression and give the 103 legs, or the heads can be milled for smaller compression jumps

I'm considering doing a light mill, street port, and .030 hg, and retaining my Andrews 48 cams. Just cant decide if I want to stay 103 or go 107

[HD Street Performance]

With a small torquer cam like that I would optimize the compression for that cam and save the funds. Best bang for the  buck unless the heads are hi miles and need reconditioning anyway.

[GMR-PERFORMANCE]

Have done many of the early CVO bikes  andrews 54 with a 107 kit will produce nice power on both sides. With out head work without bigger throttle body.etc Just a basic 107 bolt on , you will get your increase in comp ratio run the .030 H/G and there you are ready to go.  Your bike will produce more power , ( better trans lighter rear wheel etc) I have done several of these and all have run very well. On the 04 we did do a valve job ( basic 3 angle media blast ports and combustion chamber NO port work) This bike was a S&S 106 kit that had excessive piston to wall spec and rattled. So easy fix at that point bump it up to a 107.  If I poke around I can pull up the 103 bikes with the 54 bolted in with no engine mods as well. Let me know Wes if you want to view them as well.

[wnogood]

With a small torquer cam like that I would optimize the compression for that cam and save the funds. Best bang for the  buck unless the heads are hi miles and need reconditioning anyway.

My intent was to set the compression at 9.6 (Andrews recommended limit for the 48's) and the heads need worked. They will have nearly 50k on them by the fall, getting some oil consumption, suspect not only valve seals, but guide issues as well. My bike ingested crankcase vapors for the first 30k of its life and the carbon in the cylinders is ridiculous. I intend to keep this scooter for many years, so I'm willing to throw some good maintenance $$$ at it.

[GMR-PERFORMANCE]

I would at least bore the cylinders use a 103 105 106 107 piston kit ( all the same price when you get into a forged unit) Address the heads in the most basic form. Sell the 48 add the 54 and the gains will be there.

[wnogood]

I would at least bore the cylinders use a 103 105 106 107 piston kit ( all the same price when you get into a forged unit) Address the heads in the most basic form. Sell the 48 add the 54 and the gains will be there.

Every dyno on 54's gives up some at the bottom as compared to the 48's. I seldom spin the engine over 4500 rpm, so I don't think the 54's are best suited for me. I can't argue that the 48's run out of juice at about 5000 rpm, but like I said, I rarely see that anyway. I dig that low rpm tq. It suits my riding style and helps power my fat a$$ through the curves on the backroads that I frequently ride....

Although the dyno you posted IS pretty sweet!

[GMR-PERFORMANCE]

I agree however its extremely hard to test that statement as most are not keeping all things in line. So lets say the 48 is dropped into X bike  and that equlas X CCP now you have a tq curve you like great. Take the same bike increases CCP to the same level retest.. I am betting that the low end power will stay right there and keep right on pulling. +/- 2 or 3 on the tq curve is nothing that you can ever feel. Its a air pump as  you increase the compression the pump will want more and the 48 is not up to that task. Most times the cam will sine off even sooner. TQ curve is based on a few things cylinder fill being one of them. We saw this with back to back testing on a 107 with a 54 stock t/b vs 55 HPI. 1 hp gain but over 6 ftlbs and the curve became broader.

The engine was able to accept more cylinder fill with same given cam. I would bet that the 48 with a larger t/b would show some very good gains as well. Just something to toss around.

Too bad you are not closer we could do some back to back testing.  Myself would bet the 54 would kick azz in the low end and keep on pulling and give you a great bang for the buck.   Over on HTT a guy just did a 103 CNC heads and the 48 in a 14. Nice curve, for your early style trans I would add 6-8% to those numbers for an approx avg. But that t/b is larger than yours as well ..  Either way I am sure it will be a nice build.

[wnogood]

I agree however its extremely hard to test that statement as most are not keeping all things in line. So lets say the 48 is dropped into X bike  and that equlas X CCP now you have a tq curve you like great. Take the same bike increases CCP to the same level retest.. I am betting that the low end power will stay right there and keep right on pulling. +/- 2 or 3 on the tq curve is nothing that you can ever feel. Its a air pump as  you increase the compression the pump will want more and the 48 is not up to that task. Most times the cam will sine off even sooner. TQ curve is based on a few things cylinder fill being one of them. We saw this with back to back testing on a 107 with a 54 stock t/b vs 55 HPI. 1 hp gain but over 6 ftlbs and the curve became broader.

The engine was able to accept more cylinder fill with same given cam. I would bet that the 48 with a larger t/b would show some very good gains as well. Just something to toss around.

Too bad you are not closer we could do some back to back testing.  Myself would bet the 54 would kick azz in the low end and keep on pulling and give you a great bang for the buck.   Over on HTT a guy just did a 103 CNC heads and the 48 in a 14. Nice curve, for your early style trans I would add 6-8% to those numbers for an approx avg. But that t/b is larger than yours as well ..  Either way I am sure it will be a nice build.

How about a test by elimination. Obviously I expect to gain some performance by going in the engine. If I do what I suggest, will there be a significant gain? Optimize the compression and street port the heads and keep the 48's? I'm at 93hp and 106tq now...