New head help please!!!!!!

[Bear]

Going 95 on my carbed 04 RK. Will use my existing SE203 cams. HD shop says I should go with the HD MCR heads. These have comp releases which is great but with flattops the book says 10 to 1 comp. I put on 12000,or more miles a year,much of it 2 up pulling a trailer, and I was hoping for more like 9.5 comp. Will do all the work myself-just trying to get some input from you guys that know stuff! Anyone have this settup or comp ratio with the 203s. Will pinging be an issue? Do I need to change ignition? Thanks for the help!!!!!!!!        Dave

[Arrowsmit]

Approaching 10:1 w/SE 203 cams will be problematic. IMO you'd be far ahead of the game in costs & results by getting your heads (or another set of pull-offs) worked for your choice of cam.

VicW.

[FLTRI]

IMO, you are the perfect canidate for a much larger ci engine.
The reasons?: You pull a trailer so high compression is out. You need bottom end grunt so high performance cams are out.
So the solution is a big, low compression engine.
A 103 kit might just be the hot ticket for your application.
Just my $.02,
Bob

[Tattoo]

The compression created from those heads could be a problem with those cams.
Those heads with 3.37 gear ratio & the SE211 cams would be a better set up  as well.

[DarrellV]

Without wanting to "steal your posting". I'm watching and reading this thread learning myself. I'm in the same boat as you, looking to go up to a flat top 1550. I pull a trailer with my bagger and ride two-up as well. The only difference is I have the 26G cams.

I've had others talk about the MCR head being a good head. But I'm thinking it migt just be "Too Good" of a head for me. Everyone talks about the 06 and newer stock heads being great. But the prices of them heads used are high as well. Not sure if you send a stock head 02-05 away to be reworked if they would be better $ or not?

[tmsimmon]

For a pure HD setup... I would agree. this is a very nice setup. And you have an 04 TC so forget the 103 setup.
It would cost too much and not worth it for an 88ci. 95" is all you need.

The compression created from those heads could be a problem with those cams.
Those heads with 3.37 gear ratio & the SE211 cams would be a better set up  as well.

[wfolarry]

Staying with the 203's I wouldn't spend the $$$ on heads. Just have the stockers cleaned up & ride it. I've seen a lot of 203's with flat tops run fine. Of course if you're worried about pinging there are other options

[bbqjmaki]

I saw this post a couple a weeks a go thought it might be of some help 203's are a lot like Andrews 37's. Right now I have 203's in my bike. I have bought a set of Big Boyzs street ported 06 heads, Andrews 26g cams, i already have a big bore kit in the bike, This will be my next build 03 ultra. My last ride had this set up and loved it,02 RK with 3:37 gearing, had 50k on it with no problems, I also ride 2 up and pull a trailer. But defiantly get you a set of head from a head porter there are several good one on this board (WFOLARRY, Big Boyzs, and the list goes on check in Indy shops for more) give one of them a call they will lead to a good build with their head porting.  This may help a little or make your choices more confused, just my .02 worth   

From: BaggerDad   Sent: 10/25/2008 5:59 PM
From an old AMS post regarding TW21/TW26/TW37

http://www.automotivemachine.com/vtwin.htm

The hard part of choosing a cam is defining your expectations, making the appropriate compromises in desired performance and then finding the cam that best fits YOUR riding style.

Which cam TW21 or TW26 - the big difference (and the 64 million dollar question) is where you want the peak HP/torque in the rpm range?

For heavier dressers or, uh... er...uh, heavier riders, or riding two-up or for those of us who just like to chug along and then go like wild without a lot of shifting, a cam like the TW21 is best. It kicks in at 1800 +/- and pulls thru 5000 with stock heads, and ported heads will get you another 500 or so. The TW21 has a "right-off-idle" response. Since it has a little higher lift than the TW26, it can still stretch out thru the high speeds. Yet, it closes the intake valve early enough to "get on cam" quickly, making it ideal for heavy scooters / big guys/ riding 2-up. It will have enough torque to pull a freight train, without being so radical that you lose reliability of the long haul. If you are a "lazy" rider who likes to look at the scenery instead of the road, and does not always shift aggressively, or if you are a big guy or ride two-up, its best to make the max torque /HP in the lower revs...1500 to 3500. Therefore, you would want a cam that closes the intake valve as close to 30 deg ABDC this will give your engine a broad torque curve - the TW21 does this. Whereas the TW21 closes its intake valve at 30 deg ABDC, and the 26 closes at 35... the 21 will allow the engine to develop more compression than the 26, especially at low to mid rpms. and more compression = more Mean Piston pressure on the piston = more TQ (at those rpms). The rpm range for best usable TQ is 1800-4000 with the 21 & 2000-4500 on the 26. They both make the same HP & TQ, but at different rpms/mph and both cams will continue to build power past 5000 rpm).

For normal light rider solo riding, and with light passenger weight, and if you like to shift and stay on the throttle and want a little more giddy-up - then go with the TW26. With the big bores and ported heads, the bike can use the extra flow the TW26 gives. It gets "on the cam" about 100 rpm later than the TW21, but lets the engine breath easier at hi-speed touring revs. Its lower lift with a few degrees more duration is easy on the valve train, runs cooler at high revs and still pulls like a freight train. The TW26 offers a wide power/torque band, it kicks in strong at 2500 and pulls all the way to 5500. You do not have to down shift to pass, even at 75, just twist the throttle and zoom on past.

So IMO, either is a good choice for an FL series scooter. These are mild set ups, but it will put the torque in the rpm range most of us actually use. Either way, TW21 or TW26 cams have such strong and wide hp/torque curves, especially near the 3000-rpm range that they still cause uncontrollable ear-to-ear-"Potty mouth"-eating-grins.

The TW21 has .008" more lift than the TW26, but .012" less than the TW37. This is less strain on the valve train, makes your motor last longer, yet still adds some more "get up and go". The TW21's intake valve closes at 30 ABDC, instead of TW26's 35, and TW37's 38. What this means is the TW21 has 150 crank degrees of piston movement to compress the air/fuel mix, giving a higher dynamic compression ratio (CR) and makes a lot of TQ at low rpms. The TW26 has 145 crank deg for a slightly less dynamic CR, makes a lot of TQ at a slightly higher rpm, but within 100 rpm or so of the 21. And the TW37 only has 142 crank deg of piston movement to use for compressing the A/F mix, resulting in an even lower dynamic CR, making its best TQ about 500 rpm higher than the TW21. In an "ideal" engine the intake valve would slam shut at BDC. The piston would then compress the air/fuel mixture thru all 180 degrees of crank rotation to TDC. The dynamic CR would equal the calculated CR. To get power and TQ from the TW37 cam at LOW rpms, you must raise the static CR near or over the threshold of detonation. If your riding style says LOW rpm, flower sniffing', touring, passing a truck on a hill at 70, two-up, riding not hi-rev, tire spinning, solo, tavern to tavern, or red light to red light hot-roddin' then go with the TW21 or TW26. The TW37 will lack low-end torque over a TW21 or TW26. IMHO the TW37 works great on 3.37 geared touring bikes and 9.5:1 â€" 9.8:1 CR and solo riding.

[FLTRI]

Going 95 on my carbed 04 RK. Will use my existing SE203 cams. HD shop says I should go with the HD MCR heads. These have comp releases which is great but with flattops the book says 10 to 1 comp. I put on 12000,or more miles a year,much of it 2 up pulling a trailer, and I was hoping for more like 9.5 comp. Will do all the work myself-just trying to get some input from you guys that know stuff! Anyone have this settup or comp ratio with the 203s. Will pinging be an issue? Do I need to change ignition? Thanks for the help!!!!!!!!        Dave

Bear,
How much does your entire rig with you and passenger(s) weigh?

[Bear]

bike loaded 800 or so,320 for people,250 maybe for trailer so 1370 or therabouts.                       Dave

[Bear]

Larry would you think 9.5 to be best? Street port?  Squish grooves?       Dave

[PoorUB]

Dragging a trailer and high compression seems like a bad idea to me. You will like the 95". Keep the build on the mild side. You need torque in the 2500-3500 RPM range, you don't need HP at 5000 RPM!

[L-]

I would be heavily inclcined to follow WFO's advise.  95 inch, 203 cams, leave the heads ALONE change the ignition to a DTT and have a good two into one system with 3.37 gearing and you won't regret a thing. I too have seen these run in the mountains of Colorado and northern New Mexico and they flat out work with no trouble. On your bike and pullng a trailer I would say the above is pretty damn ideal. Only other opition I know that works great is the Andrews 26 cam, stock heads and 3.37 gearing ............

[DarrellV]

I would be heavily inclcined to follow WFO's advise.  95 inch, 203 cams, leave the heads ALONE change the ignition to a DTT and have a good two into one system with 3.37 gearing and you won't regret a thing. I too have seen these run in the mountains of Colorado and northern New Mexico and they flat out work with no trouble. On your bike and pullng a trailer I would say the above is pretty damn ideal. Only other opition I know that works great is the Andrews 26 cam, stock heads and 3.37 gearing ............

I have to ask a stupid question here...What,Where are you talking about having a 3:37 gearing ? My bike is a 02 FLHT and I have the 26G Andrews Cams. I'm wanting to up grade soon to 95" flat tops. But with the miles {on my motor 100,000} I'm wanting to find a good set of heads as well.

[Flat Dog]

Bear,

with that kind of advice, I wouldn't take my bike back to that shop even for an oil change...

[Bakon]

Two choises- Stay with your cams and stock heads or
Go for the heads and change cam- cam is tricky, but not. Go for something with a good lift for the head. A Redshift 575 with .575 lift is a perfect match for you. It closes the intake at 41 degrees so the 10:1 compression is also perfect.

[wfolarry]

Larry would you think 9.5 to be best? Street port?  Squish grooves?       Dave

Yes
Can't hurt
Love those grooves

[Bear]

Bear,

with that kind of advice, I wouldn't take my bike back to that shop even for an oil change...

John I do all my own work but I asked them about a build to buy parts. Dave