26's to 37's difference?

[ron1026]

Presently have a 95 flat top with stock 06 heads and .030hg and 26g's in a flht. I'm putting in a set of 37g and was wondering what change to expect in CCP between the two cams.

  Ron

[Sonny S.]

prolly only 2-3 lbs.

What's the reason for the swap ?

[TXChop]

Yup, i agree..2-3

http://bigboyzcycles.com/TwinCamComp.htm

[se]

Call dave at JD's cycleworks in PA..1-610-297-0321... he did a comparsion on the dyno with a few builds very similar.
i know he did 3 build overlays with the dyno sheets and one had a 37 g build with 9.2 or 3 baisley heads 95in compression and the other 2 were  tw6 builds and the 37g build stayed with the tw6 build. he also has a few 26 builds out there he could probey fax the sheets overr to you.
i am trying to get them so i can post them in the dyno section hopefully by the weekend
G

[Jeffd]

not enough difference to make much difference. 
http://www.bigboyzcycles.com/TwinCamComp.htm
Of course there may be other reasons to swap cams besides CCP.

[Hillside Motorcycle]

You'll need to set the 37 up at near 10:1 for effectiveness to be shown.

[Upswept]

Unless you do head work, the 37's will kill your bottom end and give you very little more top end at very high RPM's.  Don't do it.

[02GhostRiderVA]

Unless you do head work, the 37's will kill your bottom end and give you very little more top end at very high RPM's.  Don't do it.

You took the words right out of my mouth!  More compression is needed for 37s than the 26s. 

[Sonny S.]

You'll need to set the 37 up at near 10:1 for effectiveness to be shown.

Unless you do head work, the 37's will kill your bottom end and give you very little more top end at very high RPM's.  Don't do it.

Come on guy's, let's be real. You don't need or even want 10:1 with 37's, especially in a bagger. Well, maybe at 6000 ft. Heck @ 10:1 might as well go TW6 
Also, 37's don't " need " head work in a 95" to perform decent. Would it help ? yes. will it be a dog ? no. A bump in compression to 9.6 -9.7 max would help.
I had the exact same set up as he described in an 01 Ultra and the bike ran good. I had 26's in the same motor and it was stronger on the bottom, petered out early though.

Let's hear what his intentions are before  we spend his money on a hot rod that pings

[mayor]

Unless you do head work, the 37's will kill your bottom end and give you very little more top end at very high RPM's.  Don't do it.

I don't completely agree.  The problems with the early rpm's being soft is more in 88" builds with stock compression.  The big bore have more compression to start than the 88"ers do.  With a big bore using .030" head gaskets and the 37's the dynamic compression is still about 0.75:1 more than stock.  Will more compression help? absolutely, but it doesn't have to be that much more compression.  In reality, I think the difference between the 26's and 37's is probably only in the neighborhood of 400rpm's or so. The 26's are generally flatter in the early rpm's, but the 37's start to shine when aggressive throttle turns into higher shift points. The other added benefit of the 37's is, a little bit of compression and head work, and double century marks are with in reach.   

I completely agree with Sonny.  There's plenty of examples of the 37's producing very nice results without head work and with much less compression than 10:1.  Heck there's only 3 degrees difference in intake close comparing the 37's to the 26's, so that's about 0.1:1 difference in dynamic compression (or as previously mentioned 2-3# ccp). Now admittedly I'm pretty biased, since I think the TW37's are the greatest invention since sliced bread (needed disclaimer- I'm talking in a 95"  )

[Don D]

I like both of them but like a Woods 5 even better for a bagger.
That said when the build is purposely built and tuned right with a good pipe the little 26 will surprise you.
Results are SAE
http://deweysheads.com/dyno_pages/dyno35.html
This build had as-cast ports and used 1.675 Ultima rockers

[RevJim708]

Presently have a 95 flat top with stock 06 heads and .030hg and 26g's in a flht. I'm putting in a set of 37g and was wondering what change to expect in CCP between the two cams.

  Ron

I have an "02" FXDWG. At 7500 miles I put in a set of 26a cams and at 12,500 miles my warm compression was Front-175 Rear-180. Now at 37,000 miles I put in 95 Flat Top kit .036 head gasket and a set of 37b cams. At 45,000 miles my cold compression was Front-184 Rear-184.
As you can see, not much difference.
If push comes to shove I think I would have to say (for my riding style) I liked to 26a better.
Rev Jim......

[ron1026]

Sorry it a while to get back, been busy at work ( driving oil truck in winter, but summers are great! ) looking for some more get up and go, will do the heads if not happy with just cam change , easier and cheaper to swap cams right now. Have same build with big boyz heads in my fxd and runs great, got a set of 37 for good price and figured I'd give it a try. Don't do to much 2 up riding , most times just solo, also looking to pickup a supertrapp  meg and try that. Now if I can get a day off and weather cooperates I'll see how it runs with just the cam change. Thanks all for replies.

  Ron