07 dyna 103 upgrd.

[JackT]

I have an 07 fxdc I have that I have just bought SE perf heads for. Im going to do the 103 bb with forged FTs. and cant decide on cams. 251-257-258 leaning toward the 257. I have V&H slip ons that I'd like to keep but if theres better performance in another 2-2 pipes I would change. I like to ride hard, as i hit the fact. rev limiter often riding solo, but I carry a passenger alot so I don't want to get too soft in the mid range or have detonation proplems. I would like to get around 100/100 tq./hp.. I just don't want the bike to radical for normal riding. I have a PC111usb and was wondering if based on your recomendations if you could sell me a map to get close. I have been looking on comp camps web site and see that they have some new conicle beehive springs that may fit these heads.I had bad luck with cars with damper springs breaking plus noise issues. I also think 3 springs rubbing makes alot of heat. Any thought on this? Your forum is the most informative i have ever read. I see alot of wacked suggestions and opinions on the other HD forums. Thanks. Jt

[Mike]

Thanks for the kind words! You should be pretty close to 10.5 compression with your combo and so I would recommend the 258's. The 258's will produce a little more top end power vs the 257's and with the V&H slip-ons and model of bike this would be my preference. They'll also start easier and have less detonation potential. I would stay with the exh you have and see what the torque curve looks like before changing.

The Ovat coils are new and we just put a set in a 95ci with ported heads. The reason was to see if we could reduce valve spring surge and the associated valve train "rattle" we tend to get around 3200 rpm. It seemed to work but did not totally eleminate the noise. I agree with your assessment on spring rub. The only problem we've seen to date with the stock Ovats is inconsistancy in pressure and in some cases pretty alarming sag after very short miles in Buell heads we've checked. We do not know if this will be true of the Comp Cams springs but suspect Comp makes the stock springs for H-D/Buell (no confirmation on this).
Mike

[JackT]

I got your reply right after I bought a set of 257s. ( at A price I couldn't pass up). Oh well. I'm geared more towards max overall torque than max top end power. Am I on the right track with 257s? The valve seats seem to be deep in these heads leaving another 45 degree steep past the top cut in the valve job. Prabably going to blend this with a 20 degree cutter. I'm going to use the thinner cometic head gasket over the stock on to tighten the quench. I've heard even though higher comp. less detonation. Less heat in combustion chamber and more turbulence. Do you think that the Buells might have worn springs becuase they rev higher? I know from dragracing cars that once you float a valve the springs get weak. Do you think you may have a map that you could sell me close to my combo? PC111usb. Thank for your time., Jack

[Mike]

Keep the 257's. The performance heads have a "funny" seat cut that hurts flow numbers on those we've tested (really turbulent). Have not figured out the reasoning on this. We've seen the same results tightening up quench, better burn (some turbulence here is good). Yes, the spring sag may be due to higher revs and that Buells just tend to be ridden hard. We thought the same but also feel it's a heat thing, they tend to run hotter than big twins, in the heads. Sorry, not likely to have a PC map, we've been doing so many SERT installs our PC file set is not growing like it used to, very slim for 07's.
Mike