Worth doing head work??
Road Captain
Joined: Apr 2011
Posts: 529
Likes: 1
From: Illinois
If your happy I wouldn't up the comp., your hitting 100 tq at 26 or 2700, thats pretty good if you get out and put on miles you will find the quality of gas ya get is less than adequate most time and there is nothing worse than fighting pinging issue's. The sheets I've seen with 777 and 10.5 comp ain't hitting much earlier than your's and I've had a lengthy discussion with a good tuner that has had a lot of guy's with pinging issues at 10.5. If all ya do is hot rod around a 30 mile radius of home go for it. I should add that the way I see it you are at stock comp. on a 103? I f so a bump in comp. would help but in my opinion I wouldn't go any higher than 10.25, I'd stay away from 10.5.and what old hippie said for gains I agree with I just got on the 10.5 comp. rant and I run andrews 54's I was shooting for 10.25 to 10.3 and ended up at 10.5 and it's to much in my NON professional opinion.
Last edited by Rich67; Mar 4, 2014 at 10:03 AM.
Road Master
Joined: Apr 2012
Posts: 1,096
Likes: 17
From: San Jose
Thanks, but 777's are already in so not much help with that. Before installing, had lengthy discussions with motor builder and Woods people. My thought process was cams now and head work later. Was told by both that the 777's would perform fine at stock compression (would even be better at higher compression) and the torque curve would be a little more to what i was looking for. I got a lot more power from the work than I thought i would. I've looked at a lot of dyno sheets on the site and it seems like my power profile is pretty solid, so I am now questioning whether the money for headwork is worth the extra boost in power.
Road Warrior
Joined: Dec 2012
Posts: 1,335
Likes: 5
From: CT
FM told me with my 107", tw-555 and headwork to stick with the 10.25 pistons. Higher compression makes tuning much more of a process to tweak. I took their advice.
Sent from my Galaxy Nexus
EDIT: Just to be clear, they did not tell me NOT to do higher compression. They were just honest about the issues and work that may be required to tune the higher compression builds (10.5 and up). It was my decision to take that as "advice" to keep it simple(r).
Sent from my Galaxy Nexus
EDIT: Just to be clear, they did not tell me NOT to do higher compression. They were just honest about the issues and work that may be required to tune the higher compression builds (10.5 and up). It was my decision to take that as "advice" to keep it simple(r).
Last edited by 12hdrk; Mar 4, 2014 at 11:33 AM.
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Road Master
Joined: Feb 2007
Posts: 781
Likes: 35
From: St Louis
If your happy I wouldn't up the comp., your hitting 100 tq at 26 or 2700, thats pretty good if you get out and put on miles you will find the quality of gas ya get is less than adequate most time and there is nothing worse than fighting pinging issue's. The sheets I've seen with 777 and 10.5 comp ain't hitting much earlier than your's and I've had a lengthy discussion with a good tuner that has had a lot of guy's with pinging issues at 10.5. If all ya do is hot rod around a 30 mile radius of home go for it. I should add that the way I see it you are at stock comp. on a 103? I f so a bump in comp. would help but in my opinion I wouldn't go any higher than 10.25, I'd stay away from 10.5.and what old hippie said for gains I agree with I just got on the 10.5 comp. rant and I run andrews 54's I was shooting for 10.25 to 10.3 and ended up at 10.5 and it's to much in my NON professional opinion.
Ultimate HDF Member
Joined: May 2008
Posts: 7,439
Likes: 884
From: 'Noke, VA
There's just too many variables to run serious compression on a bike you intend to tour on.
Road Warrior
Joined: Aug 2006
Posts: 1,575
Likes: 7
From: Wisconsin
I have an 2011 Street Glide: Woods 777, SESPT, SE Heavy Breather, Rhinehart Duals. Had it tuned and Dyno'd with cam install. Dyno sheet attached. 100.7Hp and 117Tq. Runs very well. My question is how much more "bang" for my buck will I get to do headwork and/or bump compression a bit?
The TW-777, as others have said, like 10.5:1 compression. Your heads can be set up to achieve this compression. The heads will usually have some porting and texturing done to help with the air flow. A good set of heads set up to match your cam will give you some good results. You'll pick up some peak HP and fatten up your torque curve a bit with a good set of heads.
The other method would be to install some higher compression pistons. If you did this, you could bump the compression to 10.2 - 10.5. You won't pick up as much peak HP as you would with heads, but your low - mid rpm torque curve will be pretty close if not slightly higher than a 103 with heads. BTW, if your changing pistons you should be also going to a 107.
Personally, for a touring bike, I'd always go with displacement vs. heads if I had to make a choice with one or the other.
The TW-777s like 10.5 compression and head work. The "full enchalada" for the TW-777 would be a 107 at 10.5:1 and some matched up heads. That combination really puts these cams in their sweet spot.
Good luck.
PS - all of the above assumes your properly tuned
Last edited by equandt; Mar 4, 2014 at 03:58 PM.
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