Upgrade to 103 info.
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Tourer
Joined: Aug 2008
Posts: 403
Likes: 7
Upgrade to 103 info.
Hey gang. Thinking of going 103 this winter with headwork and cams.Been reading about compression and to stay around 10:1 to 10:5 . can this be done with stock 103 pistons. thanks in advance.
Elite HDF Member
Joined: Jul 2008
Posts: 4,741
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From: Indian Land, SC
If your starting from an 88 I can see you doing this. If from a 96, why waste your time and money on only a small improvement, go 107....Just my 2 cents....
HDF Community Team
Joined: Jun 2006
Posts: 12,774
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From: san antonio
If locked in to a dealer package, say for warranty purposes, take a look at this 103" kit.
Ultimate HDF Member
Joined: Mar 2012
Posts: 6,129
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From: Santa Cruz
You will not get to 10.5-1 with "stock" pistons. The heads will need milling to get to 10-1 with them. I'm not a big fan of milling heads because of intake/exhaust miss-alinement problems. Better to go with correct piston/head combo. No reason to not go 107 except cost. Talk to a few good builders and go with the one ya like. Or ya can do some research and start your own science project. Good luck
Intermediate
Joined: Jul 2013
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From: Spring, Tx
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Ultimate HDF Member
Joined: Mar 2012
Posts: 6,129
Likes: 143
From: Santa Cruz
Pretty easy to get in 100hp/110tq range without headwork on a 103/107. Headwork will add 10+ on both ends. All about putting proper parts together and a proper tune. Getting into the 120+hp range gets very costly.
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Tourer
Joined: Oct 2009
Posts: 280
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Just had a 103 built for my wife's 88. We lost the low end. After about 1300 miles the dealer put it on the Dino to tune the new ignition, our numbers were 91 Hp and 113 Ft lbs Tq . Her bike pulls way hard now, just a lot hotter.
Thread Starter
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Tourer
Joined: Aug 2008
Posts: 403
Likes: 7
Hey old hippie! 100/110 out of a 103 sounds good to me. I got a set of 103 jugs with stock pistons but i,m told stock pistons won,t work and plan on getting some headwork done, so what's the magic formula? also, plan on using S&S easy start cams not sure which ones to run yet.As far as tuning, i got a PCV now that has been dynod to my set up and works great but my dyno guy retired so thinking of the rxcelerator close loop fuel management system, wonder if anyone tried one.