'92 Fatboy engine questions
'92 Fatboy engine questions
Ok, so trying to figure out what route to take so I thought I would ask here and see if someone can help shed some light on the subject.
I just bought the Revolution 85" kit (cylinders, rings and pistons). I was planning on installing my EV27 cam at the same time. Then I started thinking, "since the heads are off, maybe I should upgrade". I was looking at going with the S&S heads. Not the S&S super stock heads, since I would have to use super stock pistons and I need to use the pistons that came with the Revolution cyclinders. Then I started thinking that I might get detonation with the EV27 cam, but I'm not sure.
Am I thinking correctly? If so, what would be a good cam to go with? I should mention that I do have adjustable SE pushrods to install too.
Any help would be greatly appreciated!!
I just bought the Revolution 85" kit (cylinders, rings and pistons). I was planning on installing my EV27 cam at the same time. Then I started thinking, "since the heads are off, maybe I should upgrade". I was looking at going with the S&S heads. Not the S&S super stock heads, since I would have to use super stock pistons and I need to use the pistons that came with the Revolution cyclinders. Then I started thinking that I might get detonation with the EV27 cam, but I'm not sure.
Am I thinking correctly? If so, what would be a good cam to go with? I should mention that I do have adjustable SE pushrods to install too.
Any help would be greatly appreciated!!
Road Captain
Joined: Sep 2012
Posts: 675
Likes: 32
From: Massachusetts
i'd do bigger than an EV27 if you're gonna bump the compression.
for heads, I shipped mine to BigBoyzCycles in Maine. give Bean a call. he knows his stuff, thats for sure. I bumped my compression with wiseco 10:1's rather than deck the heads (idea being that if something ever lets go, I can safely mill the heads without worrying about valve clearances).
I went with a Woods W6, and completely happy with it. seat-of-the-pants dyno says its got considerably more oomph than the SE-3 that was in it before (which is identical to an EV27)
the heads (port job, compression releases (not needed but for an extra $80 at the time was worth the peace of mind), new valve springs, 1 new valve (had a pitted intake valve), and all new seals/etc) cost me ~ $650 when all was said and done (thats including shipping, although my indy shipped em for me so I could get the "commercial" shipping rates (which were 1/4 of what it would have cost me to ship via UPS myself).
out of curiosity, why'd you do the 85" kit? a stock evo is 81.6 IIRC, and boring .005" over (i wouldnt use drop in pistons myself) bumps me to ~ 83". cylinder boring/honing was $150, and the wisecos were ~ $320. the idea of having a spare set of jugs is nice though.
detonation is gonna depend on your tune. if its pinging, you've probably got either too much timing, or too little fuel (or a bit of both). either way, a good tune is gonna make all the difference.
seriously though, look at a W6. i'm a convert for sure. SUPER happy with my build.
for heads, I shipped mine to BigBoyzCycles in Maine. give Bean a call. he knows his stuff, thats for sure. I bumped my compression with wiseco 10:1's rather than deck the heads (idea being that if something ever lets go, I can safely mill the heads without worrying about valve clearances).
I went with a Woods W6, and completely happy with it. seat-of-the-pants dyno says its got considerably more oomph than the SE-3 that was in it before (which is identical to an EV27)
the heads (port job, compression releases (not needed but for an extra $80 at the time was worth the peace of mind), new valve springs, 1 new valve (had a pitted intake valve), and all new seals/etc) cost me ~ $650 when all was said and done (thats including shipping, although my indy shipped em for me so I could get the "commercial" shipping rates (which were 1/4 of what it would have cost me to ship via UPS myself).
out of curiosity, why'd you do the 85" kit? a stock evo is 81.6 IIRC, and boring .005" over (i wouldnt use drop in pistons myself) bumps me to ~ 83". cylinder boring/honing was $150, and the wisecos were ~ $320. the idea of having a spare set of jugs is nice though.
detonation is gonna depend on your tune. if its pinging, you've probably got either too much timing, or too little fuel (or a bit of both). either way, a good tune is gonna make all the difference.
seriously though, look at a W6. i'm a convert for sure. SUPER happy with my build.
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
I wouldn't buy new heads. A decent tuning shop should be able to port yours and match them to your CR and also recommend a suitable cam. If you can't find a suitable shop in WI we're all doomed! 
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
Having been on HDF for a while now I am a convert to matching things up, to get the best out of our bikes. We can buy stuff in ourselves, cam from here, heads from there, etc, but there are some top tuning shops out there who can make the sum of all the parts work better together than any one of us can. It may cost a little more than say getting the cam from the very cheapest supplier, but well worth asking around IMHO.
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