Big bore build 88" to 95"
Elite HDF Member
Joined: Aug 2007
Posts: 4,265
Likes: 99
From: Northern VA
I do alot of 95 inch builds. I use Wiseco forged pistons, S+S 570 gear drive cams and use the stock heads with porting and polishing along with high lift valve springs and new valves. This combo has always yielded around 110HP and 110ft lbs or torque when using a good set of pipes and aircleaner.
Road Captain
Joined: Jun 2008
Posts: 572
Likes: 6
From: Ft. Worth, Texas
Well ... I do not take offense, since it is not my point (I, frankly, have been contemplating doing a bunch of work to squeeze more power out of my 88 without increasing the CID) ... I just thought I would pass on what seems to be 'common wisdom' among forum members ... yourself excluded, obviously ....
My counter would be that the additional lift of the S&S 510 cam over the stock cam is not significantly greater--given that the lift of the stock cams is .510 intake and .483 exhaust ... duration is 234 / 239 respectively ... the S&S duration figures are 234 / 252 ...
Now one thing the MoCo's cams do not feature is any overlap of int/exh cycles which is a common feature of most aftermarket cams ... also, the opening and closing are timed a little different ....
My observation is that while the 510 cam will be a modest improvement over stock (as would the SE 203 cam or Andrews 26, etc) ... he would still get a boost in performance given the big bore kit, even with the rest of the motor stock ....
Just my $0.02 ... and I do not claim to be an expert ... just a relatively well-informed lay person ....
R/
'Chop
My counter would be that the additional lift of the S&S 510 cam over the stock cam is not significantly greater--given that the lift of the stock cams is .510 intake and .483 exhaust ... duration is 234 / 239 respectively ... the S&S duration figures are 234 / 252 ...
Now one thing the MoCo's cams do not feature is any overlap of int/exh cycles which is a common feature of most aftermarket cams ... also, the opening and closing are timed a little different ....
My observation is that while the 510 cam will be a modest improvement over stock (as would the SE 203 cam or Andrews 26, etc) ... he would still get a boost in performance given the big bore kit, even with the rest of the motor stock ....
Just my $0.02 ... and I do not claim to be an expert ... just a relatively well-informed lay person ....
R/
'Chop
Now the formula for HP gained per point of compression raised is 3-4%. So on a bike with 70HP and 9.2:1 compression 4% of that is 2.8 HP So if you went with 10.5:1 compression you would only gain less than 5HP. That is not including the extra cubic inches but do you really think an extra 7 Cubic inches is gonna give you that much HP with stock cams??
I could sit here and debate back and forth all day but i do this everyday and performance figures aside i have ridden bikes with both upgrades. There is definately a big difference. Btw this is a link to cam specifications of stock H-D as well as aftermarket cams.
http://www.nightrider.com/cgi-bin/ff...?ff_config.txt
Banned
Joined: Sep 2009
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From: deland,florida
I own a shop in Arlington, Texas(about 1 mile from the new Cowboys stadium) called Monkey Wrench Cycles. Almost 10 years as a Tech and i decided to open my own. You can check out my websites at:
http://www.monkeywrenchmotorcycles.com/
http://myspace.com/monkeywrenchmotorcycles
Hope this doesnt violate any of the forums rules. Let me know admins if it does.
http://www.monkeywrenchmotorcycles.com/
http://myspace.com/monkeywrenchmotorcycles
Hope this doesnt violate any of the forums rules. Let me know admins if it does.
www.veetwinperformance.com
Road Captain
Joined: Jun 2008
Posts: 572
Likes: 6
From: Ft. Worth, Texas
-S+S 570G cams $700
-Headwork including CNC port and polish, bigger exhaust valve,
and high lift springs and retainers $650
-Wiseco 10.5:1 Forged pistons
w/rings $400
-Boring $150
-Cometic gasket kit $110
-Adjustable pushrods $140
-Power Commander or SE Race Tuner $350
-Labor 10hrs@$70 an hr $700
Your looking at around $3k without a dyno tune. So $3500 out the door with dyno.
Elite HDF Member
Joined: Apr 2007
Posts: 4,919
Likes: 23
From: Seattle, WA
Great resource on the cam info ... looks like my data was suspect ....
I think you and I are in agreement for the most part ... I was merely playing "Devil's Advocate" suggesting that if the OP wants to get the Big Bore kit and install it (not waiting to get cams, head work, hi comp pistons, etc first) that by one school of thought--"no replacement for displacement" school--he should go ahead ....
I am not necessarily a subscriber to the "displacement" school ... like you, I believe in a combination or multi-faceted approach; and, that there is power and torque to be had even in the absence of an increase in displacement ....
Also, as can be seen from the experience of many fellow forum members, once you start ... you just can't stop ... the OP indicated he would like to do a bunch of the other motor mods ... but, that for now, it is a matter of prioritizing where to put his dollars ... it seems to me our whole discussion on the subject is "splitting hairs" in a manner of speaking ....
Another point is that from a 'H-D culture' perspective there is something to be said for the "bragging rights" of saying "I have a 95" (or 103) to someone who has a 88" or a "96 ... not that someone saying that to me would 'hold any water' but just saying ....
Peace ....
* * *
To the OP ... let us know what you decide to do ... and post pictures ....
R/
'Chop
I think you and I are in agreement for the most part ... I was merely playing "Devil's Advocate" suggesting that if the OP wants to get the Big Bore kit and install it (not waiting to get cams, head work, hi comp pistons, etc first) that by one school of thought--"no replacement for displacement" school--he should go ahead ....
I am not necessarily a subscriber to the "displacement" school ... like you, I believe in a combination or multi-faceted approach; and, that there is power and torque to be had even in the absence of an increase in displacement ....
Also, as can be seen from the experience of many fellow forum members, once you start ... you just can't stop ... the OP indicated he would like to do a bunch of the other motor mods ... but, that for now, it is a matter of prioritizing where to put his dollars ... it seems to me our whole discussion on the subject is "splitting hairs" in a manner of speaking ....
Another point is that from a 'H-D culture' perspective there is something to be said for the "bragging rights" of saying "I have a 95" (or 103) to someone who has a 88" or a "96 ... not that someone saying that to me would 'hold any water' but just saying ....
Peace ....
* * *
To the OP ... let us know what you decide to do ... and post pictures ....
R/
'Chop
Road Warrior
Joined: Sep 2005
Posts: 1,511
Likes: 1
From: Michigan
Speed Freak
How much of gain would you get with a 88" if you just went with the gear drive cams and some headwork? Seems like this would be the best bang for the buck, move more in and out.
Already have Cycle Shack slip-ons and a Big Sucker AC w/Yost power tube.
How much of gain would you get with a 88" if you just went with the gear drive cams and some headwork? Seems like this would be the best bang for the buck, move more in and out.
Already have Cycle Shack slip-ons and a Big Sucker AC w/Yost power tube.
Road Captain
Joined: Jun 2008
Posts: 572
Likes: 6
From: Ft. Worth, Texas
Im sure it would be in the mid to high 90's depending on what cams you use and who does the headwork.
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Update..
Getting all the parts together
*have the se 1550 std. Flat tops pistons
*hd gasket kit
* kirby is doing my cylinders to 95"
for me ..should have those back soon,
*mikuni 42 mm carb.
So far have put this stuff together fairly resonable...!!!!
No head work at this time.....all i need now is some cams..any thoughts..been looking at the andrews tw50, tw37, se 211, crane 310 and crane 316....or ???...as i said before ...$$$$ is a issue, so i have to stick with chain drive cams...thanks to every one....
Getting all the parts together
*have the se 1550 std. Flat tops pistons
*hd gasket kit
* kirby is doing my cylinders to 95"
for me ..should have those back soon,
*mikuni 42 mm carb.
So far have put this stuff together fairly resonable...!!!!
No head work at this time.....all i need now is some cams..any thoughts..been looking at the andrews tw50, tw37, se 211, crane 310 and crane 316....or ???...as i said before ...$$$$ is a issue, so i have to stick with chain drive cams...thanks to every one....