Big Bore Ironheads
Big Bore Ironheads
In the post a pic forum there's a few with comments about their engines being bored out from 74-88" where can I find some more information about this? if it doesn't cost an outragous amount I might think about ripping the motor apart and put out some more ponies
and I don't really care about rideablilty or reliability that much anymore. theres other HD's around the house to ride.
and I don't really care about rideablilty or reliability that much anymore. theres other HD's around the house to ride.
Extreme HDF Member
Joined: Sep 2006
Posts: 10,033
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RE: Big Bore Ironheads
I thought guys learned decades ago that big bores and Ironheads don't exactly go hand in hand. The cases are weak compared to the EVO's. A set 30+ years old ain't gotten any stronger. Sure, people have done it with success and I'm sure someone will chime in and tells us so, but many have also blown the bottom end out of a Ironhead. I think I'll stick to my stock bike and ride it another few decades.
Road Master
Joined: Aug 2006
Posts: 751
Likes: 6
From: 500 miles south from Artic Circle
RE: Big Bore Ironheads
Here is some performance talk from ironhead http://autos.groups.yahoo.com/group/...adperformance/
There is 0.07" pistons avaleable but it isn't recommeted to bore stock cylinders over 0.04" and that's not yes big bore !!
There is 0.07" pistons avaleable but it isn't recommeted to bore stock cylinders over 0.04" and that's not yes big bore !!
Seasoned HDF Member
Joined: Dec 2004
Posts: 11,068
Likes: 1,476
From: Texas! Ya mean there's someplace else?
RE: Big Bore Ironheads
I had a 77" stroker, but the bore was just an .020 cleanup job. You wanna play with torque, get stroked. You really can't bore stock cylinders enough to notice any performance increase. Need to go with special jugs, and all the machine work on the cases to make 'em fit, and that weakens the cases even more.
And if you start playing with Sporty power, you'd better get a heavy duty trapdoor for the tranny. Actually, you will get the heavy duty trapdoor, it's just a matter of getting it before or after you blow the old one to smithereens! Plus sooner or later you'll miss a shift and blow the lower right rear corner of the tranny section of the cases. But they make repair kits for there, too!
I knew one dude, a very serious squirrel, who had a 118" Sporty Ironhead. It was one wild motor, but really not for the street.
And if you start playing with Sporty power, you'd better get a heavy duty trapdoor for the tranny. Actually, you will get the heavy duty trapdoor, it's just a matter of getting it before or after you blow the old one to smithereens! Plus sooner or later you'll miss a shift and blow the lower right rear corner of the tranny section of the cases. But they make repair kits for there, too!
I knew one dude, a very serious squirrel, who had a 118" Sporty Ironhead. It was one wild motor, but really not for the street.
Road Master
Joined: Aug 2006
Posts: 751
Likes: 6
From: 500 miles south from Artic Circle
RE: Big Bore Ironheads
ORIGINAL: pococj
And if you start playing with Sporty power, you'd better get a heavy duty trapdoor for the tranny. Actually, you will get the heavy duty trapdoor, it's just a matter of getting it before or after you blow the old one to smithereens! Plus sooner or later you'll miss a shift and blow the lower right rear corner of the tranny section of the cases.
And if you start playing with Sporty power, you'd better get a heavy duty trapdoor for the tranny. Actually, you will get the heavy duty trapdoor, it's just a matter of getting it before or after you blow the old one to smithereens! Plus sooner or later you'll miss a shift and blow the lower right rear corner of the tranny section of the cases.
Atleast if you are using steel trapdoor support bearing in front spocket is good idea...
-sepixlh-
Seasoned HDF Member
Joined: Dec 2004
Posts: 11,068
Likes: 1,476
From: Texas! Ya mean there's someplace else?
RE: Big Bore Ironheads
wasn't steel, just beefier aluminum design. Trapdoor, and sometimes replacing the lower right rear corner of the case, was done as part of the build.
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