95 build, compression question
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Tourer
Joined: Jan 2005
Posts: 477
Likes: 3
From: Jacksonville, Fla
95 build, compression question
I'm massing all the parts for my 95 build. I want to keep this build in the low to mid range torque area, I have a second set of heads and cylinders. The stock 88 cylinders wil be bored to 95" and have the pistons matched.
Since I have a second set of heads can they be milled a few thousandths to gain some compression that won't stress the other components? I'm staying with stock valve springs and going with roller chain SE 203 cams.
Is 60 thousanths safe enough? Will I have to have the pistons butterflyed to keep the valves from hitting at this mill?
Since I have a second set of heads can they be milled a few thousandths to gain some compression that won't stress the other components? I'm staying with stock valve springs and going with roller chain SE 203 cams.
Is 60 thousanths safe enough? Will I have to have the pistons butterflyed to keep the valves from hitting at this mill?
Outstanding HDF Member
Joined: Oct 2007
Posts: 3,437
Likes: 15
RE: 95 build, compression question
I think if you are going to use a .030 head gasket and try and go .060 on the heads I think you will have some manifold fitment problems. I also think your compression is going to be pretty high. I shaved .037 and .038 and with the .030 hg I am at 9.5 to 1 with no fitment problems and no valve to piston clearance problems. The best bet is to cc your heads and then see how much you need to take off to get to the compression you are aiming for.
Grand HDF Member
Joined: Apr 2005
Posts: 4,022
Likes: 3
From: Hudson Valley- NY
RE: 95 build, compression question
Another recommendatioin would be to speak with your builder and make sure the components that you're planning on using are all compatible. A big bore with too low a CR will be disappointing and one with too high a CR can be a bear to start and may suffer from other problems like predetonation, pinging, etc. Taking the "best" cam, "Best" headwork, "best" of this and that may give you an engine that at best may be disappointing and worst, unridable. Not to mention that the $$$ you'll have spent may be all but pizzed away for nothing and don't we all have a couple of thousand dollars to spend on other stuff?
You don't say if you are planning to do the work yourself, but if not, then talk to your builder about your style of riding, what you can realistically expect from the building etc. No sense in building a great drag motor if you plan on long distance riding and the same goes for a good strong long distance motor if all you'll be doing is wasting tires in between stops at Starbucks.
Talk is cheap and and it is a whole lot cheaper than fixing a bad or disappointing build.
You don't say if you are planning to do the work yourself, but if not, then talk to your builder about your style of riding, what you can realistically expect from the building etc. No sense in building a great drag motor if you plan on long distance riding and the same goes for a good strong long distance motor if all you'll be doing is wasting tires in between stops at Starbucks.
Talk is cheap and and it is a whole lot cheaper than fixing a bad or disappointing build.
Road Master
Joined: Oct 2007
Posts: 1,117
Likes: 4
From: Log home in SE Michigan full time. Log cabin in east TN, Smoky Mountians part time
RE: 95 build, compression question
I used Wiseco forged 10.5 /1 pistons in 60 thou over bored 95' ( if your looking for hp and tq cylinders are cheap forget about ever boring them again you wont, )kept the stock heads cc ported with Manley 1.94 intake 1.6 exhaust, with Manley springs, used 30 thou head gaskets, and Woods TW9 gear drivecams , w 2 degree advance key... 45 mm mikuni, Daytona twin tec ignition...had to use compression release's. 113hp 116 tq on premium pump gas ran strong all day in a wide glide. never spark knock ... forget the screamin chicken junk.
Extreme HDF Member
Joined: Apr 2006
Posts: 10,449
Likes: 46
From: Roswell, GA
RE: 95 build, compression question
fryeca: What kind of performance are you expecting? I know you mentioned low- and mid-range torque, and I'm no fan of dyno numbers per se, but you're describing essentially a Stage II BB kit to take an 88 to a 95 with a mild increase in CR by using a thinner head gasket and, perhaps, some milling of the heads. I ask because a friend of mine did esentially the samebuild and regrets his use of the SE 203 cams--he believes/knows he left a lot of tq/hp on the table with that cam selection. However, if the 203's deliver the level of performance you seek, great.
Road Warrior
Joined: Jan 2006
Posts: 1,504
Likes: 1
From: Sunapee, NH
RE: 95 build, compression question
Here's a link that will answer all your questions and give you a great reference every time you want to take another look.
http://www.nightrider.com/biketech/
have fun
chappy
http://www.nightrider.com/biketech/
have fun
chappy
ORIGINAL: fryeca
I'm massing all the parts for my 95 build. I want to keep this build in the low to mid range torque area, I have a second set of heads and cylinders. The stock 88 cylinders wil be bored to 95" and have the pistons matched.
Since I have a second set of heads can they be milled a few thousandths to gain some compression that won't stress the other components? I'm staying with stock valve springs and going with roller chain SE 203 cams.
Is 60 thousanths safe enough? Will I have to have the pistons butterflyed to keep the valves from hitting at this mill?
I'm massing all the parts for my 95 build. I want to keep this build in the low to mid range torque area, I have a second set of heads and cylinders. The stock 88 cylinders wil be bored to 95" and have the pistons matched.
Since I have a second set of heads can they be milled a few thousandths to gain some compression that won't stress the other components? I'm staying with stock valve springs and going with roller chain SE 203 cams.
Is 60 thousanths safe enough? Will I have to have the pistons butterflyed to keep the valves from hitting at this mill?
Elite HDF Member
Joined: Mar 2006
Posts: 4,722
Likes: 5
From: Biddeford, Maine
RE: 95 build, compression question
ORIGINAL: fryeca
Is 60 thousanths safe enough? Will I have to have the pistons butterflyed to keep the valves from hitting at this mill?
Is 60 thousanths safe enough? Will I have to have the pistons butterflyed to keep the valves from hitting at this mill?
Steve
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Thread Starter
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Tourer
Joined: Jan 2005
Posts: 477
Likes: 3
From: Jacksonville, Fla
RE: 95 build, compression question
Thanks for all the info guys...
I'm doing this build myself; I'm trying to find the sweet spot for compression and cam's that will deliver good roll-on torque from slow speeds. Also looking fordecent pull when I'm at 2800 to 3000 on the hiway and some young high school kid on his way home talking on the cell phone is about to run me over...
From what I've gathered 9.5 to 10:0 and a 510camare good numbers for compression and lift. Looking at the SE203's they have a 510 and won't stress the other components.
I'm adding V&H True Duels to this build as well.
This is my daily driver; just tryng to make it a safer ride with some extra escape velocity on tap.
I'm doing this build myself; I'm trying to find the sweet spot for compression and cam's that will deliver good roll-on torque from slow speeds. Also looking fordecent pull when I'm at 2800 to 3000 on the hiway and some young high school kid on his way home talking on the cell phone is about to run me over...
From what I've gathered 9.5 to 10:0 and a 510camare good numbers for compression and lift. Looking at the SE203's they have a 510 and won't stress the other components.
I'm adding V&H True Duels to this build as well.
This is my daily driver; just tryng to make it a safer ride with some extra escape velocity on tap.
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Grand HDF Member
Joined: Nov 2004
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From:
RE: 95 build, compression question
The 203's only have 510 on the intake and 483 on the ex, I have them in my bike and I'm going to a 95" bore as we speak, sayin that I wish I could put in another set of cams, if you are going to stay with the SE cams you might consider the 204's, they are making a little more power than the 203's.
Tourer
Joined: Dec 2007
Posts: 265
Likes: 14
From:
RE: 95 build, compression question
Agreed, 204's are much better. Andrew TW21/26 would work also depending on how low you want your torque. Flowing the heads to match the cam helps immensly if you have the bullets. Even the TW21 likeslarger valves and minor porting.