103 install problems
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Road Captain
Joined: Apr 2008
Posts: 595
Likes: 1
From: lake havasu
103 install problems
i bought 103 cylinders and cp forged pistons for my 2008 dyna after recieving the pistons i noticed that the piston say for 2007 and older bikes with 1.092 compression height ... the 2007 and newer need 1.082 ..the guy said he uses them all the time on the newer bikes with no problems ...can i make them work?
Ultimate HDF Member
Joined: Feb 2007
Posts: 7,663
Likes: 7
From: Northeast Ohio
Scott, The newer engines, the cyls are "down in the hole" by about .009. Using the earlier model pistons should get you to zero or +.001 deck height should they not?
Road Warrior
Joined: Nov 2007
Posts: 1,984
Likes: 7
If there is nothing else you can do you could install them, one at a time, and measure deck heigh with a straight edge.
You can use 2 inch length of 3/4 pvc pipe to make up space needed with no heads installed. Draw them tight enough to seat the cilenders on the case.
See what you got.
You can use 2 inch length of 3/4 pvc pipe to make up space needed with no heads installed. Draw them tight enough to seat the cilenders on the case.
See what you got.
Road Master
Joined: Jul 2005
Posts: 1,061
Likes: 5
From: Fort Worth TX
Dalton
Not all of the newer bikes pistons are that far down in the hole. Sure I have seen most of them that are down 4-6 and then you have the odd ones that are in the 7-11 range. With the 1.092 CP height you may end up with a piston that is above the deck or it may work out in your favor.
The CP pistons that we use with the 1.083 CP height ( for the 2007+) are at 0-.0015 down. As you know that is fine and there will be no gains by dropping down the cylinder to put it 0 deck. How much does the dome of the piston grow under running conditions??? No one that I have heard of has a spec. There are theory's of course but that is about it.
Also if you try to use a new piston on a old rod for what ever reason some of them are not clearanced for the non tapered rods. Or a crank that has been updated to a h beam style rod.
Ultimate HDF Member
Joined: Feb 2007
Posts: 7,663
Likes: 7
From: Northeast Ohio
Dalton
Not all of the newer bikes pistons are that far down in the hole. Sure I have seen most of them that are down 4-6 and then you have the odd ones that are in the 7-11 range. With the 1.092 CP height you may end up with a piston that is above the deck or it may work out in your favor.
The CP pistons that we use with the 1.083 CP height ( for the 2007+) are at 0-.0015 down. As you know that is fine and there will be no gains by dropping down the cylinder to put it 0 deck. How much does the dome of the piston grow under running conditions??? No one that I have heard of has a spec. There are theory's of course but that is about it.
Also if you try to use a new piston on a old rod for what ever reason some of them are not clearanced for the non tapered rods. Or a crank that has been updated to a h beam style rod.
Not all of the newer bikes pistons are that far down in the hole. Sure I have seen most of them that are down 4-6 and then you have the odd ones that are in the 7-11 range. With the 1.092 CP height you may end up with a piston that is above the deck or it may work out in your favor.
The CP pistons that we use with the 1.083 CP height ( for the 2007+) are at 0-.0015 down. As you know that is fine and there will be no gains by dropping down the cylinder to put it 0 deck. How much does the dome of the piston grow under running conditions??? No one that I have heard of has a spec. There are theory's of course but that is about it.
Also if you try to use a new piston on a old rod for what ever reason some of them are not clearanced for the non tapered rods. Or a crank that has been updated to a h beam style rod.
I have seen some in the .005 to .006 down, but most that I have run across have been in the .009 down, give or take. Bottom line is that if you use 'em, or with any piston, you do need to check deck height. And if you are runing aftermarket rods, all bets are off.
I have my 2010 Limited apart right now and the pistons were .009 down in the hole, as was the last 2010 in my shop. Maybe HD has used up their stock of mix and match rods.
Thanks for the response.
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Road Master
Joined: Jul 2005
Posts: 1,061
Likes: 5
From: Fort Worth TX
Dalton
No issues and I agree that you can find bikes with pistons that more than 6 down. but posting that some are not this may help others that are not really into checking this stuff in a home build and may end up with a issue and not know why.
We just tore down a 2010 for a 107 kit and I checked that set up they where 5 in the rear and 4.5 front. I use a digital depth mic to check the piston TDC. This posters issues are not uncommon I have had customer bring me a kit to install and I have found where the piston was proud out the hole and with the cam they choose it would have bumped the compression into a level where the pump gas here would create issues. Even with a .045 gasket. Some times the pistons are close and the heads are short. Then you get the bike like yours where the pistons are way down and maybe the heads are a bit larger that should work.
Good chatting with was nice meeting you last year. When you getting back out??
No issues and I agree that you can find bikes with pistons that more than 6 down. but posting that some are not this may help others that are not really into checking this stuff in a home build and may end up with a issue and not know why.
We just tore down a 2010 for a 107 kit and I checked that set up they where 5 in the rear and 4.5 front. I use a digital depth mic to check the piston TDC. This posters issues are not uncommon I have had customer bring me a kit to install and I have found where the piston was proud out the hole and with the cam they choose it would have bumped the compression into a level where the pump gas here would create issues. Even with a .045 gasket. Some times the pistons are close and the heads are short. Then you get the bike like yours where the pistons are way down and maybe the heads are a bit larger that should work.
Good chatting with was nice meeting you last year. When you getting back out??
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Ultimate HDF Member
Joined: Feb 2007
Posts: 7,663
Likes: 7
From: Northeast Ohio
Steve,
You really bring up a good point when saying others "bring their parts" and then there are issues. This is the reason for working with a reputable builder, getting their recommendations and sticking with what is recommended, to avoid the science projects that end up with tuning, power or rideability issues.
I am not sure when I will be back in your area but you can bet when I do, I will stop in and say hi.
You really bring up a good point when saying others "bring their parts" and then there are issues. This is the reason for working with a reputable builder, getting their recommendations and sticking with what is recommended, to avoid the science projects that end up with tuning, power or rideability issues.
I am not sure when I will be back in your area but you can bet when I do, I will stop in and say hi.
Road Master
Joined: Jul 2005
Posts: 1,061
Likes: 5
From: Fort Worth TX
I agree Dalton. I have been tuning a fair amount of those projects. Seems that some guys are finding deals on parts on the net. However much of it that I have seen thus far is far from what I would call a good deal.