I have an '09 Road Glide, with 103 cast flat top pistons (the Harley ones) and 255 cams. Looking to bump the compression to about 10.25 and run a new bolt in cam, maybe Andrews 57 or Woods 555. Pistons are 11 thou in the hole. I haven't cc'd the heads yet but based on the Big Boyz compression calculator they will need to be cut down up to about 18 thou (assuming about .006 per cc and guessing the stock volume may be something more than 85cc) - anyway that is measuring and math all to be done, just what I think ballpark might be. I'm not looking for a ton of compression, just something that would match up to the above-mentioned cams a little better than what it is now.
A couple of questions:
- am i safe to run say 10.25 to 1 with the Harley cast pistons (I'll clay it and what not for p/v clearance, just wondering if I should be going to a forged at that compression - if I need to go forged I might do something else like a 107 kit with flat tops).
- Can the squish be set as part of getting the heads milled, or do I also need to have the cylinders turned to get them sitting say .002 to .005 down in the hole then run an .030 gasket for example. I think I'd have to get the cylinders turned down as well but not sure.
Thanks for any help. John
Typical air cooled TC 06 and newer chamber volume is 86cc, and since they shortened the "-06" rods .007", deck height is typically down the same amount, +/- a couple thou. Detonation is what kills cast pistons, so reasonable build parameters/expectations, and a good tune, and cast will be fine.
Deck height has to come off of the cases or cylinders. Milling the head reduces chamber volume, but doesn't affect deck height.
Zero deck, .030" head gasket, 84cc chambers will get you there, using a 57H yields a corrected CR of 9 1/2, so no drama for a decent tuner.
I think you may find the 57H feels softer below 3K compared to your current setup, but tons better above 4K. Take a look at the CR575- I think you might like it better?
:agree: Trim the cylinders and start from there.
Thanks both, I'm definitely thinking about other cams too and I'll check that cyclerama one. Whatever I do it'll be dynotuned (it has a PV). Just wanting more on the highway which is where this bike is mostly ridden and don't mind shifting down.
Quote from: Cowtowner on January 04, 2021, 11:49:26 AM
Thanks both, I'm definitely thinking about other cams too and I'll check that cyclerama one. Whatever I do it'll be dynotuned (it has a PV). Just wanting more on the highway which is where this bike is mostly ridden and don't mind shifting down.
With the right cam and related support, you may not have to.
I would take a look at a Comp cams TC-3102 😏
Quote from: kd on January 04, 2021, 12:29:47 PM
Quote from: Cowtowner on January 04, 2021, 11:49:26 AM
Thanks both, I'm definitely thinking about other cams too and I'll check that cyclerama one. Whatever I do it'll be dynotuned (it has a PV). Just wanting more on the highway which is where this bike is mostly ridden and don't mind shifting down.
With the right cam and related support, you may not have to.
Yeah I'm figuring with something in the 36 or 38 or so IC close range, with about 10.25 it should be pretty ok. Heads are mildly ported but valves are stock size. My exhaust header is an old Cobra with the H port (H pipe) and street cannons and I'm not sure that set up's doing me any favours but I like the look of it and don't want to spend for a new one right now.
Cast pistons are fine for what you are doing,have you looked at the TMan 555 they work very well.
If .011 in the hole. Why not swap from a 020 base gasket to a 010 and then only be 001 in the hole.
OEM HD cylinders for 103" are o'ring sealed to the case, no base gaskets. Easy enough to take 0.006" off the base of the cylinder, and 0.005" from the top to also get a clean head gasket surface.
:agree:
Quote from: Ohio HD on February 27, 2021, 12:34:05 PM
OEM HD cylinders for 103" are o'ring sealed to the case, no base gaskets. Easy enough to take 0.006" off the base of the cylinder, and 0.005" from the top to also get a clean head gasket surface.
This is what I did on my last build, gives you fresh and flat gasket surfaces and gets you to zero deck height. :up:
My bad. I forgot about the o rings. I'm use to my s&s motor
0 deck, and take the rest from the head.
Manifold fitment might need attention.
The Wood 5-6 cam is an often overlooked hero.
Well, this project morphed - I'm going with 10.5-1 pistons (+5cc dome), TW555 cams and 1.900" intake / 1.630" exhaust valves into my (previously) ported heads. So no more milling heads and what not.
Got the cam chest together yesterday and I'm going to drop the cylinders on this weekend, see how far these pistons are in the hole (they list a !.0830 compression height on the box but I don't know exactly what the Harley flat tops were), and clay it for p/v clearance. Assuming these pistons are about .010 down I think I'll just go with a .030 head gasket and call it a day, rather than taking the cylinders back for more work.
I'm hoping the TW555 is the right choice, I wound up talking to Bob Woods about using the 555 or the 777 and it sounded like both would work, so I went with the more conservative one.
I gotta figure out how to drill my SE heavy breather for external catch can. I was running an SE stage 1 that I'd set up for an external breather, but I do have the heavy breather in a box and I'm thinking to change to that.
Just wondering - any difference on a set up like this, in running a Harley stage 1 vs. Harley heavy breather? Or do they both get it done about the same?
The norm is the build changes as you advance and collect more information. If it were me, and the pistons were below deck, I would take the opportunity to 0 deck them while they are off. You will have a much better quench with the .030 gasket and that will reduce any subsequent detonation or pinging. It's well worth it to do it before you assemble it. It will give you maximum combustion chamber burn control and likely a better tune. Do it. :wink:
It would definitely be ideal. I think I'll see how it measures this weekend with the new pistons then decide whether to stop there and take the cylinders for machining or stay as is and go on to clay it.
I'm trying to control costs a little too although I don't know what it would cost around here to have a few thou taken off the cylinders, and like you say, controlling detonation is a good thing.
Quote from: kd on January 04, 2021, 11:16:54 AM
:agree: Trim the cylinders and start from there.
Just have the cylinder base trimmed a little. Piece of cake
Once the seats are machined, and the tulip/dish on the back of the valves are on the picture, your combustion chamber volume increases, still warranting cylinder head cc'ing/surfacing.
Quote from: Hillside Motorcycle on March 24, 2021, 03:29:08 AM
Once the seats are machined, and the tulip/dish on the back of the valves are on the picture, your combustion chamber volume increases, still warranting cylinder head cc'ing/surfacing.
That's a good point, and something that helped me with my last build to drop the compression slightly to just where I needed it. Without having to use a thicker head gasket.
Thanks for mentioning it.
Hi again. After getting sidetracked by something else for months I realized winter is coming, I was running out of time and I wanted to ride this bike. Clayed it all was good, did a few heat cycles and now has about 200 miles before parking for winter. Will finish break-in in spring and then get dyno tuned (running a Pv canned map with some auto tune for now). Never did cc the heads or have cylinders machined. Pistons were 11 thou down. Reading Hillside's comment I am pretty curious to cc those heads, next time they're off I guess. It was an interesting point I had no idea.
Had some questions if people had thoughts. Set up is 103, 10.5-1 pistons, 030 head gasket, ported heads/bigger valves (1.900" intake / 1.630" exhaust), 555 cams, Cobra power port header and SE street cannon mufflers. This is a 2009 FLTR.
- it has an SE hi flow air cleaner with external breather. I also have an SE heavy breather that I'm drilling for an external breather. Does it matter which one it is dyno tuned with and can I switch back and forth without changing the tune? I'm assuming the hi flow flows good enough so that I don't need to use the heavy breather but is that right?
- any gains to be had with SE 58mm throttle body? Or is the stock one good for this build?
- are the street cannons good for this or are there gains to be had by changing the mufflers? I don't really want to replace the header as I like it's look but I wonder if there is any point to changing the mufflers. I'm not keen to spend the money since I may not get much for the street cannons.
Thanks for any advice.
Personally I would stop what you are doing and back up and start over. You have no clue what your compression is, but you was to add more performance parts. Getting the heads CC'd and the pistons at zero deck so you know what compression you have will return you more than anything you do with the intake.
Quote from: PoorUB on November 22, 2021, 07:25:29 AMPersonally I would stop what you are doing and back up and start over. You have no clue what your compression is, but you was to add more performance parts. Getting the heads CC'd and the pistons at zero deck so you know what compression you have will return you more than anything you do with the intake.
The only unknown is combustion chamber volume (I know deck height, dome volume, gasket thickness). Assuming 85 to 87 cc, that runs 10.4 to 10.6 on a calculator. Presumably it's on the lower end. Isn't that close enough to decide what air cleaner, throtttle body and mufflers to run?
Did the shop that did your heads CC the combustion chambers or machine them to stock or desired volume. :potstir:
Quote from: Cowtowner on November 22, 2021, 07:38:38 AMQuote from: PoorUB on November 22, 2021, 07:25:29 AMPersonally I would stop what you are doing and back up and start over. You have no clue what your compression is, but you was to add more performance parts. Getting the heads CC'd and the pistons at zero deck so you know what compression you have will return you more than anything you do with the intake.
The only unknown is combustion chamber volume (I know deck height, dome volume, gasket thickness). Assuming 85 to 87 cc, that runs 10.4 to 10.6 on a calculator. Presumably it's on the lower end. Isn't that close enough to decide what air cleaner, throtttle body and mufflers to run?
You have been given fantastic, solid foundation advice from all here. You chose to ignore it.
Carry on.
Quote from: RTMike on November 22, 2021, 08:33:36 AMDid the shop that did your heads CC the combustion chambers or machine them to stock or desired volume. :potstir:
No they didn't. I could have cc'd them but as noted above, chose not too.
Quote from: Will-Run on November 22, 2021, 09:01:05 AMQuote from: Cowtowner on November 22, 2021, 07:38:38 AMQuote from: PoorUB on November 22, 2021, 07:25:29 AMPersonally I would stop what you are doing and back up and start over. You have no clue what your compression is, but you was to add more performance parts. Getting the heads CC'd and the pistons at zero deck so you know what compression you have will return you more than anything you do with the intake.
The only unknown is combustion chamber volume (I know deck height, dome volume, gasket thickness). Assuming 85 to 87 cc, that runs 10.4 to 10.6 on a calculator. Presumably it's on the lower end. Isn't that close enough to decide what air cleaner, throtttle body and mufflers to run?
You have been given fantastic, solid foundation advice from all here. You chose to ignore it.
Carry on.
I am carrying on and I have appreciated the advice that people gave me. I had just asked whether I could trade my two air cleaners back and forth (i.e. is there much of a difference, tuning wise, between the two) and whether people thought the OEM throttle body and SE mufflers were good for a build like this.
If I need to know the exact combustion chamber volume before people can give any further views, so be it.
It's not a big deal on the cc's for what you're doing just check cranking compression and go from there if you think it's lacking something. I wouldn't think that a 58mm TB would gain anything for you. Changing from the heavy breather to the standard type AC can definitely change the VE tables, can you get away with it, yes it's not going to blow up but it's not really proper if you're wanting it to run its best.
I'd tune with the Heavy Breather installed- IME, it's slightly better in the midrange, than the normal hi-flow AC, and the onboard O2 system can compensate adequately downward during cruise conditions if you decide to swap AC units later.
:agree: If you already have this selection of breathers you can swap them out at the tuning session and actually see how they work or effect AFR. Most tuners will take the time (at least on larger builds) to remove a breather / filter to get a measure of if the breather is holding anything back (usually only on WFO performance though)
Thanks all for input on air cleaner - I think it makes sense to have it tuned with the heavy breather (I like it better but sometimes like running the football too). Good idea to have the tuner do a run with with the hi flow to check the difference from the heavy breather - I'll ask them if they'd do that, pretty simple to change them over. I'm plumbing the external breather in the same configuration on the heavy breather as it is on the hi flow - with 1/8 NPT x 6 an fittings in the comparable location so it can easily be switched from one to the other.
Sounds like on a fairly mild 103 build like this, the throttle body may not be worth it and I've been watching spending. I'll probably drop that idea.
The street cannon slips on seem to be about 1 7/8" baffle although I can't measure them very well. I'll probably run that one by the tuner to see what they think - it seems to be running strong and I'm not after the biggest numbers, just something that makes decent power and runs good.