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killer sperm
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Discussion Starter #1 (Edited)
Here's the thing. I've learned a lot here but I wanna check with you guys on this build.
'05 Ultra, rider 190 lbs passenger 115 lbs. Not a hotrod, used for commuting and touring. All I'm after is to be able to pass that guy in the hopped up Powerstroke while we're riding up to Mt. St Helens.
I'm gonna keep the SE AF, Supertrapp 4' slip-ons, and the stock redline till Power Commander can modify my PCusb to raise it. Also gonna stick with the stock 3.15 gearing. No, I don't lug my engines, but thanks for asking.
The build;
stock heads milled to 84 cc's with a basic port. blend, and valve job using stock valves .030 head gaskets
cylinders bored to 95' with SE cast flattops
Andrews 26G
clutch spring
Baisley spring
SE exhaust gasket
Any suggestions or critiques welcome.
 

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XLIII
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10,078 Posts
With the SE clutch spring, maybe the '06 "Reduced Effort" ramps. They'll take the pull back to near stock.

Why the 26? With head work, a little more cam seems in order. What CR does that CC and .030 gasket work out to?

My Two Pennies,
 

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I have been considering a similar build for my "01 Ultra. AMS in Texas specializes in this very type of build, you should give them a call. I spoke to them and they are great folks

http://www.automotivemachine.com/

I have read that with the 3.15 gearing that the 21g gives you more low end tq. There was also an article in American Rider about mild builds with the 21 by Joe Minton. He recommends it highly. A good thread on HTT about the article.

SB
 

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I thought the 26Gs were best for an 88 or a 95 with no headwork.
I'm thinking the 37G would be the better choice. Pretty sure that's
what some of the builders on this board suggest.
There is a desired compression ration for the 37's but not sure
what it is.
 

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Id go with a different set of cast flat tops other than screamin eagle. KBs perhaps. Im told that the screamin eagles have .020 deck height....also some people have run into valve clearance issues with these pistons. Im no expert, just my observations.
 

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rpajewsk said:
Id go with a different set of cast flat tops other than screamin eagle. KBs perhaps. Im told that the screamin eagles have .020 deck height....also some people have run into valve clearance issues with these pistons. Im no expert, just my observations.
The SE cast pistons are made by the same manufacture as the stock 88" flat tops. This give stock like duribility and reliability.

Assuming .020 deck height there should still be plenty of clearance. But I don't think there is a .020 deck height issue because they run .030 cometic gaskets in a 95" and that would only leave .010 clearance between the top of the piston and the squish area of the head. But whoever is doing the build should always check clearances by claying the valves.

Also the 26g cam only has a 0.129 intake lift at TDC. as compared to say a 37 cam with 0.151 @ TDC.
 

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07', 04', 03', & 02
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95FLHR said:
There was also an article in American Rider about mild builds with the 21 by Joe Minton. He recommends it highly. A good thread on HTT about the article.

SB
Joe Minton’s recommended Bagger build. This recommendation is from a fall 2002 e-mail of another Bagger rider to Joe Minton regarding recommended build . Joe Writes for American Rider magazine. He works with Mikuni. He has built engines for all types of motorcycles. He did a lot of work on the Mikuni Tuning manual and the questions and answers along with the cam article on the Mikuni site is his.

Compression ratio, in and of itself, has little meaning. Your engine cannot count. However, it can feel pressure. When the cranking pressure reaches a certain value, which varies with every engine design and individual engine, destructive detonation becomes likely. Cranking pressure is the number you get when you perform a typical compression test (warm engine, gauge in plug hole, hold full throttle & crank with starter until the needle stops climbing -- typically 5 -7 full compression cycles).

Two factors determine cranking pressure the compression ratio, and, the intake valve-closing angle. Thus, if one combines a long-duration, late closing cam with the stock compression ratio, the cranking pressure will be lower than with the stock cam.
On the other hand, high-compression ratio pistons and the stock cam results in raised cranking pressure.

Now, let us get practical. The Twin Cam motor can tolerate cranking pressures as high as 200 psi with premium pump gas if, that is, it is in an excellent state of tune and has an effective squish band. I have found 190 psi to be a much more practical maximum. A combination of Harley’s high compression pistons and ‘mid-range’ cams create very high cranking pressures and destructive detonation. Their high compression piston sets were meant to be used with Harley’s SE-211, SE-257, SE-258 or similar cams, and carefully at that. I have reports from the field indicating that they often detonate even with these cams. Let us get even more practical: If you fit high-compression pistons together with the appropriate cams, say a set of SE-211s or Andrews TW55s, you can avoid destructive detonation. You will also avoid any useful power below 3,800 rpm which almost 90 mph in top gear and about 78 in fourth. This is not a bike that has much useful, everyday “roll-on” power. In fact, it may not make as much power at 60 mph (in top gear) as a stocker.

I advise cam sets that close the intake early to make the most power in the “normal” rpm range of 2000 - 4000 rpm. I designed the JM20 to do this (no longer available). It closes the intake valves at 31-degrees ABDC and truly useful power is available from about 2200. A 95” motor with a Mikuni 42, flat-top pistons, thin head gasket (Cometic .030” steel), JM20 or Andrews TW21 cam set, 6200 rpm “Performance” ignition module and a good exhaust (White Bros “E” or the SuperTrapp 2-into-1) will do the following: It will smoke the tire in first gear at 2500 rpm. It will have no torque dip at any rpm (the Thunder header falls off very noticeably between 2300 and 2800). It will reach 100 lbs/ft torque at or near 3000 and about 87 HP at 6000, (if you fit a Mikuni 45, you will get 90 HP).
Several hundred folks have built this motor and none of them has expressed regret at having done so. This combination of cams, thin (anti-detonation) head gasket, and flat top pistons (Harley’s are fine) produces a cranking pressure between 170 & 180 psi. Stock, by the way, is 160 psi. You can run any gasoline without fear of detonation. The power increase over stock is awesome. Stock torque is about 72 lbs/ft at about 4000 rpm; this modification package delivers 105 at about 3800. The modified engine produces more torque at 1600 (83 lbs/ft) than the stocker does at peak! Stock power is about 59 HP; the modified engine delivers 87+. And, it does all this while running better; it is smoother, more responsive, has a much wider power-band, and runs cooler too. High compression pistons lock the engine into long duration, late-closing cam designs. These cams are necessary to take full advantage of ported heads and achieve the greatest HP numbers at high rpm but often, no --- usually virtually destroy the manners and usefulness of the engine at normal, top-gear road speeds. Before you decide what to do, please carefully consider how you ride and at what rpm you want your engine to its best work. Pick the cam set accordingly and—the pistons to go with the cam.
 

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springer- said:
The SE cast pistons are made by the same manufacture as the stock 88" flat tops. This give stock like duribility and reliability.

Assuming .020 deck height there should still be plenty of clearance. But I don't think there is a .020 deck height issue because they run .030 cometic gaskets in a 95" and that would only leave .010 clearance between the top of the piston and the squish area of the head. But whoever is doing the build should always check clearances by claying the valves.

Also the 26g cam only has a 0.129 intake lift at TDC. as compared to say a 37 cam with 0.151 @ TDC.

I pointed out the deck height to say that pistons without dech height would be better (or less than .020) to improve squish...
 

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killer sperm
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Discussion Starter #11 (Edited)
MegaGlide said:
Man, that's right in the sweet spot for a no-detonation 37G build!
Dave I'm burdening this build with a 5800 rpm redline and 3.15 gearing. I don't think the 37 would be happy here. Looks like I guessed wrong, the compression is a point or two higher than than I figured. Don't know if 9.6 compression (thanks Springer) is too much for a no hassles 26 build.
The Hippo says newer twin cam chambers run pretty consistantly at 85 cc's though some still run large. Looks like I may save the cost of milling the heads.
 

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XLIII
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When I started my build, I was thinking 26 as well, but as the good folks on this forum pointed out to me, the 26 starts lower, but doesn't make as much power anywhere. At any given RPM, even down low, the 37 makes more power. Here's my dyno. My mufflers are choking it off up top, but as you can see, this is NOT a high rpm setup.
http://65.38.172.84/forums/showthread.php?t=62097
 

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Milehog, I do see one glaring problem. Like me, you live in the Pacific Northwest. Who you gonna get to tune that bad boy when you get it done? If you know of a competent tuner up here, please let us know. I heve talked to plenty of PNWers on here all with the same problem..... NO ONE TO TUNE:(
 

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Throw in a +2 advance key on the 37 and the 5800 rpm redline should pose no problem and give you a broad power band.
 

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The Andrews 26 with 580 lift almost mimicks the TW5 as a very broad high torque cam...............on my software.

What many dont realise is that its the torque curve that gets you down the road in a hurry and then from 5250 the HP curve kicks in but as it has been said here so many times........who rides around at 5000 plus rpm very often.

As Doc has stated also many times.............you got to aim for a torque curve that starts out say in the 90`s and builds up to or over the 100`s at around 4000/4500 on average and the broader the better........this type of curve gives the most enjoyment when you ride................lets you roll on if that suits...........lets you smoke up the rear wheel when the mood suits and is more controllable and less "purpose built"

All the best, Ozzie
 

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IronButt
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Looks ok for a 95 I think you would be ok with out milling the heads if you where to use a piston other than the SE cast. CP pistons will get you there with out milling. Please this is not a statement to open up the whole cast forged debate. I am only stating that CP makes a piston in the 95 bore that will give you 9.5 with a stock thickness gasket or 9.7 with a thinner one that is it. LOL

Steve I think you have a good basic set up that is a no frills build and should work well. TO up the over build going to a 98 with a 37 would provide more overall tq an have MUCH more tq in crusing range. NOt to take away from the 95 but as you know there is NO replacment for displacement " Maybe a 131 and a turbo' YEa now we are talking, and NOS to why not that would get that bagger movin or maybe flying would be a better choice of words.
 

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springer- said:
I think the Andrews 26 cam has a .490 lift
Ah yes it does Springer but I have a desk top dyno that I added .580 lift to the 26 and it showed an almost identical curve as the TW5.

Also shows the TW5 putting down more torque in the useable rpm range than the TW6H in every build I have put together.

I would very much like Beans flow numbers, port sizes, head cc`s and valve sizes so I could run some numbers and suggest possible cam combos.

All the best, Ozzie
 

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FWIW, I've attached my dyno showing a TW21 run and a TW26 run.

Both dynos and tuning were done by HD Frederick, Maryland in an enclosed dyno cell.

RED LINE is TW26 (92.33 HP / 99.73 TQ)
2002 Road King Classic (Delphi EFI)
AMS Heads
.030" head gasket
KB 348/95" flat top pistons
Andrews TW26G
RB Racing LSR 2-1
Doherty PowerPacc air filter
Stock 40 mm throttle body
3.37 final gear ratio
HD Stage 2 ECM download
Dyno Jet PCIII USB

BLUE LINE is TW21 (85.94 HP / 102 TQ)
2002 Road King (Delphi EFI)
AMS Heads
0.030" head gasket
KB 348/95" flat top pistons
Andrews TW21G
RB Racing LSR 2-1 exhaust
SE Air Filter
Stock 40 mm throttle body
3.37 final gear ratio
HD Stage 2 ECM download
Dyno Jet PCIII USB
 
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