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Discussion Starter #1
HD stage IV build, the bike dynoed at max HP 78.31 and max torque 82.63 had a comp and leak down test done and front and back cylinders had 130psi comp and 8% leak down.

All SE parts put in the bike and this is the parts list

1- 22143-08 high comp piston 3 7/8 bore + .10 over
2- 17165-08A ACR performance cylinder heads which were polished
3- 17997-99A adjustable pushrods
4- SE 259E cam kit
5- 27713-08 SE 58mm throttle body
6- 27796-08 SE 5.3 gram per second fuel injectors

The only problem I can see is the builder used high comp pistons for stock heads when he should have used high comp pistons for the ACR performance heads which would have been HD part #22141-08B. I am disappointed in the results and am looking for suggestions on the fix would the wrong pistons give me that much performance drop or is there another problem?
 

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130psi , I'm surprised it even fires up.
 

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130psi could mean a couple things.

#1 The test was run with the throttle plate closed. If the engine can't pull in air it can't compress it either. The throttle plate MUST be wide open for a proper compression test.

#2 the cam is installed off a tooth or 2.

#3 pushrods are adjusted wrong holding the valves open.

Given the dyno test results I'd say the compression test was done right, and something else is wacked. Properly assembled you should have 180 to 200psi compression with any of the SE combos.

You just can't catch a break apparently..........sorry.
 

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Wow, stage IV and almost stock numbers....disappointed is an understatement, a simple cam would've done better. What does the builder have to say? I'm speechless, but it would have to be resolved. :eek:
 

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Even if the cylinder heads and pistons were mismatched AND were a complete mismatch to the cam you'd still be getting 175psi or more compression.
Those pistons make 10.5:1 with stock heads, if the heads have anywhere close to stock size chambers you should be at 190psi.
 

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Discussion Starter #7
The comp test was done with the throttle plate full open so it is done right. Leaning towards the wrong pistons put in by the builder, the builder used 10.5-1 pistons for stock heads but needed to use 10.5-1 pistons for the ACR performance heads. The ACR performance heads were for 99 to 06 models, HD discontinued the ACR heads and only have the MVA heads now but both heads have the same piston application. The builder ordered all the parts so I would think he is responsible but the only problem is that I don't want to take the bike back to him.
 

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I'm assuming the builder did not perform the dyno test - that would have been a shock to him as well I would think!
 

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Any idea what the chamber ccs are for those heads??
Using this compression calculator, http://bigboyzheadporting.com/TwinCamComp.htm

If I use 103", stock flat top pistons, the biggest cc SE heads I can find listed at 98cc's and a cam with a 47* intake close, the lowest compression I can come up with it 160psi.

Either way, the builder, if he's built more than 1 V-twin motor, should have known better, and should have been able to tell by ear it was gonna be a dog as soon as he started it.
 

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The comp test was done with the throttle plate full open so it is done right. Leaning towards the wrong pistons put in by the builder, the builder used 10.5-1 pistons for stock heads but needed to use 10.5-1 pistons for the ACR performance heads. The ACR performance heads were for 99 to 06 models, HD discontinued the ACR heads and only have the MVA heads now but both heads have the same piston application. The builder ordered all the parts so I would think he is responsible but the only problem is that I don't want to take the bike back to him.
I understand you don't want to take the bike back to that builder, but if the builder is any good at all, they should feel obligated to get it right at there cost. If not, then yes you should go somewhere else, but first ask the builder. And if the builder is who dynoed the bike..... well he should know better.
 

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Where was it done? I hear Torq Monster near Port Huron does great work, might consider giving them a call.
 

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That's sucks doing all that work and dealing with problems.
That's normal leak down. ? Could this be a bad ring?
 

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Discussion Starter #13
I understand you don't want to take the bike back to that builder, but if the builder is any good at all, they should feel obligated to get it right at there cost. If not, then yes you should go somewhere else, but first ask the builder. And if the builder is who dynoed the bike..... well he should know better.
The builder did dyno the bike and after a day on the dyno he called me and told me my bike was done, I went to pick it up and the bike would hardly start and after it started the bike wouldn't even restart for about a hour. I had to take the bike to the HD dealer to get it to run again and when I dropped it off at the HD dealer it took us 20 minutes to start the bike and then after the bike did start it would not restart. It turned out that when the builder put in the wiring harness for the ACR he did not wire the harness according to HD instructions because the builder did not have the digital tech to flash the ECM and the ACR were not functioning properly. After the HD tech rewired the ACR harness they could get the bike to start and then the HD dealer tried to dyno tune the bike and that is the best numbers they could get.
 

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Were the ACRs disabled for the compression test?? That would explain alot too.
For that matter, are they now energized(open) all the time??
 

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Leak down of 8 percent is way too much for a new motor. A properly built motor with correct break-in shouldn't have more than 3 percent, and that is maximum! You also stated in a earlier post that the motor was smoking. When performing the leak down test, listen to where the air is escaping. If it is predominantly heard when you remove the dipstick, you have a piston ring - cylinder problem.
 

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Discussion Starter #16
When the dealer did the comp test they said they did the test with and without the ACR disabled and the # were the same. They also did a test on the ACR to see if they function properly. HD dealer called and after talking to the MOCO they said that the pistons that are in the bike are not compatible and the correct pistons need to be installed. I have 2 options when it comes to getting the bike to run right

1- put in the correct piston that are meant for the build.
2- put race springs in my stock heads and keep the pistons that are in the bike.

The cost between option 1 & 2 would be about the same because I would have to have manual CR put in the heads along with the race spring. The only advantage to option 2 would be that I would go back to the stock throttle body so I could sell the performance heads and TB and recover some of the cost and I would still have 10.5-1 pistons which would still give me higher compression and improved performance.
 

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When the dealer did the comp test they said they did the test with and without the ACR disabled and the # were the same. They also did a test on the ACR to see if they function properly.

This statement throws up a huge red flag!!
IF the ACRs are working correctly, they CAN NOT be getting the same compression readings with and without them enable/disabled. That's the whole purpose, they are Automatic Compression Reliefs, if they're not affecting the compression they are there for no reason.

Again, looking at the SE catalogs I had, I couldn't come up with a combination of heads and pistons and camshaft that could possibly create only 130lbs of compression.
 

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Here is my dyno taken during the tune from a canned map to a map made just for my bike and engine. The tune is good and fueling is exellent everywhere and is very easy to ride at any rpm in any gear.
259E, 58mmTB,V&H PowerDuals/Hi-Output mufflers,CNC heads,Forged pistons,Heavy Breather, SERT, SE adj. Pushrods, Scott Port Matching.
 

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Discussion Starter #19
This statement throws up a huge red flag!!
IF the ACRs are working correctly, they CAN NOT be getting the same compression readings with and without them enable/disabled. That's the whole purpose, they are Automatic Compression Reliefs, if they're not affecting the compression they are there for no reason.

Again, looking at the SE catalogs I had, I couldn't come up with a combination of heads and pistons and camshaft that could possibly create only 130lbs of compression.
They may have did the comp test with the ACR activated to check the function of the ACR and I misunderstood the test. I went to original builder tonight and told him he installed the wrong pistons and after some discussion he agreed to put in the correct pistons at no cost to me but he still claims that he did nothing wrong and replacing the pistons will not change nothing and the problem is the 58mm throttle body and that the injectors are to big. He also claims that he did a comp test and he was getting 170psi and that HD doesn't know how to do comp test even though the HD dealer documented the test and he has no documentation of his comp test. Of course this is the same builder that did not wire my ACR properly causing them to malfunction, put the wrong breather bolts in my brand new heavy breather that prevented the crankcase to vent, put the old valve seals in my new heads after polishing causing the bike to burn oil, told me the 255 cams would work just fine with this build and took 3 months to do the work and when the bike was done it would hardly start and I had to take the bike to the HD dealer just to get it to run and then the bike produced below stock numbers on the dyno. So who should I believe and should I take the bike back to him so he can install the correct pistons.
 

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When the dealer did the comp test they said they did the test with and without the ACR disabled and the # were the same. They also did a test on the ACR to see if they function properly. HD dealer called and after talking to the MOCO they said that the pistons that are in the bike are not compatible and the correct pistons need to be installed. I have 2 options when it comes to getting the bike to run right

1- put in the correct piston that are meant for the build.
2- put race springs in my stock heads and keep the pistons that are in the bike.

The cost between option 1 & 2 would be about the same because I would have to have manual CR put in the heads along with the race spring. The only advantage to option 2 would be that I would go back to the stock throttle body so I could sell the performance heads and TB and recover some of the cost and I would still have 10.5-1 pistons which would still give me higher compression and improved performance.

I'd give a call to Ray C's, over in Lapeer.
Scott
 
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