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Discussion Starter #1 (Edited)
So, Ive got two FXDX bikes. One, a 99, the other an 04, carbed, and both have comparable mods.

The 99 has 37k miles, a Thunderheader, Big Sucker intake, stock pistons, and SE 204 cams, and made 86 lb ft and 79 hp on the dyno.

The 04 has 56k miles, a Supertrapp 2-1 with closed end cap and 20 plates installed, Big Sucker intake, stock pistons, Mikuni HSR42 carb (50 AC pump nozzle, AC pump set to engage immediately and full travel, 98 needle with clip in middle, 17.5 pilot, 160 main jet) and, according to previous owner, SE 203 cams, which are close to SE 204s, from what I can tell by the specs.

The issue is that the 04 has noticeably less torque than the 99, so Ive been investigating why. First, I was thinking perhaps cam timing was off, so I did a compression test to see if there was a big difference in readings between the front and rear cylinder on the 04, as Ive been told youd see around 30 psi difference IF the cam timing was off a tooth. I also did both bikes, so that Id have a basis for comparison.
Firstly, 160psi is perfect for the 88ci motor from what can tell, with these cams installed and OEM headgaskets and pistons.
04 has 140 psi in both holes. 99 has 155psi in both holes. I dropped about half an oil cap full of oil into both holes on the 04, and the compression reading went to 150 psi.

So, if 160/100= 1.6, and bike should make 79 ish hp to the wheel and 79/100= .79 and 160- 140= 20/1.6= 12.5% loss which would theoretically be 10hp if the correlation between hp and compression is linear.
IS 140 psi enough to make this bike a slug in comparison to my other bike with 155 psi? I also was wondering if the crank case was filling with oil due to sumping and that was slowing it down, but I took it for a rip and then promptly pulled the plug from the bottom of the crank case, and only 1-2 oz of oil came out, so its not that.

Im going to perform a leakdown test tonight to see if the valves are sealing properly next. Im just wondering, the head gaskets are clearly stock, so Im sure adjustable pushrods were used in the cam install, and if theres major leakdown from the valves, could it be that the rods were adjusted too long and are preventing the valves from seating fully? If the rods were adjusted too short, could they be keeping the valves from opening fully, thus giving a false lower compression reading and also hindering performance? If either of the previous mentioned issues were present, wouldnt the valve train be noisy and perhaps have grenaded by now?
 

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Wonderful. Are pistons stock compression, how many miles...? Now go introduce yourself. Write a long dissertation just popping in here. This is forum of bikers who enjoy our passion for HD's. We get testy and helpful with one another. This not some internet ask and ye shall receive some instant gratification web site. Show a little respect for us here. Go along way to help solve your problems. .
 

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Discussion Starter #4 (Edited)
So I put the thing in fifth gear. I got the front cylinder close to the compression stroke. I put 5 PSI into the system and then I gently Rock The Wheel back and forth until there was no hissing out of the intake or the exhaust. I then had April hold the foot brake on the rear wheel so it could not rotate inject it to 100 PSI and with the main gauge reading 100 the other gauge was reading 97.5 PSI with no hissing out of anything not even into the oil crankcase. The exact same is the case for the other cylinder. So I do not know where my power is going. I pulled the cam cover to check cam timing. With the rear cam sprocket dot on the line on the cam chest, the front cams dot is at 9 oclock. Thing is, theres no dot on the crank sprocket, so the ****er must be on upside down, which could mean the cams are lined up but the crank is not, so tomorrow i will pull the sprockets off and see.
 

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So I put the thing in fifth gear. I got the front cylinder close to the compression stroke. I put 5 PSI into the system and then I gently Rock The Wheel back and forth until there was no hissing out of the intake or the exhaust. I then had April hold the foot brake on the rear wheel so it could not rotate inject it to 100 PSI and with the main gauge reading 100 the other gauge was reading 97.5 PSI with no hissing out of anything not even into the oil crankcase. The exact same is the case for the other cylinder. So I do not know where my power is going. I pulled the cam cover to check cam timing. With the rear cam sprocket dot on the line on the cam chest, the front cams dot is at 3 oclock. Thing is, theres no dot on the crank sprocket, so the ****er must be on upside down, which could mean the cams are lined up but the crank is not, so tomorrow i will pull the sprockets off and see.
The pinion sprocket has a flat that aligns to a corresponding flat on the pinion shaft, only fits on one way. Same with the rear cam sprocket, keyed to the rear cam splines. The cam timing marks on the inside of the cam plate is the critical alignment. Those marks are on the plate side of the cams and can't be seen with the cams installed in the plate. The procedure is to transfer the marks to the other side of the chain sprockets with a marker so they can be aligned as the cams are pressed into the plate.
 

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Discussion Starter #6
I apologize, guys. I meant to say the front cam mark is at NINE oclock, with the rear cam sprocket mark on the line on the cam chest, and I edited it to reflect that. Just to be clear, regarding the absent timing mark on the pinion sprocket, what I meant was while its keyed and only fits in one position, if it was flipped so the timing mark is on the back side, it would be easy to have the crank off a tooth one way or the other. The mark on the pinion sprocket on the 04 very well could be under the washer. When I built a 99 for my girlfriend, the mark was on the tooth of the pinion sprocket, so I just expected the mark to be the same on this one, though Im aware they changed quite a few parts between 99 and 04. Guess I will go buy a new pinion sprocket bolt from HD, as youre supposed to replace em any time you remove em per the manual, and I will pull the bolt and washer and see if the timing mark is under the washer and confirm alignment.
 

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Discussion Starter #7
Well, Im going to take it to the dyno this week, so we will see if its just my butt thinking its low on power. Im probably going to do a 95" on it next month anyhow.
 

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Discussion Starter #8
Well, never made it to the dyno. I tore the bitch down to do a 95 inch kit. What do ya effin know, the cams are cvo 253, which im pretty sure came in the 103 and have an intake close of 51 degrees abdc, so no wonder the bike is a slug and read low on the comp test. Oh well. Im going to do Andrews tw37b and cc the heads and set compression to 9.5:1 cause hd has a pair for 40% off.
 

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IMO, do the compression test with a warm engine. WOT and crank 10 times on both cylinders.
 

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Discussion Starter #10
That is indeed how I did the test, took bike out for a few miles, came back, turn off gas and run carb dry, pull plugs and unplug coil pack, wide open throttle, and several revolutions.
One thing I noticed is that both my bikes (both 88s) made max compression on the gauge at around what appeared to be three revolutions or so. The reading in the 140's is normal with CVO 253 cams and stock compression 88, according to the Big Boyz calculator. I just wish the previous owner knew what cams were actually in the bike, as that would have saved me a lot of time, and frustration, cause I was told they were SE203, and if I had known they were 253 cams, I would have just changed the cams to SE 203 or SE 204 or Andrews 21- 26 and called it a day. The motor even has ported, 06 heads on it, and the SE 45mm intake manifold with the HSR42 carb, and had a 175 main in it. All with an 88 incher, its no surprise it was so slow. In any case, Ive got 95" flat tops, TW37B cams, .030 gaskets, and Im going to cc the heads at my friends shop and do a valve job and new valve seals, set deck height to 0, and try for 9.6:1 ish comp and see what happens on the dyno.
 

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Well it sounds like you know way more about that shit than I do ... I'm just a lowly service mechanic !:dunno
 

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Discussion Starter #12
I definitely wasnt trying to state I know any more than anyone else, just stating how I performed the test is all. Speaking of which, would you happen to know which is better for the oil pump spigot and if they are made of different compounds- the 11293 oring or the 11157 oring? I sent my gf to go get me an oring from HD for the oil pump spigot, cause my top end kit did not come with the orings for between the pump and cam plate, the two between cam plate and engine case, or the one for the pump spigot. At work, I had all the orings in viton except for the one for the oil pump spigot. I am aware that the spigot oring and upper pushrod tube orings are the same size, and that the manual for 99- 05 called for the 11157 in the spigot and upper pushrod tube positions, but one manual called for the 11157 OR the 11293 on the spigot, and the parts guy insisted that the 11293 is for pushrod tubes only. I think he is incorrect and that the 119293 is the better of the two for the pump. Am I wrong??
 

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Per Ronnies the '04 oil pump spigot o-ring number is 11157. 11293 is the top pushrod tube o-ring.
 

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FYI the oil pump o-ring is made from a different material than the pushrod tube o-rings. From memory the OEM pump o-ring is yellow.
 

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Discussion Starter #16
Thats what i was thinking. And the parts guy insisted that the black 11157 was the right one. I told him it should be yellow.
 

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Discussion Starter #17
Oh and one more thing. I thought that this motor had 06 heads on it because its got beehive springs and i never measured the valve stems to see if theyre 7mm.I noticed the seals on the guides are the 99 to 04 style seals and I noticed the number on the heads is 16725-99 and 16723- 99, so theyre 99 to 05 heads? Any clue what springs these are? The cvo 253 cams that were in it are .530 or .540 lift, so they had to change springs, I just dont trust much of anything thats been done to this motor at this point. The cams ive installed are only .510 lift so lift is a non issue, i just want to make sure the right springs are on the heads.
 

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