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Buell Forum » Knowledge Vault (tech, parts, apparel, & accessories topics) » Dyno Charts/Testing (Show us the POWER!) » Dyno Test Results - Breather Check Valves « Previous Next »

This page is here to share the results of my (Aaron Wilson's) dyno testing evaluation of breather check valves. You can add comments below.

The first time I did this was on my S1 only, Don Casto and I spent several hours testing both the Hayden and Spyke brand devices. The results were published in Battle2win awhile back. Here are the results of that testing:

breather testing results

"Kuryakyn" is the result that represents recycling the blowby, like the factory does it. So named because we used an adapter from Kuryakyn that sits between the carb and air cleaner and provides a breather hose connection.

"Closed" is just that.

The others are vented to the atmosphere, two of them through two different brands of magic valves, the other just open.

We also did one other thing that didn't get published, we connected a vacuum pump. There was no detectable effect on the power of the motor.

The whole thing was kind of a let down after hearing all the hype about how you could make your motor run so much better with these devices. We just couldn't make the motor run better no matter what we did. The only thing that mattered was removing the blowby from the intake, and anyone can do that for free. That gave a nice 1 to 2hp gain over a wide rpm range.

That article generated quite a response from one of the manufacturers, ET Performance, who apparently makes the Spyke device. They really took exception to it. So in the interest of fairness, I retested the Spyke device on 4 bikes. Below are the results of that testing.

There are some things the reader should know, though, before looking at all of these results. First, It's very important to understand that dyno results are not 100% repeatable. The temperature of the motor, and the "heat soak" effect, can really play hell with the repeatability. When you're looking for potentially very small differences, the only solution I've found is lots and lots of pulls, playing the heat soak rythym. That's a whole other discussion, though. Here I'll post enough sheets that you can see the range of results in each configuration. One of the nice things about putting the results here, versus Battle2win, is I can post a whole lot more data.

Something else I'd like to point out, too, is that you have to pay attention and be careful when you're doing this kind of testing to keep from being fooled. For example, I had a guy write to me and tell me how he got 1-2hp with a krank vent device. When I queried him about his testing procedures, it turned out he had done some baseline pulls, then pulled the breather from the air cleaner and attached the Spyke device and did some more pulls. So he inadvertently changed 3 things: he removed the blow-by from the intake, left the hole in the air cleaner thereby allowing more air into the air box, and attached the device. He had no idea which of the 3 things changed his power, yet he was crediting the vent device!

One last note and then we're on to the results. Several people have tried to make the claim that even though it doesn't show up on the dyno, their engine revs up quicker with the device. That is total BS, folks. A Dynojet like this one literally measures how long it takes to spin up the drum. If it spins up faster, it'll show more torque and hp, period.

Okay, enough background, here are the results ...



M2 Dynos

Here are all the baseline pulls on my '99 M2, no breather check valve in place other than the factory umbrella valves. The peak power ranges from 84.1 up to 85.4. Mikuni and a Bullett muffler and an air cleaner, that's it (not bad for a near-stock M2, eh? It's done a lot of dyno time).



M2 Spykes

Here are all the pulls I did on the same bike, same day, with the Spyke device in place. The power varies from 83.5 up to 84.8.



M2 Spyke result

Blue: With Spyke Device
Red: Without Spyke device

And of course, this the best pull from each configuration, overlaid onto the same chart. Yeah, I know, it *looks* like the bike ran a tad better without the device, but it didn't, this is normal variation. I guarantee you if I did enough pulls with the device, and played the heat soak just right, I could've equaled the other results. This is a tie.





S2 Dynos

Here are all the baseline pulls on my '96 S2. The power varies from 85.9 up to 87.1. Pretty fair for an S2 ... this bike has Brian's stage 1 work on the stock Sportster heads, a set of N4 (Lightning) cams, a race kit module, and a V&H muffler. Stock CV carb.



S2 Spykes

Here are all the pulls I did on the same bike, same day, with the Spyke device in place. The power varies from 84.7 up to 87.4.



S2 Spyke result

Blue: With Spyke device
Red: Without Spyke device

This the best pull from each configuration, overlaid onto the same chart. Again, it's a dead heat.




S1 Dynos

Here are all the baseline pulls on my '96 S1. The power varies from 92.6 up to 95.3.



S1 Spykes

Here are all the pulls I did on the same bike, same day, with the Spyke device in place. Pulls 38 and 43 are omitted, because the tach pickup screwed up and if I put those on the chart, I can't show rpm and torque. They were not as good as pull # 42. The power varies from 93.7 up to 95.1.



S1 Spyke result

Blue: Without Spyke Device
Red: With Spyke device
(sorry for the color inversion vs. the other results)

This the best pull from each configuration, overlaid onto the same chart. Again, it's a dead heat. I didn't actually use the "best" baseline pull, this one has a tad less peak hp but a little nicer curve.



FXR Dynos

Here are all the baseline pulls on my '90 FXR. This is a little different animal from a Buell, in that it breathes off the lower end using a timed breather gear. I don't believe there's actually a check valve in place. There are only 3 "baseline" pulls because this was a tune-up, and I did all my tuning that day with the device in place. Only towards the end, when I had it all tuned up, did I remove the Spyke device for comparison purposes. As you can see, the power varies from 85.7 to 86.9. This is a classic "heat soak" set, too ... notice how the first one is the best, then they fall off. Let it cool for 7-8 minutes and do this again, and once again the first one will be far and away the best.

Torquey somebitch, huh? Has Brian's stage 1 work with a Crane 316 & Mikuni.

I've learned a few tricks for generating legible dyno sheets from Winpep, too.



FXR Spykes

Here are all the pulls I did on the same bike, same day, in the final tuning configuration, with the Spyke device in place. The power varies from 86.2 up to 86.6.



FXR Spyke result

Blue: With Spyke Device
Red: Without Spyke device

This the best pull from each configuration, overlaid onto the same chart. Again, it's a dead heat.


Bottom line here, folks, I tried my damndest, I can't find power with these devices. I know that pisses some people off. All I have to say is "show me". Don't just show me a result, either, anyone can skew procedures or pick and choose among the full range of results to support what he's trying to say. Show me procedures and ranges of results.

Aaron Wilson
NRHS

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Chrism
Posted on Wednesday, January 02, 2002 - 07:52 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Aaron,
The comments you have about your S1, and accompanying dyno charts, are they your wifes' with the the thunderstorm heads? I'm still dicking around with my S1. Having modified the Supertrapp you sold me a year ago. It now has a 2.5" inlet and outlet, along with the core being gutted and opened to 2.5" also. I also cut the 2' collector off the stock headr and grafted on a 2.5" collector. Did you ever do the A/f ratio to horsepower comparison? I'm getting 80+ torque at 3800 but its falling off so hard that its only mustering 77 hp. Any suggestions? I don't know what my timing is set at. I'm still running the stock 40mm CVK with 42 slow 195 main and the N65C needle with a .030 shim. according to the last A/f dyno run the accelerator pump hits so hard I'm getting so fat it runs off the scale., then gets close to 14:1 and then starts to fatten up on the top end. I went and bought a stock sporster slide because I had drilled the first thinking the bog was fuel starve. Look forward to hearing from you.Chris
Boxerkid@a0l.com
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Aaron
Posted on Wednesday, January 02, 2002 - 09:46 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

"The comments you have about your S1, and accompanying dyno charts, are they your wifes' with the thunderstorm heads? "

Yes.

"Did you ever do the A/f ratio to horsepower
comparison?"


Yes, I've done some fiddling with it. Not at liberty to disclose everything, but all the textbooks are right, you make more power at slightly richer than stoic. I have the a/f monitor for my dyno now, too.

Dyno tune it properly. If the torque falls off at high rpm, it means your cyl fill is falling off. Heads, cams, exhaust all play a big role. Wish I could offer more but I'd only be speculating. I like Mikuni's myself. Good luck!

AW
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Chrism
Posted on Friday, January 04, 2002 - 06:23 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Aaron,
Thanks for getting back to me. I guess I'll have to break down and pay some one to dyno tune it correctly. The closest guy who has an A/F monitor on his is on the far side of Baltimore. Some day my wife will get a scanner and I can post my runs to date. You're in Colorodo right? Well if not, do you have snow yet? God, I miss the white stuff.
Chris
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X1glider
Posted on Thursday, July 25, 2002 - 03:24 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I finally got around to this page after all these months.
Aaron, when you tested the FXR, you said you didn't know if there is an umbrella valve because it uses a timed breather gear. Or did I misunderstand you? It does have umbrella valves in the head as does the TC88 and Spyke says to remove them, which I did. I use a mini krank vent for each cylinder and do not join them at a tee. I figured the expelled blow by from each cylinder would battle each other trying to get out the shared outlet. Instead of the typical breather bolts with the cross drilled holes I used nipple fittings to fit tubing over. I wanted to eliminate the right angle banjo fitting thiking air would back up as it tried to change directions. Then I ran the krank vents and more individual tubing to an inconspicuous place to vent.
I don't know if it made a difference at all like you said as well as nightrider.com. I did a bunch of other things at the same time. If you didn't remove the umbrella valves from the FXR, you might want to redo your test.
IMO, the timed breather gear does a decent job but could probably use some help. I've heard of people adding another vent from the crankcase to decrease the amount of air going up the pushrod tubes and possibly reduce puking, which none of my bikes, evo or TC ever did. I would guess that the umbrellas need a minimum pressure to operate properly and the extra vent at the crankcase might make them less effective. But that's pure guessing.
You've gotta admit the hype did sound good and I bought into it. "Lower and more stable crankcase pressures=more HP and faster revs and no more blown gaskets. A deeper sound too!" Another $100 lesson.
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Aaron
Posted on Thursday, July 25, 2002 - 04:02 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

The breather on a '90 big twin comes off the lower end, not off the heads. There are no breather holes in the heads and no umbrella valves.
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X1glider
Posted on Thursday, July 25, 2002 - 04:25 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Aren't you tired of being right? I now seem to remember the Big Twin head breathers starting in '93. But didn't the sporties start breathing thru the heads in '91?
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Hardie42
Posted on Wednesday, March 24, 2004 - 08:59 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Hi,
although the testing is somewhere long ago - i just want to add some comments:

First iŽll have to say that the following happened to a Buuell-powerd Sporty with TS-heads, S3-Cams and a Buell-Race header and Muffler under the Frame and HSR42 with SE-Aircleaner mounted.

While driving "normal" (speed appr. up to 70 Mph/ 120 km/h) there was nothing wrong.
When i hit it realy strong (up to 120 mph), i noticed a significant greater oil-consumption.

To this point the heads where vented into the aircleaner.

I than changed to a "free-air-venting", using the 90° parts from the original Buell-setup - result: no oil-consumption anymore (only some "fog" on the groundplate of the the SE-cleaner).

Ok, this has directly nothing to do with power, but i guess, there may be negative effects if too much oil is routed back into the engines burning-process.

Ride safe,
Christian
Hamburg, Germany
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Andys
Posted on Wednesday, March 24, 2004 - 12:55 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Christian,

I haven't run my vent tubes back into the carb for years now. I run all (including the removal of the timing plug to install a fitting to breathe the cranckcase) the vents to a catch bottle. Doing so gave me an extra bit of throttle response, but no added HP. Plus by using the catch bottle there's no oil to drip all over the place.

Best part of all this that I no longer have any oil mist in the airbox. That just gets messy.
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Bombardier
Posted on Monday, May 12, 2008 - 06:33 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Oil also deteriorates the O2 sensor in the FI bikes and plays havoc with the Air Intake Temperature sensor.
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