Rigid_EVO so i put my bike back together, got a dyno tune, NOT HAPPY.

[aswracing]

Failure to follow correct gentle break-in procedures risks ring microwelding. Once you've microwelded your rings, you've forever condemned the motor to be a mediocre performer. Read these articles:

http://www.axtellsales.com/RonsDocs/Ring%20Seal.pdf

http://www.axtellsales.com/RonsDocs/...g%20report.pdf

BUT ... your symptoms aren't pointing to this. So let's assume for the moment that you broke it in gently and did not cause the damage described in those articles.

I can't diagnose what's wrong over the internet, but a few comments really jump out at me:

i noticed that the bike ran about 30 degrees hotter than it did stock

he had a tough time getting a steady curve out of the bike

do i need to time it off the line or the dots?

These are major, major red flags.

There is something wrong with this bike and the first thing I'd do is make sure the timing is right. You want 28 degrees total advance. That's personally where I'd look first. The symptoms match and it seems you didn't know how to set it. Of course, a good dyno tuner should set it, but not all do.

The other really basic thing you always do when trying to understand a disappointing result is to verify the mechanical integrity of the motor. Leak down and compression tests are the best way to do this. You need both. A leak down will immediately point out a leakage based problem. A compression tester will immediately point out a cam timing problem.

Good luck.

[Jimbos883]

Aaron quick question about this advance figure. You state and Buzz also states that 28 degrees total advance is the magic number for the Sportster motor.

A few members of the forum are writing custom maps for the Daytona Twintec TC88a ignition which have upwrads of 35 degrees total advance in them. Some people feel that by not going past the 28 degree mark you are leaving HP on the table. Could you address this issue. What's the reasoning behind all of this.

I don't really mean to hijack the thread but your statment got me thinking again and that is very dangerous.

[Shu]

The VOES controls two different advance curves based on vacuum. Is yours stuck in the advanced high vacuum position? With that setup I would have thought the dyno operator would have heard it pinging horribly when he hit the throttle at 2000 rpms or so. Anyway, that has to be fixed first.

If you use the light on the module to static time the engine, that will get it close to the 20 degrees at idle mark. If you use a regular non adjustable timing light you would then use the two dots on the flywheel and center them in the window. That will give you exactly 20 degree at idle. If you use an adjustable timing light then you can dial whatever starting point you want into the light and then center the groove in the flywheel to get the desired dialed in timing. I run mine about 16 or 17 degrees at idle depending on which pipes I have on the bike. This effectively takes three or four degrees out of the entire curve from idle to red line making my stock 883 total advance 27 or 28 degrees on the power curve. If you play with it long enough and do it in one degree increments you will find a sweet spot. For my stock head pipes and SE2 slip-ons the sweet spot is 4 degrees retarded but for the Thunderheader I found it to be 3 degrees retarded.

30 degrees warmer in the first several heat cycles isn't abnormal however after 500 miles that really shouldn't be happening. It could be timing induced or AFR induced or engine friction induced. Fix the VOES first then dial the timing in and see if it gets a little closer to normal heat. HOWEVER not that I think about it, 30 degrees over what? What is the actual temp? Where are you reading that temp? It could be that prior to this conversion you had it tuned a little rich and now you are correct. We need to know more to give advice on the possible heat concern.

The exhaust is a crucial to performance as any other part. When you open up the heads and throw in a different set of cams with different valve timing you completely change the dynamics of the exhaust. Reversion becomes much harder to control in these types of engines and a less than ideal exhaust will undoubtedly show just how poor it really is once you go the the level you have gone.

I see you are from the 'Midwest'. If you are anywhere near West Central Illinois, I have a Thunderheader I just took off that we might be able to make arrangements for you to bolt on for a dyno pull to see the effects of a 'better' pipe. With your setup I'd bet NRHS would recommend the D&D 2-1 or the SuperTrapp but the Thunderheader would help show the positive effect of a decent 2-1 over those Bassani's.

[aswracing]

Originally Posted by Jimbos883

A few members of the forum are writing custom maps for the Daytona Twintec TC88a ignition which have upwrads of 35 degrees total advance in them. Some people feel that by not going past the 28 degree mark you are leaving HP on the table. Could you address this issue. What's the reasoning behind all of this.

I've spent hundreds, if not thousands of hours dyno tuning bikes, the vast majority of which were Harleys and Buells. 35 degrees virtually never results in the maximum power. The power falls off and the motor runs hotter.

Most single plug HD motors with a little compression in them and a reasonable combustion chamber at all will want 28 to 30 degrees total. That's where they'll put up the biggest number. Dual plug the motor and you typically have to take 5-6 degrees off that figure.

A stock hemi-head 9:1 motor might want 35 degrees, I don't know, I almost never tune stock stuff. But not a 10:1 motor with a squish band. It's quite a bit faster burn.

[seajay]

Originally Posted by Terp84Alum

Oh, and ditch the Mikuni. That's costing you HP.

As compared to what?

[Terp84Alum]

Stock CV. You will get a little better throttle response from the Mikuni but I lost HP so I put the CV back on.

[Shu]

The CV and Mikuni will perform basically identically when both are tuned to provide the correct AFR. The difference you will find is once the engine dimensions are increased and or the RPM max is increased and or the amount of possible airflow is increased or all three then the Mikuni will start to outperform the CV. It is 2 mm larger in bore and can handle the above a little better than the CV. Keep the Mikuni. Out of the box tuning and it should be close but may not be perfect and will need to be tuned using the complete Mikuni tuning kit to be perfect. Same holds true for the CV though. I find the tuning kit Mikuni offers to be a great asset compared to anything Keihin has failed to offer as a kit for the CV.

[way fast whitey]

so if im just using the red timing light that blinks on the nose cone ignition . WHAT DO I WANT LINED UP IN THE CENTER OF THE TIMING WINDOW! the line or the single dot or the double dots? then i turn the ignition unit clockwise til the red light shuts off on the ignition correct? i dont have a timing light so ive been trying to time it off the red light on the ignition!

[Jimbos883]

Originally Posted by aswracing

I've spent hundreds, if not thousands of hours dyno tuning bikes, the vast majority of which were Harleys and Buells. 35 degrees virtually never results in the maximum power. The power falls off and the motor runs hotter.

Most single plug HD motors with a little compression in them and a reasonable combustion chamber at all will want 28 to 30 degrees total. That's where they'll put up the biggest number. Dual plug the motor and you typically have to take 5-6 degrees off that figure.

A stock hemi-head 9:1 motor might want 35 degrees, I don't know, I almost never tune stock stuff. But not a 10:1 motor with a squish band. It's quite a bit faster burn.

Thanks Aaron, makes sense.

[dshef007]

You want the straight line in the window when adjusting to the red light.