CV 51 Tuning

[WhipLash96]

For those that are using a CV 51. I am running pig rich in my opinion in the lower rpm. The 51 comes stock with a 48 slow  and a 240 main. We increased the main to 250 and dropped the the slow to 42. Even with that drop in the slow jet, I am still pig rich. We aren't done with this tune.

What is out there as far as needles are concerned that I can try?

The build is a 124 with a custom ground cam.

Thanks

[98fxstc]

maybe air filter is too restrictive and not allowing enough air for the motor

[Don D]

This is common. Back in the day I had one on a 95" motor and it worked well. It has been a long time but I remember drilling more holes in the emulsion tube and something else to add idle / low speed air.  I remember studying the operating circuits and went for it but sorry I don't remember the specifics, that was 19 years ago. The guy on this forum that would know what to do is Bruce Woltz.

[WhipLash96]

maybe air filter is too restrictive and not allowing enough air for the motor

That did run through my mind but in this particular case I think that it is more cam related as this cam has a lot of duration and overlap. This engine is making 136 hp and 142 ft lbs of torque. Doesn't seem restrictive to me considering the intake lift is 585 and the exhaust is 601.

[WhipLash96]

This is common. Back in the day I had one on a 95" motor and it worked well. It has been a long time but I remember drilling more holes in the emulsion tube and something else to add idle / low speed air.  I remember studying the operating circuits and went for it but sorry I don't remember the specifics, that was 19 years ago. The guy on this forum that would know what to do is Bruce Woltz.

So basically what you are saying is that I may have to bite the bullet and use the set up offered by Woods? I see that he has different needles available?

[Don D]

Well yes unless you want to do some experimenting, some not easily reversible, or get some concrete suggestions. Send a PM to Bruce, AKA Admiral Akbar

[Hossamania]

Maybe something to help.

https://harleytechtalk.com/htt/index.php/topic,114764.0.html

What rpms does your cam seem to like? Some cams just don't operate in a "normal" range. Mine prefers to be run a gear short most times, ie: 4th gear at 55, 60, even 65 mph, 2nd gear at 30 mph under any type of load..

[Hybredhog]

   I'm running a cv51 on my 124, and I got it pretty dialed in by using a "L" needle that was in their tuner kit, but that's next to impossible to find now. I'm useing a 48 pilot & a 240 main, but I'm at 4000ft.

[Hossamania]

The link I listed is a tuner kit for sale.

[Admiral Akbar]

Either the software here sucks or they are deleting my messages. Post the information as to why you think it's rich on the low end and where the 2 AFRs came from at the bottom.   If they are for each cylinder, the issue likely is not the carb. 

[WhipLash96]

Either the software here sucks or they are deleting my messages. Post the information as to why you think it's rich on the low end and where the 2 AFRs came from at the bottom.   If they are for each cylinder, the issue likely is not the carb.

Sorry that it took so long for me to respond. You are correct, those were 2 WOT pulls. But since I sent you that message, I also realized 2 things. 1. The bike wasn't up to normal operating temp. It was only at 150 degrees. 2. No steady state information. He had 2 sniffers so I am assuming that the graph you saw is showing average for both.

When I first looked at the graph, I thought that it was showing each cylinder separately which is why I posted and was a little worried. A little prematurely it seems.

[Don D]

When you described rich at the low end I thought you meant steady state, just checking AFR on the floor out of gear. Can you bottom the mixture screw and kill the motor? If not and a smaller pilot does not cure that this is what sent me on a journey to clean up the idle circuit. The result is not seen on a dyno run but the mileage does go up dramatically and so does the lack of building carbon.

[WhipLash96]

When you described rich at the low end I thought you meant steady state, just checking AFR on the floor out of gear. Can you bottom the mixture screw and kill the motor? If not and a smaller pilot does not cure that this is what sent me on a journey to clean up the idle circuit. The result is not seen on a dyno run but the mileage does go up dramatically and so does the lack of building carbon.

Right. It needs to go back on the dyno in warmer weather and up to temp. The engine is making good power but I do have to consider fuel economy to a point. I myself confused  AFR graph as front and rear cylinders but in reality they were two different pulls. I will send you a PM with the graph if you would like?

[Don D]

I think my point is WOT high gear pull from 2200 rpm or thereabouts is nothing that relates to real world riding. If it is rich as hell, which mine was low to mid and not cured by jets, on the road at part throttle it will drink fuel and build carbon.

[WhipLash96]

I think my point is WOT high gear pull from 2200 rpm or thereabouts is nothing that relates to real world riding. If it is rich as hell, which mine was low to mid and not cured by jets, on the road at part throttle it will drink fuel and build carbon.

Thank You for your time Sir! I will revisit this thread once it gets warm enough to where I can see what the AFR is doing at stead state. A buddy showed me a gauge that I can mount to my bike using an O2 sensor for real time data.