Carburetor for a mild Evo - CV40 vs HSR42?

[Winston Wolf]

I don't think you are going to be able to tune that out.  It's just the nature of the beast when the throttle is wacked wide open, it takes a big gulp of air.  I have a similar lean spot on this curve with a Mikuni.  Here is an example on one of my Evo bikes. I tried more accelerator pump, and it helped slightly, but the problem is still there.  I think it may be the sensor being affected by exhaust reversion.  This has an EV13 cam, stock head pipes, and the old HD catalog slip on mufflers, HSR42.  162.5 main jet, 97 needle.  You can see on these 2 sheets, that when you look at it vs time and not RPM, it is just a blip.  Notice the A/F is right on, and then the dip, and it's back to right on.  You can't notice it on the bike, so that's why I think it's just the reversion affecting the sensor.

[Finn]

Yes, I'm starting to agree on that being difficult to iron out.

I'm still tempted to try CV Performance Velocity needle but that's about it. Unless I choose to spend the coming tax return on a Mikuni... 

[hattitude]

Yes, I'm starting to agree on that being difficult to iron out.

I'm still tempted to try CV Performance Velocity needle but that's about it. Unless I choose to spend the coming tax return on a Mikuni... 

I used that needle in my CV40 on a 2001 88" Stage I Twin Cam with 45/190 jets. I had the N65 needle and didn't like the way it ran......

I put that CV performance needle in my carb and it now runs excellent in my set up...

[Finn]

That is good to hear. 

We should know tomorrow how it works on mine. Got EV13 + lifters + needle bearing etc. done today. Jetting and such is for tomorrow.

[Finn]

When I was riding 100 km trip to my dealer this morning I was all smiles as the bike ran so well after last re-jetting: no pinging, pulled very well from low rpm and barked really nice when opened throttle a bit more.

One thing was sure: the cam in there was not stock but even the previous owner did not know anything about it so that was going to be interesting. My money was on EV13 or 27 but all sorts of other possibilities were on table, too.

Well, there was an Andrews 27 with stock (probably original) lifters and plastic breather gear in.

My mechanic said that that is a surprise as everything points to stock compression ratio and his experiences of 27 + stock CR have been fairly negative and my bike ran very well. We will see how the heads look come winter.

I had my mind set on EV13 as I want a workhorse and plenty of low to mid range TQ.

New Feuling lifters and needle bearing and S&S steel breather will give peace of mind for years, I hope.

I was quite clean inside after Valvoline VR1:

[Finn]

FWIW, with Andrews EV13 Evo made today 72 hp @ 5390 rpm and 82 ft-lb @ 3980 rpm. These are pretty much exactly same numbers as with EV27 plus/minus 1 hp/tq. Compression ratio is stock.

On the road 27 "felt" like it had more mid range although dyno graph says otherwise. The EV13 is a "rubber band" ie. torque is always available whenever you need it. And pulls nicely with higher rpms, too.

We had earlier big problems with jetting with original needle. Now CV Performance's Velocity Needle corrected the problems. We ended with CVP needle without shims, 46 pilot and 205 main.

A bit strange the 205 but she asked for more fuel so we needed go up in size.

Touring cam the EV13 but still gives a nice rumble. 

[Hossamania]

Glad you got it dialed in. That 205 is much bigger than I would have guessed necessary, interesting result, good hp and tq numbers.
Have you had a chance to check mileage yet?

[Finn]

No, not yet. They got it ready late in the afternoon and I then just rode back home 100 km. I'm going to spend whole weekend on it so will soon know the mileage.

[Finn]

FWIW, mpg seems to be around 40 in mixed riding.