The little Ducati Featherweight

jcw said:
Have you used a wideband on a carb'd bike before?

Interested in seeing how useful it will be. EFI is so adjustable there is utility.

Carbs and jets are such a compromise that the complexity seems overkill.

Are you using an A/F gauge or a cheap datalogger like Innovate's stuff. I've used Innovate's stuff in past.
Click to expand...

Why wouldn't it be useful? Measures the same thing regardless. If anything it will make life a lot easier. AEM wideband UEGO so true wideband.
 
Ha, I was reading the carb section of the Virago service manual an it says right in it if you want to rejet, get the exhaust checked by a wide band AF sensor and save yourself misery.
 
Maritime said:
Ha, I was reading the carb section of the Virago service manual an it says right in it if you want to rejet, get the exhaust checked by a wide band AF sensor and save yourself misery.
Click to expand...

Lol! Time, money, frustration. Shit, I can reject for every season if I want to and it won't take much time. I welded in the bung, just have to make it pretty. I'm not keeping the gauge on the bike, just for tuning.
 
Yep, and that manual was published in like 1988. I think you'll be happy you put the bung in and are using it to tune. Got to be easier than plug chops and guess work.
 
Maritime said:
Yep, and that manual was published in like 1988. I think you'll be happy you put the bung in and are using it to tune. Got to be easier than plug chops and guess work.
Click to expand...

You just named why I hate carbs.nows it's as simple as screw it in, tune it, unscrew, and cap. Only drag is I had to mount it where it will be seen, there wasnt room otherwise. Oh well. I'm going to grind and file out the weld and make it look as pretty as I can.
 
Wideband o2 sensors and tuning is a huge topic that I hardly completely understand.

But that AEM gauge is more a pretty accessory than a true tuning tool.

Not saying you won't get lucky and it gets in the ballpark but so will old fashion tuning.


Watch the O2 sensor heater current draw on that small engine, too.

Good luck.
 
jcw said:
Wideband o2 sensors and tuning is a huge topic that I hardly completely understand.

But that AEM gauge is more a pretty accessory than a true tuning tool.

Not saying you won't get lucky and it gets in the ballpark but so will old fashion tuning.


Watch the O2 sensor heater current draw on that small engine, too.

Good luck.
Click to expand...

I have 100W available, can't see it needing that. Also getting me in the "ball park" is a lot better than guessing, but I disagree about is being only an accessory. While it isn't as good as a sniffer in a dyno, it's certainly better than nothing.
 
Take this for what its worth but here's a tuning question.

What a/f ratio are you tuning for? 14.7, 13.5, 12.0? Why?

What if you tune your particular engine to say 13.0 and its running hot and you have that roll off surge and the plugs are crispy lean?

Or you tune to 13.0 and your engine is boggy, exhaust is black and you pull the plugs and they are sooty black?

You still need to go through the process of tuning because an AF number is just that. A number. It is not necessarily a best power indicator, best driveability number.

Add to that the potential inaccuracy of the AEM and the finnicky fueling of carbs, and the utility of a simple AF meter decreases.


Ok. Just wanted to say that. I don't mean to be a dick. I'm sorry if it comes off that way. Ill be quiet now and watch this nice build progress.
 
jcw said:
Take this for what its worth but here's a tuning question.

What a/f ratio are you tuning for? 14.7, 13.5, 12.0? Why?

What if you tune your particular engine to say 13.0 and its running hot and you have that roll off surge and the plugs are crispy lean?

Or you tune to 13.0 and your engine is boggy, exhaust is black and you pull the plugs and they are sooty black?

You still need to go through the process of tuning because an AF number is just that. A number. It is not necessarily a best power indicator, best driveability number.

Add to that the potential inaccuracy of the AEM and the finnicky fueling of carbs, and the utility of a simple AF meter decreases.


Ok. Just wanted to say that. I don't mean to be a dick. I'm sorry if it comes off that way. Ill be quiet now and watch this nice build progress.
Click to expand...

Thaks for the input. You're absolutely right when you talk about tuning to what number. But, the way i see it, it will still have a little trial and error, but data points can be made. Once i feel im close as i can get i can log dyno time and need less time if im in the neighborhood vs way the fuck off. It isnt like im running a stock bike with a stock carb, i have no idea where anything is, and i need data to get a more complete picture. This gives me that to a degree.
 
When i tuned a couple EFI bikes with the innovate system you could log rpms against time, for WOT i tuned to quickest acceleration and skipped the dyno all together.
A/f ratios became a interesting side note. I used them to make sure I didn't go too lean.

For part throttle tuning, it was for best drive ability and smooth throttle pick up.


When you do tune the bike. Follow the recommended order for carb tuning. It is not all guess work. If you do it right, its not hard at all. And its a great skill to learn.
 
jcw said:
When i tuned a couple EFI bikes with the innovate system you could log rpms against time, for WOT i tuned to quickest acceleration and skipped the dyno all together.
A/f ratios became a interesting side note. I used them to make sure I didn't go too lean.

For part throttle tuning, it was for best drive ability and smooth throttle pick up.


When you do tune the bike. Follow the recommended order for carb tuning. It is not all guess work. If you do it right, its not hard at all. And its a great skill to learn.
Click to expand...

First of all, that sensor uses a whopping 10 watts. Secondly, obviously I am not a fan of traditional carb tuning or I wouldn't be putting an 02 sensor on my bike. Hey, you do It your way, i'll do It mine. I'll bet mine is faster, and more precise ;D
 
jag767 said:
First of all, that sensor uses a whopping 10 watts. Secondly, obviously I am not a fan of traditional carb tuning or I wouldn't be putting an 02 sensor on my bike. Hey, you do It your way, i'll do It mine. I'll bet mine is faster, and more precise ;D
Click to expand...
What does your 10 watts comment have to do with anything? An AF sensor produces it's own voltage, that's how they work. A 14.7:1 reading means your sensor is producing .5 volts.
 
irk miller said:
What does your 10 watts comment have to do with anything? An AF sensor produces it's own voltage, that's how they work. A 14.7:1 reading means your sensor is producing .5 volts.
Click to expand...

Read back, it was mentioned it will stress my charging system so I was debunking that.
 
Gotcha. Yeah, unless you have to wire the DRO to power, the unit uses none of the bike's power. And like you say, at 10 watts it's drawing like .73 amps at 14v.
 
I swore i wasnt going to add any more work to this bike: oh well that went out the fuckin window. I just fitted the t500 hub i had kicking around. Im gonna try to cheap out and use a cb77 from rim and spokes i got for cheap. Maybe I'll get lucky. Shit should stop on a dime and give me change.
 

Attachments

  • 20170301_115659.jpg
    20170301_115659.jpg
    1.8 MB · Views: 183
  • 20170301_115612.jpg
    20170301_115612.jpg
    1.1 MB · Views: 182
Man what a bitch to get that aligned. Still off by 1mm but I'll get it. Have to cut a small spacer then i can refinish it.

So the real reason for the harsh change of plans was i noticed you cant really engine brake this motor, so i am on the brakes a lot abd the 160mm hub wasnt enough for me. Im hoping this provides the additional stopping power im looking for.
 
stroker crazy said:
It gets better and better!

Crazy
Click to expand...

Lol. Started sanding the bitch down. I fucking hate refinishing aluminum, and this is the worst hub I ever had to make pretty. I'll have 10 hours in this fuckin thing before it's anything to talk about. I have about another hour with 220 still. The shape is all fucked up on these things, so i'm having to make it all symetrical, and get rid of the insane amount of lip on it. Then I still have the panel! Once the 220 is done though it goes a lot faster.
 
I got new shoes, wow they weren't cheap. I'ver never arched shoes before, please explain. Trying to tie everthing up by next friday, I have a photo session booked. And yes if it didn't look so Damn good sitting next to it I wouldn't have gone through the trouble of narrowing it to fit, which took a long time with no lathe. I had to take 3/8s out of the hub and almost an inch out of the panel. The bitch was every time I took some off I had to square my cut by hand with a file. Fml. It's still ever so slightly off, just add it to the list haha.
 
You must log in or register to reply here.

DTT Light or Dark

  • DTT Light
    • www.jadusmotorcycleparts.com
    www.lostapostle.ca/
    www.sparckmoto.com

    Spread the Love

    Back
    Top Bottom