 Re: single carb for parallel twins
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Joined: May 2010
Posts: 5,720
Check Pants
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Check Pants
Joined: May 2010
Posts: 5,720 |
With the timing staggered as is our lot with 270 degree engines, is the fuel mix velocity the same to each cylinder? Seems that a 360 engine would naturally be easier to regulate a same same dose of velocity, fuel and air. Have you attached your set up to a Bonnie or a Thrux. yet? I totally agree with Ken, you need a set of headers with bungs, so you can attach a on board, ride along sensor, the dyno would only be needed to authenticate actual output, once you had the set up dialed in.
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Re: single carb for parallel twins
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Joined: Sep 2010
Posts: 8,393 Likes: 1
Second Wind
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OP
Second Wind
Joined: Sep 2010
Posts: 8,393 Likes: 1 |
Quote:
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Yea thats a thought, However I am already faster than it was with the freak mod, and now its faster than it was with the S&S.
How do you know this? "Seat of your pants" is very deceptive for mods where you gain or lose small amounts.
I can't remember how many times I have modified something, gone for a ride and think, "wow this is much better", then go for a dyno run and have lost some power. Perception is a funny old thing.
With the mods you are doing, you do need to carry out a run on the same dyno after each mod, otherwise you don't know where you are or where you're going.
This is the best question so far, and thanks for the input.
What I have been doing is controlled timed runs on a certain stretch of road that has very accurate measurements on it. So its a stop watch and a complicated marker to marker, throttle position, speedometer, and note book thing.
I am finding it difficult to find a dyno to run on because most of the fellows here who have them will only run harleys on them or sport bikes. Weird huh? Thats the problem that I am facing right now. I do want to get some dyno results and I will eventually. I haven't found the guy who has one that will work with me yet. I cant afford to buy one or I would.
I have no faith in human perfectability. I think that human exertion will have no appreciable effect upon humanity. Man is now only more active - not more happy - nor more wise, than he was 6000 years ago.
Edgar Allan Poe
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Re: single carb for parallel twins
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Joined: Sep 2010
Posts: 8,393 Likes: 1
Second Wind
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OP
Second Wind
Joined: Sep 2010
Posts: 8,393 Likes: 1 |
Quote:
, you need a set of headers with bungs, so you can attach a on board, ride along sensor, the dyno would only be needed to authenticate actual output, once you had the set up dialed in.
Thats an excellent idea. That would help me to have very accurate fuel mixture reading through out the throttle range. I am going to look into that and see what would take.
No I have not tried it on anything other than the America 790 as of yet I want to get it right there first and then go on to other applications.
I will also try to get a fuel efficiency improvement tunning as well for those who are more interested in that as well.
For now I still have lots of work to do to get this right. Thanks for all the questions and input, everybody, even the scepticts. It helps to not be the only one thinking. Because its easy to over look something or over think something and miss a detail.
I have no faith in human perfectability. I think that human exertion will have no appreciable effect upon humanity. Man is now only more active - not more happy - nor more wise, than he was 6000 years ago.
Edgar Allan Poe
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Re: single carb for parallel twins
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Joined: Feb 2007
Posts: 23,220 Likes: 61
Fe Butt
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Fe Butt
Joined: Feb 2007
Posts: 23,220 Likes: 61 |
I think the timed run is as good as you can get for seat of the pants as long as you do what you say you are doing like record throttle positions, temp, etc... but I still think a dyno would be your best gauge if you can get one to use. Most guys I know with them will run anything as long as you have the cash to pay them.
When my friend Vic ran my SM he was amazed at the TQ and HP I got out of a stock 790. He normally runs HD and S&S HD knock-offs.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
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Re: single carb for parallel twins
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Joined: Feb 2008
Posts: 2,671 Likes: 15
Loquacious
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Loquacious
Joined: Feb 2008
Posts: 2,671 Likes: 15 |
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I think the timed run is as good as you can get for seat of the pants...
That is true for WOT runs, but not so much for things such as driveability, fuel economy, idle quality, cruise, throttle & fuel circuit transitions, & other things that really matter in the real world.
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Re: single carb for parallel twins
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Joined: Sep 2010
Posts: 8,393 Likes: 1
Second Wind
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OP
Second Wind
Joined: Sep 2010
Posts: 8,393 Likes: 1 |
No, you can make runs at certain throttle position and accelerate from one throttle position to another from one marker to another, and decelerate as well.
Yes its harder than a dyno but what else can I do right now?
I have no faith in human perfectability. I think that human exertion will have no appreciable effect upon humanity. Man is now only more active - not more happy - nor more wise, than he was 6000 years ago.
Edgar Allan Poe
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Re: single carb for parallel twins
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Joined: Sep 2007
Posts: 198 Likes: 1
Adjunct
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Adjunct
Joined: Sep 2007
Posts: 198 Likes: 1 |
With timed runs it's crucial that your take off is identical on each run. If you open the throttle at a slightly different rate from one run to the next, your figures will be out and might make you think you're doing better or worse than you really are. It's really hard to be accurate enough for subtle differences, but I wish you the best of luck with it as that's the only option available to you right now. 
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Re: single carb for parallel twins
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Joined: Feb 2008
Posts: 2,671 Likes: 15
Loquacious
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Loquacious
Joined: Feb 2008
Posts: 2,671 Likes: 15 |
Quote:
No, you can make runs at certain throttle position and accelerate from one throttle position to another from one marker to another, and decelerate as well.
Yes its harder than a dyno but what else can I do right now?
Get a wide-band AFM for starters.
Why you would engage in pioneering development work without that, in this day & age, is beyond me.
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Re: single carb for parallel twins
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Joined: Sep 2010
Posts: 8,393 Likes: 1
Second Wind
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OP
Second Wind
Joined: Sep 2010
Posts: 8,393 Likes: 1 |
Quote:
Why you would engage in pioneering development work without that, in this day & age, is beyond me.
Because you do not understand does not make you wrong, or right. It only means you do not understand, and thats ok. The knowing is the most important part of the doing, but the doing does not happen just because of the knowing. On this project it is the same, The knowing and the doing are equal.
I have no faith in human perfectability. I think that human exertion will have no appreciable effect upon humanity. Man is now only more active - not more happy - nor more wise, than he was 6000 years ago.
Edgar Allan Poe
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Re: single carb for parallel twins
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Joined: Feb 2008
Posts: 2,671 Likes: 15
Loquacious
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Loquacious
Joined: Feb 2008
Posts: 2,671 Likes: 15 |
Quote:
...The knowing and the doing are equal...
Eh?  ...
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Re: single carb for parallel twins
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Joined: Apr 2008
Posts: 3,937
Loquacious
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Loquacious
Joined: Apr 2008
Posts: 3,937 |
Quote:
Quote:
...The knowing and the doing are equal...
Eh? ...
Ancient Chinese Proverb.
And you may see me tonight
With an illegal smile
J. Prine
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Re: single carb for parallel twins
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Joined: Sep 2010
Posts: 8,393 Likes: 1
Second Wind
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OP
Second Wind
Joined: Sep 2010
Posts: 8,393 Likes: 1 |
I have no faith in human perfectability. I think that human exertion will have no appreciable effect upon humanity. Man is now only more active - not more happy - nor more wise, than he was 6000 years ago.
Edgar Allan Poe
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Re: single carb for parallel twins
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Joined: Jan 2009
Posts: 123
Adjunct
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Adjunct
Joined: Jan 2009
Posts: 123 |
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Re: single carb for parallel twins
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Joined: Sep 2010
Posts: 8,393 Likes: 1
Second Wind
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OP
Second Wind
Joined: Sep 2010
Posts: 8,393 Likes: 1 |
I have been too busy to mess with it much. I am running it on my bike now and prefer it to the two carb set up.
I was working on a way to shorten the intake manifold, but have been too consumed by working on customer bikes to do anymore testing. All I need is a dyno run to have some paper results to post.
About 20,000 miles of running it on mine has me personally satisfied with the results.
I have no faith in human perfectability. I think that human exertion will have no appreciable effect upon humanity. Man is now only more active - not more happy - nor more wise, than he was 6000 years ago.
Edgar Allan Poe
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Re: single carb for parallel twins
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Joined: Aug 2009
Posts: 558
Adjunct
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Adjunct
Joined: Aug 2009
Posts: 558 |
Man, has anyone told you that you need a dyno?
Yes, that was a joke. Lots of doubters in this thread but I think it's bad ass. Keep working!
2008 Speedy, AI removed, DIY airbox destruction with K&N filters, spectres, re-jetted and "custom" rattle can paint job.
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Re: single carb for parallel twins
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Joined: Jan 2005
Posts: 11,126 Likes: 13
Should be Riding
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Should be Riding
Joined: Jan 2005
Posts: 11,126 Likes: 13 |
Quote:
...About 20,000 miles of running it on mine has me personally satisfied with the results.
since March 11, 2012?  
Blowing gravel off rural roads
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Re: single carb for parallel twins
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Joined: Sep 2010
Posts: 8,393 Likes: 1
Second Wind
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OP
Second Wind
Joined: Sep 2010
Posts: 8,393 Likes: 1 |
Wow, now that ya mentioned it thats a lot of miles. Nearly nine months and didnt much consider how many mile that mounts up to.
I have no faith in human perfectability. I think that human exertion will have no appreciable effect upon humanity. Man is now only more active - not more happy - nor more wise, than he was 6000 years ago.
Edgar Allan Poe
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Re: single carb for parallel twins
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Joined: Sep 2010
Posts: 8,393 Likes: 1
Second Wind
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OP
Second Wind
Joined: Sep 2010
Posts: 8,393 Likes: 1 |
I rode an America the other day rejetted drilled box and custom exhaust. No comparison at all can be made to the way Matilda runs.
I have no faith in human perfectability. I think that human exertion will have no appreciable effect upon humanity. Man is now only more active - not more happy - nor more wise, than he was 6000 years ago.
Edgar Allan Poe
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