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Christopher, really impressed with the output of the board, looks great!
Christopher_55934 wrote:
I'd be curious what AFR meter readings would look like. Hopefully the runs are repeatable enough to see what each change does for power and torque.
Is there a recorder for AFR? Imagine if you could overlay a graph of the AFR over the dyno! It would be great.
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Quote:
Is there a recorder for AFR? Imagine if you could overlay a graph of the AFR over the dyno! It would be great.
When you measure AFR, if throttle remains at WOT during measure - would it give the same AFR for the whole run or would it vary with RPM?
I like the idea of AFR for optimizing learning.
Another tool in the belt then an absolute I would think.
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GSF curve on the board makes the job really easy. More accurate too.

Was that run on the home made BE5? Sounds like it's still lean at the top. Bigger main jet. How is the bottom end? Graph looks like it might be ok.
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Molto Verboso
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Following along.. need to tune soon.

Thoughts about using the speed sensor input option for GSF?

Love the board solution. Awesome it works so well.

To float another idea... wonder if the right piezoelectric sensor/pickup in the right place would be a super simple solution. They can be used on acoustic instruments as pickups or drums to become 'triggers' - they pickup vibration rather than sound so wouldn't be so susceptible to unwanted noise. Dunno about their heat tolerance - but one one the exhaust pipe might be all you'd need.
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charlieman22 wrote:
Quote:
Is there a recorder for AFR? Imagine if you could overlay a graph of the AFR over the dyno! It would be great.
When you measure AFR, if throttle remains at WOT during measure - would it give the same AFR for the whole run or would it vary with RPM?
I like the idea of AFR for optimizing learning.
Another tool in the belt then an absolute I would think.
I use it as a tool, along with my temperature gauge. My ears and experience aren't tuned well enough to know what is going on from sound. It also lets me not have to pull my spark plug 20 times a ride and try and determine rich lean etc. I

The AFR meter isn't tied to anything directly, it's sniffing the exhaust gas. In the lower rpm of the run, if your running rich it might give you a 9:1 ratio. In the higher rpm if it's leaning out as the rpm goes up it will show that also.

I haven't figured out how to record the AFR with what I have beyond recording the screen. I like to mark the throttle positions 1/4 , 1/2, 3/4 etc. Then I find a flat spot and cruise in say second or third gear at a steady rpm at each throttle position. Then record what AFR I get, make any changes and try again. Really helps me with getting to know where I'm at, not good at tuning by ear.
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Edit - I realized that now that the input recording is so clean, I can change how I have the GSF software settings.
Mic filter setting altered to 1 from 3.
There is no longer any clean up at all.
Software simply identifies the line and you click done.

Pheas' - it would probably work! but with that said - I've posted instructions for how to build (using Christopher's notes) here:https://modernvespa.com/forum/topic171710

Note: this version would need a slight modification to one of the resistors (R3) if it was used on 12V instead of 4.5 volt.

Jack - I'll experiment with larger main today. I have small mains between 112 and 115 on the way.

AFR meter Christopher posted looks cool.
Might go on the xmas list.
Forum member supplied image with no explanatory text
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Little more on GSF.
Ran 115, 116, and 118 MJ.
All on the BE3 - to keep things simple.
No carb top - my method is to get close on main before popping top on - takes me about 2 points up in richness I think.
Note: would be interesting to run the AFR device with and without the top to confirm that.

Anyway - the SI is temporary - and I just wanted to see what it would output.
Below are two charts.
First is with normal settings.
Hard to choose between the jets.
Pretty consistent results all around.
Kinda boggy at 3K RPM (15mph in 3rd) when I first get on it.

The second chart is what happens with the same runs when I increase the drag coefficient. Jack - in all likelihood, my standard settings understate my HP a bit - but im not going to change them now just to see a bigger number as it would ruin the relative measures.
Normal settings: 115, 116, 118 MJ
Normal settings: 115, 116, 118 MJ
Just for fun - increase drag from wind 50% and I get this.
Just for fun - increase drag from wind 50% and I get this.
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Which you prefer, 115 or 118? They seem to be the same. Could be jet tolerance or just not showing up. Keep the one that feels better but 118 would be sensible.

The low bog is just when cold or all the time? Is just the pilot jet or needs the BE5. Did your home made BE5 not work out? You have a sound recording of the bog?

SC will be back on soon.

The increased drag does make a better curve. More like the power it should be too. Still want to see the packer raised that 0.3mm. Sure it will go better in the middle.
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Weather's been so hot here - dampened the enthusiasm a touch.
118 feels best - from a smoothness POV.

Bog is not a full hollow blown waaaoooooo.
Instead - there is just nothing there when I spin the throttle wide open at 15MPH in 3rd.
Is it the lifted cylinder/higher blow down?
Is it the SI carb?
Is it my jetting?
Suspect combo of lift and jetting.

This condition is worse with the 116 and likely worse yet with the 118.
It's best - though not great - with the 112.
For this reason - I shoved the BE3 in for the speed runs rather than homemade BE5 for the time being.
Here is a recording of the 112/BE3/52-120 idle.
Feels pretty thick at idle already to me.
https://youtu.be/j0eTmnfvo5M
Without proper set of idle jets and mains to experiment with - haven't really bothered to get to factory smooth through whole throttle range as much as I have focused on maxing out WOT for peak power.
I wanted to know what the SI would produce.

Don't think I'll bother messing with the packer until I am back on the Smart Carb.
This is still just a diversion to practice a little SI jetting - and get a read on SI Peak.
enthusiasm dampened but not extinguished by heat
enthusiasm dampened but not extinguished by heat
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Bog is not bad but can be improved. Put in the 118 and BE5 look alike. Keeping the 120 part on the pilot jet, reduce the small number until you like it.
Should be done by this point. Something like 42/120 would be a nice size to end up on. Then take it all off and change to SC.

Would have felt better low down (sub 3000) pre tune but probably no faster.
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The Smart Carb gang are sure taking their sweet time.
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VU
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Ginch - That caused a good chuckle.

Few jets appeared at my door in a box at 6:00 pm.
Honey - i'm not that hungry.
How about we catch a cocktail later?
I'll mix 'em.
You guys grab dinner now if everyone's hungry.

10 minutes later - I ran these.
This is with a slightly leaner pilot.
One of the things I learned previously - on SI's - don't underestimate the subtle effects of a pilot on the top end.
It may not be dominant - but it's there.

Christopher - wholly cow - that board is so much nicer to use.
Every run records.
There is no clean up. I just click the next button.
Thanks man.

Jack - decent guess from 5,437 miles away - tho of course you could actually be John from Arkansas and none of would be the wiser.
When I use the homemade BE5 - the 118 gets a bit too rich.
But the 116 has guts.
Your recipe was pretty damn close

Below are 4 runs using the lener pilot, the homemade BE5, and the 118/116 in comparison.
All measures taken using my standard settings - which may be a bit muted, but are consistent.
One interesting thing - I have seen both at 112 and when too rich - that dip you see in the blue line at peak.
One interesting thing - I have seen both at 112 and when too rich - that dip you see in the blue line at peak.
I cant get enough of this.  Just click "done" - no clean up at all.
I cant get enough of this. Just click "done" - no clean up at all.
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I just guess well. This Dyno is looking better at 116, so must be riding better. Everything slightly affects WOT running. Takes a few rounds to get correct even for a pro. 50/120 is probably still to big though. A video of ticking over and pulling away would confirm it.

I wouldn't be from Arkansas. Used to work in Texas for a few years but wouldn't be from there either. My hypothetical US location would be Florida, Atlantic coast, down the bottom. Not Miami, no offence.

Think I might be able to do GSF Dyno with a board. It's the editing bit that is the pain.
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Molto Verboso
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CM, you say that you run it with the carb top off. Is that with or without any kind of filter or bellmouth on top of the SI carb?
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Glad you're liking the board,


How about a set of graphs overlaying your previous graph with the be3 and this one with the be5. Looks like the power is up across the board with the be5 and smaller pilot. I like to see the entire curve not just WOT top numbers.
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Jack - agreed -it does feel better and there's a little room left in the pilot. Working with what I've got next one up would be 52/140.
I am using a vid app with GPS: https://www.hitcase.com/pages/vidometer.
I pull it in and edit video down to 21 seconds for every run.
I upload all the cut down videos to: https://convertio.co/files and change them to WAV files.
Then process those files with the GSF.
Takes a few minutes - but not so bad - and no guessing about which section of my recording is the right one.

Swa - no filter, no top, bell mouth - carved so I can change jets without removing (see pic). This allows quick swaps. I don't even get off the bike or remove my helmet - as tools and jets are in the side car sitting on the seat. I estimate a 1 point drop on the main when I put in the plug at the back of the box and the top of the box on. The missing tool for perfecting this would be an AFR meter to identify exactly the change of adding back the top and plugging the back of the box.

Christopher - power is up with this jetting. Below is the requested graph. Not sure if you mean the area on the graph around 5K rpm - or if you mean running the tests by spinning the throttle open more slowly? This graph shows WOT the entire time - but at different RPM's of course.

Though I keep noting it - I find myself frequently looking at the graph and thinking - oh - Im rich in the middle, or lean - then remembering - no - its WOT only that is being read the entire time...
Red is BE3 - Blue is BE~5 (homemade)
Red is BE3 - Blue is BE~5 (homemade)
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That there is some advanced stuff for these vintage Vespas . I still can't comprehend doing dyno graphs and outputs , I gotta read wayyyy back.
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You still have a pilot jet in the 40s? Think you had 42, 45 and 48 at one point.

How many mixture screw turns on the 50/120?
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My 40's stuff has all been drilled out when I was chasing trying to tune in the Polini.

Mixture screw was 2.5 turns on the 52-120.
I then tried same on 50-140
Then 55-160

Each time - was an effort to nock out the flat spot at hand off moving up in richness with what I have available.
I toyed with the mixture screw with the 55-160 by a half turn to make it 2 turns.
Flat spot remains with all of these.
55-160 comes right back down to idle when revved - so I am not wildly too rich even with that.

I also sorted my jets using a jet boring tool which I marked - sliding each jet on to see how far it would go.
I then put them in order - leanest at bottom of page and richest at top.
The numbers next to them are what is actually printed on the jet.

Posting a diagram below to show something I see frequently when experimenting.
I often find that I see a good top speed and feel like I must be with the right jet - when in fact I am too lean.
The graph picks this up - and it does it frequently.
The green line is a "115" jet.
Look how the peak moves to the right - giving a good top speed - but how you lose power at other RPM. Bad trade off.
Without the Dyno - this would be hard to spot - and I might see that top speed matching or bettering a richer jet - when in fact I am giving up usable power.
Something to keep an eye on if you do any Dyno runs yourself.
Low are lean - higher up on page you go is richer.  Marked sizes are written in the margin next to the jets.  Lots of miss marked jets...
Low are lean - higher up on page you go is richer. Marked sizes are written in the margin next to the jets. Lots of miss marked jets...
When you start to move to lean - you don't gain extra power - just move the power band to the right.  116 is the golden spot for this one.
When you start to move to lean - you don't gain extra power - just move the power band to the right. 116 is the golden spot for this one.
⚠️ Last edited by charlieman22 on UTC; edited 1 time
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There's nothing that says you can't take a recording at 1/4, 1/2, and 3/4 throttle to see how you're performing at each of those points. Just do those runs, too, and you can start to really see how your carb is set up.

For the AFM, I find it to be extremely useful for validating carb adjustments, testing mixture at fixed throttle position (the 1/4, 1/2, 3/4, WOT, again), and validating expected impact of a particular tuning change.

I don't run it all the time, either, just when I'm making jetting changes. The rest of the time, the bung just has a plug in it.
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If I'm looking at this correctly, you should set your cruising rpm about 8000 RPM. Then when you hit a hill and the motor slows you'll be coming into your peak power band.
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Quote:
There's nothing that says you can't take a recording at 1/4, 1/2, and 3/4 throttle
There are only so many hours a day I can get away with riding.
🙂
Quote:
For the AFM, I find it to be extremely useful for validating carb adjustments, testing mixture at fixed throttle position (the 1/4, 1/2, 3/4, WOT, again), and validating expected impact of a particular tuning change.

I don't run it all the time, either, just when I'm making jetting changes. The rest of the time, the bung just has a plug in it.
Thanks CM - that validates what I was considering - and answers un unasked question I was pondering - does one leave the sensor in all the time - or take it out to preserve it. That might alter where I mount it.

Your timing is good - pulled the trigger on an AFM tool like Christopher's today.
Now I just need to know what the heck the target ratio is supposed to be at various throttle positions.

Christopher - I can hardly keep up with motor temp, side car position, the lady putting makeup on in the lane next to me,... now this? 🙂. Actually - I think we naturally find our power band through ear when we ride - and im probably using what I am now measuring.

General: With jetting - my impression is - you have to have more than 1 data point to get things really dialed in to a magic level across the throttle range - tho I have gotten pretty decent at getting it to go BaWAAAAAA without the AFM - there is improvement to be had in my game. Kinda psyched about adding that tool
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In my case I was thinking of I want to run 60 mph reliably and not slow down for hills. The gearing shows I'll be turning 6000 rpm at 65 mph with a 23 tooth gear. I want to get my peak around 6000 rpm.


https://www.2strokeheads.com/index.php/site-map/articles/80-technical/111-air-fuel-ratio-definition-and-effect
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Christopher_55934 wrote:
In my case I was thinking of I want to run 60 mph reliably and not slow down for hills. The gearing shows I'll be turning 6000 rpm at 65 mph with a 23 tooth gear. I want to get my peak around 6000 rpm.


https://www.2strokeheads.com/index.php/site-map/articles/80-technical/111-air-fuel-ratio-definition-and-effect
Smart^
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Seems like you don't have the jets to get the SI idle finished. With a correct pilot jet the idle should never hang after a hot run but rev crisp and high on hardly any throttle. Snapping the throttle wide from tickover should rev high immediately and closing should not stall. Seems like the SI will not get this far but the SC will be back on soon.

My 221 has no tolerance for running weak at WOT. Will be fine on that score.

AFR meters are a useful tool but not to be trusted for fine tuning. Certainly good for roughing out jetting.
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CM, I'm shadowing you to a great extent, although my PX150 engine has a DR177 cylinder with enlarged transfers matched to the case, enlarged inlet, sporty 57mm crank, SIP Road 2 and a recently added 24/24e.

Current carb setup is 55/160, 120/BE3/112, 2mm feed from float chamber to MJ, and an OopsClunkThud bellmouth. I'm getting a 'cough' somewhere around 1/4 throttle, but it's lovely and crisp when I open it further. I think the cough is a lean condition, but hard to tell. Going to try a BE5 next to see it that improves (it was too lean) or makes worse (it was too rich). It seems a bit weird running such a small main, but I guess that a consequence of using the 120 AC and having the float chamber hole drilled out??

Not meaning to hijack your thread, but my observations might help
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charlieman22 wrote:
There are only so many hours a day I can get away with riding.
Oooh. I know this one... wait... is the answer 13?
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swa45 wrote:
CM, I'm shadowing you to a great extent, although my PX150 engine has a DR177 cylinder with enlarged transfers matched to the case, enlarged inlet, sporty 57mm crank, SIP Road 2 and a recently added 24/24e.

Current carb setup is 55/160, 120/BE3/112, 2mm feed from float chamber to MJ, and an OopsClunkThud bellmouth. I'm getting a 'cough' somewhere around 1/4 throttle, but it's lovely and crisp when I open it further. I think the cough is a lean condition, but hard to tell. Going to try a BE5 next to see it that improves (it was too lean) or makes worse (it was too rich). It seems a bit weird running such a small main, but I guess that a consequence of using the 120 AC and having the float chamber hole drilled out??

Not meaning to hijack your thread, but my observations might help
Lean cough is like miss firing without the popping. Rich cough is like the choke is still a bit out. Probably doesnt help but I know what I mean.

Does sound the same issue as CM had. BE5 will fix it. Main jet might go down one size after that. 55/160 will be too rich and lean. 48/120 will be better but might still need tweeking.
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charlieman22 wrote:
My 40's stuff has all been drilled out when I was chasing trying to tune in the Polini.

Mixture screw was 2.5 turns on the 52-120.
I then tried same on 50-140
Then 55-160

Each time - was an effort to nock out the flat spot at hand off moving up in richness with what I have available.
I toyed with the mixture screw with the 55-160 by a half turn to make it 2 turns.
Flat spot remains with all of these.
55-160 comes right back down to idle when revved - so I am not wildly too rich even with that.

I also sorted my jets using a jet boring tool which I marked - sliding each jet on to see how far it would go.
I then put them in order - leanest at bottom of page and richest at top.
The numbers next to them are what is actually printed on the jet.

Posting a diagram below to show something I see frequently when experimenting.
I often find that I see a good top speed and feel like I must be with the right jet - when in fact I am too lean.
The graph picks this up - and it does it frequently.
The green line is a "115" jet.
Look how the peak moves to the right - giving a good top speed - but how you lose power at other RPM. Bad trade off.
Without the Dyno - this would be hard to spot - and I might see that top speed matching or bettering a richer jet - when in fact I am giving up usable power.
Something to keep an eye on if you do any Dyno runs yourself.
Is the jet marked 118 the jet that was on the rich side earlier and you had a dip in power? Is the 116 that is marked fast the 116 that's seems to work best with the be5? If so you have two more jets in the middle to try, I was going to suggest you get a bit and custom drill a few 117 jets, it It seems you may already have them.

What is The metal rod your using for measuring may want to get one myself.
@chandlerman avatar
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Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 79 P200E, 66 Lammy S3
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Lucky
@chandlerman avatar
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 79 P200E, 66 Lammy S3
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77 Days Since Last Explosion
UTC quote
Ginch wrote:
charlieman22 wrote:
There are only so many hours a day I can get away with riding.
Oooh. I know this one... wait... is the answer 13?
Nope, it's 25 Razz emoticon

CM, I run the Koso AFM. I put a couple of neodymium magnets on the mounting bracket and can stick it to the frame wherever I need it.

External inline image provided by member with no explanatory text

It's a great safety check that nothing has changed unexpectedly before you push a motor. I could have saved myself a dead cylinder if I'd had it after I accidentally put in a too small main, then went to do a WOT dyno run.

With a 4t motor, you can run an AFR full-time, I guess, but the dirtier exhaust of the 2t will eventually cause the sensor to fail, so I only use it as-necessary.

Christopher, I like your thinking about aligning desired cruising speed to the power band. I kind've skirted that problem a little bit by historically going for builds with wide power bands, but I'm also paying the price a little with my PM Tuning exhaust, because I didn't realize how much around-town riding I do where I'm alike 250 RPM's below where I would want to be in 4th gear, meaning lots of downshifting (and annoying everyone around me) for anything but holding steady at 30-35 MPH.
OP
@charlieman22 avatar
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Nedminder
62 VBB1T Round Tail W/ leaner sidecar
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Location: california
 
Nedminder
@charlieman22 avatar
62 VBB1T Round Tail W/ leaner sidecar
Joined: UTC
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Quote:
CM, I'm shadowing you to a great extent, although my PX150 engine has a DR177 cylinder with enlarged transfers matched to the case, enlarged inlet, sporty 57mm crank, SIP Road 2 and a recently added 24/24e.
The flat spot at hand off between idle and main is not uncommon on a tuned engine with an SI.
Would be interesting for us to sleigh.
There are only so many levers to mess with.
If we can identify why it's occurring - we should be able to address with one means or another.
May have another go at it today with what I have on the bench - just to see if I can nock it out.
As Jack notes - I'm in need of some jets I may not have to get full smooth tuning... We'll see.

Chandlerman. - thanks for explanation. I had wondered about the whole 2 stroke and oxygen sensor deal. I will make mine so I can plug it when not in use.

Christopher - the metal rod is from a set of jet "reamers" that I bought from Scooter Center. It was about half this amazon price: https://www.amazon.com/JET-REAMER-dune-buggy-baja/dp/B003LIUZEO
OP
@charlieman22 avatar
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Nedminder
62 VBB1T Round Tail W/ leaner sidecar
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Nedminder
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UTC quote
Had a few minutes with the scoot t'day so looked into that flat spot between idle and main hand off - 1/3 throttle.

Took two steps to see if I could nock out.
Assumption - its lean there and gasping - until the main comes on.
This because - if I put it on the stand and look down the throat to the carb and slowly open the throttle - I can see that it is not "choking" on the first drops of main jet - but rather revving.
Swa - you might take a similar look see.
If it is too rich - I would expect it to choke on the first drops that you see come from the main jet.

I took the richest jet I own - 55/100 (1.8 ratio) and plugged it in - expecting it to be way to fat and smokey. It was neither.
Rather than getting boggy - the throttle got more responsive down low.

This didn't quite nock out the baBWAAAA that I was getting when I twisted the throttle quickly - tho it improved it. So I then put in a BE4 - which should enriched the middle - and it again improved the issue.

Net/net - I think it was starving at the top of the idle jet range as it approached 1/3 open - and taking off when the main hit - creating the "flat spot" defined by not enough fuel being provided by the idle on one side and the moment the fuel from the main hit on the other.[/b]
Bottom THROTTLE much better with richer idle jet.  HP a bit off in mid RPM - likely related to BE4.  Perhaps the BE5 and a richer yet idle or adjustment of the idle screw would deliver.  These things hard to tune full range-even if you know what you want
Bottom THROTTLE much better with richer idle jet. HP a bit off in mid RPM - likely related to BE4. Perhaps the BE5 and a richer yet idle or adjustment of the idle screw would deliver. These things hard to tune full range-even if you know what you want
@ginch avatar
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Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and '66 Blue Badge Smallframe
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Location: Victoria, Australia
 
Veni, Vidi, Posti
@ginch avatar
74 Super, 75 Super, PX project, LML off-roader and '66 Blue Badge Smallframe
Joined: UTC
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Location: Victoria, Australia
UTC quote
Very interesting re the atomisation/lack of/droplet size giving an indication of rich or lean. That is what you're saying, right?

Wonder if it would be visible in a video?
@chandlerman avatar
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Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 79 P200E, 66 Lammy S3
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Lucky
@chandlerman avatar
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 79 P200E, 66 Lammy S3
Joined: UTC
Posts: 9976
Location: Nashville

77 Days Since Last Explosion
UTC quote
Ginch wrote:
Wonder if it would be visible in a video?
I saw something similar with my VBB last time I had time to mess with it, and I think that it would be pretty obvious in a video. If I get a chance, I'll try to sneak out to the garage and shoot one.
OP
@charlieman22 avatar
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Nedminder
62 VBB1T Round Tail W/ leaner sidecar
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Nedminder
@charlieman22 avatar
62 VBB1T Round Tail W/ leaner sidecar
Joined: UTC
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UTC quote
Quote:
Each time - was an effort to nock out the flat spot at hand off moving up in richness with what I have available.
KNOCK. KNOCK. KNOCK.
Think of my spelling like lifting your cylinder.
Is it faster? Sure.
Will it pull down low - not so much.
Trade offs.
What can I say.
Quote:
Wonder if it would be visible in a video?
Gauntlet thrown.
(note - read his signature...)
Quote:
I'll try to sneak out to the garage and shoot one.
I'l take a shot as well.
Easy to see with the eye.
Perhaps will translate to vid.
UTC

Molto Verboso
One or two fun scoots....nothing too precious
Joined: UTC
Posts: 1983
Location: UK (South East)
 
Molto Verboso
One or two fun scoots....nothing too precious
Joined: UTC
Posts: 1983
Location: UK (South East)
UTC quote
CM, you've ended up with pretty much T5 - 24/24G jetting. Probably not a coincidence that it runs well. the T5 used a 110 MJ with the 120/BE4 stack, and a 50/100 pilot. Most people just change the MJ to 122-128 when upgrading to the Malossi 172, depending on the level of tune, so you may need to go up a bit for a BGM 187.
OP
@charlieman22 avatar
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Nedminder
62 VBB1T Round Tail W/ leaner sidecar
Joined: UTC
Posts: 4109
Location: california
 
Nedminder
@charlieman22 avatar
62 VBB1T Round Tail W/ leaner sidecar
Joined: UTC
Posts: 4109
Location: california
UTC quote
Quote:
CM, you've ended up with pretty much T5 - 24/24G jetting. Probably not a coincidence that it runs well. the T5 used a 110 MJ with the 120/BE4 stack, and a 50/100 pilot. Most people just change the MJ to 122-128 when upgrading to the Malossi 172, depending on the level of tune, so you may need to go up a bit for a BGM 187.
Oh that made me laugh.
Its my Christoper Columbus moment.
I've discovered India!
Wait.
America!
Coming at all this from 50K feet, it's all new to me.
Didn't know that's what T5 used. Successfully (re)discovered the wheel.
But the takeaway for me is this:
0-1/3 throttle: idle jet 80%, mixture screw 10%, atomizer 10%
1/3 - 1/2 throttle: idle jet 5%, atomizer 10%, main jet 85%
1/3 to full throttle: idle jet 5%, atomizer 5%, main jet 90%

Did I make those up with no hard data behind them?
Of course I did - I don't even own an air fuel meter.
But I'm getting there - and its not miles off.

I mention it only because - using above - I feel I can tackle a given issue at the top, middle, or bottom with this. As many of us struggle with a flat spot at hand off - I see both the atomizer and the idle jet potentially in play.

Swa - will be interested to see what Knocks out your issue in the end.
Will be fun to apply an AF meter to mine to get some data as well.
-CM
UTC

Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
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Posts: 4605
Location: London UK
 
Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
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Location: London UK
UTC quote
Main jet has been too small all along. Never seen a 55/100 and BE4 not be rich enough low down.
Back to the start, what size of main jet gives WOT flood out?
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