Author Topic: carb jetting with tecnigas pipe and Uni pod airfilter  (Read 6386 times)

chaz35

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carb jetting with tecnigas pipe and Uni pod airfilter
« on: April 10, 2015, 03:01:22 AM »
I installed a Uni pod air filter and re-jetted carb with 38 idle jet and 105 main jet.  Runs really nice, but could probably go to larger idle jet and main, especially when weather cools off this fall, but that's a long way off.  Next I will try 108 main, my largest main jet.

Took awhile to get it tuned, was pretty sensitive to jetting with pod filter, was hard to start, couldn't tell if rich or lean.  I bought after market Keihin 38 idle jet from jets-r-us, don't know why, but this idle jet will not work.  I need to throw it away, but keep messing with it, wasting my time, trying to figure out why it doesn't work.  I have OEM Keihin 35 and 38 idle jets that work fine, but with this aftermarket 38 idle jet installed the engine will not run.  The after market main jets work great and save some $'s, but this aftermarket idle jet wasted a lot of my time.

Previously, with the air box installed, I disconnected the tube from the intake under the plastic body panel and could easily choke the air box for easier starting.  With the pod air filter it's harder to choke, so I ended up wrapping it with a plastic bag to choke it.  Works great, so I now carry a plastic bag in the box.  Another trick I saw on a Genuine scooter make ready vid was to use a vet syringe to pull a vacuum on the fuel auto petcock, works great, and beats sucking on the vacuum line with your mouth.  Every time you change a jet you have to recharge the carb bowl with gas, using the syringe makes it easy. 

My next project was to tune the CVT.  Up to now it was OK, seemed to work pretty well when I first got the scooter.  As I learned more and rode it more I realized it likely needed lighter rollers to stay in lower gear longer, and probably needed stronger torque spring to return it to lower gear when the scooter gets slowed down going up a hill, especially with a head wind.  With the new pod air filter and larger carb jets the engine sort of came to the CVT and CVT is behaving a lot better.  Just seems like the engine is making more torque, accelerates faster, pulls harder, maybe a little faster, but not much faster, but will maintain speed better going up a hill or into a head wind.  I am very pleased.

I was concerned about the additional noise, but seems acceptable.  I had a neighbor tell me scooter wasn't that loud, definitely noticeable but not offensive.  Also, I don't feel like I need ear plugs, so not that loud to me especially with helmet on.  The engine always sounded cool with the pipe, but now is even better.  Accelerating hard away from a stop sign engine sounds mean, once you are at speed, it has a very pleasing tone as you give it more gas or let off, you can really control the volume, sound, and tone.  Music to me.

Cheers





1st and 2nd usually have an unfair advantage.  3rd is usually the best, can learn the most from.  paraphrased from Don Quixote, over 400 years ago, still true today

Triesandluth

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Re: carb jetting with tecnigas pipe and Uni pod airfilter
« Reply #1 on: April 10, 2015, 07:18:39 PM »
Thanks for the info!  Definitely going to use it to my advantage.  Not sure when I'm going to stray from my airbox and take the plunge into crazy air flow.  Maybe with the 19mm carb and a new bbk.  I'll probably let it be as of now. 
Are you still using a stock variator?  I "upgraded" to a cheap "racing" variator to avoid the continuous breaking of the plastic slide clips with the stock.  It really helped with takeoff and keeps the rpms lower at high cruising speeds.  It took a bit of trial and error to dial it in, ran fine for a while,  but recently has gotten buggy.  Seems like it came defective,  wore out quickly,  or all my tinkering around had caused it to sit loose on the boss drive. It now has a very wicked shift at about 25 mph speedometer.  Sounds kinda cool,  like I intentionally shift it,  but can really get the performance if  coming around a corner into a long hill.  Puts me right below the power band and takes a sec to get back to it. 
That reminds me,  I need to get looking for a replacement asap. 
Almost...at...speed...limit... Aww, brake lights..

chaz35

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Re: carb jetting with tecnigas pipe and Uni pod airfilter
« Reply #2 on: April 12, 2015, 02:16:08 AM »
I have never opened the CVT, so don't know if variator is stock or not.  I think someone did something to it, cause one of the side cover bolts was missing, the one in front that's hard to get to behind the plastic.  After I get the carb sorted out with the air pod, I will probably just run it the way it is for awhile.  I have People 50 2T I got pipe for I want to work on next.

I am pretty happy how mine runs once I get it started, but it definitely has issues starting, especially 1st time in the morning.  I think just needs larger idle jet, is very sensitive to air temp, will not start until warms up a little, then will start up.  May be problem with auto bystarter, but don't think so, with stock air box it starts easy, with the pod air filter always hard to start.  I guess I will order some larger idle jets and see if that helps.

Seems like main jet at 105 is probably rich enough for warmer weather, but low end seems lean.  I might try raising the needle.  I bought some spacers and e clips, but don't know it they are the right ones.  I think the plastic retainer for the needle is easy to break, so hesitate to mess with it, don't want to buy another carb just because I broke a $1 or less part.

Rode some today, running strong, speedo going past 50mph almost 1/2" from time to time depending on if going down hill or which way wind is blowing.  Staying with traffic and passing some cagers on 40 and 45mph roads, most cagers driving 5 to 10mph over speed limit, so I think I am doing 50 plus from time to time.  Cheers

1st and 2nd usually have an unfair advantage.  3rd is usually the best, can learn the most from.  paraphrased from Don Quixote, over 400 years ago, still true today

Triesandluth

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Re: carb jetting with tecnigas pipe and Uni pod airfilter
« Reply #3 on: April 12, 2015, 11:15:03 PM »
If it's not broke,  don't fix it,  right? 
Odd,  I have the opposite problem with my starting.  Starts rather easily right off,  but once nice and warm when I restart it I have issues.  It will fire up with throttle,  then I have to feather the throttle to keep it from dying until I ride it for just a few seconds,  then it's fine. I've grown used to it and will hopefully acquire the jets to put in the 19 Mm carb, so I'll just deal with it. 
Sounds like you've got great speed.  Mine is very similar.  Often keeping with traffic on the 45 labeled roads,  sometimes better,  conditions involved.  Definitely have the speedo past the numbers more often than not.  Usually on the mph/kmh marker.  And mine is just the cheap cast iron 70 cylinder. I believe that the windscreen I added helps more than I expected though.  That thing is great!
Almost...at...speed...limit... Aww, brake lights..

chaz35

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Re: carb jetting with tecnigas pipe and Uni pod airfilter
« Reply #4 on: April 13, 2015, 02:32:15 AM »
Yes, have read windscreen helps with top speed.  What brand do you have?
1st and 2nd usually have an unfair advantage.  3rd is usually the best, can learn the most from.  paraphrased from Don Quixote, over 400 years ago, still true today

Triesandluth

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Re: carb jetting with tecnigas pipe and Uni pod airfilter
« Reply #5 on: April 14, 2015, 07:31:50 AM »
I got a cheap universal one from scootdawgs??  I think.  It didn't just mount up though.  It is intended to mount at the mirrors but the instrument cluster plastic and such doesn't allow for it.  I ended up mounting it differently.  If you're interested I can show some pics of what I had to do.  It isn't the cleanest job,  but after putting it on then riding without I found the pros to outweigh the cons.
Almost...at...speed...limit... Aww, brake lights..

0BARK4322

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Re: carb jetting with tecnigas pipe and Uni pod airfilter
« Reply #6 on: April 22, 2015, 08:25:19 AM »
get the slipstreamer windshield, it's a perfect fit for the 9's
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Scootsuper9

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Re: carb jetting with tecnigas pipe and Uni pod airfilter
« Reply #7 on: May 18, 2015, 12:09:02 PM »
Ya speaking of warm up, sometimes my idle gets a little shifty. There's times where I  idle at about 1200!rpms and theres other times sometimes after a cruise that it'll idle at about 3500 which seems strange. Any ideas why?

demeter

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Re: carb jetting with tecnigas pipe and Uni pod airfilter
« Reply #8 on: May 19, 2015, 03:13:26 AM »
Ya speaking of warm up, sometimes my idle gets a little shifty. There's times where I  idle at about 1200!rpms and theres other times sometimes after a cruise that it'll idle at about 3500 which seems strange. Any ideas why?

Enricher coming on and going off maybe.
2010 Like 50 2T (Malossi 70cc BBK, Tecnigas Next-R, Blue Polini Torque Spring, Yellow Clutch Springs, 5.5g Sliders, Stock Carb: 95 MJ, Stock Airbox Drilled, PIAA GT-X Headlight, Kolite 5630 Running Lights, 140/70-12 Rear Tire)

Scootsuper9

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Re: carb jetting with tecnigas pipe and Uni pod airfilter
« Reply #9 on: May 19, 2015, 11:03:11 AM »
Sorry not big on carb terminogy or anything but you are referring to the choke right? I got the dellorto phbg -19 mm with the manual choke. I think my issue is probably the throttle cable. I think it needs a little modification to seat perfect but no idea.

Triesandluth

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Re: carb jetting with tecnigas pipe and Uni pod airfilter
« Reply #10 on: May 19, 2015, 12:39:22 PM »
Sorry not big on carb terminogy or anything but you are referring to the choke right? I got the dellorto phbg -19 mm with the manual choke. I think my issue is probably the throttle cable. I think it needs a little modification to seat perfect but no idea.
My stock keihin (sp????) carb does the same idle thing.  High after running,  but will calm itself. 
How do you like the dellorto carb? Noticeable performance increase?   I have a arreche carb that I've attempted to put on,  but found that the bowl seal is leaking and the needle was too rich.  Got to get all rebuild kit for it. 
Almost...at...speed...limit... Aww, brake lights..

Triesandluth

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Re: carb jetting with tecnigas pipe and Uni pod airfilter
« Reply #11 on: May 19, 2015, 12:50:57 PM »
Ya speaking of warm up, sometimes my idle gets a little shifty. There's times where I  idle at about 1200!rpms and theres other times sometimes after a cruise that it'll idle at about 3500 which seems strange. Any ideas why?
Checkout this.  http://www.2strokeheads.com/Carb_Tuning.htm
At the bottom it mentions hanging rpms and idle jets being too small.  I may have found my issue,  at least!
Almost...at...speed...limit... Aww, brake lights..

Scootsuper9

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Re: carb jetting with tecnigas pipe and Uni pod airfilter
« Reply #12 on: May 19, 2015, 01:07:33 PM »
Dellorto, other than my 70cc kit is the best performance upgrade i made. Love the manual choke n it hauls.

0BARK4322

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Re: carb jetting with tecnigas pipe and Uni pod airfilter
« Reply #13 on: May 27, 2015, 08:44:53 AM »
Checkout this.  http://www.2strokeheads.com/Carb_Tuning.htm
At the bottom it mentions hanging rpms and idle jets being too small.  I may have found my issue,  at least!
Did you try it out
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Scootsuper9

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Re: carb jetting with tecnigas pipe and Uni pod airfilter
« Reply #14 on: May 27, 2015, 11:15:58 AM »
I still have to dial in my precise range of jets, right now runnin a little rich about 2 jets off on the main. I'll get to that n get back to you on the idle, but the 1200 rpm was a great advancement for me

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