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Stella 2T 150, Honda C70
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I'm wondering what other people are getting for fuel economy with their BGM177 kit. SLUK claims they got about 4L/100km or about 60mpg.
I'm only getting about 30 tops. My jetting seems pretty close to spot on but I'm wondering what else could have a major impact on fuel consumption. Would switching from a 20/20 to a 24/24 help? I'm assuming it would breathe better which could lead to more efficient combustion.

Anything else I'm missing?

Hal
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parallelogramerist
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parallelogramerist
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UTC quote
Depending upon just hard hard you twist the throttle will have a huge impact on your fuel economy. I've gotten as low as 30mpg (yeah, 60 miles on one tank), and as high as 90mpg for a tank as well. This was all on a stock P200.
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Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
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Jet Eye Master
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UTC quote
This is controversial; if you're jetting is too lean it will use more fuel. Because, as wdc just said, you are spending more time at higher throttle to make it go.
Too rich obviously uses more too. So, that leaves optimal jetting (and timing) as the most efficient. Which is really hard to find, when on a non stock set up.
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Ossessionato
2007 Stella 225
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2007 Stella 225
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UTC quote
What speed were they cruising at when they got 60 mpg? What speed are you cruising at when you get 30 mpg? I can cut my fuel economy in half by cruising at 60-65mph vs 30 -35 mph.
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2007 Stella 225
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UTC quote
Jack221 wrote:
This is controversial; if you're jetting is too lean it will use more fuel. Because, as wdc just said, you are spending more time at higher throttle to make it go.
Too rich obviously uses more too. So, that leaves optimal jetting (and timing) as the most efficient. Which is really hard to find, when on a non stock set up.
Have you ever tried adding a degree or two if advance?
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These are all really good suggestions. I do think i'm still running a little lean with the 125MJ. I am just struggling to find 126-128 MJs to experiment with.

I also think I still may be a little lean on the idle jet but finding a 50/140 is proving to be a challenge.

I may start with a little shift in the timing, I've been thinking about that myself.

H
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2007 Stella 225
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I ordered more jets but I am completely baffled now. Scooter runs great with a 125. It runs passable with a 128. Putting in this new 126 that I bought and it runs like crap. The one thing I notice is that the tip of the 126 seems a little more truncated than the 125. I dont' have a needle set that can truly measure 1.25, 1.26, 1.27, etc. mm bores. Is it possible I just got crappy jets? One point difference in jetting shouldnt make a difference this huge.

h
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parallelogramerist
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parallelogramerist
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whereshaldo wrote:
I ordered more jets but I am completely baffled now. Scooter runs great with a 125. It runs passable with a 128. Putting in this new 126 that I bought and it runs like crap. The one thing I notice is that the tip of the 126 seems a little more truncated than the 125. I dont' have a needle set that can truly measure 1.25, 1.26, 1.27, etc. mm bores. Is it possible I just got crappy jets? One point difference in jetting shouldnt make a difference this huge.

h
SIP jets have different sized orifices than genuine Dellorto jets. So a 125 jet from one manufacturer could be a completely different from another company.
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Hooked
px 125 disc
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whodatschrome wrote:
SIP jets have different sized orifices than genuine Dellorto jets. So a 125 jet from one manufacturer could be a completely different from another company.
Agree 100% Ive got some bgm jets that go to 130 and a 132 sip jet That I can see with my eye is smaller than the 130, dont know which is 'correct' But I'd deffo work with set from 1 manufacturer. Also means any advice on here about jets needs not to be taken literally, i.e ' i use a xxx jet, you should too, it'll be spot on'
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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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@ginch avatar
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andyx wrote:
... I can see with my eye is smaller than the 130, dont know which is 'correct' ...
Correct is 1.3mm. I measure with a knitting(?) needle from a craft shop... push it in until it stops and measure the needle with a vernier.
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bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
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UTC quote
Aside from occasional wacky tolerances, if you look closely you'll see that a Dellorto jet is different from a Spaco jet … which is different from a BGM jet … which is different from a SIP jet. Best to stick with one brand when setting up your carb.

All Jets Are Not Created Equal
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Ossessionato
1979 P150X, 1983 P200E, 1987 PK125XL Elestart, 1988 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
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@safis avatar
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UTC quote
^
This...

KMT jets are the way to go on a tuned motor. I have tried every brand, each one's different. KMTs are the best, but pricey...
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Molto Verboso
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SaFiS wrote:
^
This...

KMT jets are the way to go on a tuned motor. I have tried every brand, each one's different. KMTs are the best, but pricey...
^^
Double this.
First brass bit batch go-through. BGM/SIP/Dellorto. Going to re-label/drill a few.
First brass bit batch go-through. BGM/SIP/Dellorto. Going to re-label/drill a few.
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So where do you get the drill bits? I would love to buy a set of stepped bits from 1.21 to 1.3mm in .01mm increments.

H
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Hooked
px 125 disc
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px 125 disc
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whereshaldo wrote:
So where do you get the drill bits? I would love to buy a set of stepped bits from 1.21 to 1.3mm in .01mm increments.

H
seconded
@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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@ginch avatar
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UTC quote
Not precisely what you're looking for but not too far off.

https://www.amazon.com.au/Micro-Engineering-Spiral-Drills-Metric/dp/B01MDUG8JV
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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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UTC quote
Or get some metric pin gauges so you can measure what they actually are?
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vespa 125 vnb1t
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vespa 125 vnb1t
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UTC quote
even sip themselves say that some of their jets are not the size stamped on them !
i ended up buy this set its pricey but at least you can make them the correct size
stahlwille jet reamer set
stahlwille jet reamer set
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@whereshaldo avatar
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Stella 2T 150, Honda C70
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UTC quote
The issue I'm having is that the Jets I need do not seem available and even this jet reamer doesn't seem up to the task. If I have a 125 and want to go to a true 126 or 127 how is that achieved? 125 is a hair too lean and 128 is a hair too rich.

H
@shipscat avatar
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vespa 125 vnb1t
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UTC quote
the reamers in this set are progressive so each one is tapered increasing in size one following the other , this set will do every size from 0.33mm up to 2mm
whereshaldo wrote:
The issue I'm having is that the Jets I need do not seem available and even this jet reamer doesn't seem up to the task. If I have a 125 and want to go to a true 126 or 127 how is that achieved? 125 is a hair too lean and 128 is a hair too rich.

H
@ray8 avatar
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Molto Verboso
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Ginch wrote:
Not precisely what you're looking for but not too far off.

https://www.amazon.com.au/Micro-Engineering-Spiral-Drills-Metric/dp/B01MDUG8JV
That's what I have there, along with different sized tapered sewing needles following your tip on another thread Clap emoticon

I haven't even gone through the older/replaced jet batch, but I've seen enough.
Measure and re-label (at min the main jets) people!

Been marking the needles with a sharpie and measuring the OD at the point it snugs.

Btw the process KTM (Britain) uses to achieve that level of accuracy is just wild.
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Molto Verboso
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shipscat wrote:
even sip themselves say that some of their jets are not the size stamped on them !
i ended up buy this set its pricey but at least you can make them the correct size
That reamer set is cheaper than replacing 'em all with KMT jet sets
Thanks!
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Addicted
PX 150
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PX 150
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UTC quote
You could try and ecu and fuel injector from a GTS300 and have amazing fuel economy.
Has anyone tried this?, oh BTW, don't forget the 02 sensor
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Stella 2T 150, Honda C70
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UTC quote
I finally got an app and started tracking my mileage. I'm getting about 32mpg on average right now. I still think I coudl be a little richer on the idle jet but my temps have really settled down unless i'm hogging it WOT up one of the seattle hills.

H
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Molto Verboso
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Molto Verboso
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UTC quote
whereshaldo wrote:
The issue I'm having is that the Jets I need do not seem available and even this jet reamer doesn't seem up to the task. If I have a 125 and want to go to a true 126 or 127 how is that achieved? 125 is a hair too lean and 128 is a hair too rich.

H
After that mini-dive into my jets, the stamped numbers on these jets are close to useless for the hair levels of true you're looking for.

Got the reamer set mentioned above on Amazon. Without magnifiers it will be tough to measure jets vs tapered (assorted carpet) needles, since the reamers are square.
But you can get a stamped 130 mj that's actually a 126 to 130 in a minute by hand. Better than drill bits that also have to be measured and aren't tapered.

Gone up $20 since I ordered last week Facepalm emoticon

https://www.amazon.com/gp/product/B001D2X6QY/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
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