chandlerman wrote:
You want to drill the entire passage, but not all the way through and out the bottom of the carb. If you've done it correctly, you'll be able to see the to of the drill bit when you look down into the jet stack hole
Ossessionato
![]() Joined: Fri, 14 Oct 2016 21:32:14 +0000
Posts: 2337 Location: northern New York |
Thu, 10 Aug 2023 23:21:01 +0000
quote
chandlerman wrote: You want to drill the entire passage, but not all the way through and out the bottom of the carb. If you've done it correctly, you'll be able to see the to of the drill bit when you look down into the jet stack hole |
|
Thu, 10 Aug 2023 23:21:49 +0000
quote
dsmith181 wrote: Ok. Did this. Just to confirm. Only drill 10mm and that's it. It creates a wide hole and then a small one. The bit shouldn't go all the way through If you can see the tip if the bit with a flashlight down the main stack bore you're through. Remove the idle jet and blow out through that bore first! You can make things much easier going forward if you cut the mixture screw at the red line below, and cut a slot for slotted screwdriver turning. Will also allow you to fit the rubber plug when you're "done" jetting ![]() ![]() |
Hooked
![]() 1965 Allstate, 1979 Rally 200
Joined: Thu, 16 Feb 2012 16:24:57 +0000
Posts: 136 Location: Philadelphia, Pa |
Thu, 10 Aug 2023 23:34:35 +0000
quote
Ok got it. I'll finish drilling it through then. I was a little confused with the 10 mm and big hose, small nozzle so was thinking it's not all the way through
|
OP
![]() Thu, 10 Aug 2023 23:36:48 +0000
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: Thu, 16 Jun 2011 14:59:35 +0000
Posts: 8433 Location: Nashville |
|
OP
Lucky
![]() 76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: Thu, 16 Jun 2011 14:59:35 +0000
Posts: 8433 Location: Nashville |
Thu, 10 Aug 2023 23:36:48 +0000
quote
It's all good. Better to stop short and ask than drill too far and cry.
Positive
|
Hooked
![]() 1965 Allstate, 1979 Rally 200
Joined: Thu, 16 Feb 2012 16:24:57 +0000
Posts: 136 Location: Philadelphia, Pa |
Thu, 10 Aug 2023 23:44:38 +0000
quote
Ray, I used the 2.7 mm bit you sent the link to. Just need to finish drilling it through. I'll blow it all out starting with the idle jet hole.
Chandleman, exactly I have a tendency to drill first and ask questions later and I end up breaking things so I'm trying to try questions and patience now |
|
Fri, 11 Aug 2023 00:22:54 +0000
quote
dsmith181 wrote: Ok got it. I'll finish drilling it through then. I was a little confused with the 10 mm and big hose, small nozzle so was thinking it's not all the way through You're drilling the big hose. You should feel much less bite resistance when you're through, which should be VERY close at 10mm in. |
![]() Fri, 11 Aug 2023 09:21:57 +0000
Hooked
VBA1T/Px200 iris
Joined: Mon, 22 Aug 2022 13:37:01 +0000
Posts: 179 Location: Belgium |
|
Hooked
![]() VBA1T/Px200 iris
Joined: Mon, 22 Aug 2022 13:37:01 +0000
Posts: 179 Location: Belgium |
Ossessionato
![]() Joined: Fri, 14 Oct 2016 21:32:14 +0000
Posts: 2337 Location: northern New York |
Fri, 11 Aug 2023 13:23:14 +0000
quote
Is there any advantage to drilling it larger than 2.3mm?
I think I got that size because it's a common SAE size for drill bits. |
Jet Eye Master
PX221 MHR, O tuned PX200, PX181 Quattrini and some motorbikes
Joined: Thu, 15 Jun 2017 05:16:54 +0000
Posts: 4109 Location: London UK |
Fri, 11 Aug 2023 16:55:40 +0000
quote
No panic. 2.3mm is the ideal size. Bigger has the risk of having thinner wall thickness on a non optimal casting.
|
Hooked
![]() 1965 Allstate, 1979 Rally 200
Joined: Thu, 16 Feb 2012 16:24:57 +0000
Posts: 136 Location: Philadelphia, Pa |
Sat, 12 Aug 2023 01:16:08 +0000
quote
So after drilling it out I put a 130-be3-160ac in there and it's still starving at WOT. Should I keep going with an even bigger main or start messing with the air corrector or even the mixer tube? The sequence in this thread seems to say keep going bigger on the main first but 130 is super big right?
|
OP
![]() Sat, 12 Aug 2023 01:24:32 +0000
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: Thu, 16 Jun 2011 14:59:35 +0000
Posts: 8433 Location: Nashville |
|
OP
Lucky
![]() 76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: Thu, 16 Jun 2011 14:59:35 +0000
Posts: 8433 Location: Nashville |
Sat, 12 Aug 2023 01:24:32 +0000
quote
First off, drop your air corrector to a 140. And remind us what your setup is. 130 main is a little big for a mild tune, but not out the reason of possibility. Also, did you pressure test to make sure you don't have an air leak?
|
Ossessionato
![]() Joined: Fri, 14 Oct 2016 21:32:14 +0000
Posts: 2337 Location: northern New York |
Sat, 12 Aug 2023 01:29:12 +0000
quote
dsmith181 wrote: So after drilling it out I put a 130-be3-160ac in there and it's still starving at WOT. Should I keep going with an even bigger main or start messing with the air corrector or even the mixer tube? The sequence in this thread seems to say keep going bigger on the main first but 130 is super big right? |
Hooked
![]() 1965 Allstate, 1979 Rally 200
Joined: Thu, 16 Feb 2012 16:24:57 +0000
Posts: 136 Location: Philadelphia, Pa |
Sat, 12 Aug 2023 02:57:32 +0000
quote
chandlerman wrote: First off, drop your air corrector to a 140. And remind us what your setup is. 130 main is a little big for a mild tune, but not out the reason of possibility. Also, did you pressure test to make sure you don't have an air leak? I did a pressure test a few months back and it was tight. But worth another test. When the 140 comes in I'll update |
Hooked
![]() 1965 Allstate, 1979 Rally 200
Joined: Thu, 16 Feb 2012 16:24:57 +0000
Posts: 136 Location: Philadelphia, Pa |
Sat, 12 Aug 2023 03:00:30 +0000
quote
orwell84 wrote: I just went through this. I didn't drill the hole all the way through. I swore I was through… but wasn't quite. You can back the whole main stack out a turn or remove the main jet to see if it will sputter rich like mad. If that doesn't get you enough fuel, then it's time to look at other possible culprits. |
OP
![]() Sat, 12 Aug 2023 13:28:03 +0000
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: Thu, 16 Jun 2011 14:59:35 +0000
Posts: 8433 Location: Nashville |
|
OP
Lucky
![]() 76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: Thu, 16 Jun 2011 14:59:35 +0000
Posts: 8433 Location: Nashville |
Sat, 12 Aug 2023 13:28:03 +0000
quote
dsmith181 wrote: I hear you but I could see the end of drill bit in the main jet hole. Pretty sure I'm good there. So you're saying if the main stack is turned out a little it will make it extra rich? Just as a test? |
Ossessionato
![]() Joined: Fri, 14 Oct 2016 21:32:14 +0000
Posts: 2337 Location: northern New York |
Sat, 12 Aug 2023 15:41:16 +0000
quote
I tested this by drilling out an old jet with a drill bit to make a stupid big main jet. The scooter barely moved because it was so rich. All it told me was that fuel flow was not restricted, which was all I needed to know at that point. Removing the main jet entirely does the same thing quicker.
|
![]() Sat, 12 Aug 2023 15:58:48 +0000
Banned
3:5
Joined: Fri, 12 Jan 2007 02:38:46 +0000
Posts: 8740 Location: San Francisco |
|
Banned
![]() 3:5
Joined: Fri, 12 Jan 2007 02:38:46 +0000
Posts: 8740 Location: San Francisco |
Sat, 12 Aug 2023 15:58:48 +0000
quote
When you screw in the stack it bottoms out on the tapered tip of the main jet, doesn't it?
If you leave the main jet out what would it bottom out on? |
OP
![]() Sat, 12 Aug 2023 17:55:10 +0000
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: Thu, 16 Jun 2011 14:59:35 +0000
Posts: 8433 Location: Nashville |
|
OP
Lucky
![]() 76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: Thu, 16 Jun 2011 14:59:35 +0000
Posts: 8433 Location: Nashville |
Sat, 12 Aug 2023 17:55:10 +0000
quote
oopsclunkthud wrote: When you screw in the stack it bottoms out on the tapered tip of the main jet, doesn't it? If you leave the main jet out what would it bottom out on? |
|
Sat, 12 Aug 2023 19:38:07 +0000
quote
dsmith181 wrote: So after drilling it out I put a 130-be3-160ac in there and it's still starving at WOT. Should I keep going with an even bigger main or start messing with the air corrector or even the mixer tube? The sequence in this thread seems to say keep going bigger on the main first but 130 is super big right? Do try a 140 AC if you have one, especially if you're riding with a drilled filter. The heart above the jets is also an air corrector. |
Ossessionato
![]() Joined: Fri, 14 Oct 2016 21:32:14 +0000
Posts: 2337 Location: northern New York |
Sat, 12 Aug 2023 20:18:42 +0000
quote
I needed to go to a 138 MJ to get to the point of too rich (on a 187cc). Not surprising at all that a 130 MJ wouldn't get you there.
|
Hooked
![]() 1965 Allstate, 1979 Rally 200
Joined: Thu, 16 Feb 2012 16:24:57 +0000
Posts: 136 Location: Philadelphia, Pa |
Sat, 19 Aug 2023 19:06:47 +0000
quote
chandlerman wrote: First off, drop your air corrector to a 140. And remind us what your setup is. 130 main is a little big for a mild tune, but not out the reason of possibility. Also, did you pressure test to make sure you don't have an air leak? My setup is a 79 rally with a 210 malossi kit ported with the sip 2.0 pipe. I now have a 132-be3-140ac on there and it feels a little better but sputters at 3/4 throttle and wot |
Hooked
![]() 1965 Allstate, 1979 Rally 200
Joined: Thu, 16 Feb 2012 16:24:57 +0000
Posts: 136 Location: Philadelphia, Pa |
Style Maven
![]() '74 50s x3 '78 P200 E '84 Cosa '91 PK50XL2 - & - '58 AllState '68 Sprint '66(?) Super125 and '72 DanMotor Super150
Joined: Tue, 23 Nov 2010 02:37:37 +0000
Posts: 9348 Location: seattle/athens |
Sat, 19 Aug 2023 19:37:12 +0000
quote
dsmith181 wrote: Pressure tested and it's 150psi. My setup is a 79 rally with a 210 malossi kit ported with the sip 2.0 pipe. ... |
Hooked
![]() 1965 Allstate, 1979 Rally 200
Joined: Thu, 16 Feb 2012 16:24:57 +0000
Posts: 136 Location: Philadelphia, Pa |
Mon, 21 Aug 2023 20:00:20 +0000
quote
V oodoo wrote: That's your compression test. He was talking about crankcase pressure test to check for any air leaks which could come in play here, so more like 5psi. Look here for more info: Pressure test question Would the fact that the plug seems dark and still starving at 3/4 throttle support a leak? The bike idles and accelerates perfect before 3/4 |
OP
![]() Mon, 21 Aug 2023 20:58:57 +0000
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: Thu, 16 Jun 2011 14:59:35 +0000
Posts: 8433 Location: Nashville |
|
OP
Lucky
![]() 76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: Thu, 16 Jun 2011 14:59:35 +0000
Posts: 8433 Location: Nashville |
Mon, 21 Aug 2023 20:58:57 +0000
quote
dsmith181 wrote: Oh great. Guess I'll buy more crap to test more things. This is the life. Would the fact that the plug seems dark and still starving at 3/4 throttle support a leak? The bike idles and accelerates perfect before 3/4
Positive
|
Hooked
![]() 1965 Allstate, 1979 Rally 200
Joined: Thu, 16 Feb 2012 16:24:57 +0000
Posts: 136 Location: Philadelphia, Pa |
Mon, 21 Aug 2023 21:57:47 +0000
quote
chandlerman wrote: You're fuel starved. You need to drill out your float bowl passage to at least 2.5mm. Stock, SI carbs can't flow more than a 125 MJ worth of fuel from the float bowl to the jet stack. |
|
Mon, 21 Aug 2023 22:11:59 +0000
quote
dsmith181 wrote: I did drill it out. 2.7 mm hole. And I took off the main jet and put just the air corrector and mixer in there and it idles but when I hit the throttle it bogged down hard and would die. Do you have an un-drilled filter? |
OP
![]() Tue, 22 Aug 2023 03:00:33 +0000
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: Thu, 16 Jun 2011 14:59:35 +0000
Posts: 8433 Location: Nashville |
|
OP
Lucky
![]() 76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: Thu, 16 Jun 2011 14:59:35 +0000
Posts: 8433 Location: Nashville |
Tue, 22 Aug 2023 03:00:33 +0000
quote
Ray8 wrote: Have you tried a 140 ac? Do you have an un-drilled filter? |
|
Thu, 24 Aug 2023 00:04:34 +0000
quote
dsmith181 wrote: Oh great. Guess I'll buy more crap to test more things. This is the life. Would the fact that the plug seems dark and still starving at 3/4 throttle support a leak? The bike idles and accelerates perfect before 3/4 If you have an air leak, rpm's will dance (hunt for fuel) and not return quickly to idle at operating temperature. CHT won't settle under load. Was this the same experience with your previous carb? What ignition are you riding with? |
|
Thu, 24 Aug 2023 00:06:36 +0000
quote
chandlerman wrote: He said a few posts up that he's already on a 140 AC. Probably should try no filter, just bellows-to-frame next. I'd try both. Easy enough method to provide more clues. |
![]() Thu, 24 Aug 2023 16:17:31 +0000
Hooked
'71 Rally 180,'81 P200, Lambretta GP200, 1980 Vespa 90(125), 2023 Ducati Scrambler Pro Stealth
Joined: Tue, 12 Feb 2019 01:06:26 +0000
Posts: 188 Location: Tempe, Arizona |
|
Hooked
![]() '71 Rally 180,'81 P200, Lambretta GP200, 1980 Vespa 90(125), 2023 Ducati Scrambler Pro Stealth
Joined: Tue, 12 Feb 2019 01:06:26 +0000
Posts: 188 Location: Tempe, Arizona |
Thu, 24 Aug 2023 16:17:31 +0000
quote
To all that have posted in this completely awesome thread, thank you thank you thank you! After 35 or so years some basic stuff now makes more sense.
|
OP
![]() Thu, 24 Aug 2023 16:24:06 +0000
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: Thu, 16 Jun 2011 14:59:35 +0000
Posts: 8433 Location: Nashville |
|
OP
Lucky
![]() 76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: Thu, 16 Jun 2011 14:59:35 +0000
Posts: 8433 Location: Nashville |
Thu, 24 Aug 2023 16:24:06 +0000
quote
GrandpaNate wrote: To all that have posted in this completely awesome thread, thank you thank you thank you! After 35 or so years some basic stuff now makes more sense. It was supposed to be the content discussion for the Wiki article, but it's taken on a life of its own since then. I need to go make some updates to the wiki where things were unclear or could be expanded based on questions in this thread, so it's adding value either way.
Positive
|
|
Thu, 24 Aug 2023 16:36:45 +0000
quote
Ray8 wrote: If you have an air leak, rpm's will dance (hunt for fuel) and not return quickly to idle at operating temperature. CHT won't settle under load. |
Hooked
![]() 1965 Allstate, 1979 Rally 200
Joined: Thu, 16 Feb 2012 16:24:57 +0000
Posts: 136 Location: Philadelphia, Pa |
Tue, 29 Aug 2023 15:14:21 +0000
quote
chandlerman wrote: Thanks! It was supposed to be the content discussion for the Wiki article, but it's taken on a life of its own since then. I need to go make some updates to the wiki where things were unclear or could be expanded based on questions in this thread, so it's adding value either way. I have no hesitation returning to idle after throttling. The idle is perfect (55-160). Just to be clear pilot jet and idle jet are the same? People are using different terms. My rally is a 1979 so it's the Ducati electronic ignition. I started going the opposite direction and using leaner jets. I'm now down to 116-be3-160 and it's running lean but the hesitations at wot are less for some reason then when I was 130-be3-140 I actually thinking my fuel line might be clogged a bit. |
Hooked
![]() 1965 Allstate, 1979 Rally 200
Joined: Thu, 16 Feb 2012 16:24:57 +0000
Posts: 136 Location: Philadelphia, Pa |
Wed, 06 Sep 2023 23:34:51 +0000
quote
I'm done hijacking the thread. Just wanted to give an update in case anyone's wondering what the deal is.
Built a leak down test and i definitely have a leak so I'll investigate further on that. However. The hesitating at wot is fixed. The spade connector going into the cdi was a little loose where the wire crimped into it. When the bike was at wot the connection was too weak to keep it consistent. Now that it's tight theres no issue there |
OP
![]() Thu, 07 Sep 2023 16:43:42 +0000
Lucky
76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: Thu, 16 Jun 2011 14:59:35 +0000
Posts: 8433 Location: Nashville |
|
OP
Lucky
![]() 76 Sprint V, 63 GL, 62 VBB, 05 Stella, 66 Smallstate, 08 Stella (for now)
Joined: Thu, 16 Jun 2011 14:59:35 +0000
Posts: 8433 Location: Nashville |
Thu, 07 Sep 2023 16:43:42 +0000
quote
dsmith181 wrote: However. The hesitating at wot is fixed. The spade connector going into the cdi was a little loose where the wire crimped into it. When the bike was at wot the connection was too weak to keep it consistent. Now that it's tight theres no issue there ![]() Glad to hear you're back up and running. Now get that leak fixed!
Positive
|
|
Fri, 08 Sep 2023 00:38:47 +0000
quote
chandlerman wrote: Just our regular reminder that 90% of all carb problems are actually electrical. ![]() Glad to hear you're back up and running. Now get that leak fixed! An air leak would not improve with leaner jetting. |
|
Fri, 08 Sep 2023 00:44:50 +0000
quote
*Leaner mix is more ignitable, so it makes sense that things would feel better riding with an electrical rev limiter.
|
![]() Tue, 12 Sep 2023 15:58:20 +0000
Member
2009 Stella DR177, 1966 Super
Joined: Wed, 07 Jul 2021 23:58:44 +0000
Posts: 17 Location: Madison, WI |
|
Member
![]() 2009 Stella DR177, 1966 Super
Joined: Wed, 07 Jul 2021 23:58:44 +0000
Posts: 17 Location: Madison, WI |
Tue, 12 Sep 2023 15:58:20 +0000
quote
Main jet tuning question:
Can anyone clarify a bit on what it means to "Rev out cleanly"? I'm trying to find my main jet by revving through 3rd. I find that I'm gurgling most of the way there to above 3/4 throttle even on WOT. However once my RPMs get up there, everything cleans up. And once I'm into the power band the scoot takes off and feels wonderful. Then I can wind up and down and it's got crazy pull. Would you say that is or is not revving out clean? If I drop the mj a few points I can rev all the way to WOT in 3rd without a gurgling. Would that be revving out clean instead? |
Ossessionato
![]() Joined: Fri, 14 Oct 2016 21:32:14 +0000
Posts: 2337 Location: northern New York |
Tue, 12 Sep 2023 16:18:12 +0000
quote
PattyMcPatterson wrote: Main jet tuning question: Can anyone clarify a bit on what it means to "Rev out cleanly"? I'm trying to find my main jet by revving through 3rd. I find that I'm gurgling most of the way there to above 3/4 throttle even on WOT. However once my RPMs get up there, everything cleans up. And once I'm into the power band the scoot takes off and feels wonderful. Then I can wind up and down and it's got crazy pull. Would you say that is or is not revving out clean? If I drop the mj a few points I can rev all the way to WOT in 3rd without a gurgling. Would that be revving out clean instead? I usually take short videos of my WOT tests. If I get one of a bonafide spluttery WOT test, I will post it for the good of the order. |
Modern Vespa is the premier site for modern Vespa and Piaggio scooters. Vespa GTS300, GTS250, GTV, GT200, LX150, LXS, ET4, ET2, MP3, Fuoco, Elettrica and more.