Barnesville Driving Event Summary

Barnesville Driving Event Summary

By Bob Barthelemy
Photos by Brian Allardice

The Georgia weather was a little nippy Thursday morning with temperatures in the mid 40’s followed by temps over 70 by mid-day. Mother Nature was kind to us Thursday and Friday but on Saturday morning a heavy mist followed by a drizzle and later a downpour resulted in no on-track activity. Thank you to Mike Adkins, GSKA President, and the entire GSKA team for a well-run event! Thank you to all the Vintage Karters (44 entries) for participating at this event, and especially the large group from Saltillo, Mississippi.

After a round of safety tech inspections, the track was opened for practice at 9:15. We started with open practice for all single engine senior drivers with a max of 10 karts on the track at a time. The junior drivers were then allotted a practice session followed by the dual engine drivers taking their separate practice session. We repeated this order throughout the day and closed the track for practice at 5:00 pm. I believe everyone had plenty of practice time.

Foreign 8.2 Sidewinder means big power and close racing. Jimmy Gay trails Marc Nagel and winner Bowen Carlock into Barnesville’s signature corner.
There were four entries in the popular Yamaha Dual class. Here 2nd place finisher Gary Combs (14) leads the winner Mark Green’s Margay SR-16 (2).

Friday morning temperatures were in the mid-50’s and rose to the mid-70’s and it was an absolutely gorgeous day. Practice began at 9:00 and went through noon. After the lunch break, we conducted our driver’s meeting including a brief devotional recognizing what God did to save Bill Jackson’s life and to pay respects to my friend, Ronnie Smith, who recently passed away (I conducted the eulogy at his funeral Saturday morning). After a few last-minute corrections to our running order to ensure participants were not driving in back-to-back classes, we were able to get the first Heats started by 1:45 pm. We had 13 classes represented, and by grouping some of the classes together, we were able to run 10 groups. We proceeded with our 1st and 2nd round of demonstration Heats. All Heats went smoothly with no substantial incidents on the track.  

Sportsman Rear winner, Billy Dalton from Mt. Washington, Kentucky was both fast and his kart was show-worthy. Robert Rizzuto and Tony Severino also competed in Sportsman Rear.

We all enjoyed a great evening buffet meal (chicken and rice, pork loin, and a wide range of vegetables and salad) prepared and served by Vicki & Glenn Forsyth in the concession/registration pavilion (outside to comply with COVID-19 protocol). “Legends of Karting” awards were presented in recognition to Dicky Wilson and Bill Berry by Bob Barthelemy. A Longest Distanced Traveled award was presented to Romero Llamas from Canton, Ohio. Romero was also presented the coveted traveling “Yankee Award”. He will be able to cherish it for only five months due to the 2021 Barnesville event scheduled for the March 25th-thru the 27th weekend, when it will be presented to another honored recipient.  

Due to the continuing rain Saturday morning, the vintage karters in attendance voted to call the 3rd Heat. We then presented the awards for the demonstrations (based on finishing order of the 2nd Heat) and finished before 12:00 noon.

Lots of intensity between these two in 100cc Classic, Romero Llamas (11) and victor Tony Ellison had a great on-track battle. Romero also took home the Long Distance award.
Here are the top three in Yamaha Piston Port. Scott Nagel (7) won, George May (14) was second and Jarod Brannon (9) was third.
If vintage karters thought that they’d be rid of the Nagels anytime soon, they haven’t been watching young Ben Nagel who drives his SAE “like he stole it”! This photo shows why the sprocket guard is necessary as Ben rolls the rear tire away from the rim.
Rick Williams (6) and John Pagans (16) take the checkered flag in Over 60 Yamaha. Jeffery Conner finished third.
The 6.1 Sidewinders take the green. Winner Rick Williams (6) had a busy day running in at least three classes. Sean Collins (9) finished second and Todd Breedlove (12) finished third.
Nobody had more fun at Barnesville than Marc Nagel who “wheelied” his dual SAE all over the place. Can’t wait to see young Ben in this rig!
Dual Sidewinder alway7s brings the spectators to the fence. Here Bob Barthelemy gets a little sideways but still held on to second place. Ron Caldwell (7) is considering his options as winner Jerry Nagel exits the photo.
Jerry Nagel always runs up front in Dual Sidewinder. His dual BM 130s give the Komet “Bomb” boys fits.
Mark Green (2) not only won Yamaha Dual, he doubled up with a win in Yamaha Limited. He is followed by Brian Carr (87) who finished 4th, and Bowen Carlock (8) who finished 2nd.
The Juniors had just two entries but excellent driving and speed. Alden Riley from Nettleton, Missouri battled Ben Nagel from Napoleon, Ohio. Maybe we have a Haddock – Dismore rivalry brewing…

VKA News- Jan 2021

International Kart Month

By Rolf Hill

I may have jumped the gun with my initial announcement last month of the International Kart Day, but in my defense, it was necessary. The part I didn’t explain in the December announcement was that the process started in 2019. There is a website that manages/publishes a calendar of “National Days.” They made it clear they get thousands of requests every year. (Keeping in mind we have national pizza day, national lemon meringue pie day, national hot dog day, and even national clean out your refrigerator day [right before Thanksgiving], it is no wonder they get thousands of requests.) They also made it clear they don’t notify applicants until it is approved…. and they didn’t. They also said they would not accept applications from “individuals.” I submitted the request as “Editor, VKA FirsTurn,” but I guess that didn’t carry any weight. Go figure. So, I asked Gary Wlodarsky, VKA President, if he would sign a “Declaration” that established the day. He was agreeable and the VKA Board approved. I re-applied in November.

On Dec. 1 we hosted a zoom meeting and invited Regional Coordinators, track owners, promoters, as well as representatives from other vintage karting organizations. Another meeting is scheduled for December 15. As you might expect there was plenty of discussion and differing points-of-view. All of them needed to be heard.

Kart Day Vs Kart Month

The issues that were raised included the date, primarily the perceived conflict for the inaugural event with the 20th Anniversary of 9/11; how to include/excite modern karters to celebrate the day; the need for a mission statement that can be taken to national modern event organizations and others; some suggestions for what modern event could include to recognize the heritage we all share. Too much to discuss here, so stay tuned or visit Facebook.*                       

International Go Kart Month is a time to celebrate the people, the events, the equipment, memories, the innovations…our history, and to make people aware of all of that.

Hopefully, the official announcement will be made in the home-state of karting at the Adams Kart Track in Riverside, CA, at the first 2021 VKA event February 5. 2021. Throughout the year, we hope all VKA events will honor the inaugural event by holding a 5-minute session where all the karts parade the track with a small American flag. Also, modern karting events will be encouraged to include Parade Laps to recognize the history their karts share with Art Ingles’ creation. On September 11, 2021, join the fun at Oreville, PA, for a special event, on this special day.

Check out the Facebook page (International Go Kart Month – September) too. It will be updated as this concept takes shape.                                                            

Rolf Hill, Executive Director
International Go Kart Month

 

REMINDER!!! Procedure & Rules Updates for 2021

As you can see The VKA Board is upgrading its operations for 2021 with a new website and a digital version of FirsTurn. The primary goal is for you, the VKA member to have a better experience as a participant at VKA events, and as a vintage karting enthusiast in general. To make this happen, we need your help. Simply put, without information on you and your karts, we cannot do any meaningful event coverage. We need to be able to identify your kart by either a number panel when on the track or a show entry card with a visible number on it. Then we need a corresponding race or show entry form with as much info as possible about the kart and yourself, like where you live. Without this we can only run random photos with no captions that have no relevance.

Changes:

  1. Karts will NOT be allowed on track at any time without number panels
  2. Only event photos with captions will be considered for FirsTurn publication
  3. PLEASE fill out both the show or race entry form with as much information as possible including the best way to contact you. The FirsTurn editor may be contacting you for more information or photos of your kart.
  4. You must be a VKA member in good standing to participate in the driving or show portions of the events
  5. Helmets will be checked for Snell Approval dates. Only Snell 2015 and later helmets are acceptable
  6. Hoosier R60 compound tires are no longer on the modern kart tire list. They have been replaced by the Hoosier R70s
  7. Vintage 4-Strokes have been added into the Classic class structure

Hopefully, we will close out the Covid 19 pandemic in 2021. Until that is a reality, let’s protect each other and our ability to hold events with common sense protective measures.

Wanted

Rolf Hill here… I’m fried. Stick a fork in me … I’m done. Len Emanuelson is taking over as Editor, but he’s doing the electronic version. For those of you who still want a paper copy, we’ve heard you and you will still be getting paper until your membership runs out or I run out of gas … and my tank is nearly empty. I’m only good for a few more issues, but that’s it.

We’ve had some people who have helped with writing event summaries and some technical articles along the way, and even had an editor for a year. I’ve appreciated all the help. So now VKA needs a Print Editor for those who still want paper.

There were 134 who sent in the post card and requested paper. I’m still not sure how many of those are 36-month members, but my tank is going to run out well before those memberships do. So, if anyone wants to be the guy (or gal) who puts together the print version, now is the time to step up. The alternative may be to offer pro-rated refunds, but that’s up to the Board, not me. (Better to get Print Editor. Send me an email: KartNumber4@yahoo.com)

Len and I have a plan … I think. Anything I get, I will send to him. He will put it into the e-FirsTurn. In the interim, I will continue to put together the event summary tables of demo and show winners for both versions. All other input including pix needs to go to Len effective with Jacksonville and Riverside … and beyond.

Jacksonville Event Flyer

VKA Barnesville Kart Show

VKA Barnesville Kart Show

By Bob Barthelemy
Photos by Brian Allardice

Editor’s Note:

Due to space limitations in the digest-sized print edition of FirsTurn, our stalwart editor, Rolf Hill has not had the ability to publish very many event photos, especially show photos. Now, with the new digital version of FirsTurn we have the space to display those beautiful karts that show up at our events. However, we need your help to provide the information needed to give them the proper coverage. So, please fill out your registration card (complete with comments), and we welcome any additional photos you may have. Please send to VKAeditor@gmail.com.

It may look like a piece of sculpture, but it really is a 1971 Blackhawk race kart beautifully prepared by Bill Skelly. It won both the “Modified Rear” award and “Peoples Choice”. Bill needs to get FirsTurn a good set of photos so we can look this rare kart over in more detail.

The kart show judging activity got going at 9:00 a.m. Saturday morning under the grid canopy due to the heavy mist. Kart Show judging and the presentation of the awards was completed about 10:00am by VKA President Gary Wlodarsky, who also identified Steve Mox as the 50/50 raffle winner of $275.00. Steve donated $50.00 back to VKA, so Gary presented a total of $325.00 to the VKA.

Due to the continuing rain, the vintage karters in attendance voted to call the 3rd Demonstration Heat. We then presented the awards for the driving demonstrations (based on finishing order of the 2nd Heat) and finished before 12:00 noon. When I arrived back from the funeral at 1:45, all but George May had already hit the road home. George loves Barnesville and vintage karting and we love him and his dedication to the sport!

HISTORIC

 

Unrestored

1961 Go-Kart 800; Duel WB 610; Bob Barthelemy

Restored

1961 Rupp A Bone; Robert Rizzuto

REAR

 

Restored

1970 Hornet Duel Mac 91’s; Blain Young

Modified

1971 Blackhawk; Bill Shelly

SIDEWINDER

 

Unrestored

1974 Bug Wasp; Chris McMullen

Restored

1971 Margay Cheetah Mac 91; Dewey Brewer

Modified

1987 Coyote Bullet; Rick Williams

PAST CHAMPION

1969 Margay Enduro; Bill Shelly

ENDURO

1973 Bug Stinger; MC-91; Dewey Brewer

PEOPLES’ CHOICE

1971 Blackhawk; Bill Shelly

Can you image how loud this thing would be? Bob Barthelemy’s ’61 Go-Kart 800 has a pair of West Bend 610s with huge megaphones. It won the “Unrestored” class in the Historic division. Would be quite the restoration project, but it’s plenty cool just the way it is.
When you look up go-kart in the dictionary, you will see a photo of Robert Rizzuto’s Mac-powered 61 Rupp A Bone. He won the “Restored” award in the Historic division.
“Rear Restored” went to Blain Young’s ’70 Hornet with dual Mac 91s. The attention to detail and workmanship is incredible! Looks like it has a lot of leg room for a rear-engined kart and the seat looks “couch-like” comfy.
Chris McMullen’s ’74 Bug Wasp looks like it just needs a motor to be track ready. This survivor won the “Unrestored Sidewinder” award.
That unique flared seat can mean only one thing – Margay Cheetah. And Dewey Brewer’s ’71 model features a Mac 91 with a beautiful overhead pipe. Dewey walked away with best “Restored Sidewinder”, the first of two awards he took home from the Barnesville show.
Rick Williams’ Yamaha-powered, 1987 Coyote Bullet captured the “Modified Sidewinder” award, and it looks like it would be all business on the race track. Yamaha sidewinder like Rick’s were the backbone of sprint racing in the eighties.
You’ll never get tired of gazing at Past Champion Bill Shelly’s twin Mac-powered ’69 Margay endure.
Dewey Brewer was a double award winner too scoring his second win in the “Enduro” category with his ’73 Bug Stinger with a MC-91 for power.
14th Annual Southern Vintage Kart Classic

14th Annual Southern Vintage Kart Classic

By Dick Charest
Photos by Alan Lidke

The 14th Annual Southern Vintage Kart Classic was held at Roebling Road Raceway on October 17-18, 2020. The track is located near Bloomingdale, GA. It is 2.02 miles long with nine turns. The facility features a 60-acre paddock with paved access roads.

Each year in March the Southern Kart Club (SKC) hosts the 2nd race of the World Karting Association National Road Racing Series. However, in October the SKC holds a club race at Roebling Road with special emphasis on vintage karts. The vintage karts run four exhibition races over the 2-day weekend. There are two, 15-minute vintage exhibition races on Saturday and two more 15-minute vintage exhibition races on Sunday. Both vintage lay-down enduro karts and vintage sprint karts are welcome to participate.

The weather was beautiful on both Saturday and Sunday. It was sunny and cool in the morning but warmed up nicely as the day progressed. The turnout was more than expected and registration on Saturday morning extended throughout the 1st practice session. To help those who missed the 1st practice session, a short 3rd practice session was run before the races started.

I missed the 1st practice session and during the 2nd practice session my engine did not run well, the clutch under slipped, and I could not get the CHT up to the desired range even though I leaned out the carb HS needle. By the 2nd lap the spark plug was getting badly fouled so I came into the pits. After practice I installed a new spark plug and turned in each of the clutch adjusters to increase clutch slip. During the short 3rd practice session, the engine ran better but I still had an ignition problem and the clutch still under-slipped. I figured that the clutch under-slipping prevented the engine from getting into its power band and the bogging at low RPMs caused the spark plug to foul. After practice I turned in each of the clutch adjusters again to increase clutch slip and installed a new spark plug for race #1.

Tony Severino brought his “old skool” 100cc Mac-powered Hegar to Roebling and ran very well.
Tony Severino brought his “old skool” 100cc Mac-powered Hegar to Roebling and ran very well.
On the grid – Terry Armstong’s Quicksilver powered by a 135cc Dap T62 reed sits besides the number 7x7 sit-up sprinter.
On the grid – Terry Armstong’s Quicksilver powered by a 135cc Dap T62 reed sits besides the number 7x7 sit-up sprinter.

Vintage Exhibition Race #1 on Saturday

Tony Ellison’s kart (#13) next to Harry Foskey’s kart (#18) on the starting grid

When the green flag dropped, Tony Ellison got a good start and took the lead of the race. I was gridded last of the 11 karts that were in the vintage race. I got a good start and started passing karts. The engine ran well but still at low temperature. The clutch worked better but by the 3rd lap the ignition problem returned. I ran another lap, but the ignition problem got worse, so I came into the pits rather than getting stranded out on the track. Tony Ellison set fast time for the Vintage 1 race and won the race with his K-35 completing 10 laps. Arthur McKenny was 2nd with his Yamaha, Chris Foskey finished 3rd with his Yamaha, and Terry Armstrong finished 4th with his DAP T-62. Arthur, Chris, and Terry all completed 9 laps. All 11 karts that started completed at least one lap. Five entries in the Vintage race did not make the grid.

Since my ignition problem occurred only after the engine electrical system got warm even with a new spark plug, I suspected that the coil had gone bad. After the race I installed a good spare coil and test ran the engine in the pits. It started up easily and ran well so I tried it again in Vintage race #2.

Vintage Exhibition Race #2 on Saturday

As in race #1, when the green flag dropped, Tony Ellison got a good start and took the lead of the race. I was gridded 9th of the 10 karts that started the race, but I got a good start and started passing karts. Although the engine ran well, the clutch under-slipped and that hurt my lap times in the curves on the backside of the track. I had a difficult time getting the engine up into its power band. However, I drove on and completed the race. Tony Ellison set fast time for Vintage 2 race and won the race with his K-35 completing 10 laps.

Arthur McKenny’s kart (#6w) at the head of the starting grid
Bill Anderson’s piston port powered Van K finished 3rd in Sunday’s Heat 4. All types of vintage karts, laydowns and sit-up sprinters are welcome to compete. Just change the gear and get ready for a high-speed ride!
Bill Anderson’s piston port powered Van K finished 3rd in Sunday’s Heat 4. All types of vintage karts, laydowns and sit-up sprinters are welcome to compete. Just change the gear and get ready for a high-speed ride!

Arthur McKenny was 2nd with his Yamaha, Chris Foskey finished 3rd with his Yamaha, and I finished 4th. Arthur, Chris, Scott Orr and I all completed nine laps. Bill Anderson, Bennett Armstrong, and Harry Foskey all completed eight laps. They were followed by Terry Armstrong and Trevor Armstrong. Six entries in the Vintage race did not make the grid.

After the race I changed engine and adjusted the clutch for Sunday’s Vintage 3 race.

I ran a short practice on Sunday morning to verify everything was OK with the engine. Although the engine ran well, the clutch over slipped badly so I came into the pits after one lap. I backed out the clutch adjusters to the setting I came to the track with. Since there was no more practice, I tested the clutch engagement in the pits, and it seemed to be OK for the race.

Vintage Exhibition Race #3 on Sunday

Tony Severino on track with his McCulloch powered Hegar kart (#62)

I got a great start and passed everyone before entering turn one to take the lead of the race. Chris Foskey, Terry Armstrong, and Tony Ellison were fairly close behind. Tony dropped out on lap one due to a stripped drive belt. Terry Armstrong and Bill Anderson dropped out on lap three. Chris was quicker than me on the back side of the track because my clutch under slipped which slowed me down on that portion of the track. However, I consistently pulled away from him on the straight. He drafted me to stay in contact, but he could not overtake me. The engine ran well, and I maintained the lead of the race to the end. I set fast time for Vintage 3 and won the race by only 3.119 seconds. Chris Foskey finished 2nd, Bennett Armstrong finished 3rd, Scott Orr finished 4th followed by Alan Lidke, Harry Foskey, Tony Severino, and Trevor Armstrong. Three vintage karts did not make it to the starting grid for race 3.

After the race I adjusted the clutch to get more slip and prepared the kart for Vintage race #4.

Vintage Exhibition Race #4 on Sunday

As in Vintage race 3, I got a great start and took the lead before getting into turn 1. After one lap I got a high CHT warning light so I richened the carb HS needle. However, the high CHT warning light persisted so I richened the carb HS needle again. Then I noticed that the CHT was reading 485°F then 520°F while the engine continued to run well. I realized that the CHT reading was erroneous, so I returned the carb HS needle setting to about where it was originally and continued throughout the race with the high CHT warning light on. Tony Ellison and Chris Foskey were close but on lap three, Tony Ellison dropped out. His engine mount had come loose, and the engine tipped over in a turn. Terry Armstrong had engine problems early in the race and dropped out. While lapping a couple of back markers I got enough of a lead on Chris Foskey that he was not able to draft me. I pulled away from the field and won the race by 1 minute and 21.673 seconds over Scott Orr. Bill Anderson (173) finished 3rd followed by Chris Foskey and Harry Foskey. I set fast time for the Vintage 4 race.

This event wrapped-up the vintage enduro season for 2020. The next road racing event with a vintage class is the WKA event at Daytona International Speedway between Christmas and New Years. That will be the first event of the 2021 racing season.

Dick Charest’s Invader looks pretty inviting. He ran both K99 and K299 B-bombs and after struggling the first couple of days, came through with a victory in Sunday’s Heat 4.
Dick Charest’s Invader looks pretty inviting. He ran both K99 and K299 B-bombs and after struggling the first couple of days, came through with a victory in Sunday’s Heat 4.
Arthur McKenny’s Yamaha-powered entry made a great showing buoyed up by Van Gilder of Elite Karting (shown getting ready to start Arthur).
How To Set Pop-Off Pressure

How To Set Pop-Off Pressure

By Len Emanuelson

First, let me start by stating that I’m no 2-stroke carburetor expert. However, I’ve been forced to learn certain things about how to setup and service my carbs as part of my race prep. One of those procedures is checking and setting pop-off pressure — the pressure required to unseat the inlet needle and seat, or in some cases, the carburetor’s gross jet. What this affects is the carburetor’s calibration (rich or lean) especially in the lower rpm ranges. There are as many target pop-off pressure settings as there are opinions and engine combinations, but the generally accepted settings are 8.5-10.5psi for gas and 5-7.5psi for methanol. You can’t go wrong picking a mid-point in those ranges as a starting point.

After you remove the pumper stack, what you see is the “brain” of the carburetor, the fulcrum arm/inlet seat assembly. It’s hard to believe, but this crude little lever spring arrangement operates at engine rpm, or in my case 15,000.
After you remove the pumper stack, what you see is the “brain” of the carburetor, the fulcrum arm/inlet seat assembly. It’s hard to believe, but this crude little lever spring arrangement operates at engine rpm, or in my case 15,000.

There are a couple of other factors that affect low-rpm mixture control. The most important is the fulcrum lever height. A good starting point is with the top of the arm adjusted (bent) so that it is flush with the adjacent “flats” on the carburetor. If you bend the arm up, you richen the mixture. Typical settings for raised fulcrum arms (at least on my carbs), is .030” for methanol carbs and .060” for my gas carbs. Another consideration is the type of inlet valve, needle and seat or gross jet. My Buller methanol carbs run dual-ball gross jets that flow more fuel (even at smaller openings) than needles and seats. My gas carbs use needles and seats that run cleaner on the bottom end and seem to give snappier response.

The way you check pop-off pressure on a typical Mikuni or Tillotson pumper carburetor is to remove the pump “stack” breaking the carb down to the carb body with it’s inlet valve, fulcrum arm and spring. Next, you pour some type of liquid in the inlet valve well. Kermit Buller recommends and sets his carbs up with Marvel Mystery oil, but gas, solvent, WD40 or most lubricants will work. Then you take your pop-off gauge and insert it in the passage that leads to the chamber below the inlet valve (see photo), and slowly pump pressure into this chamber. Keep watching the fluid around the inlet valve for bubbles if the gauge doesn’t seem to be holding pressure as you pump it up. Dirt or a bad gasket or surface under the inlet valve often leads to leaking here (you will see bubbles around the inlet valve).

Most inlet valves, needle and seats or gross jets require a liquid to provide a seal. I use Marvel Mystery Oil because it’s what Buller recommends for checking gross jets, but lighter oils like WD40 or your actual premix fuel work well too.
Most inlet valves, needle and seats or gross jets require a liquid to provide a seal. I use Marvel Mystery Oil because it’s what Buller recommends for checking gross jets, but lighter oils like WD40 or your actual premix fuel work well too.

When you get to the set pop-off pressure the inlet valve will open releasing pressure (usually spraying oil all over). If you are using a needle and seat, it should be an audible “pop”, initial pressure release and then the gauge stabilizing at a “holding” pressure. If you are using a gross jet, the pressure will simply release at the pop-off number and then stabilize at a lower number. As Buller’s info sheets describe it, the gross jet acts more like a fuel regulator.

To change pop-off pressure you need to adjust that very tiny coil spring under the fulcrum arm. It’s good to have a large supply of pop-off springs as they have a nasty habit of launching, never to be found. For a given spring wire diameter etc., the length determines the pop-off pressure. I purchase my springs from Comet Kart Sales, but they are available from others such as E.C. Birt. As they come from Comet they are approximately .750”-long and produce a needle and seat pressure of 9.5psi in a Mikuni carb. That is nearly ideal for many gas foreign motors. By compressing the spring (squeezing it several times to coil bind between my fingers) to .570”, the result was 6.5psi in my gross jet methanol carb. It’s strictly a time-consuming trial and error operation. However, after you establish the correct length spring for your application, you can usually hit the pop-off number in just a couple of tries.

Get a good pressure check gauge. If you run 2-strokes, you’ll need it often. I found this one on the internet for about $35.
Get a good pressure check gauge. If you run 2-strokes, you’ll need it often. I found this one on the internet for about $35.
To check the pop-off pressure, slowly pump up the gauge until the inlet valve releases the pressure. This carb popped-off at around 6psi and held at 3.5psi, which was perfect for methanol fuel.
To check the pop-off pressure, slowly pump up the gauge until the inlet valve releases the pressure. This carb popped-off at around 6psi and held at 3.5psi, which was perfect for methanol fuel.

The photos here (iPhone7 camera) show me checking the pop-off pressure on an eBay carburetor I purchased (atomized methanol Mikuni) and also setting the pop-off pressure on an existing Buller atomized Mikuni I have been racing with that was too lean causing engine damage. It’s not a bad idea to check your carburetor’s pop-off pressure whenever you are installing a fresh diaphragm kit.

If the pop-off wasn’t correct, you remove the fulcrum lever and axle by simply loosing the Philips-head screw seen here to the right of the gross jet ball. Just loosen so that the fulcrum axle tilts up and slips out. If you remove the screw every time you need to grow a third hand to put it all back together.
If the pop-off wasn’t correct, you remove the fulcrum lever and axle by simply loosing the Philips-head screw seen here to the right of the gross jet ball. Just loosen so that the fulcrum axle tilts up and slips out. If you remove the screw every time you need to grow a third hand to put it all back together.
The stamped steel fulcrum lever is pretty fragile, so if you need to bend it to adjust fulcrum lever height (described further on), be gentle. The bottom side has a dome that helps retain the spring. Make sure the fulcrum lever rotates freely on the axle.
The stamped steel fulcrum lever is pretty fragile, so if you need to bend it to adjust fulcrum lever height (described further on), be gentle. The bottom side has a dome that helps retain the spring. Make sure the fulcrum lever rotates freely on the axle.
Spring length determines pop-off pressure. The longer the spring, the higher the pop-off. Once you determine your correct pop-off spring length through trial and error, use that as your baseline.
Spring length determines pop-off pressure. The longer the spring, the higher the pop-off. Once you determine your correct pop-off spring length through trial and error, use that as your baseline.
If you noticed leaking around your inlet valve during pop-off testing, or the inlet valve just wouldn’t build to a pop-off pressure, there’s a good chance it is leaking under its seat. As you can see the debris in my second carb here that was allowing the gross jet assemble to leak by it completely. I cleaned it with a small screwdriver and added a fiber washer.
If you noticed leaking around your inlet valve during pop-off testing, or the inlet valve just wouldn’t build to a pop-off pressure, there’s a good chance it is leaking under its seat. As you can see the debris in my second carb here that was allowing the gross jet assemble to leak by it completely. I cleaned it with a small screwdriver and added a fiber washer.
There is a love-hate relationship with both gross jets and conventional needles and seats.  I’m an equal opportunity hater – I use gross jets for methanol and needles and seats on my gas carbs. The gross jet on the left is from Buller, the needle and seat in the center is from E.C. Birt and the need and seat on the right is from Speed Parts.
There is a love-hate relationship with both gross jets and conventional needles and seats. I’m an equal opportunity hater – I use gross jets for methanol and needles and seats on my gas carbs. The gross jet on the left is from Buller, the needle and seat in the center is from E.C. Birt and the need and seat on the right is from Speed Parts.
Fulcrum lever height plays a role in determining a carburetor’s inherent richness or leaness. Level with the surrounding “flats” is kind of the neutral position. This lever is actually raised .040” above the carb body for a richer mixture.
Fulcrum lever height plays a role in determining a carburetor’s inherent richness or leaness. Level with the surrounding “flats” is kind of the neutral position. This lever is actually raised .040” above the carb body for a richer mixture.
The best way to check fulcrum lever height is with the depth end of a caliper. My methanol atomizers are .030”-.040” higher, and my gas Mikunis are setup with the levers .060” higher.
The best way to check fulcrum lever height is with the depth end of a caliper. My methanol atomizers are .030”-.040” higher, and my gas Mikunis are setup with the levers .060” higher.
Here are some brutalized fulcrum arms in my collection. The one on the bottom with the sharp kink came off a carb with a gross jet. It is a good example of how to “dog-leg” a lever so that when you raise it, it is still parallel with the top of the carb. Likewise for the top lever.
Here are some brutalized fulcrum arms in my collection. The one on the bottom with the sharp kink came off a carb with a gross jet. It is a good example of how to “dog-leg” a lever so that when you raise it, it is still parallel with the top of the carb. Likewise for the top lever.