CUSTOMBIKE 4/17 THE MASTER OF CARBURETORS
- Thorsten Ihlo
- Apr 26, 2017
- 7 min read
Updated: 7 days ago
Thorsten Ihlo's carburetor manufactory breathes new life into old carburetors. He is now a globally recognized specialist in his field. Privately, Thorsten rides a Late Shovel. Naturally, we take a look at their carburetor.
Carburetor maintenance in an ultrasonic bath” was the title of a technical article in our September 2014 issue that dealt with the overhaul of carburetors.
At that time, it was not foreseeable that Thorsten Ihlo, the protagonist of our article, would develop into a globally sought-after specialist for tricky carburetor-related issues within just two years. His work is represented at pretty much every popular event. They could be found at the Born Free Show in the USA, the Wave and Wheels in France, the Art and Wheels in Switzerland, the Kustom Kulture in the Ruhrpott or at our own CUSTOMBIKE-SHOW in Germany. This was a small but significant contribution to the show successes of numerous custom bikes from Hamburg. So it makes perfect sense to take another look at the head of Vergaser Manufaktur. And because our magazine is first and foremost about bikes, we asked Thorsten to roll his own bike in front of the lens to explain what he finds particularly appealing about working on a carburetor.
No matter how perfectly designed an engine may be, it is nothing without an equally perfectly tuned carburetor. So if the engine can be regarded as the heart of a machine, then in Thorsten's understanding the carburetor is the soul of the whole. “And the soul needs empathy,” Thorsten is certain. His own machine, consisting of a Late Shovel engine modified to just under 1400 cubic meters in a 52 Wishbone rigid frame, is a good example of his attitude. Over a period of two years, he built his Harley with a lot of passion and in a classic style - unobtrusive, but perfect in every detail. As you can see from the technical data, the engine was fitted with the finest internals in order to reliably transmit its power to the rear wheel. To produce the necessary brackets and rods, Thorsten consistently used stainless steel as the base material, which was used with a high standard of craftsmanship and a satin-brushed surface.
“You can't just put a kit on your bike and assume that it will fit straight away. I have unscrewed and re-screwed the carburetor countless times for tuning”
However, the absolute highlight of the machine is the Sudco Nos carburetor kit, which was specially manufactured for use on Shovelhead engines. The original kit is extremely rare and is based on two Mikuni VM-29 carburetors. As there are plenty of these on the market, there are always kits that are thrown together and offered as Sudco kits but are not.
Thorsten was correspondingly enthusiastic when he had the opportunity a few years ago to secure one of the kits in its original condition and packaging. It goes without saying that you don't just screw something like this onto the engine and then assume that the two will harmonize with each other straight away. But before Thorsten could even think about the set-up, the problem of the kit's considerable weight had to be solved. He was rather critical of the traditional brackets and preferred to construct his own stainless steel bracket, which now securely supports the kit via three carefully selected mounting points. The subsequent fine-tuning took three full working days.
In the end, Thorsten can no longer say exactly how many times he screwed the kit on and off to swap jets, check fits and perfect the set-up. The only thing he remembers fondly is the first extensive trip to the Hamburg area, “I was simply deeply satisfied.”
In conversation
Name: Thorsten Ihlo
Year of birth: 1970
Profession: Trained wholesale and foreign trade merchant, as well as communications and graphic designer
Company: Vergaser Manufaktur Hamburg
CB: How long have you been working with carburetors and when did you make them your profession?
Thorsten Ihlo: In 1994, I began to take a close look at classic cars and their technology. At first it was four-wheelers, but then two-wheeled vintage bikes soon followed. As I was a BMX rider from 1983 to 1992 and was already building my own bikes back then, the motorized two-wheelers were only a logical consequence. I somehow had a screwdriver fetish - and when I overhauled the first Solex 28 PCI carburetor for my VW Karmann Ghia in around 1996, my screwdriver fetish turned into a carburetor fetish. I had found my own comfort zone in the screwdriver area without ever having thought about it. I have been working professionally in the trade since 2014 and have also been registered with the Hamburg Chamber of Crafts since 2016 in the craft requiring authorization for: Motor vehicle technician trade, partial activity: Restoration and general overhaul of mixture preparation systems.
CB: Where does your love of carburetors come from?
Thorsten Ihlo: Just like an engine or gearbox, a carburetor “lives”. This is probably why there are people who develop a special love for these components. It breathes, drinks, “beats” in a rhythm, it stinks, leaks and sometimes makes strange noises - that's where sympathy and love come from if you have an affinity for machines.
CB: What influence does the choice of carburetor have on a motorcycle - technically and visually?
Thorsten Ihlo: The same great influence as in other vehicles such as automobiles, old airplanes, old gasoline-powered ships, etc. Simply put, the carburetor is actually an atomizer. The carburetor atomizes the fuel and mixes the correct ratio with air. It must also adapt the required mixture quantity to the respective operating state of the engine. To list all the related theoretical values, data and factors here would be too technical and your readers would fall asleep while reading.
From a visual point of view, carburetors have always played a role in the chopper and custom sector, albeit a subordinate one. Unfortunately, the carburetors on custom bikes are often simply mounted unseen and hidden behind something creative like an old coffee grinder from the flea market. The custom bikes from the 1970s by Arlen Ness show the influence of custom carburetors. On these bikes, every component - including the carburetor - was consistently processed and further developed down to the last detail in terms of its function and appearance. When I saw one of these bikes on display at the Born Free Show in California in 2015, it gave me goosebumps.
“When it comes to custom bikes and choppers, creativity usually stops at the carburetor. If the handlebars, the tank, the paintwork or the custom-made leather saddle are a special style element, why don't we look at the carburetor with the same eyes? ”
CB: What are the most common mistakes that can be made in connection with carburetors?
Thorsten Ihlo: That the carburetor environment is ignored. Around two thirds of so-called “carburetor problems” can be traced back to the carburetor environment or other engine components. Sluggish throttle cables or lack of lubrication, defective or incorrectly adjusted ignition, centrifugal governor and ignition box, old or dirty fuel filters, swollen fuel hoses and tank seals or fuel additives are just some of the points that need to be mentioned at this point. Even the best carburetor restoration/general overhaul is useless if, for example, the ignition and valves are not set correctly. Especially for the old Harleys - although, actually, always - the issue of secondary air/false air is an eternal companion. I can only ever repeat one piece of advice: The carburetor on Harley models such as Knuckle, Pan, Ironhead, Shovel etc. should always be supported, even if it doesn't look good. Simply supporting the manifold is not sufficient in the long term. Harley-Davidson still does this today with its mixture preparation systems ex works - and they know why. No clamp or clip in the world is sufficient to support the carburetor correctly in the long term. Incorrect air/side air is the quick consequence. Sources of error are basically also settings, jetting and the correct dimension of carburetor and jet. These are always individual to the engine and the selected setup of ignition, exhaust, air filter, valve control and other engines.
CB: What are the most common problems you have to deal with when restoring carburetors?
Thorsten Ihlo: With “broken” carburetors and worn carburetor housings in the throttle valve area. Unfortunately, there are also repeated cases of carburetor batteries from cafe racers, where the customer wanted to save money on the carburetor overhaul and thought that a 4-carburetor battery could be immersed in an ultrasonic cleaner in one piece and after half an hour of “soaking time” all would be right with the world again. Unfortunately, such dubious offers for general carburetor overhauls/cleanings are also available online and are offered for less than 100 euros. After that, the problems are only worse and carburetor workshops have even more work to do with the carburetor battery than before.
Another funny example was the wife of a customer. She had opened the package for her husband after I had sent her the finished and fully adjusted carburetor. He was still at work. She liked the carburetor so much that she turned all the brass adjustment screws she could find - that was a nice problem.
CB: Which is your favorite carburetor?
Thorsten Ihlo: Like other specialist carburetor workshops, I also have my special areas and preferences. For me, these include air-cooled Volkswagens and German automobile manufacturers and the carburetors they use. And of course the Indians and Harley-Davidsons. So I don't have ONE favorite carburetor, but I am fascinated by the Schebler, Linkert and all pre-war carburetors up to the year 1900. I also have a strong passion for motorcycle racing carburetors, especially from the 60s and 70s. The oldest carburetor I was allowed to restore was from 1907 - you never forget one of those.
CB: How much longer will we be riding carbureted mopeds?
Thorsten Ihlo: As long as there is gasoline.
“For over 100 years, even seasoned bikers have been kicking a handle on their legs from time to time. Accept the lack as an integral part of old technology and gain experience. The rest will come naturally at some point.”
Ihlo.carburetor.com Carburetor restoration from the expert: Thorsten Ihlo. Precision for historic vehicles. Individual solutions for collectors and specialist workshops.
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