Carburetor Rebuild FAQ
Questions You May Have About Carb Rebuilding
- What is the process?
To keep things orderly, I ask that you use my shipping checklist and also stop by my shipping tips page. When I receive your shipment I log it in and send you an email. Within 24 hours in most cases, but sometimes 48, I will have your precious carburetors completely apart and in the ultrasonic bath and a service order already partly filled with notes of things observed during the disassembly. Most of that is for my own use so I remember to either double-check something during the second after-bath inspection, or a reminder of an item to make you aware of when I next email. Upon removal of the carbs from the sonic bath the sparkling clean parts are laid out on clean white doctor's exam paper and a second inspection made of everything, looking for example for cracks or other things not usually visible before cleaning. The next thing I do is manually and individually flush out each carburetor circuit with a strong aerosol cleaner to both ensure proper cleaning internally (where it counts) and to make sure I know the real condition before sending that second email aprising you of the condition of the project and, in rare cases, changes in the estimate or timeline, if any. From that point the promised timeline begins. You will get another email either at the finished point or slightly before, including an itemized invoice, an opportunity to confirm your shipping address, and a brief summary of outstanding findings if any and suggestions for future maintenance. After payment I email you to expect the return shipment, with a tracking number, and offer some final tips for using your newly restored carburetors.
Not everyone is aware what junk they are putting in their carbs when they use carb rebuild "kits.". A valve made like this will not seal, resulting in constant fuel overflow issues. From a K&L kit for the Yamaha XS750.
- Which rebuild kits do you use?
I rarely use carburetor kits. Kits are problematic. Whether Keyster, K&L, whomever, they usually contain many parts you do not need, and more importantly, leave out many that you do need. Plus, the quality of the metal parts is way below the standard of the original, no matter what their sellers claim. On Honda DOHC fours and the CBX, for example, significant performance problems can be traced to the use of Keyster carb kits. And K&L are not any better, and CrusinImage, Sabre Cycle, Napco and the rest are even worse. I realize this is counter to what many others say, but it is true. People who like aftermarket kits are not testing the float valves, and not paying attention to how the parts actually fit. I use only top quality parts, OEM where a must (as in float valves) or top quality replacement parts available from a small handful of specialist suppliers.
- Are the o-rings used in your rebuilds the superior Viton synthetic rubber, or some other material?
I use only the more expensive, harder to use and harder to get Viton material o-rings in my carburetor projects. They cost three to five times as much as the buna rubber many use, because I want my projects to be absolutely leak-free for as long as possible. This is just one of many areas where the "kits" marketers make their money, by using o-rings made of inferior materials.
- Where do you source the float valves from?
With rare exception, I use factory Keihin float needles in all the Keihin carbs I do. Not aftermarket. See question number 2 above. Aftermarket float valves are very poor quality, heavy, zinc material, chrome plated. The stock valves are not chromed but plain aluminum. They don't peel, they seal immediately right out of the package, and they last scores of years instead of just two or three. This is probably the single most critical part in your carburetor and, ironically, the thing most differentiating carburetor rebuilders. Most do not use exclusively factory float valves. My nearest competitor certainly doesn't.
- Do you take the carburetors completely apart, including active circuits such as air cut valves?
I take all the rebuild jobs I do completely apart, even though some things need to be removed only for inspection. The only things not disassembled are the throttle shafts and butterflies, which is neither necessary nor is it advisable. On some jobs however I even disassemble these, and I have the replacement factory felt and rubber seals for the rare event that it is necessary to remove these shafts. As for the aircut valves, on CBX1000 and GL1200 carbs I am probably the only one who removes the air cut valve from the casting because it requires a special tool that I made myself. Everything is inspected, nothing is left to chance.
- Are you factory certified by the maker or distributor of these carburetors?
I was certified by American Honda Motor Company in 1983, eventually taking over 220 hours of Honda training. My most recent factory Honda course was in 2003. I probably have more Harley-Davison, Yamaha, Suzuki, Kawasaki and Honda training than any carburetor rebuider presently making a living doing carburetors.
- Did you work on these carburetors when they were new?
In fact I did, something few other rebuilders can say. I made my living by servicing these carburetors and the bikes they are part of, during the 70s and 80s. I was there, I know the bikes, and continue to dervice them even today, which helps me understand the carburetors better too.
- Do you use the ultrasonic cleaning method?
Yes. Rebuilders who dismiss ultrasonic cleaning are at best misguided. They don't know what they are talking about. While ultrasonic is not a silver bullet, that is, it doesn't allow cleaning carbs without disassembling, there is no better method for cleaning carburetors when it is used professionally. I use an expensive industrial grade ultrasonic machine to get the outside of the carb castings the right clean sheen, to get difficult internal passages completely clear, and to clean all the non-metallic and smaller metallic mechanical parts, all of which it does very well and which without ultrasonic require many different chemical approaches. Avoid rebuilders who won't specify the cleaning method they use or who use Simple Green, which leaves behind a corrosive residue, or Pine-Sol, which imparts a dark stain to the carbs and does little to clean them. Moreover, I strongly question the quality of "cleaning" carburetor in an abrasive blast cabinet, which many rebuilders increasingly do.
- Do you use a special workbench just for carb work, separate from engine work, machining, and other kinds of work?
Of course. My carburetor bench is just for carburetors. It houses over 40 special tools used just on carburetors (including for example the factory float level gauge), many of which I have made myself, and over 100 bins of new replacement parts (most of them OEM). The bench gets covered with a fresh sheet of medical exam paper (just like at the doctor's office) before I assemble each set of carbs I do. The conditions your carbs are assembled in is practically a "clean room" environment.
- Do you have a supply of critical repair parts?
I have many thousands of dollars worth of parts carbs in inventory, plus an enviable supply of quality NOS replacement parts.
- Do you offer metal parts replating?
Yes. I frequently re zinc plate the steel brackets on carburetors, on request. I don't do chrome however.
- Is vapor honing available?
Yes. On request I do vapor honing also.
- Do you have the special tools required to properly disassemble carburetors without damage?
There are areas on these carbs that require special tools to service, tools that are not available for sale. I have them, and few others are likely to have anything similar, as I made them myself to do the work properly. The air cut valve tool mentioned above, for example, and tools that service other similarly non-removable parts. Mass-produced Japanese motorcycle carburetors weren't actually made to be rebuildable. Thus it takes some creativity to do a good rebuild job on them.
- How do you clean the non-removable float valve seats such as those on early Honda DOHC four carbs?
On those models whose float valve seats are non-replaceable, ultrasonic cleans them very well. But I also hand-clean them with carb cleaner. I do not use abrasive on them! Avoid those rebuilders who put anything else in the float valve seat, whether toothpaste, valve lapping compound, anything at all, as this runins the seats. Hack stuff, that.
- Do you offer Allen screws as part of your rebuilds?
I'll use Allen screws if requested. But, I don't like them. See my article on this. At the end of the day, the factory screws look the best and give the least trouble if handled correctly.
- Do you offer chroming or powder coating of carburetor castings?
No, I don't. If you look around you will find that pro carb rebuilders do not engage in this treatment. There is a good reason. First, chrome plating never permanently adheres to cast aluminum, so it is not all that good a practice. But more importantly, carburetor parts such as CV vacuum tops are highly at risk when chrome plated. Chromers seldom avoid getting plating into tight tolerance areas, and on vacuum tops, the whole part is a high tolerance area! Chrome on its edges will cause binding of the slide, and chrome on the inside of the top will similarly affect slide movement. There is just too much bad stuff going on here. The same principles hold for powder coating. The best treatment for carburetor parts is to properly clean them and leave them alone.
- What is your guarantee?
My guarantee is simple. I am not satisfied until you are. Until your bike runs as good or better than you expected, I will continue to work with you. I may however insist that you take responsibility for tuning adjustments on your machine other than the carburetors.
- Why aren't a lot of dealers or repair or restoration businesses using your services?
One reason primarily: I don't like having a layer between me and the customer. I have tried it and it doesn't fit the way I do business. I like to keep open the line of communication between the end user -- the fella who will be twisting the throttle -- and myself. I typically email my customers three to five times during the job's progression, just to keep them in the loop and encourage them with progress reports. I figure my customers like to see how the carbs get taken apart, what condition the parts are in, what I look for in terms of problem areas, and I think they enjoy a kind of look over my shoulder as the carburetors go back together. Another reason I don't pursue work with dealers is I don't like to be rushed. That's a biggie too. There are more reasons, such as most shops having a poor communication ethic, many shops being challenged when it comes to installing and adjusting vintage Honda carbs (there are a lot of mechanics out there that hammer on the backs of carbs instead of heating up their manifolds), and not the least, my pricing just doesn't include enough margin that I can give up for dealers. But, insulation from my customer is the primary reason I haven't developed relationships with dealers, and probably never will.
- Do you do proprietary mods to enhance the way the way the carbs work?
I do. The standard specifications for some circuits in VB carbs for example, as well as others such as the Keihin VD series, benefit from knowledgeable tweaking.
- How do you sync carburetors on the bench?
I use a method used by most rebuilders, I line up the bypass outlets. It works very well as reported by my customers, who seldom have to change it once they mount the carbs up and are running again. Stay away from rebuilders who stick anything, wire included, under the throttles. This damages the throttles, particularly the throttle plates on CV carbs which when abused this way usually need replacing, at some considerable cost.
- Do you run completed carburetors on a test engine?
No, I don't. While that may sound like a huge advantage, first, all this does is adjust the carburetors to that particular engine, and second, it introduces gasoline and therefore starts the varnish clock ticking. So there is no real advantage, and some potential disadvantages. Running carbs on a test engine actually benefits the rebuilder more than the customer, as it allows him to catch mistakes and discover leaks. Leak testing on a bench, which I just as most rebuilders do, has the same benefit. I work hard to give my customers a turnkey experience. The throttles are mechanically bench synchronized, which leaves them only to be checked on your running bike, a task you should be doing every 6,000 miles anyway. But it won't be the end of the world if you don't. Many of my customers report they haven't needed to sync the carbs once bolted on and the engine running. I also adjust the idle mixture screws. The only thing the customer has to do is adjust the idle.
- Do you offer unlimited after-the-job support?
I maintain continuous email and web support for all my customers, including as mentioned above online updates as the project progresses, but also questions answered if they come up afterward. Each of my customers gets an itemized invoice of all the work done and parts rebuilt, replaced and serviced. Also included is a tips sheet on how to make the reinstallation of the carbs the best it can be, for example suggestions for making sure the rest of the engine is up to snuff as well.
- Do you spend time talking with folks about their carburetors?
Yes, definitely! There are other carburetor services who do not like to communicate with people. But I do. I make a point of providing as much information as I can. The way I look at it, it's the people quotient. When it comes time to spend the money, who are people going to go to, the guy who can't be bothered, or the one who takes the time to make sure his customers are well informed and equipped?
- Do you offer instruction in how to clean and rebuild carburetors should the customer decide to do it himself?
Yes. I have frequently walked folks through difficult parts of the job by email. Plus I offer how-to books, geared toward the do-it-yourselfer with lots of pictures.
- Who are some of the folks you have done carb work for?
My customers' comments may be found on my website guestbook. It is gratifying to know that people get so much enjoyment out of the small part that I contribute to their riding experience.
- How do I initiate the project?
If your bike is running, measure cylinder compression, ignition timing and spark strength (using a special opened up
spark plug), and ensure good fuel flow through fuel tank and petcock. Then confirm the final diagnosis with the t-shirt test. Loosely wrap a t-shirt around your air filter element as a test. If the engine runs better, then carburetion is indicated as a (if not the only) problem. If there is no change or the result is worse, repeat the test with neither t-shirt nor air filter element. Improvement in either case indicates carburetion. No improvment in either case mostly exonerates your carburetors as the trouble. My goal is your satifaction. You won't be satisfied if all or most of your bike's issue is something other than the carburetors. When ready to send me your carbs for shipping, be sure to drain them well before packing, include in a baggie any loose pieces. Be especially careful with the float bowl overflow nipples or hoses, they are the most delicate parts during shipping. In fact it's best actually to remove the hoses and keep them. Please advise me of any modifications on the motorcycle, especially the type of air filter used, changes to the exhaust, what you have been getting for fuel mileage, and be sure to aprise me of any peformance issues you have been experiencing and what if anything has been
done in response. Please also include your ship-to address on a note inside the box. For your convenience I have a shipping checklist (including my shop's address) here, shipping tips here, some removal/reinstallation tips here, and my email here.