Tech Corner
Technical Q and A for classic motorcycle maintenance and repair.

Stuck 1969 BSA Victor Engine

Motorcycle Classics tech expert Keith Fellenstein
Editor's note: If you're having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send your questions to: Keith's Garage, Motorcycle Classics, 1503 SW 42nd St., Topeka, KS 66609, or send an e-mail with "Keith's Garage as the subject.

Q: My 1969 BSA Victor, bought decades ago and never ridden much (other, better bikes at hand) has been stuck for quite some while. The bike was well stored, the tank is clean, and it ran well when I lost interest in it (it was never an easy starter). How do you think I should proceed in getting the engine turning again? I'm pretty sure I ran some penetrating oil into the combustion chamber many years ago.
— Howard/via email

A: The inexpensive penetrating solvent of choice is a 50/50 mix of ATF and acetone. I'd first pull the left case cover off, and using an appropriate socket and gentle pressure, see if you can't get the engine to rotate a little. If that doesn't work, then pour in enough of the penetrating solvent mix to cover the piston top and let it sit and soak down for a couple of days. Repeat these two steps until you achieve success. You can also try using some mild heat from a heat gun (not a torch!) applied to the cylinder, which might speed the process along, too.

1976 Honda 360T Carburetor Trouble

Motorcycle Classics tech expert Keith Fellenstein

Editor's note: If you're having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith's Garage, Motorcycle Classics, 1503 SW 42nd St., Topeka, KS 66609, or send an email with "Keith's Garage" as the subject.

Q: I have a 1976 Honda 360T in very nice original shape with just 13,000 miles on it. I just had the bike tuned up at the local Honda shop (new points and condenser, set the timing, adjusted the timing chain, set the carburetors, new plugs). The carbs were not taken apart and cleaned. Upon getting the bike back it fired right up and idled. Taking it on the road for a good run, however, I noticed it missing on the right cylinder, with a "popping" from the right exhaust. Back home, I took out the plugs. The right side plug was fouled badly with black soot, while the left side was a nice medium brown. I tried a new plug and rode it again, but I got the same result: a fouled plug. Using a "color tune" kit I had gotten from England awhile back I was able to see that the plug color changed with increased rpm, from blue to yellow (hot to cold, hence, the fouling). My question is, what could be causing this? The points are new, as I said. I'm wondering if a clogged jet or other carburetor problem on the right side is the cause.
— Bill/Rhode Island

A: I think you've hit the nail on the head. It sure sounds like carburetor trouble from the symptoms you describe. First, I'd try to drain the right side carb and see if there is any clue there. Then I'd pull the right carburetor and make sure it's set up correctly. Water precipitated out of the gas/alcohol mix we seem to get these days will often pool in the bottom of the carburetor and get sucked into the main jet at wider throttle openings.

1959 Triumph 500 Fuel Tank Cleaning

Motorcycle Classics tech expert Keith Fellenstein

Q: My dad has a 1959 Triumph 500 that has been off the road and stored for 14 years. We just had a look in the fuel tank — not good! Do you have any restoration solutions for such a mess? This tank is probably not salvageable (protective coating on interior is completely corroded with heavy scale). Everything else on bike is in very good shape. Thinking about a Father's Day gift.

Mick/via email

A: This arrived too late for Father's Day this year, but I hope you can get it sorted before Father's Day next year. With old gummy tanks I usually go through several processes to clean them, trying my best to not make a bad situation worse. First, drain what you can and dispose of it properly. Then, depending on the condition of the paint, you can try a couple of things. If you are sure you've got all the gasoline out, sometimes a trip to the car wash with the pressure hose will dislodge the crusty crud left behind. After that, Evapo-Rust is safe on paint, but usually won't penetrate any crust left inside. Vinegar is also a possibility. It's a weak acid and it will etch the rust away. If the tank has been previously sealed with something like Kreem, you will have to resort to strong solvents like methyl ethyl ketone to dissolve the rubber-like liner. MEK will also dissolve your tank paint and is best handled with rubber gloves and a respirator. If the tank paint is bad, or if you plan on having the tank painted, you might be able to get a radiator shop (if you can find one these days) or a machine shop to hot tank wash it clean.


Editor's note: If you're having trouble with that old Suzuki, BSA, or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith's Garage, Motorcycle Classics, 1503 SW 42nd St., Topeka, KS 66609, or send an email with "Keith's Garage" as the subject.

Suzuki TC185 Carburetor Jetting

Motorcycle Classics tech expert Keith Fellenstein
Editor's note: If you're having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith's Garage, Motorcycle Classics, 1503 SW 42nd St., Topeka, KS 66609, or send an e-mail with "Keith's Garage" as the subject.

Q: I have just acquired a 1976 Suzuki TC185. The bike starts easily and runs, but has some minor problems. It has a 71.5 main jet, but my manual says it needs a 130 main, so now I doubt any of the jets are correct. What is the correct carburetor setup for this TC185? I can't find any information, much less the parts. So far I've cleaned the carb, the air filter, the gas tank and the spark arrestor. I've replaced all the fuel lines and added an inline filter and a new spark plug. As I said, it starts and idles but then gets blubbery, like it's holding back. I think my top speed might be 30mph with the throttle wide open. I've tried the dual-range transmission and that works fine. My problem is in the carburetor, but I need to know what the right jets should be and where to get them.
— Dean/via email

A: That's a sweet little scrambler you found. That main jet size is correct for the 185 twin, but not the single. The main jet should be 130, as you found out. The pilot or idle jet for that model should be 17.5. You need standard Mikuni jets. If you have a local motorcycle shop that's been in business a few years, they may have what you need on hand. If not, Dime City Cycles has the jets. Just search on their site for those jet sizes.

Pinging Noise in a Kawasaki 350 S2A

Motorcycle Classics tech expert Keith Fellenstein
Editor's note: If you're having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith's Garage, Motorcycle Classics, 1503 SW 42nd St., Topeka, KS 66609, or send an e-mail with "Keith's Garage" as the subject.

Q: I recently purchased a 1973 Kawasaki 350 S2A triple. I'm using regular gasoline. The issue I'm having is a pinging noise coming from cylinder No. 3. This pinging noise is more noticeable at low rpm (below 2,000rpm). What could be causing this problem? — Mario/via email

A: I suppose there could be a carbon spike glowing and pre-igniting cylinder No. 3, but having it happen at idle makes me think it's something else, like a bearing rattle. Pinging usually occurs under moderate throttle while choosing a gear a little higher than conditions require. A mechanic's stethoscope, available at Harbor Freight or any auto parts store, is a handy tool for chasing down odd noises coming from your engine, but a long screwdriver held against the engine case with the other end pressed to your temple can give similar results. What you'll be listening for is the frequency of the sound. Is it every revolution or one in three? If you hear the sound on every revolution, then it's probably bearing related, but if you only hear it every one in three it would be specific to that cylinder.

Yamaha SR500 Petcock Challenges

Motorcycle Classics tech expert Keith Fellenstein
Editor's note: If you're having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith's Garage, Motorcycle Classics, 1503 SW 42nd St., Topeka, KS 66609, or send an e-mail with "Keith's Garage" as the subject.

Q: My 1979 Yamaha SR500 has a vacuum fuel petcock. I've found no way to eliminate it for a simple gravity-style petcock. I installed an inline fuel shut-off in the fuel line below the petcock. When I'm done riding, since the stock petcock has no "off" position and relies on engine vacuum to allow fuel flow, I turn the inline one to "off" and let the carburetor run dry to eliminate any gas going stale inside the carburetor. My problem is, when I go to start it, it takes anywhere from 5 to 20 kicks to get it started. The engine is running a 1980 Hi-Per-Kinetics Stage Two 650 stroker with 97mm x 88mm bore and stroke, a Megacycle 5120HP cam, Mikuni VM36 and other goodies.

I've owned three Yamaha TT500s, and they all had the on/off/reserve manual petcocks and all started first kick, hot or cold. How can I eliminate the funky stock petcock without replacing the tank? Does it require a lot of kicks to get the fuel flowing from the petcock because of the engine modifications? Should I just not run the carb dry after riding? I use octane booster and fuel preservative. The bike had sat for over 25 years when I bought it in 2012. The inside of the carburetor was surprisingly clean, with no gum at all. — David Fruhling/via email

A: It is taking so many kicks because there would normally be enough gas in the carburetor to start, then engine vacuum would open the petcock and refill the bowl before it ran dry. There should be a "PRI" or prime position on the petcock that bypasses the vacuum and flows gas to the carb for those instances when the bowls are dry, such as after a carb rebuild. After a little searching I found a good option. It's an adapter that bolts directly to your tank and allows you to use a standard non-vacuum petcock. They also offer the petcock that fits the adapter, making it a one stop shop. Don't forget to plug the vacuum port on the intake manifold.

Kawasaki KZ1000R1 Engine Paint Codes

Motorcycle Classics tech expert Keith Fellenstein
Editor's note: If you're having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith's Garage, Motorcycle Classics, 1503 SW 42nd St., Topeka, KS 66609, or send an e-mail with "Keith's Garage" as the subject.

Q: I'm slowly restoring a 1982 Kawasaki KZ1000R1 and am having difficulty identifying the correct black paint to use on the engine and carburetors. I'm under the impression that the paints used in 1982 no longer meet regulatory requirements in the U.S. and finding a suitable replacement is difficult. Any chance that you have insight on this matter and a source for the paint codes and type of paint? — Drew Jones/via email

A: I've never worried too much about a correct match for black barrel paint; it's more important to get a heat-resistant paint. Most of the time I just use a quality brand spray paint made for BBQ grills. It's meant to take the heat and has worked well.