Commando Recommendations and Slipping Clutch: Q and A

Keith gives advice on fixing a slipping clutch, an oil leak, a slave cylinder and more.

Reader Contribution by Keith Fellenstein
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by Nick Cedar
1975 Mark III Norton Commando

Recommended Commando

Question: I’ve been a fan of Motorcycle Classics since the premiere issue, and your column is always the first thing I look for. I really love my 1979 Suzuki GS1000E, and I’ll never give it up, but a friend had a bright yellow Norton Commando in college, and I’ve always wanted one ever since. Strictly from the standpoint of performance and the joy of riding, what year, model, and upgrades would be the best choice? Do you know of any shops on the west coast or in the Midwest (I live in Alaska) that specialize in Commandos? Other than eBay, where should I be looking for one? Thanks for your advice.

Doug/Anchorage, Alaska

Answer: The Roadster models seem to be the most numerous, with the Interstate models scarcer and the HiRider model the least liked (and perhaps less expensive as a result). The early Fastback model is beautiful, but suffers from a fiberglass tank that is problematic with ethanol-laced gasoline. I’ve got a 1974 Roadster model and with the Colorado Norton Works electric start upgrade (see story at it’s as easy to use as any modern bike. Since you have a Suzuki as your favorite ride, you might be best served looking for a 1975 model Commando with electric start. After 1974, U.S. safety standards required all motorcycles to have left-foot-shift/right-foot-brake, so there wouldn’t be any control confusion between motorcycles. As I mentioned above, I’d avoid any bikes with fiberglass tanks due to fuel issues. As for where to look, Craigslist, Facebook Marketplace and word of mouth are all options to add to eBay.

Clutch issues

Question: I have a 1966 Yamaha YDS3C with a slipping clutch. When I purchased the bike it had three 3.5mm friction plates and three steel plates. The owner’s manual I have shows a diagram with four friction and four steel plates. I ordered new friction plates (3.6mm) from Barnett and an extra OEM steel plate. I installed everything and put it back together. It still slips when kicking it over. I noticed as I tighten the nut that holds the clutch in it slips worse. I’m stumped and at a complete loss of what to look for. I’ve heard from Facebook forums that there should be five plates but it’s impossible to fit five plates into my clutch housing.

Luke/via email

Answer: I’ll start with the simplest solution first and then move to more complex measurements. Make sure you’re not using a modern automotive oil, often rated a low 5W or even 0W. Those have friction modifiers in them that can cause wet plate clutches to slip. Use an old formulation oil such as Castrol GTX. Next, measure the clutch friction plates and springs to make sure the right parts are installed. The friction plates should measure .169 inches or 4.3mm thick and the springs should have a free length of 1-inch or 25.5mm length with a tolerance of .08-inches or 2mm. Note: I heard back from Luke and he replied: “I ended up fixing my slippage. My plates were for the later year with the 3.5mm clutch plates. I resolved the issue by adding an extra steel plate to get the right stack height, my springs were all 25.5mm.”

Wet sumping problem

Question: I have a 1974 Triumph Trident T150 that drains oil into crankcase after a few days. I have read a few articles on the problem and was hoping you might have an easy replacement or repair strategy where I don’t have to take the engine apart for a proper fix. Many thanks!

Bryan Domachowski/via email

Answer: The Trident engine has an anti-wet sumping valve built in that works fairly well. Yours could have a bit of debris holding it off the seat. On the underside of the engine, on the left side near the oil sump plate you will find the bolt holding the ball and spring. Place a pan under the engine to catch any oil and parts that may fall and loosen the bolt. A spring and steel ball should fall out when the bolt is removed. Clean both and replace the parts, ball first then spring, then bolt. If your setup has a copper washer used to seal the bolt, don’t forget to anneal it with a propane torch to soften the copper before reusing the washer. If, after this procedure you still have wet sumping there is one more thing you can do to try and stop it. Repeating the removal procedure, place the ball back in the cavity and, using a brass drift on the ball, give it a tap with a hammer. Don’t overdo it. A light rap should be enough to conform the seat and ball to each other. Then replace the components as before.

Slave cylinder issues

Question: I have an 1985 Suzuki Madura GV700, and it has lost all its clutch fluid. I’ve been told it’s the clutch slave cylinder because of the fact I’m not leaking fluid. I’ve watched videos of replacing them but never on a Madura. I have found that the head of the bolts holding the cylinder are not on the left hand outside. They’re on the inside. From what I get from the owners repair manual, I have to take the back wheel off, then the driveshaft, then remove the secondary gear set before I can get at the bolts. Let me know if I’m headed in the right direction, and if you have any tips to doing the repair. Thanks!

Ed Shaver/via email

Answer: Unfortunately you’re right, you have to remove the driveshaft first, then the secondary gear set. Only then can you remove the clutch actuating cylinder from inside the secondary gear set. This is another bike I have no experience with so I don’t have any shortcuts to share. Again, maybe our readers can help out.

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.

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