Starter slipping

[Aeronca]

When attempting to start my 1980 CBX COLD the starter engages and turns over the engine for 5-10 seconds and then slips and spins freely. When the spinning exhausts itself and stops re engagement will produce the same results eventually. Just wandering if the bendix may be the issue and if anyone here has had a rebuild done on the starter itself

Thanks again in advance.

[steve murdoch icoa #5322]

Here is an excellent tutorial on a starter rebuild.
viewtopic.php?f=21&t=8972&hilit=starter+rebuild

It almost sounds like your problem might be the starter clutch instead.
Does it only do this when the engine is cold?
What kind of oil are you using? It has never been an issue for me but some starter clutches do not do well with synthetic oil or too thick an oil.

[daves79x]

I'm with Steve - it's your starter clutch. Are you using synthetic oil? If so, that's likely the problem. Switch back to regular dino oil and see what happens. Repairing the starter clutch involves removing the engine and splitting the cases. Let us know what happens.

Dave

[Aeronca]

Once again this place is such an amazing resource. I would never have guessed oil could make a difference. I recently did an oil change change using for the first time, Kimpex synthetic 10W40. I have also been attempting to start the bike in temperatures around freezing. Hopefully those two changes are causing the problem as splitting the engine will start a whole new chapter getting the bike back on the road.

[Rick Pope]

Why are you attempting to start the bike? If you're not going to ride it and get it fully warm, leave it alone. Condensation is not kind to a motorcycle. Or any other vehicle for that matter.

[Aeronca]

Rick
Im starting it only to drain fuel from the carburetors for the remainder of the winter as it just came back from the shop where they had it running.

[Larry Zimmer]

I would suggest you just open the carb drains. This will remove everything from the carbs and bowls. If you have any doubts about residual in the fuel line(s), disconnect the line at the fuel valve that goes to the carbs when you drain. That's worked here in Michigan for 30 years plus. Add a double dose of Techron or similar when you start in Spring.

[Rick Pope]

I'm not sure, but isn't the accelerator pump well lower than the drains? I've slept since having the bowls off...... If so, a few twists of the grip would clear the pump as well.

But Larry's right, draining will cause no harm, and won't introduce moisture everywhere, especially the exhaust.

[Aeronca]

After the carbs starve I open up the drain screws as well. There is always some residual that drains out. I went through three sets of exhaust pipes back in the late 80s early 90s due rust at the lowest point in the exhaust system. I tried drilling a few holes right around the lowest point and sure enough I have never had a problem since. Prior to that I tried everything else including spraying rust inhibitor up the pipes in the fall before storage but that didnt work out so well when I smoked out the entire city when running it the next spring. LOL

[EMS]

It always cracks me up - the reoccurring fairytale about the synthetic oil causing clutch and starter clutch slippage...It is almost as bad as the fairytale about DOT5 brake fluid.
It is not about using synthetic oil but all about using the WRONG synthetic oil. If you use modern automotive spec synthetic oil, you will have the same issues as using regular automotive oil. Added friction inhibitors prevalent in these oils will cause slipping. There is absolutely no scientific evidence that synthetic oil is more "slippery" than conventional oil, if you compare apples to apples.
Some "experts" even claim they have experienced oil leaks with synthetic..
If you use a motorcycle specific synthetic oil you will have no problems, neither with the clutch nor the starter clutch. I run 16 motorcycles of various designs and where I use synthetic oil, I have no problems. Never had in more than 35 years.

[daves79x]

Sorry Mike, but starter clutch slippage has been proven to occur when switching to ANY kind of synthetic in many cases. If you will remember my many previous remarks on this discussion, I've readily admitted that my personal '79, switched to Mobile One around 1990, never had the starter clutch slip, then switching to Golden Spectro semi-synthetic several years later (M/C-specific oil) it has never slipped either. But I've had several bike here, and many other testimonials, that the starter clutch did indeed slip badly on synthetic oil, and when changing to regular oil, stopped. My latest testimonial was on none other than the Katrina Bike, just last year. Don had a constant problem with the starter clutch kicking out, after he switched to synthetic oil some years ago. He basically quit riding it because of that and other issues. When I got it here, I did a re-commissioning and oil change to Honda GN-4 regular oil. The starter clutch never kicked out one time in the remaining time I had it until it was sold and the new owner has never had it kick out.

Synthetic oil IS a problem for many starter clutches on CBXs. It does not hurt to try it and see, maybe even try many different types of synthetic (that gets expensive), yours may not kick out and synthetic is indeed good for these bikes in general. But if the clutch does kick out after changing to synthetic, change back and you'll likely have 'cured' the starter clutch.

Mike - do not try to confuse this issue by mixing in drive clutch slippage. I never claimed synthetic oil caused drive clutch slippage. We're talking about strictly starter clutch slippage/kicking out here.

This is NOT a myth Mike.

Dave

[daves79x]

Now, back to your issue of starting the bike briefly to clear the carbs and your history of rotted-out exhaust systems. THAT is the problem - starting the bike too often and not running it out on the road 25 or more miles to dry out the exhaust (and oil for that matter). A tremendous amount of moisture accumulates when the hot exhaust gas hits the massive amount of cold metal in the CBX exhaust. It must be burned completely off or you will indeed get premature rust-through.

As Rick and Larry said, just drain the bowls after the last long ride, fill the tank, cover it up, keep the battery charged and forget about it until Spring.

Dave

[EMS]

Yes, Dave, I know. There are these nasty little ferrous alloy molecule assemblies in the starter clutch that are on the watch for synthetic oil. As soon as they detect some of it coming, they decide: "Let's make it slip"....This has to be the explanation! I cannot see any other. And I was involved my whole professional life dealing with hydraulic systems, assessing fluid features and qualities for a wide range of applications.

[spencer]

You can poke fun at the people who say that synthetic oil causes starters to slip, but that will not change my mind. From the time I bought my CBX, I used nothing but Mobil 1 Racing 4T motorcycle oil. I read accounts from many people telling how synthetic oil makes the starter clutch slip. I never had any slip. I figured I was lucky. Then, a couple of years ago, one spring, all of a sudden, my starter clutch started slipping a lot. And, when I released the starter button and the starter motor slowed down, all of a sudden it would engage again and it made some terrible noises. I changed to a conventional oil and my slipping was immediately gone and it has never, not once, slipped again. As much as I liked that Mobil 1, I don't use it any more.

[EMS]

…..
It is not about using synthetic oil but all about using the WRONG synthetic oil. ....

Once again, as so many times in the past, you guys NEED TO READ MY POST...
On a side note: Mobil 1 is a terrible oil to use in a motorcycle, unless you use their 20W40/50, which, unfortunately, you cannot find anymore. At least, I can't.