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I bought a 2005 Honda CBF 600S, rode it for about a week, and then asked my mechanic to check if everything is OK, and to replace the clutch cable.

The mechanic also replaced all the fluids, including oil. I took the motorcycle back to my garage, and on the next morning, I started the bike on neutral, gave it some time (a minute or two) to warm up, pulled the clutch lever, shifted into first gear -- and the engine stopped. I then started the engine again, and this time there was no problem.

This situation occurred again and again.

Now, EVERY MORNING, after the warm up I turn the engine off, shift into first, give the bike a wobble while pulling the clutch, and after the clutch plates disengage, I start the engine again.

I asked my mechanic what might be the cause, but his only idea was that the previous owner might have used some gasoline additives, which are known to interfere with the oil's quality. But that doesn't make sense, the bike had no such problems prior to my visit to the mechanic's.

My first thought was that my mechanic might have replaced the oil with a lower-viscosity one, but both SAE 10W-40 and SAE 10W-30 are fine for Honda CBF 600.

Questions:

  1. What might be the cause? I should add that, other than the problems in the morning, the clutch works fine.
  2. Is my wobbling the bike in first gear somehow foolish? I've heard that the cam chain tensioner may become mis-adjusted if the bike is pulled backwards while in gear, but I couldn't confirm that using google.
  • @DucatiKiller must be taking the weekend off ... I'm sure he can answer this question though. – Pᴀᴜʟsᴛᴇʀ2 May 15 '16 at 12:19
  • It is suppose to use 10w30 semi synthetic – Moab May 15 '16 at 16:52
  • @Moab, I guess it depends on the ambient temperature. The Haynes Manual says that both 10w40 and 10w30 are fine (although the 10w30 is OK up to ~30 deg. Celsius / ~86 deg. Fahrenheit), but does not say whether the semi or fully synthetic is the one to go with. It says: "Oil type: API grade SE SF or SG". Personally, I always thought that fully synthetic oils are generally better, although more expensive. Anyway, I don't think this might be the cause -- both 10w30 and 10w40 should have the same viscosity at lower temperatures (mine is about 20 C / 68 F). – ponadto May 15 '16 at 19:45
  • @ponadto I assume they put in the proper amount of oil... – Moab May 16 '16 at 18:32
  • I"m totally skeptical of the oil theory. I've never had this happen to me unless the bike sat for a few months and it only happened once. When I was younger I ran the crappiest oil ever. There is something physical going on here outside of the oil. Additives and all of the mumbo jumbo...where the citations? I just can't buy into it. – DucatiKiller Jun 3 '16 at 8:04
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Motorcycle clutch plates sticking together in the morning is a fairly common complaint. The oil squeezes out from between the plates overnight, and they don't want to separate when you first pull in the clutch lever. One could conjecture that this is a sign the clutch is getting old and tired, but I had this problem with a brand new factory clutch in a Kawasaki KZ1000. So I don't think it's just age.

First, if this wasn't a problem before the oil change, then it's a pretty good bet that the oil just isn't right for your clutch. It would be great if you knew what was in it before so you could use it again, (perhaps you could contact the previous owner and ask?) Honda specifies a JASO (japanese automotive standards organization) "MA" certified oil. JASO MA includes some multi-plate wet clutch specific tests, as well as standards for ash, etc, so it's worth giving it a try. A surprising number of motorcycle-specific oils sold are NOT MA certified. On the other hand, Shell Rotella-T diesel truck oil IS MA certified, so go figure.

Second, yes, turning the engine backwards puts unusual forces on the cam chain guide and tensioner, so best to avoid it.

Besides pushing it in gear before starting (and you aren't the only person I've known to do that,) you could also try pulling in the leaver and blipping the throttle a few times before dropping it in gear. That often is enough to free the clutch.

To summarize, this isn't some sign that your clutch is about to come apart, it's just something that motorcycle clutches do. And if you find an oil that cures it, please post a follow-up so we can all benefit. Thanks!

  • Thanks, that's a very valuable answer! No, it's not possible to ask the owner :\ I'll ask my mechanic about the oil. I did find out that by blipping the throttle a few times I can free the clutch, so that's a 'confirm'. And I'll definitely let everyone know, once I find the source of the "problem" (or a lack of problem)... – ponadto Jun 3 '16 at 6:38
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This sounds like the kickstand safety switch has gone astray. Almost like the switch gets stuck and the bike thinks the kickstand is still down when its not. After 'wobbling' the bike, the switch gets unstuck?

  • That's the first thing I've tested, and no, that's not the cause. I'm guessing someone down-voted you because it's more of a comment rather than an answer (?) – ponadto May 16 '16 at 4:03
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Why not slip a cable tie over the clutch lever, or something similiar, as I do when leaving my show bike for a longer period,and your clutch will never stick, just a thought. Paul.

  • This doesn't seem like an answer to the specific question - rather a piece of general advice. – mike65535 Apr 3 at 11:41

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