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It's a BigBoy DRT-250, a cheap Chinese import, normal manual gearbox motorbike, not scooter, which probably already partially answers the question, but at 10,000km I have had no prior mechanical problems. It's been serviced by the dealer at 500km, 3,000km, and 6,000km, and should be due for one now, at roughly 9,600km.

When I start it, in neutral, and kick down to first, I can feel the gear taking, with a small nudge forward, but as soon as I pull off, it's as if I was still in neutral. I have to first push the bike around (down as many hills as I can find) while in 1st, then it improves a little, and I can ride around in first, but very slowly, even at high revs. After about fifteen minutes of this, I can start really revving the engine very high, and feel the clutch start taking. A few of those and I can get back up all the hills I've gone down, and ride almost normally. Sometimes while riding at a steady speed, in any gear, the clutch will slip for a second or so then normal riding resumes.

I find it difficult to believe normal wear will do a clutch it at only 10,000km; I've loosened the cable totally, so there is plenty play on the gearbox lever when the clutch is released, and I have only used the oil recommended by the dealer, Motul 20W50 mineral oil.

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    I don't know much about the "cheap Chinese import" but would bet the springs which close the clutch are worn out or have been over stressed, which are allowing the clutch and steels to slip past each other. I'm not aware if the clutch is cable or hydraulic actuated. If cable actuated, there may be some adjustment there.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    May 1, 2014 at 10:32
  • It's cable, and I've adjusted the hell out of it. While waiting for a tow this morning, a fellow biker suggested I smell my oil, and it does indeed smell something like burnt friction plate.
    – ProfK
    May 1, 2014 at 16:01
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    After your description, I have no doubt it smells like burnt friction plate. I doubt a change of oil is going to help you, either. I'm really thinking you need a clutch rebuild. Hopefully it's still under warranty, though wouldn't have a clue how well Chinese companies back their product.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    May 1, 2014 at 19:08
  • Ive voided the warranty. It was a cash trap. Must service every 3000km or three months. I hardly do 1000km in three months. Every few thousand km something else falls off the warranty. A fellow biker stopped to help yesterday, and suggested I smell the oil. It smells like something, no doubt friction plate, has burnt.
    – ProfK
    May 2, 2014 at 2:02
  • Did you use the correct oil? on my ducati synthetic oil is known to cause clutch slip, it needs to be semi-synthetic at most.
    – Mauro
    May 2, 2014 at 10:44

2 Answers 2

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I think you've answered your own question

You said.

cheap Chinese import

Once a clutch starts to slip a little bit it can go all the way to useless pretty quick.

Once it's slipping regularly it creates a great deal of heat from friction. When the steel and neoprene plates are locked together there isn't any heat be released from friction because they are locked into place.

Your plates are probably glazed from over heating. You can take them out and use 250 grit sandpaper to take the glazing off of everything. Be sure you clean them exceptionally well when are done as you don't want any of the grit leftover getting into your engine.

I've done this on liter size bikes to get the clutch through, or to get home, and it's been effective. I've had them continue to work for an extended period of time too. When your a kid and you don't have any money, you're motivated to make it last longer.

This trick could be permanent solution until it actually where's out, or a stop gap. You'll find out.

You may discover your neoprene plates are completely destroyed and ground up in your oil, if that's the case, change your oil and filter ASAP and check your oil catch screen.

Cheers!

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You can also put little washers under the springs to get a little more out of it, another poor boy trick.

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  • A perfectly good tip, for a "poor boy". I feel sorry for the illiterate prick that downvoted you.
    – ProfK
    Feb 24, 2017 at 7:43

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