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Weird problem, beyond my knowledge!

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knockout_bar
Scooby Slapper



Joined: 06 Jul 2005
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PostPosted: 17:49 - 22 Oct 2005    Post subject: Weird problem, beyond my knowledge! Reply with quote
Hi all!

I'll get straight to the point Razz.

Basically my bike used to do 80kmph (50mph) at exactly 7,000rpm. I checked today and the bike now does 65kmph at exactly 7,000rpm (both cases in 5th gear/top). This means I now have to do 8,200ish rpm to hit 80kmph (50mph).

WTF?

I haven't done anything to the gearing or sprockets. The only culprit I can possibly think of is clutch slip, but the bike is under a year old?????

This is beyond my knowledge and it's probably going to get worse. I really don't want to have to redline my bike in top gear to hit 50mph.

Please help me!
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Robby
Dirty Old Man



Joined: 16 May 2002
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PostPosted: 17:51 - 22 Oct 2005    Post subject: Reply with quote
Clutch slip seems the only possible cause. Pull it apart and have a look.
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knockout_bar
Scooby Slapper



Joined: 06 Jul 2005
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PostPosted: 17:54 - 22 Oct 2005    Post subject: Reply with quote
It only happens past 6k rpm tho Confused.
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125 trail bike, custom bars, handguards etc. - ?500.

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Robby
Dirty Old Man



Joined: 16 May 2002
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PostPosted: 18:12 - 22 Oct 2005    Post subject: Reply with quote
Certainly sounds like clutch slip then. Tends to happen more at higher revs.
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knockout_bar
Scooby Slapper



Joined: 06 Jul 2005
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PostPosted: 18:15 - 22 Oct 2005    Post subject: Reply with quote
robby wrote:
Certainly sounds like clutch slip then. Tends to happen more at higher revs.



Ok, well that sucks as I don't really want to be spending anymore money on the bike.

I think I may just keep quiet and sell it Shhh!.
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125 trail bike, custom bars, handguards etc. - ?500.

"egg flied lice" - R6jonny (inspired by McGee) Thumbs Up
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White Noise
Mr Dudwee



Joined: 17 Dec 2004
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PostPosted: 20:17 - 22 Oct 2005    Post subject: Reply with quote
when was the ast time the oil was changed?
WN
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knockout_bar
Scooby Slapper



Joined: 06 Jul 2005
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PostPosted: 21:34 - 22 Oct 2005    Post subject: Reply with quote
About 2000 miles ago, had a plug change at the same time.

I've been out on her since the original post and the difference doesn't seem to be that big.

It might be because it's been derestricted and the increase in power (not much) makes it seem that way.
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125 trail bike, custom bars, handguards etc. - ?500.

"egg flied lice" - R6jonny (inspired by McGee) Thumbs Up
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flat spot
World Chat Champion



Joined: 29 Aug 2003
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PostPosted: 22:03 - 22 Oct 2005    Post subject: Reply with quote
To check for clutch slip ride up a hill in top making it pull hard. The revs will rise when they shouldn't. Maybe it needs adjusting if it's only a year old?
Your tyres aren't worn right down by any chance?
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knockout_bar
Scooby Slapper



Joined: 06 Jul 2005
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PostPosted: 22:10 - 22 Oct 2005    Post subject: Reply with quote
flat spot wrote:
To check for clutch slip ride up a hill in top making it pull hard. The revs will rise when they shouldn't. Maybe it needs adjusting if it's only a year old?
Your tyres aren't worn right down by any chance?



It wont go up a hill in top gear, it's a 4t 125. It doesn't slip when it's under load.

The rear tyre is worn, I see where you're going, the wheel base won't be as big if the tread is worn down. It is a trail bike so the tread would be fairly deep.
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125 trail bike, custom bars, handguards etc. - ?500.

"egg flied lice" - R6jonny (inspired by McGee) Thumbs Up
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Robby
Dirty Old Man



Joined: 16 May 2002
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PostPosted: 22:21 - 22 Oct 2005    Post subject: Reply with quote
More power wouldn't make a difference. If it does X mph at Y rpm, more power won't make it do Z mph at Yrpm without fiddling with the gearing.

2000 miles is a long time for a CG to be on the same oil. I wouldn't leave more than 1000 miles between changes on one. Use cheap oil and change it often.
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knockout_bar
Scooby Slapper



Joined: 06 Jul 2005
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PostPosted: 22:24 - 22 Oct 2005    Post subject: Reply with quote
robby wrote:
More power wouldn't make a difference. If it does X mph at Y rpm, more power won't make it do Z mph at Yrpm without fiddling with the gearing.


Very true. The bike seems to pull alot better now, but the torque range is alot narrower than before.

robby wrote:
2000 miles is a long time for a CG to be on the same oil. I wouldn't leave more than 1000 miles between changes on one. Use cheap oil and change it often.


Ok thanks, i'll change it asap.


Cheers for all the help guys Thumbs Up!
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125 trail bike, custom bars, handguards etc. - ?500.

"egg flied lice" - R6jonny (inspired by McGee) Thumbs Up
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Old Thread Alert!

The last post was made 20 years, 172 days ago. Instead of replying here, would creating a new thread be more useful?
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