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Hi all,

Just wondering if anyone can confirm my suspicion on an issue I have, I think relating to the slipper clutch.

When going over these 'slow' bumps:

https://www.google.co.uk/maps/@53.36853 ... !2e0?hl=en

EDIT: the site doesn't like this URL, you'll have to copy then paste unfortunately.

Basically, I think the slipper clutch kicks in. The revs drop, power is completely killed and the engine backfires (like a machine gun!). When the bumps are over, there can be a nasty jolt when it sorts itself out, depending on what im doing with the throttle.

This is most noticeable when coming out of the corner and going over these bumps when accelerating, however it does still do it even at neutral throttle.

It also happens when going into a corner with these bumps, albeit only slightly detectable.

I went over these a few more times to do some testing. If I pull the clutch in and hold the revs while going over the bumps, everything is fine. At first I thought the chain was slipping or jumping because of the bumps, but it doesnt seem to be that.

Today I was also overtaking a car and the slipper kicked in under heavy acceleration, it was towards a gear change so maybe 8-9krpm.

Does it sound like the slipper clutch to anyone else? Not knowing how these things operate, what might the potential causes be?

Dalemac wrote:Hi all,

Just wondering if anyone can confirm my suspicion on an issue I have, I think relating to the slipper clutch.

When going over these 'slow' bumps:

https://www.google.co.uk/maps/@53.36853 ... !2e0?hl=en

EDIT: the site doesn't like this URL, you'll have to copy then paste unfortunately.

Basically, I think the slipper clutch kicks in. The revs drop, power is completely killed and the engine backfires (like a machine gun!). When the bumps are over, there can be a nasty jolt when it sorts itself out, depending on what im doing with the throttle.

This is most noticeable when coming out of the corner and going over these bumps when accelerating, however it does still do it even at neutral throttle.

It also happens when going into a corner with these bumps, albeit only slightly detectable.

I went over these a few more times to do some testing. If I pull the clutch in and hold the revs while going over the bumps, everything is fine. At first I thought the chain was slipping or jumping because of the bumps, but it doesnt seem to be that.

Today I was also overtaking a car and the slipper kicked in under heavy acceleration, it was towards a gear change so maybe 8-9krpm.

Does it sound like the slipper clutch to anyone else? Not knowing how these things operate, what might the potential causes be?

Symptoms don't sound slipper clutch related. If the slipper kicked in the revs would rise due to a drop in load.

I think it's an electrical issue.
Check your tip-over switch is secure and test it according to the workshop manual.
Sidestand switch / wiring, kill switch / wiring are other candidates .... along with the source that it eventually turns out to be that I haven't identified.

Anyway, my money is on an intermittent electrical issue that is affected by vibration (not of the type the engine produces).

The backfiring when it gets going again would be consistent with this - lots of unburnt fuel-vapour in the cans - when it chimes back in, the hot gasses will set that off nicely!

Hi all,

I had a similar problem awhile back, try under the airbox on the near side and look for a twin wire one strand black one black and white. The rubbing has caused the insulation to melt and the bare wires short to ground and intermittantly cut the power... Took me ages to find it...

Hmm, I find this rather intriguing because when I go over the bumps with the clutch pulled in, and hold the revs, it rides normally, no dip in revs, backfires, etc. I did it a couple of times but i guess it could have been a fluke.

Its not a massive problem for the time being as I don't ride over these bumps often, but I think i'll lift the tank next weekend and check everything over.

I have been tidying up the rear electrics while i'm getting the frontend sorted, i discovered that the fuel pump connector into the harness has some el;ectrical tape wrapped around it. I removed the eletrical tape and the middle wire just fell out.



Hopefully that is the root of the issue then.

I'm going to cut this connector out and replace it - will the following suffice?

http://www.ebay.co.uk/itm/Tyco-AMP-Elec ... 339ef98bca

Dale