Thursday, 31 October 2013

[Fixed] Honda VFR 800 Clutch Slipping - Simple DIY Repair

My VFR800 was slipping it's clutch at high revs, mainly in 3rd gear.

For wet weather riders, this could sometimes be mistaken for wheel spin in the rain, anyway it got worse so I nursed it home and tried a few things, one of which worked and now it's operating perfectly once again, so if you've got a few tools and about an hour to spare, try this before ordering a replacement clutch for your Honda vfr800 vtec.

The VFR800 clutch is on the right hand side as you're sitting on the bike, and the clutch slave cylinder ( basically a housing that actuates a piston in the same way as a brake caliper would, only instead of pushing pads it pushes a foot long metal rod across the engine to the right-hand side and engages/disengages the clutch system) is on the left right beside the foot-peg.

Well this 'rod' (im sure there's a technical term for it) was covered in crap, had no lubrication and was 'sticking' on my VFR ultimately leaving the clutch 'half engaged' some of the time and leading to slippage (and ultimately premature wear if not
sorted early).

I had initially thought the Master Cylinder could be at fault as the fluid looked dirty & contaminated and I had read about a tiny return hole potentially getting blocked in there, so cleaned this pinhole and flushed the clutch system with new fluid to start with, which (made the clutch action 'feel' a little better and less vague and) may actually be what's wrong in your case so here how I did it ;

1/ Cover the tank and paintwork with an old rag / cloth as brake fluid (which is also used in the clutch lines btw) can damage the paintwork on your bike ;


2/ Remove the clutch master cylinder cap with two small hex bolts ;




3/ Then drain the Master cly. with a syringe or cloth to soak up the old fluid and allow access to remove this metal clip ;




4/ The metal clip's function is to prevent fluid spray up from the master cylinder return hole (which it covers), so I used a needle to clean this hole, and then re-fitted the clip and filled the reservoir with fresh brake fluid ;




5/ Onto the 'Clutch Slave Cylinder' then, which is held on with 3 bolts, two very long ones - one of which requires the removal of your fairing / or at least (in my case) removal of some fairing bolts and bending back in order to full extend and remove the slave cylinder.

With a bit of luck the gasket won't fall apart and here's the long rod I was talking about ;




6/ The slave cylinder piston was a bit manky, and the rod very stiff in movement with some slight corrosion / enamel flaking and the whole thing very sticky in operation so I cleaned both and lubed them with copper grease and tried to remove any debris from the hole in towards the clutch system.

The clutch slave piston is spring loaded ;




7/ So to bleed the system, I wedged the piston back into its housing and clamped it in place with a vice-grips to allow no movement or possibility of air entering the system, I used an old brake pad to keep the cylinder level so as not to cause leaks or burst seals etc. ;




8/ Then I twisted the vfr slave cylinder arrangement so the bleed nipple was facing upwards (for air bubbles) and bled the system with a few pumps of the clutch lever until new fluid began to appear, taking care not to allow the master cylinder reservoir to run low and introduce air into the system ;




9/ While bleeding the Clutch/Brake fluid from your slave cylinder, it's getting pretty close to the fairings at this point so would be advisable to keep a cloth between them to avoid contact & spills ;




That's it !, everything went back together easily enough and the clutch doesn't slip anymore, even when deliberately provoked at high revs in all gears, the whole thing was easy enough, just make sure the metal rod is well lubed and moves freely, if your clutch is still slipping then your plates are probably feiced - they're not that expensive in any case (about €10 each) and look relatively easy to replace with the side fairing and clutch housing removed.

2 comments:

  1. Thanks for such a clear explanation of this fix. Why not bleed the clutch slave cylinder when it is bolted to the engine or is it better to do it out?

    ReplyDelete
  2. Excellent, thats great advice with good photos. Thanks.

    ReplyDelete