Member Contributer Stray Posted September 5 Author Member Contributer Share Posted September 5 Quick update on the 5th gen Donkey: Dropped the oil after last month’s track day and to do three little jobs: - upgrade to VTR SP1 oil cooler (5 rows instead of 2) with slightly less corroded 5th gen tubes - investigate why the clutch is slipping - possibly fit a Factory Pro shift kit Cooler fitted with a new aluminium bracket I fabricated to move it a little more to the right (as you sit on the bike) and away from the fan. Hangs a bit skew but it seems to work so I’m calling it good. Couldn’t believe how corroded the lines on this 28k bike are. I swapped in the ones from my 70k bike because they were much better. Corroded one below. Then I decided to put a Samarium magnet on the sump plug to catch any swarf in the oil. Stupid - should have just bought one. But I did it anyway… It’s a 6mm magnet so I drilled a 6mm hole with no wiggle room. The magnet will attract strongly to the recess in the bolt, but for extra security, it’s an interference fit. Punched it in the centre but drill wandered. Never mind - the swarf doesn’t care where the magnet is. Break out the torch to heat up the bolt and expand the hole, just enough to squeeze the samarium magnet in so it hugs it tight when it cools. Once the magnet is placed, a few love taps with a wooden hammer (careful, magnets are very brittle) to drive it home. And now the magnet snugly ensconced in the bolt - done! Quote Link to comment Share on other sites More sharing options...
Member Contributer Stray Posted September 5 Author Member Contributer Share Posted September 5 So I finally opened up the clutch cover (and broke the gasket of course), to investigate why the clutch is slipping. Swapped out the centre bearing as a blind stab at removing that squeak I hear when clutch is released. It just comes out with finger pressure - easy! Weird because everything works out within spec. The springs are slightly down on new but in the middle of spec. The fibre plates are almost up to new spec. Little glazing. Basket doesn’t have any pronounced notches. The steel plates are very slightly glazed, but not enough to explain the monumental slip (lasts a couple seconds) at 8,000rpm. Could this be an aftermarket clutch kit, maybe? The tabs on my new plates look different to the tabs on the old ones. Friction surface on the new ones looks more mottled than the old, but that could just be lack of oil. Steels look different too. New ones are smooth and old ones have dimples. Interesting aside: here are 3 x VFR 800 springs in order of firmness: 1. Old 5th gen springs slightly worn 2. New EBC 6th gen springs slightly longer and stiffer 3. New Barnett 100lb springs for a Harley racer. Stiffest of all and slightly shorter Going to deglaze the steel discs, install new fibre discs (although the old ones look great) and fit new EBC springs to see if they can stop the slip. What do you guys think of my discs, old and new? Quote Link to comment Share on other sites More sharing options...
Captain 80s Posted September 5 Share Posted September 5 Typically if I have the clutch apart like that because I'm chasing a slip or verifying status of a new to me bike, it's not going back together without new fibers and springs. I don't want to do the work over and now I have a known starting point. I have found in the past that sometimes fibers are just "done' regardless of their thickness. I almost always scuff the used metals a bit radially. My new to me Hawk GT started slipping just in 4th or 5th under heavy load (38K original clutch). I had the clutch cover off but the way the clutch is designed you have to remove the staked nut on the clutch basket to replace the disks. I just popped in new EBC springs (which you can easily do) and it got me thru the rest of the season, but finally started slipping again. New fibers and scuffed metals and it is now awesome. 1 1 Quote Link to comment Share on other sites More sharing options...
timmoer Posted September 17 Share Posted September 17 Checking back in, really appreciate the quick guide on fuel tank re-keying. Easy peasy and with a good bit of cleaning with brake cleaner and some dry teflon lube (for my bike chain) the locking mechanism is working better than ever. Who knew pressing down on the cap would actually turn the key from unlocked to locked! Didn't do that before Quote Link to comment Share on other sites More sharing options...
Member Contributer Stray Posted September 18 Author Member Contributer Share Posted September 18 Finally got round to replacing the clutch parts in the 5th gen Donkey. Fist (and hardest) job was to remove the old gasket. Took over an hour with a blade! Dipped the new friction plates into the old engine oil I’d just drained in the pan. Left them for a couple days. Whilst waiting, I treated the pushrod to a 3-stage polish. Swapped it round so the pristine end was pushed back into the engine and put a dab of Redline grease on the end. Here’s what it started out looking like…grim corrosion on the slave cylinder end. After a 1st stage polish… After a 2nd stage polish. Closeup of the polished end shows scars from corrosion but couldn’t snag a fingernail on it…smooth. Now for a bit of flash and dazzle - buffed it with Tungsten Disulphide powder to make the surface slick and rust proof. Hoping it will make for smoother clutch action going forward. Had a new set of steel and friction discs on hand, but not the smaller friction plate that goes over the judder spring. The old one was within spec so I just scuffed the gloss off it with some 800, as per @BusyLittleShop advice: “Just enough to bust the glaze”. See how it’s glossy everywhere except where my thumb is. Then fitted all friction and steel discs as per manual. Followed by the slightly stiffer EBC clutch springs, progressively wound in a cross-cross pattern and torqued to spec. Final job was fitting the gasket, and to avoid breaking it in future I smeared a little copper slip on one face, and engine oil (from the drain pan!) on the other face. Should come off in one piece next time I open the cover. Once finished, I idled her for 5 mins to ensure there were no leaks (there were none, thank God!) and promptly took her for a 600 mile tour of Wales. What a ride. And not a hint of clutch slip either! Other than a slightly heavier clutch lever, she’s a dream to ride now. Power goes straight to the back wheel and rolling acceleration is fantastic. Big thanks to all those like @Captain 80s who kept me honest and didn’t let me cut corners. Costs a bit more but happy I did it properly in the end. 1 1 Quote Link to comment Share on other sites More sharing options...
Captain 80s Posted September 18 Share Posted September 18 Killer!! Sounds like a very satisfying test ride! Glad it worked out, but it pretty much had to. 1 Quote Link to comment Share on other sites More sharing options...
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