Just catching up on a few bits and bobs, most of it completely unconnected, so I hope you like more than 1 flavour of M and M's.
First up just a bit of revision on something I mentioned earlier, but kinda glossed over in typical half-arsed fashion: rebuilding those Brembo GP billet 4 pad 30/34mm calipers.
These are the garden variety reasonably common billet GP calipers, for real exotica look to the almost identical 32/36mm version with Ti bolts and Ti pistons standard, and I've also heard whispers of ceramic pistons fitted. I picked them up as part of a small package deal for a fair price; considering what they were missing in detail parts like pad pins etc they made up for with some stainless bolts filed in a drill to mimic tapered Ti (since replaced with actual Ti). But there's not that much to a brake caliper is there? How bad could they be?
This bad:
Note the piston set at the bottom look different to those at the top? These GP billet calipers are lighter (by 100gm) and stiffer than theoretically similar 4P 30/34 cast calipers available on road bikes. Being a race caliper they don't employ dust seals so the pistons are slightly shorter.
So what you are looking at with the bottom pistons is a set of longer cast road caliper pistons cut to billet GP caliper piston length.....with what looks like a hacksaw.
Dumbfounded I was....but not nearly as much as when I found piston/seal kits, complete with grease, are easily available for a pocket friendly $45aud/$30usd!
I mean, it would take longer to cut down the bunky pistons than to fit a new piston and seal kit. Words fail me.....
Moving on, here's something owners of Ohlins forks will be well familiar with: weeping/leaking fork seals. For whatever reason, be it reducing stiction or whatever, Ohlins fork seals are renowned for leaking prematurely. For the small amount of time the 851 has actually spent on track these should last for-bloody-ever, but no such luck.
On the flip side, the good news story with these old FG9050/9051 forks is just how incredibly simple it is to change the seals....if you can find them.
These are what I'm talking about, the "Jennifer Aniston of motorcycle forks" - of a certain age, still absolutely gorgeous, and completely unattainable:
Mine aren't anywhere near as lovely, having had the outer tubes polished (?!) at some stage, but I'll touch on that later on. After looking a lil' wet for some time the tell-tale drops started appearing on the concrete and it was time to stop kidding myself and replace the seals.
And it's surprisngly simple: you simply unscrew the blue locknuts, then fork cap, (best loosened with the fork still secured by the lower triple clamp) and the tube slides free (hint: before doing so would be a good time to measure the oil level so you can replicate the level if you're happy with the action...or give you a baseline from which you can make adjustments):
While you are loosening the cap, also loosen the lower knurled tube "nut", it's a lot easier than trying to wrestle a free-floating fork into submission. With the tube free, unscrew the knurled nut and you'll see this serves as a carrier for the seal/dust scraper:
After flicking out the the O-ring/washer the seal/scraper are easily removed/replaced with "judicious use of force", you don't even need a seal driver.
Admittedly I've never really pushed the ol' girl but damping seemed to be condensed into about 2/3 of the fork stroke. Ignoring the clickers I'd already played with, and the shim stack I wasn't game to play with, there were 2 things I could look at while they were apart:
- spring rate
- fork oil level
I didn't actually know the fork spring rate prior and Ohlins, in their wisdom, don't mark it on the springs themselves, instead using paint colours.
But as luck would have it a bit of truffle hunting around the 'net found a relevant spring chart:
So somewhere along the line the "for Raymond Roche use only" 1.1kg springs had been replaced with more mere-mortal friendly 0.95kg springs. From previous Superbike/749R experience I know these are in the ballpark for me, although given the bike is now fairly light, with old school brakes, 0.9kg would probably be an even better option.....if I could find some.
But in the meantime an oil level adjustment made sense: drop the level to increase the air gap for less "air spring" effect and just plush things up a bit. So I went -15mm, using Motul Factory Line Light 5W, (18cst@40degC) which is about as close as I could find (within 1.5cst@40degC) to the specified Ohlins 1305-01 oil viscosity of 16.5Cst@40deg.
The fork action hasn't been horrendous, but if I'm in there why not, and I figure the more comfortable/controlled the front end is the more confidence I'll have, and it's an easy thing to re-adjust if/when my pace picks up.
So we're good to go right? Performance wise? Absolutely. Aesthetically? Not so much. The polished tubes are a love/hate thing: I love that this sacrlilege made the forks affordable, but the look of them is really starting to grate. Unfortunately re-anodising is fraught with danger, from achieving the right surface finish prior, to having a milky result, there are many horror stories.
In desperation I popped in to see Wayne at Ducati Bunbury and picked his brain: he and son Todd live and breathe modified/turbocharged Ducati's and with all their incredible projects over the years I hoped he might have some advice and possibly a local recommendation/solution:
Sure enough he threw out an interesting left-field option well worth exploring...but in the interim I thought I'd try a lil' quick 'n dirty experiment:
No, it's not gonna win any bike show awards but the vinyl wrap is....er...less bad...than the travesty of polished alloy on a race bike. I'm thinking some of that realistic carbon fibre-look wrap would be good for a laugh: she has the GP calipers, I could go "full faux" Cagiva V593 carbon fork legs...
...which would absolutely get the false teeth flapping in the classic racing ranks, carbon forks being prohibited 'n all.
Now for a complete change of direction: I've also been pottering away with the 799RS project.
A quickshift sensor is dead easy to fit, what isn't so easy is finding an appropiate sensor, at a reasonable price point. Considering what I've spent on this cockamamy project so far it seemed an odd time for my wallet to snap shut tighter than a fish's ar$ehole, but it just offended me that folks were charging another 50euro just to ship a small 150 euro switch that would fit in a letter-sized padded bag. It was either that or get bent over by local suppliers charging double what I could see it listed for overseas. GRRRRR! But eventually my petty bullheadedness was rewarded finding a near new used unit for private sale without shipping profiteering.
The Nemesis ECU has an inbuilt quickshift function triggered by a digital input, so the sensor is just a switch, unlike many other units which are actually strain gauges (the two are not interchangeable). Some folks prefer the latter as you can adjust the sensitivity but it's not something I've ever wished I had available. (I have a switch type QS on the 749R and strain gauge type on the 851, both are adjustable for cut-time and neither seems better than the other).
Fitting is just a case of choosing the appropriate PUSH or PULL type unit, shortening and rethreading the shift rod and inserting the switch/sensor inline:
Then refit the rod:
To be honest I can't even claim this as a financial victory, I need to replace the connector to suit the ECU so the "win" pretty much evaporates.....but it's the principle!
Update: another lil' housekeeping job tidied up about this time.....wow, look at me trying to follow an accurate timeline, who'd have thunk it.....
As mentioned previously, the coolant reservoir wrapping around the steering head is not an overflow, it is actually part of the pressurised cooling system, such that the cap on the reservoir is the equivalent of a radiator cap. I had the big ticket cooling system items sorted, but I needed to square away the associated tubing. Refering to the RS parts diagram below, I'd bought Item 12, made Item 18 and I'd also have a crack at Item 10, the alloy tube up to the reservoir. :
It's not the most difficult of jobs but hey, this is me, so I wasn't going to get ahead of myself:
This is slightly different to the Corse item as the reservoir arrived with a precurved rubber hose attached, unlike the straight Corse item. I didn't see the point in reinventing something that would obviously work so just rolled with what I had. And it fitted up first time:
There are a couple of flexible hoses to sort but the cooling system is basically done.
