Check Valve AP8104251 – symptoms

Aprilia Caponord ETV1000 Rally-Raid AP8104251vacuum check-valve exploded viewA couple of folks have asked what the symptoms where that prompted the replacement of the check valves (AP8104251). Well, for a while I’d had an intermittent ‘cough’ or momentary stumble when lifting the throttle off idle …. maybe once every twenty times or so. More than enough to make your heart skip a beat when you think she’s about to stall just as everyone’s powering away from the traffic lights! Other than this annoying habit, everything in the garden was Rosie. Or so it seemed.

I’d cleaned and rebalanced the throttle bodies and all the vacuum hoses and inlet rubbers were perfect as they’d been replaced – but it kept happening. In the end with nothing much else to go on, I’d pulled the check valves and found them both to have failed.

Since replacing them, I realise there were other symptoms – very subtle –  and the sort of thing you adapt to without realising it.

  • Reduced engine braking. This was really noticeable within a couple of miles after the valves were replaced – Engine braking  is certainly  stronger now
  • ‘Burble’ from the exhausts on overrun. This is greatly reduced, especially at low RPM
  • Eratic idle during warm-up. The idle became lumpy at 65°C then smoothed out again by 70°C – now stable throughout.

With a few hundred extra miles under the belt, it’s fair to say that the intermittent off-idle stumble has well and truly gone which is great of course …. but I do miss that bit of ‘Burble’ on the overrun! So if you have idle issues and any of these symptoms ring a bell, then take a moment to check the valves as well as the usual old favourites – IACV, vacuum lines and inlet rubbers. You might be surprised.

Let’s all do the Shimmie-Shimmie Shake …..

10mm shim kit ...... and stickers!!!It took the best part of three weeks for the valve shim kit to arrive from the USA ….. and I think that’s rather good, considering the surge of Christmas post whizzing around the world, not to mention the holidays themselves getting in the way.

I’d ordered a Hotcams (SHIM-31) 10mm  shim kit (thickness range: 1.85-3.25mm) that’s sold for the HD V-Rod and Buell 1125, but has a whole bunch of shim sizes in it that suit the Capo, or any V990 motor just fine.

Three shims of each sizeThe V990 engine uses shim sizes from 2.3-3.0mm in 0.025mm increments, so quite a few of the Hotcams kit are redundant, not only that, the kit only contains shims in xx.000mm or xx.050mm sizes, not the xx.025mm and xx.075mm that may be needed. Now this may appear to make the kit a rather poor choice, but look again at what you do get for your money when compared to the shims an Aprilia dealership/stockist will sell you.

So let’s compare ……..

Shim close upHotcams Shim Kit – delivered to Italy was $82.35 / £49.94 / €59.73 including customs duty & taxes. That’s 15 usable shim sizes (x 3 each) and works out at approximately $1.83 / £1.11 /€1.33 per shim. Now compare that with genuine shims from AF1 in the USA – $14.99 each*, or Ultimate Parts in the UK – £9.15-£12.85 each all of course with package and posting on top. I think it’s fair to say that if 50% of the shims are on hand for around 10% of the Aprilia list price …. well I can live with that!

*AF1 do sell a shim kit and it may well be the same one that Hotcams sell. Certainly the range of shims is identical – as is the box by the pictures on the website. Why didn’t I buy from them? Simply price, at $75.99 + $40 shipping, they weren’t even close to Ebay stockist Powersportsplus.

Santa and his sack of Capo goodies

Ho, ho, ho ... dashboard inlay for MrB!!!!!I’ll start off by wishing you all a hearty Merry Christmas and a very happy New Year wherever you are on this wonderful globe of ours. For the Capo and I, it’s proving to be an extra special one this year, with Santa dropping off a few extra goodies for the riding-year ahead.

The dashboard has been especially good, and so merits the star prize of a new OEM quality inlay with all the new graphics in place. So as I write, the old one is on its way to Lockwood International Ltd in the UK to act as a template,  meanwhile the plastic chassis has been Finished inlay templatecleaned and preped ready for the big day. Like a kid on Christmas morning, I’m all on edge – and I’ve got to wait at least three or four more weeks yet before it’s installed!!

Probably the most needed bits are for the (very) overdue service. Yes folks, I’m hanging my head in shame as I admit that the Capo’s mileage overran a tad ……. a couple of thousand tads give-or-take! Now I’m waiting for a few packages to arrive for this truly international service to take place – Hiflo HF564 oil filters and ‘O’ rings from the UK, Hotcams valve shims from the USA, Athena air filters from Germany and 15w50 engine oil from Italy. Cosmopolitan or what!

That just leaves the parcels snuggling together under the tree …… a Shoi Neotec or a pair of socks? Slippers or a slipper clutch? Hmmm ….. roll on tomorrow!! 😉