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.

MCCruise control revisited

Aprilia Caponord ETV1000 Rally-Raid MCCruise CIU throttle servo cablesWhile the Caponord was stripped for the vacuum check-valve replacement, I decided to get my act in gear and finally, once and for all, unequivocally ….. Sort out the MCCruise control/throttle cables. Last year I relocated the CIU (Cable Interface Unit) to the left hand side of the throttle body. This had pros and cons ……….. The upside was a lighter feel on the throttle grip, the downside, the Servo/CIU and CIU/Throttle body cables were overly long and the Servo cable fed into the CIU from the wrong side. However, the cruise was working perfectly and so it became one of those ‘mañana’ jobs!

Well today is that tomorrow! First I jotted down a list of what had to be done:

Aprilia Caponord ETV1000 Rally-Raid MCCruise CIU cable interface unit1. Make a spacer to fit onto the side of the CIU. This is to move the throttle cable adjuster further out and make the inner cable a better fit on the spool.
2. Drill new cable holes in the CIU so it can be rotated 180° so the Servo cable enters from the rear not the front as is the current arrangement.
3. Shorten the CIU/Throttle cable while allowing for the new spacer at the CIU – 350mm down to 190mm.
4. Shorten the 1,150mm Servo cable to a more reasonable 750mm!

I have to say here and now that I do like learning new skills or adapting old ones to suit a new task. I also have to admit that in a good few years on this Earth, I’ve never made up or adjusted Aprilia Caponord ETV1000 Rally-Raid throttle cablethe length of clutch/choke/throttle cables before! So time to adapt the electronics soldering skills and brush up on required technique courtesy of the Internet. Now I’m not going to bore you to tears telling you how to do it – there is tons of advice on various websites/YouTube. Suffice to say, sort out the duff advice from the good, have the right equipment to hand and practice, practice, practice  …… do the job once and do it right! All the cable bits and pieces I needed came from Venhill in the UK.

By late afternoon everything was buttoned up and the cruise control recalibrated after the throttle bodies were rebalanced, fault codes cleared and TPS reset via TuneECU. As the sun faded behind the hills I cracked open a cold beer happy with how the day played out …. Time then to put the tools away and get back to revising for the next Amateur Radio Exam!

Aprilia Caponord ETV1000 Rally-Raid MCCruise controlThe MCCruise has been installed for approx. 25,000 miles and worked perfectly throughout. The CIU was relocated because the initial location proved to be problematic – causing slight binding of the throttle cable. This meant that the cables supplied in the kit (as specified by me) were now the wrong length and the orientation of cable entry into the CIU was wrong.This is not the fault of MCCruise, what they sent is what I asked for! Should anyone else wish to go down this route I will of course be glad to provide notes/measurements etc so a kit will be a simple bolt-on job.

Stuff …. 6 months and 12 months on

Aprilia Caponord ETV1000 Rally-Raid dashboard - new right-hand indicator repeater!A couple of anniversaries this week ….. firstly the dashboard. Yes a full 12 months since it was finished and put back into the Capo for the last time, resplendent with its new inlay to complement the electronic changes. The auto-dimming back lighting and split indicator repeaters have been absolute winners – I couldn’t go back to a standard board again without missing them. Moving the side-stand and low-fuel lights toAprilia Caponord ETV1000 & Rally-Raid Voltmeter and re-located side-stand light on dashboard accommodate the twin indicator repeaters has had no impact, positive or negative. The voltmeter has been a different kettle of fish …. generally unused as the Sparkbight battery monitor handles voltage feedback when riding around – however it has proved a real benefit during start-up when the dashboard goes through its self-test phase. Now it’s become second nature to eye-ball the tacho needle to see what the battery voltage is pre-start. >12.6v and I know I should get a good kick from the battery!

Aprilia Caponord ETV1000 & Rally-Raid MCCruise controlThe second anniversary, although shorter at 6 months and a tad over 11K miles, is the MCCruise cruise control. After a rushed install (not clever) I knew I had a heavier throttle than pre-installation ….. this was purely down to throttle cable routing and nothing to do with the cruise control itself. It simply didn’t like being re-routed behind the radiator, so I gave up and relocated the CIU (cable interface unit) to a new location by the throttle bodies. Now everything works fine – a light throttle and a happy cruise control. It’s been 100% Aprilia Caponord ETV1000 & Rally-Raid New MCCruise CIU locationreliable and functional. As a demonstration of its finesse I ran the bike in 1st gear at 25mph and let the cruise control take over the (100 horsepower!) throttle – all I can say is WOW! I would never have believed that the system could have the sensitivity to operate the throttle with such precision, but it did – up hill, down dale – never an ounce of jerkiness. Ok I admit no one wants to ride around in 1st gear …. but as an experiment, it proved to me that MCCruise have indeed developed an absolutely fantastic piece of kit.