Hitchcocks Forum

Colleagues, I've noticed in other threads that the electric start sprag clutch seems to be regarded as unreliable. Does this apply to the current UCE/EFi models? It won't stop me buying one, I just wanted a heads-up. Cheers.

I am your man for this one Thack... I probably own one of the earliest EFIs out there as mine is a 2008 model which insurers do not acknowledge exist!! Registered for road use on 21st December 2008 If a problem exists, I have had it...




Anyhoo... the early EFI sprags are the same as the old Electra X ones and they are known to be weak. Now, the debate about whether a weak sprag should be subject to kick back at all is irrelevant, some bikes kick back and if they also have a weak sprag then that will be what gets it the most. A stronger sprag may survive this abuse, a weak one wont... EFIs have an auto-decompressor on one of the cams which kicks in (and lifts the valve slightly) at low revs to ensure now kick back - this sometimes sticks. Potentially causing kick back and potentially causing a broken sprag.




There is more... the sprag is high in the crank case clutch side, sitting way above the natural standing oil level in the clutch case. A good oil quantity will mean that it is coated in oil, but a low oil level causes problems. If you run low on oil, the sprag clutch suffers first, leading to wear, slipping, then ultimately cracking. This can be overcome by kicking over very gently two or three times, allowing the autodecompressor to open the valves, so you wont start the bike, but you will flow oil around the case... it is also overcome by maintaining oil levels!!




If the sprag does break it is dead easy to whip out of an EFI, I last did mine in around 35 minutes when my starter motor jammed on during a commute to work... I wasn't late for work that morning. However, you do need something to jam the clutch and engine sprocket... the issue is a new sprag and sprockets is around 200 quid at which point you choose to go kick start only, and get a kicking routine down to a tee




The thing to remember is that realistically something caused the sprag to break, and that thing was probably kick back/timing. It could have been low oil pressure or low oil levels which cause wear first, then a break. It could be becuase autodecompressot is not lifting the valve and the engine rolls on, gets to compression and then the crank rotates backwards against this compression momentarily. It is unlikely the sprag spontaneously breaks on its own

A couple of points - I'd say that the sprag on the EFIs is unpredictable rather than unreliable. Many have no problems at all with them - but it does seem that a few owners have had them fail, for a variety of reasons.
Second thing: most EFIs don't have a kickstart, so that's not an option if the sprag does fail.

I have had an Electra X (from new)and a secondhand 2009 EFI (6000 miles when i bought it 2 years ago)- also with a kickstart.The Electra X was terrible.It was a reluctant and sometime unreliable starter and the sprag went twice in very few miles.I only did a total of 3000 miles on it in 3 years.The decrompressor was none existant on the Electra whereas i can easily kick over the EFI.The EFI doesn't always start on the kicker first time but it often does paradoxically.I have recently had to replace the battery on my EFI -from our hosts by the way -delivered as usual the next day-.I'm assuming that after 5 years of intermittent use the battery is on its way out because often when i pressed the starter button nothing would happen although it was reading well over 12 volts on my multimeter!I assumed it was breaking down when under load.The point i'm trying to make in a long winded way is that i have had no issues with my EFI sprag todate(fingers crossed long may that continue!)even though they say you are not supposed to let the battery run down.I think what Michael says must be right as in my experience i do often change the oil and filter (every 1000 miles) and regularly check that the level in the window is at its uppermost.