Posting this as a thread as I have a problem in that my xchallenge will not start. I'll post what I do until I can i/d the problem.
I've had this bike for about a year and done approx 3k miles on it. It now has just short of 11k on it.
Occasionally on start up it would clatter a bit, but would soon stop. It sounded like worn hydraulic tappets on the old Vauxhall engines. It didn't always happen. As bike ran very smoothly i didn't worry about it.
It was a clean burning engine, smooth and good power delivery. Returned 72-78 mpg.
I took it on a trail trip to Portugal in september, parked it up when back and left it, attempting to start it earlier this week.
A bit of a sharp clack when it first turned over, but refused to start.
Whilst thinking it was a little early for the fuel to have gone off, it's an easy remedy so drained the fuel and put fresh in. Still no luck, but smelling of petrol.
Airbox off, plugs out. Soaking, and a pool of liquid resting on the piston. Splashed out when turning over on battery. Left plugs out overnight to allow to vent and dry.
Coolant checked; still full in rad. No obvious contaminants in oil.
New plugs in, battery charged, no avail. Plugs wet. Dry them off, checked for spark. Both have strong spark that would jump approx 1cm+ to the frame.
Check injector - seems to be injecting fine when turning over. Hmm.
Take injector plug off to help vent it withou addition of further fuel, and intermittent blue flame would occasionally come back through the inlet manifold, extending 8" or so above it. Hmm.
Valve cover off. All cam lobes intact. Decompressor lever may have been a little sticky, but seemed to spring back okay and consistently.
All 4 valve shims move up and down when under compression from the lobes. All would spin freely when not under load.
Valve clearances. Visually and from the ones i could see, this was millimetres, as opposed to point of millimetres. However, they seemed to match the others so i ASSUMED, that maybe had misread the manual, they were normal as there was no apparent signs of wear on either shims or cams.
Checked valve timing. Both holes on cam sprockets point upwards and horizontal marks align. I did not check this with reference to the piston at this time.
Bike back together. Still no starting
Current hypothesis is that for some reason the valves are not fully retracting. Possible cause timing chain slip due to cam chain tensioner.
Plan. Check valve gaps. Check tdc cam sprocket markings in relation to piston position.
I have never had a significant mechanical issue on these engines and never had one fail to start, so am a little bemused. Hmmm.. .
I've had this bike for about a year and done approx 3k miles on it. It now has just short of 11k on it.
Occasionally on start up it would clatter a bit, but would soon stop. It sounded like worn hydraulic tappets on the old Vauxhall engines. It didn't always happen. As bike ran very smoothly i didn't worry about it.
It was a clean burning engine, smooth and good power delivery. Returned 72-78 mpg.
I took it on a trail trip to Portugal in september, parked it up when back and left it, attempting to start it earlier this week.
A bit of a sharp clack when it first turned over, but refused to start.
Whilst thinking it was a little early for the fuel to have gone off, it's an easy remedy so drained the fuel and put fresh in. Still no luck, but smelling of petrol.
Airbox off, plugs out. Soaking, and a pool of liquid resting on the piston. Splashed out when turning over on battery. Left plugs out overnight to allow to vent and dry.
Coolant checked; still full in rad. No obvious contaminants in oil.
New plugs in, battery charged, no avail. Plugs wet. Dry them off, checked for spark. Both have strong spark that would jump approx 1cm+ to the frame.
Check injector - seems to be injecting fine when turning over. Hmm.
Take injector plug off to help vent it withou addition of further fuel, and intermittent blue flame would occasionally come back through the inlet manifold, extending 8" or so above it. Hmm.
Valve cover off. All cam lobes intact. Decompressor lever may have been a little sticky, but seemed to spring back okay and consistently.
All 4 valve shims move up and down when under compression from the lobes. All would spin freely when not under load.
Valve clearances. Visually and from the ones i could see, this was millimetres, as opposed to point of millimetres. However, they seemed to match the others so i ASSUMED, that maybe had misread the manual, they were normal as there was no apparent signs of wear on either shims or cams.
Checked valve timing. Both holes on cam sprockets point upwards and horizontal marks align. I did not check this with reference to the piston at this time.
Bike back together. Still no starting
Current hypothesis is that for some reason the valves are not fully retracting. Possible cause timing chain slip due to cam chain tensioner.
Plan. Check valve gaps. Check tdc cam sprocket markings in relation to piston position.
I have never had a significant mechanical issue on these engines and never had one fail to start, so am a little bemused. Hmmm.. .
D) as in the 1st pic, the exhaust at a little under a set 
