Hey guys, new to the site. I have an issue if anyone would like to take a stab at it. I have an 07 400ex that will not run. Here is what's been done and the status for start:

Battery on charger, full charge
Kill switch in start position
Full tank of 93 with full flow to carb
Bike in neutral
Confirmed spark, confirmed fuel, and confirmed air
Brand new following:
Top end kit (piston, rings, wrist pin, clip) cylinder in good shape and honed
compression at 168
leak down test at 15 percent
hot cam stage 2
timing confirmed on point (all the ones that say confirmed by dealer when I couldn't figure this thing out).
CDI, coil, plug, and plug wire (confirmed spark)
pulse generator, and stator
Brand new carb, with 152 and 40 jets
aftermarket exhaust
air filter (tested with on and off etc)
and finally valves were adjusted (confirmed good)

So this is everything that was done. The engine spins over all day long with no noise (bad metallic ones), it's easy to turn, has no binding at all. I confirmed timing, spark, fuel, and air (given) with no resolve. I finally took it to the dealer and they only were able to confirm what I did. They had zero clue as to why it wouldn't fire up. They suggested that I open the case to possibly find something in the bottom end, which Im not against doing, however even with a bent rod (which I dont have) or a spun bearing or anything wrong with the bottom end, shouldn't it fire up and just run like sh*t?? So right now its looking like a new engine unless anyone on here has any suggestions. Thanks for your help.

 

It is strange but some engines will run with settings a mile out whilst others refuse when everything appears to be right. Fitting new bits does not always work, as fitting a faulty new part gives you two faults when you only had one to start with, so you may then cure the original fault but the thing won't run because of the new one you have introduced. Although you have fuel, it has to be in exactly the right fuel air ratio, try starting an Eiger without choke on a frosty morning but, once warm, it won't run on choke. The other main cause of non starting when you have a spark is a weak coil or pulse generator, try putting the old ones back, one at a time. A faulty regulator can draw almost all the power from the alternator leaving not enough for a healthy spark.

 

Nah I understand what you said. Each part was installed and verified individually. So for instance, replaced the CDI, checked spark, replaced coil, checked spark, replaced wire, checked spark etc. Each part went in and then checked for correction. Everything is in order. Spark is perfect, nice strong pretty blue. Fuel is good as well. Plug does't foul out, and smells like fuel so not too leaned out, but not flooding either. And in any case, the Honda dealer I took it too is reputable, so if they missed it then....I dont know. I imagine that there would be at least some backfiring through the carb or exhaust if it had some combustion going on, but nothing is happening at all, just turns over.