Tried everything I can think of, but my "new to me" XR400 isn't starting.
Got the 1996 XR400 from a mate, had been sitting in his shed for 2-3 years without being started, with fuel in the tank.
He'd said the cylinder was worn, so I ordered and installed a 440 kit, a stage 2 HotCam, new UniFilter, had the heads machined (lapped, ported, valves cut and reseated) while I was at it. I also MIG welded up some rust in the frame, but unplugged the ignition while I was doing it.
New Hotcam means elimintation of the Auto-Decompressor mechanism, and I also removed the spring and pin for the auto-decomp mech.
Once back together with new fuel and new spark plug, it wouldn't start.
My start routine has been:
* Decompressor lever in, 5-10 kicks
* Decompressor lever out
* Kick until i feel resistance, pull decompressor and get past this point
* let kick start come to top, then give it a good kick.
I haven't even heard a backfire or anything like it's going to fire.
After this, I tore the Carby apart, cleaned it up and put it back together, I think the float had stuck and no fuel was getting in, but after putting it all back together again, still no luck.
When removing the spark plug one time, the cap came off, so I cut some off the end of the HT lead, and reatttached it to the Cap, I then took out the resistor from the spark plug cap, and replaced it with a length of stainless (leg of a Stainless rivet) and put back together.
Did a spark test and I get a blue spark, although I don't really know what to compare it to if it's not strong enough.
Just now I took off the tank and cylinder head cover, double checked that I was at TDC and the cam was facedown, looked at the sprocket markings compared to the cylinder head, and the left marking was slightly below the cylinder head (invisible when viewing straight on), with the right just visible, and I think if I changed it by one tooth it would be way out the other way....
Left the timing as it was and put the cylinder cover back on and readjusted the valve clearances, then put tank back on and tried to start up.
Took new filter off, and tried again, nothing. The only real sound is from the piston pumping up and down and the flow of air, there is no firing, coughing or anything from the engine.
Only other things I can see:
* Fuel flows freely from the tank, and the Carby bowl is full.
* Noticed that oil is leaking from the crankcase breather tube? (slow leak, puddle forming overnight)
* When finding TDC for valve adjustment, I notice that there is a lot of resistance when I'm near the F timing marks, but then this passes by the time I get to the T mark. When I'm at the T mark, and Cam is facing down (checked when took cyl cover off) there is little resistance, and it moves quite easily.
* Haven't checked compression, as I dont have the right adapter, but kicking with the decompressor in is far easier than without.
* If no decompressor lever pulled, there is a point where I can't kick past, and I need to use the lever.
* Kicking without spark plug installed is similarly easy, so assuming I'm getting compression.
Help, really stuck at this point....