Hello,
I am struggling to figure out why my bike wont start with the ES.
Prior to the rebuilding the top end, I never had any issues with the ES working. Bike use to fire right up until it was in need of shimming the intake valves until I got to the smallest shim that would fit. Once I got to the smallest shimms i could put in there, it would take a couple min(10 sec pushes and a few sec rest) on the electric start to get the bike to fire guessing cause compression was crap and needed to warm things up. When I did a leak down test cold i was only getting 25% compression and could hear it leaking right through the air filter which is what lead me to do a top end rebuild since I had no idea of the condition from previous owner.
I just finished a new top end rebuild with new OEM piston, rings, pin, cam chain, tensioner and KW SS valve kit on the head. I put things back together and excited to start the bike and when i try and start with the ES it sounds like its struggling to start. I initially thought it was the battery so I purchased a new lithium battery and installed. After this, starting still sounded the same. Upon initial engagement of the starter it sounds like it wants to take off but then anywhere between 1/2 to 1 turn of the cam seems to encounter some resistance. I also attemted using a optima car battery with ~600 CCA and connected it to ground and bypassing the relay to see if it would have better results and it did not so I think that rules out forking the money for a Shorei battery. I did do a little research and others might say its the cam decompressor adjustment, a tooth of timing off, or the starter motor.
Exhaust clearance was initially set to .010in since the manual says .011in +/- .001in when initially piecing things back together, but i pulled it apart again to adjust cam decompressor clearance to exact specs per the manual. I set the exhaust clearance to .011in and then set the the decomp clearance to .025in(right ex cl + .014in). Put things back together and same as initial start after rebuild.
I'm almost certain the timing is not off, but cant rule this out yet. I have checked it at least 3 or 4 times after adjusting with the tensioner applied. Every time I line up the dot on the clutch side cover then come around and check the cam gear, it is spot on with alignment.
The last thing would be the starter, but I can imagine it when bad during the process of the top end rebuild. It may be possible that the starter never came under the same load as before when compression was horrible allowing the starter to turn the engine over.
When I opened up the cylinder head cover after the rebuild to check the decompressor system, I did a further inspection of the decomp assembly. First, I noticed that the cam was positioned so the decompressor lifter was at/right before engagement to open right exhaust. Maybe compression was too high here already before the decomp could do its job? Then, I checked the weight/spring again to make sure it retracted after swinging it out facing down to ensure the spring is stringer than gravity of the weight itself and was good there. Finally, I noticed that there was some lateral movement of the decompressor weight. The movement was side-to-side 90 degrees offset from the swinging out and in movement it is supposed to. I wonder if that play makes the decompressor not fully engage? I was thinking about altering the .025in clearance between the ex rocker arm and the decompressor arm to something like .015 but dont know whats safe to do so vs possibly replacing the entire cam decompressor assembly.
All these parts are expensive and I dont want to just start shooting from the hip and replace the cam decomp assembly, starter motor, ect as It starts to add up real quick!!! I think I am leaning towards a faulty decompressor assembly but dont want to waste money! Any ideas, next steps, or suggestions are much appreciated?