[FastLane]

I have a 2016 ex300 and the valves seized up on me after a long ride through the hills. Long story short I changed the cylinder head which came with valves, shims and buckets pre-installed so i pretty much just bolted it on. Pistons looked fine from what I could see but I'm by no means a professional mechanic (just a guy in his garage with a wrench). After everything was put back together i turned the key to "on" and it made a weird clicking noise for about 15-20 seconds. It's never done that before. I changed the starter hoping that would fix it, it didn't. Now I'm realizing the noise is coming from the throttle actuator. I just want to know if I'm on the right path or if I missed something because like I said I'm not a professional nor do I have any specialty tools or non of that. And I'm on a very tight budget (hence why I'm trying to fix it myself). Any help at all would be greatly appreciated. Please and thank you.

 

[SparkyMJ]

Hey man,

I recently worked on my 300 motor and did some top end maintenance and new piston rings and all new gaskets. So I may have some advice for you! My bike is running great 2000 miles after that service, and I plan to go to track next month.

Now you said you are no professional. Absolutely not to worry, nor am I. Not even close lol I am in the same boat as you. Couple questions though when you did the work.
-What exactly did you replace/upgrade? Was this an aftermarket head? Or a head with aftermarket parts?
-Did you follow the service manual? It is free on manualslib, and I followed it to a T and my stuff is working great.
-Did you replace the parts recommended when taking these parts apart? Like gaskets, crush washers, ect.
-Were you meticulously clean when assembling the engine parts? There must be as little debris as possible on all engine internals.
-The camshaft sprockets can be confusing, they have multiple markings, and only the correct ones are used. Did you take pictures of the timing setup, and triple check counting the chain links?
-After assembling the motor, I usually turn the crankshaft over a couple times with a 14mm wrench on the left side to ensure the valve clearances are tight, and the timing is right.
-Did you check the valve clearances? This bike will still run with quite off valve tolerances, but if they are insanely wrong or someone forgot to put a shim in, you will definitely have issues.
-Did you assemble with assembly lube or at least oil on all the metal on metal parts?
-Any leaks or other artifacts now that the motor is seized? Did it overheat?

This will help us understand what happened to your motor.
Sorry to hear it didn't work out so far.

-Mike