Are the valves adjustable? Fire in the intake is often due to valve or ignition timing. Is this one you can change spark timing and or advance with any of the components you have worked on? Paging Professor_Brap
Are the valves adjustable? Fire in the intake is often due to valve or ignition timing. Is this one you can change spark timing and or advance with any of the components you have worked on? Paging Professor_Brap
In reply to Justjim75 :
It's post EPA, so without forcing access to blocked things, like I did with the carbs, I can't access timing.
Brap is knowledgeable on Yamaha 400s, I messaged him and he said he would check this out to see if he has insight. He is the Rainman of sub $750 bikes and a common contributer here
Check the valves, I'll post the cranking timing cranking specs, check the carbs again and make sure they are balanced and fuel screw is not to far out. Slso check the intake boots for leaks. Also would be worth your time to check the physical timing when checking valves.
I have seen in the last two weeks float height doing some super goofy stuff to the carbs including huge backfires.
In reply to Professor_Brap (Forum Supporter) :
Intake boots and gaskets are new, replaced last fall when I was doing everything else. Mixture screws are 2.5 turns out per the most common starting point from the xs400 forum. Valves and timing I don't know how to do, but I'll figure it out like I'm figuring everything else out. I appreciate the help! I know we've talked about this moody pain in my rear before, too.
In reply to Professor_Brap (Forum Supporter) :
Will a Clymer book have that stuff in it?
In reply to Justjim75 :
Clymer book should have how to check valves and physical timing.
You'll need to log in to post.
