Bike Dies
 

Just got the bike. Had 5 miles on a brand new complete rebuild when first bought it.
My confidence and trust in the person who did the work is pretty high. He is (and verified to be) a mech for a major power sports company and former gasgas rider/racer.


Not long after getting the bike home, at about 30 miles I started to experience some hard starting and the bike has died a few times on decel, normally after being at cruising speed and then shifting down (and having clutch pulled in) a couple times the engine has just cut out completely.
Then usually has started back up, sometimes with 2-3 pushes of the button.

Details:
Hard starting -
-usually when started for the 1st time of that day. (Doesn't have difficulty when it is started after being shut off for only a few hrs).
-temps : Normal 50-65 degree weather cond.
- usually emits a "POP" on one of the failed starts.
- seems to help if I kick over a couple times (which have never successfully kick started the bike )
- kicking: never successfully kicked this bike to life. (Yes I am lil 120 lbs but have had no issue kicking a wr450f and yz250fs, this one doesn't wanna kick --- my dad who is almost 200 lbs couldn't kick it either)


Any ideas/suggestions ?

Edit: I LOVe LOVE LOVe this bike. If there is a problem I can correct I want to do it right away, because this is THE BIKe of my dreams... But I don't want to lose confidence....

Which bike do you have? 4 stroke? Almost sounds like something (like a rag) is lodged in your airbox or your choke is stuck on or something like that. Might look at the easy little things like that that may have been overlooked on reassembly.

07 450 FSR (4 stroke).

I took the air filter out and checked it and put some more oil on it and put some grease on it while I waited for my new one to come in.

The original air filter seemed to fit not quite right I must say.
Having had a KX 100 and YZ250f before this for MX, I am no stranger to air filters cleaning them and putting them back in.

On this one before the filter had much dirt at all I put some extra oil and a bunch of grease (note: Li ion - didn't like it as much as amsoil poly red)
Also I have always greased my filters in the past - (the poly red stuff) and never had any issue. However with this bike it was trickier on this bike with everything being pretty tight w the battery etc.

I took great pains to make sure the filter was seated on there correctly,
It was a lot tougher to determine than on my Yzs and KX ,

Also, one reason I did this is I was just not super confident in the seal and Fitment . Original (Twinair) filter seemed to fit not so good (skinny coverage to one side) and lack of grease/substantial oil .

NOTE: bike does not always die, nor does it do it so often I can't get anywhere.... It is just kind of unnerving especially when it does this in traffic, or conversely when way out in the bush! Usually has died within first 5 mins or so of operation too when it does this . No other adverse effects observed ; it is very powerful throughout

You are certainly not the first to experience this. Read through some of the threads i the Engine 4-stroke forum section. Lots of useful info there.

That's not what I wanted to hear after just buying the bike ... A persistent model specific issue.... :( :-( :-(
Well thanks for being honest and pointing me in the right direction

i have had some crazy symptoms caused by the gas tank vent tube.
i just throw that thing away and run a long tube.
the other is a sparkplug gets really weird if the air fuel mixture screw is adjusted with the bike running.
so i would suggest a simple vent tube without any check valves and a new plug