xr650r 3/4 throttle problem(hesitation)

I have a 05 xr650r with a yoshimura header/exhaust and a uni airfilter with a couple of the round vents in the cover.

It starts really easily, 1st or 2nd kick, does not pop on decel and the plug is nice and tan.

the problem I have is when rolling on the power at around 3/4 throttle the bikes seems to hesitate for a bit, then it smooths out as more throttle is added.

I don't know the jetting in this bike as I figured if it ain't broke, (except for the hesitation it runs really well)

I am at sea level, what would be a starting point for sorting this out..



Seems like something might be sticking... Try cleaning the carb out, and see if that might make a difference...

If that does nothing, try adjusting your main (bigger) or needle...

My bike came with a 68s and 175 main. I am around 1000 ft, the bike looked to be running a bit rich, and it had the same hesitation you mentioned. Mine seemed to almost sputter a bit at 3/4, then would settle out.

I had the UNI filter and the stock tip drilled out with a 2 in hole saw. I found that I was able to open up the exhaust tip by cutting the enclosed end off the inside of the tip and covered it with screen. Anyway, this seemed to lean up the mixture just enough to get rid of that hesitation. I have not checked my plug yet, but the bike runs alot better.....and faster.

Try 172 main.

That is what I ran at 1000ft/70 F.

Uncorked, UNI,Holes in Side cover, White E-series.

thanks for the replies,

Bigtooth, you mentioned opening up the tip, to lean it out a bit, what I did do was add a yosh quiet insert, which I think would restrict a bit more than the way it was originally. I wanted to quiet the bike down a bit. I wonder if i pulled the quiet insert out if that would help.


Sounds like needle and main............

This may sound weird, but check your valves while you have it apart if you haven't done so recently. A couple of thousanths makes a big diff in the higher rpms. Other than that it sounds like you need a little more air flow on the intake side.

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