2011 wr250r problems after upgrades

So where do I begin !? lol

Over the winter I decided to mod my stock wr. removed ais system, opened airbox and removed the emissions crap on top of the airbox plugging the appropriate vacuum holes and block off plate for the cylinder jug. I also installed a fmf PP and a full fmf exhaust.

Bike fired right up as soon as I touched the start button like it always did. Using a tune that was suggested 3- 5.5 -.5- 8- 4 - 4.5 and the bike rips pretty damn good. During the initial ride everything was good until I had to jam the brakes on tight corner causing the bike to stall. No biggie right? Wrong!! The bike would just turnover with nothing. Would hear the fuel pump prime but no start. Checking kickstand switch and kill switch, still nothing. So I decided to pop start it on a hill which it imediatly fired right up!!! It's been about 5 rides now and all my buddies are sick of me not being able to start my bike if it stalls lol . And I'm sick of having to pop start it!

Anyone have any suggestions? I tried turning up the idle with no luck. I do notice if I shut the bike off with the kill switch it will fire right up also. Please help me out :)

G'day mate,

Those FMF settings seem way too rich for my money - mostly for the 2nd number. Even with a full exhaust and 290 kit, my 2nd number is not that high / rich. During un-intended stall condition, your cylinder is so "full" of un-burn't fuel, that the spark plug is being saturated. This is then why the hard re-start, as the plug will be "wet" as per a flooded engine condition.

I would just go straight back to the FMF reccommended settings for your level of mods. They have spend alot of time & money during design & development with this product, therefore have come up with the best overall figures from both dyno & on-road testing. To maybe go slightly richer than their spec's will help with the placebo effect - but your 2nd number setting is way above & beyond.

It is only the 5th number that is a known issue with their spec's as being a problem. On the majority of bikes, with the 5th number set to the "default" of 4, a severe "dead spot" can occur during WOT roll off.
This 5th number is not for any amount of "extra" fuel added, but is just a "duty cycle" for when the 2nd number setting kicks in. When the 5th number is set at default, it "overlaps" too much from the WOT setting and causes an operating problem. Therefore it is best to just re-set the 5th number to a level of 6 or higher. ( I would have thought that the guys at FMF would have been aware of this by now, and changed the default settings along with the recommendation in the instruction manual ).

Anyway, back on track with the OP's actual issue..... If your problem still occurs after winding back your FMF settings, and after a really good "clear out" run, then you may also need to replace your spark plug. It could very well be "fouled". ( See my reply about this possibility in another current thread titled "FLAME OUT" ).

Lastly i also assume that you have good fresh & clean Hi-octaine fuel + inspected / service air filter etc ?

Cheers.

What settings do you suggest he try?

ac

Gt-250- I put the settings back to the stock fmf settings and changed the spark plug. Also noticed the negative on my battery was loose and a connector on the fmf pp was not plugged in all the way until it clicked into place. Needless to say the bike seems to run much better!! Thanks for your informative response!!

^^ No worries mate - glad to hear that it now seems to be sorted. Looks as though there were several factors all adding up to cause your issue. Obviously it's hard to isolate any single major factor, as you rectified all issues together. But the main thing is that you have been able to sort it out pretty quickly & easily yourself.

Also just keep in mind that it may be best to re-set your 5th number to 6. Otherwise you could very well experience the known issue of a severe "dead-spot" after roll off at WOT.

Cheers.