Anyone else have/had trouble with their bike starting after re-jetting? Mine has been really hard to start since adding the jet kit if it's below about 60 degrees out. My brother, who is a certified tech, installed the kit and said it would be more cold-blooded now, but I don't think it should be this much different. Any ideas on how to fix this?
It's a 2012, stock bore, 128 main jet, snorkel removed, and FMF Q4 pipe, & stock gearing. l live at 1200 ft, but ride between 800-3000.

 

The DJ kit shouldn't have any effect on cold start. It alters midrange and full throttle only. Make sure that he didn't accidentally change the float level and that the pilot mixture screw is set properly. The only other mod would be to increase the size of the starter jet-that's what sets mixture when you pull the 'choke' ****.

 

Thanks for the info. I will check into that.

 

As G stated, that jetting mod should not have affected cold starting. However, maybe you could describe your starting procedure to clarify this. Are you using the choke? Now, jetting changes can affect how quickly you can get off the choke, and of course, other performance response from the engine. If your bike was starting just fine on the choke before the rejet, it should start the same on the choke now. A search on the site will show a fair amount of cold starting problems for many owners. Usually, a drilling of the starter jet to .018" will fix this. If yours was starting just fine before, I'd look at the work you did during the rejet first. The choke circuit is totally independent of the other fuel/air circuits that you modify when you rejet.

 

I've always had to pull the choke out to start cold. It would always start right up unless it was cold out (40ish) or it had set for a while without running during the winter. Now it takes several tries to get it going and it usually shuts right back off once or twice while idling. Once it starts and idles a couple minutes though it runs great and starts right back up when the engine is warm (no choke).

 

when I bought my 2011 KLX250s, it came with an 'aftermarket' (home-made by the PO) exhaust. It was loud, popped lots under decel and needed the choke for a few minutes on startup. I picked up a used stock exhaust and put it in. Much quieter, of course, no more decel popping. now, I pull the choke to start it and then am able to push the choke back in after about 10-20 seconds. My son and I both rode it after putting the stock exhaust back on and did not notice any reduction in power, but rather seemed smoother all through the rev range.

The PO had put a dynojet jet kit in.

So, so sum up my story, going back to stock exhaust, with the dynojet kit dramatically improved the cold starting without any loss in power (yes, this is butt-dyno, so it's possible that on a real dyno, you might actually see a drop in power, but if so, it's so minor that you can't notice it and I'd gladly trade that off for the smoother acceleration across the RPM range.)