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more 650l jetting and mods

Posted: Wed Nov 15, 2017 4:02 pm
by dduny82
Im new here and i have done TONS of searching. im sure this is covered somewhere.

2013 650l currently daves, q4, desnorkled, desmoged, jetted at 58/158 maybe 155(been a while), shimmed .020 1000-2000 above sea level and i run ethanol free 91

ive ordered a 10.5:1 piston(i know it wont be 10.5:1) a fmf header, a hot cam, and honda gaskets. i will be port matching and polishing the head while i have it apart. the bike has 4-5k on it.

Im not real sure how big i should go on the jets. i hate unnecessarily spending money so im just trying to narrow it down to within 2 sizes im thinking upping 2 sizes on each. also thinking of adding a oil cooler, not sure if its worth the $300. and any other tips while its apart or reassembly, or with the porting. ive worked on cars/wheelers/bikes my whole life but not a xr. tips and tricks are welcome

Re: more jetting and mods

Posted: Wed Nov 15, 2017 4:20 pm
by JoeRC51
You're jetting , if anything , may go slightly richer on it's own due to the compression increase , your Q-4 is your flow limit on the exhaust.The port matching is a good idea , but remember , polish the exhaust ports and leave the intakes somewhat rough like they came. At a couple thousand feet elevation you probably should be at 55/155 or 158 on your jets. Google Sutton Cycle Works for the oil cooler.