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Honda guys 250r jetting


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My friend just picked up a Honda 250r cheap. He doesnt have much time to work with it, and the piston was stuck. I picked it up and tore it down, and got the piston and cylinder off the bike. He orginally thought it was prolly on its 2nd to last or last bore. Oddly enough it was actually standard bore size, with a wiseco piston I believe. It also looks like it has some heavy porting. It appears not to be real professional porting, but doesnt look too bad.

 

Anyways, He is running a 38mm pwk airstyker flat side carb, with fmf pipe, carbon reeds, no airbox, k&n What would you guy estimate a good starting point for this carb. I wanna make sure when I get it all back together the jetting is close enough to break it in, and then start doing some plug chops.

 

If anyone has any idea please let me know.

Edited by bobbybonilla
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Its a mild dune port with a stock carb esr trx 6 pipe and no airbox. I'm at 54 main, i think, i thought it was rich but its what it needed for the woods pipe. I'm at a 165 main i believe so i figured for the 38mm carb a 180 might be close. The pilot is a complete guess at this point. But this is for west coast jetting, which i'm sure most of the people who have jetted for both know its a whole different ball game. I'm jetted for sea level around 80 degrees, just to give a baseline. Hope it helps.

Pete

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ported R like that id say mid 170's main with a mid 50's pilot

but there are so many variables if he picks 175 main and 55 pilot IMHO it should be fairly close and then you can see how it "acts" and then do a "plug chop" :bolt:

 

i think it should go something like this on that bikes jetting anyways:

 

160 being the leanest and 185 being richest main

50 being leanish and 60 being rich pilot

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Want to do it RIGHT? Pull the needle out and read it. If you have the good needle DDJ you will run somewhere in the 160-168 range, with a 50-52 pilot and with porting most likely 4th position down on the clip. If its the shitty DGH needle then you will be more like 175-185 main with the higher pilot. I would suggest dumping that needle and buying a DDJ they work much better and jet much smoother. I have 3 DGH needles that will never be ran. On a hot day it may run even leaner than that with a DDJ needle my suzuki used to drop down into the low to mid 150's while I dont think the honda has ever ran that low, its always at 160 or 162.

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