View Full Version : Jetting my 85 250r
slaytanic
04-10-2016, 03:18 PM
She's an 85 honda 250r, stock motor, carbon fiber reeds, nology hotwire spark plug wire, e3 spark plug (i noticed quite a difference), stock carb bored to 36mm (broke needle jet set rebuilding old carb couldnt find individual part. Bought this one on ebay for cheap.), and a Fatty fmf pipe and silencer. I ride from 3000 ft to 4500ft elevation. I ride trails alot and spend alot of time in the dunes. Temperature is a big swing anywhere from 40 to 110+ degrees F. (Southern utah desert) I just need help dialing this bad boy in. Rebuild kit came with 142 and the ebay carb came with a 180. Hope this is enough info. Looking forward to an answer. Thanks all in advance!
slaytanic
04-11-2016, 07:50 PM
No takers? I would really like to get her up and runnin again and would appreciate some help.
yaegerb
04-11-2016, 08:49 PM
So you bought a new carb on eBay for cheap or you just replaced the needle jet?
If you bought another carb off eBay, what size is it?
DohcBikes
04-11-2016, 10:54 PM
communication is changing dramatically
slaytanic
04-12-2016, 01:53 AM
Its a stock carb. The side facing the motor has been bored to 36mm rather than 34. I can use the needle jet from the ebay carb in my old carb if its easier to figure out the jetting. I had been experiencing cutouts higher in the powerband, which prompted me to rebuild the carb when it started moving down the power band. and this is when i broke the needle jet. I figured with the fatty fmf (another recent edition,also used off of ebay) the bigger bored carb would be better. Im not an expert with carbs and that is why i am here i know there are some on this site.
yaegerb
04-12-2016, 09:40 AM
airbox stock/filter stock? what is the current temperature? Any crankcase leaks?
slaytanic
04-12-2016, 02:57 PM
stock airbox, moose foam filter, no leaks that I know of. currently its getting up to about 80 here. within the next month or so I think we'll be up around 100.
yaegerb
04-12-2016, 08:22 PM
This is assuming you are running a lid on the airbox with no holes drilled in it and 80 degree and up weather with low humidity.
Pilot: 50
Main: 145
Needle clip: 3rd from top
Airscrew: 1-3/4 turns out
That should get you in the ball park.
slaytanic
04-12-2016, 09:19 PM
Yup lid on, no holes low to no humidity.
slaytanic
04-13-2016, 12:46 AM
Thanks a bunch yaegerb. I must say thats a sic looking r you have. Ill have to get a couple better pictures of mine and post em. Not as nice as yours but it takes me where i wanna go.
edizzle89
04-14-2016, 09:50 AM
carb tuning can be tricky, usually the best way to do is get a bunch of jets and try them all out and see what works, but to start with you may just try to move up a jet size or 2 with the mods you have and move from there.
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