Thread: New rider.
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Old May 9th, 2018, 11:44 PM   #19
NinjaRacer
ninjette.org member
 
Name: guram
Location: tbilisi
Join Date: Apr 2018

Motorcycle(s): ninja 250r

Posts: 14
Thanks. It makes sense now. Japanese cars are tuned the same way. I didn't knew about head port sizes and such. Thanks for sharing. Yes overly rich topend. I also have snorkel deleted and needles raised. It gives best performance I can feel it on my butt dyno. Also I tried 95 fuel. Runs really good now. I can feel its still little rich. Main jet also affects off idle speeds very much not onlY WOT. You must have correct mains first to tune. Then 2.5 open screws and play with needle thats it. I had wideband in tailpipe not very accurate on idle but with 110 jets topend was below 12's and thats when it starts to bog really hard like hitting a wall bog.

I also adjusted valves. It was way out of spec. 0.10mm exhausts and 0.15 intake. I didn't have shims so I rearanged them and got all exhausts 0.20 and intakes 0.15. Not within specs but close. I don't care really. It should be ok. I hope. I'm happy with it now.

Didn't check AFR after but it should be pretty close 13's like yours Don't want to go much leaner. I heard timing is really high on these and compression is 13:1 like.
note: you don't have to remove carbs(such a pain) you just have to remove left side fairing and tank. Then you can access both needles and main jets with little patience and get new hex bolts. They don't have to be super tight btw. You gonna lose some bolts and some are gonna strip. Get the bolts and it makes it really easy and fun job. 15 minutes and your done.
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