I know this topic has been beaten to death but I think I actually found something that might work this time!
As you know, our Ninja 300 is basically the same thing as Ninja 250 in Japan, except USA version has longer stroke.
This company called Technical Inc. happen to have a 290cc big bore kit for Ninja 250(JDM Ninja 300) for the price of 43,000 Japanese Yen
bore/stroke: 67mm x 41.2mm (JDM Ninja 250 with this kit)
bore/stroke: 62mm x 49.0mm (stock Ninja 300)
So I was thinking we could achieve bore/stroke of 67mm x 49mm, which would make it 345cc.
Do you think it's possible or would there be another problem for this big bore kit?
Looks doable. My guess, with a PCV, Yoshi R77 and BMC race air filter, 47 hp on pump gas and 50 with MR12 race gas. Of course that beast won't be legal in any class so no real reason to run race gas.
You could add more stuff to possibly make more power?
Japanese tuner, BEET makes a high cam for Ninja 250(JDM Ninja 300)
Apparently you can still use stock valve spring.
I don't know how much power it would add, also I wonder if you would lose low end power...because I know for cars, if VTEC kicks in at low rpm, it may cause you to lose power. Although Peske makes variable valve cam gear, is that supposed to be like VTEC?
Not necessarily, think about all the low compression piston kit for Toyota Supra and all the other cars with turbo set up.
You can change the compression without changing bore and stroke. It all depend on the design of piston. So if the piston was designed to compress hard at top dead center, like how some pistons are shaped like bottom of valves to make sure that they're compressing every space of air possible to achieve high compression, you can get a high compression because of this. Whereas top of piston was flat, you will probably end up with low compression.
I'm not good at explaining engineering stuff so I hope I'm making sense..
Yep I get that, cheers. I assumed that the pistons for the kit were about the same as original hence same compression. Maybe I didn't read something properly....
If you don't change the stroke and only make tiny changes to the piston head or keep it relatively the same but increase bore, you will increase the compression ratio as the relative volume at BDC gets a greater increase compared to what you get at TDC. Hence compression ratio increases. The problem is that at the relatively tiny volumes of these engines, the change in volume is actually pretty huge leading to a pretty large relative change in compression ratio. It's designed around the ninja 250 and brings it up a point. I think we did the calculation for this kit or similar last time on the ninja 300 and saw something like a 3 point increase.
There is a 2013 engine for sale in my area for $500. Could mod that engine, then just swap the engines out. I'd rather just get a different bike tho. (Looking at an FZ6.)
I never have experience with that , if you change piston and camshaft its increase the power also clean the engine block wall
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