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99 Kx250 Torque engine setup

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Hello TT members! I am a long time lurker on your site. You have lots of great people and info here. I have a 99 Kx250 with PC pipe/silencer, Rad valve, MCR Porting, and cut head for race fuel. The bike has an explosive mid range, with tons of top end. However I am finding myself riding more single track trails and less motocross. I want to buy the components to make this more of a torque monster. In other threads it has been said the 97-98 engines make this power. My question is what is the easiest way to this goal? Should I buy a 98-99 cyl(same), and 98 ignition (because 98 uses the powerjet carb also, and I shouldnt have to buy another carb)? Or is the 97 setup easier because of the lack of the power jet? Thank you.

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I use the 98 ignition with the 99 carb, you just don't use the throttle position sensor in the carb. You do have to use the 98 stator and wiring harness. Allso put a flywheel weight on it and a FMF Gnarly or a 98 pipe too. If your cylinder is ported for top end you may want to get a new 98-99 cylinder.

Ed

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Jeekinz has a good point, since it is a 99 you should put t 94-98 1'st gear in it too.

Ed

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Retard the timing by turning it counterclockwise. this mellows out power and gives more bottom end. its free and easy.

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I am running stock gearing. I was thinking if I geared it down the "hit" would increase. Thanks No1clyde, that is what I was looking for! I forgot all about the timing trick too. The 450 guys are faster this year, I dont want them getting near me! How well does the lower first(94-98) ratio work for MX?

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Works great with the 99, with the 94-98 1'st gear it is then the same trans that the 94-98 had.

Ed

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Is it the Works pipe? That would cause a "hit" with absolutely ZERO bottom end.

IMO, those bikes were pretty smooth running stock. I'm not sure if the trans swap will help you out for MX as I never used 1st (unless I fell somewhere). You might want to try a 97/98 pipe, or stock for that matter.

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I have a PC platnum pipe, with access to a stock 99 pipe (I should try it). Im thinking the "hit" is from the MCR porting. That coupled with the high first gear makes it not want to pull from the bottom. I think will do a 98 cyl / ignition / pipe / transmission swap. I want to try a bike that pulls hard off the bottom. It seems it would be easier to ride in tight trails and small supercross tracks. Thanks guys!

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i wud try stock gearing , fatty and shorty ... my bike has plenty of bottom ... low 2nd pulls front up ... 14 / 49 gearing may have to try couple different combos and take the time to jet correctly :bonk:

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He can and I have and at times it has helped but if he is going to get into trail riding copying the 98 motor is a great way to go.

To the OP the 99 pipe is not the same as the 98 and is made for higher RPM power. The cylinder's are the same between the 98 and 99 it's the ignition,pipe and jetting that make them run different. Also the 98 has that lower 1'st gear making it stronger in low.

Ed

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Im pretty sure they dont make gnarlys for that year, but if you want low end thats it!. as it sits you could only put a shorter muffler on it for more lowend in terms of your exhaust. other than that you could jet it, change ignitions, and mess with the gearing. you should probably jump to a 13 front sprocket, the 14 will destroy your slow speed acceleration and power 'feel'. If you mess with it enough you will in time get the setup you are looking for. Its ALL I do!

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Well as for the Gnarly pipe any Gnarly for a 94-01 will fit and work fine. I have one for an unknown year that I got off ebay and it works great. Messing with mine is something I do alot too and I have friends that say I never ride my bike just test it LOL.

Ed

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