13t front on 03 300MXC? and jetting Q

[426 Pilot]

Anyone put a 13t front sprocket on a 300MXC? This thing doesn't bridge the gaps between 1st and 2nd and 2nd and 3rd as well as I would have expected. Gearing seems like it would be an easy fix but the gaps I have felt would need at least 2 teeth on the rear and I don't want to go that big. This problem is only noticeable in the hills, but I live in Nor Cal... lots O hills. The gears are taller than I am used to so I am finding myself in 1st and second a lot more than my yz. While shifting up hill from 1st or 2nd to the next gear, it can be difficult to keep the revs up. I'm also thinking jetting could be a slight factor. I dropped the main from a 178 to a 175 and it really cleaned up the top, but the transition from the lower throttle postions seems a bit fat. I haven't had time to mess with the pilot or needle.... no need to reply to the jetting question if you don't live in nor cal or similar climate. 1000-3000 feet 65 degrees (this time of year)

JL

 

[D Lafleur]

Down in the southeast, where we run in the tight technical stuff, we run 13s all the time. With a 52 rear you will be limited to ~ 65mph. Around here you have to be on the interstate to need more speed than that.

KTMs around here always show up with one needle size too small. I would look at my needle size. I run an NOZI with great results. The manuel says I should be running an NOZH, but the bike was too fat for tech. riding, and still managed to foul a plug every 300 or so miles. With the I needle life is sweet, the plug is nice and brown, and the power is everywhere.

Good luck.

D

 

[wsmc831]

I'm in San Jose and ride from the Southern Cal Desert (yearly enduro trip) to Shasta Area (last weekend) but mostly Hollister and Clear Creek.
Don't worry about gearing, just put a VForceII on. I was thinking I'd go up in the back until I did that, last weekend was the first ride on it and the bottom is now so strong I don't need to mess with gearing. I've got stock jetting but after the reeds I think it's a bit rich on top (175 stock, going one smaller to try) on my 02 300mxc. I don't want to mess with jetting, and Im not looking for perfection, it just dies a bit on top, especially when I was at 4200 feet. At 500 feet it ran unbelievable, but I want the best jetting at 2k or so.

hope it helps....

 

[Gardener]

I'm not in nor cal but I'm gonna reply anyway. Going to a 13t countershaft sprocket is the same as going up 4 teeth on the back if you are currently at 14-52 so its a fairly drastic change in final drive. You'll loose top speed but the gear ratio might suit your terrain. I personally run 13-52 on my 300exc, for 90% of my terrain, its perfect. FWIW NOZX needles are rich in the first transition, thats where your rich condition is coming from. I ride 3500-6000ft and I'm no where near that temp now so I'll let someone from nor cal suggest a needle.

 

[LocoCD]

I just bought a 300 and have switched back and forth between the 13 and 14. I tend to like the 13 better, 2nd gear is very good on tighter trails and you always have 1st available.

 

[426 Pilot]

Loco,

Did you need to take a link out of the chain when you put the 13 on? My adjusters are right in the middle right now so I'm thinking I would have to take a lnk out to avoid being maxed out on adjustment.

J

 

[lawman]

426: don't forget that they are reversible. if you are in the middle, even with the adjuster blocks with the "long" side to the front, it probably will be ok. i didn't take out a link when i switched my 300 to a 13.