[Zunman]

So I just bought a 450x, wondering what works best or gearing to run 75% street and 25% trail.looking to maybe gain some top speed.13/52 gearing maybe. Also I'm wondering if maybe the Tokyo mods smog kit and carb kit would be a good upgrade? My primary riding type will be around town... So Maybe a fan too..

[JimDirt]

Welcome to the site !!

13/52 gearing would be gearing it lower not higher , it will have less top speed than you have with the stock 13/51 , for a easy cheap attempt to see if you like the gearing , try a 14 tooth for the front , this will alter your gearing by 3 teeth on the rear , higher , so if its too much for the trail , or not enough for the street you will know (you will probably like it)

You did not mention what type of off-road riding your doing , is it fire road type , or very tight single track , as there is always a compromise between what works off-road and what works on the street , but with a smaller rear sprocket you will gear higher , so more top end speed , but less bottom end torque , with a smaller front sprocket you will gear lower , and have less top end speed , but more bottom end torque

Stock gearing should be a 13/51 , so you need to decide what your wanting the bike to do , and what your willing to compromise with for gearing , if you only ride fire roads (faster open trails/roads) , then a taller gearing more suited to street riding will be fine , especially if the off-road riding is only 25% , you need to focus on what you will mainly be doing , and settle for what you get with the other riding type , but you will lose the ability to go on tight trails without compromising your clutch and/or overheating

If you only ride tight single track for off-road , then you will lose the ability to go on the freeway or any highway/road where anything over 60 MPH constantly will become a issue

So you need to decide what type of riding is more important , and set your goal to that and just live with the other , either way its a compromise and you will have to settle for what works OK in both , as it will be real hard to find a ratio that works great in both

I run 13/52 and can reach speeds of about 75 mph , but i don't like to rev the engine that high for that long , so i only reach that speed for brief periods of time , and the majority of my riding is tight single track , where the 13/52 is better suited , i do not ride my bike on the street at all , but do ride open desert , so i do attain speeds , but usually for short periods

Choose what your willing to live with , and what your needing to do with the bike the majority of the time , this will determine which way to go , and where to focus your gearing selection , i would think you would be happier with a 14/51-52 , or even a 14/50 , again , the taller you go the less bottom end you will have , and this is all dependent on your riding ability , and how well you work the clutch and what gear you use while off-road

[crazybrother]

I use a 13/49 for dirt and 14/48 for dualsport works well for me.
I have two sets of wheels, which makes it much easier.

[Zunman]

I'm thinking 14/48 or 14/49 might work for me. I will be mostly street and some class 6 roads (dirt roads mostly). What kind of 5th gear speeds will I see with these sizes? Thanks guys.

[JimDirt]

You can use this to give you a idea of where you would be , or where to go gearing wise for your needs

http://www.crfsonly.com/forum/viewtopic.php?t=37723

[crazybrother]

With 14/48 you can cruise at 70 all day.

[Zunman]

I'm assuming at a major loss in low end and no more clutch less wheelies? Haha

[crazybrother]

Not at all, my bike can still wheelie all day.