sprockets

[gwcrim]

So I bought this '08 KLX450 and it needs new sprockets and chain.  I want to gear it low so I'm looking for a 12t and a 55t or so in the back.  Can't seem to find those sizes.  Any pointers?

[meangreen]

I would hesitate to put a 12T on a motor with  grunt - wrapping that tight can severely shorten chain life.  13/50 was stock - and it was designed as a enduro/woods bike with a "wide ratio" gearbox.  That means it has a lower first and a higher fifth than motocrossers (like its evil twin the KX450F). 

With a 55 on the rear and a 12 up front you are going to see some massive torque/slow speed on the low end and a substantially lower top speed (trials bike style).  Are you going to be using this machine in extremely technical terrain?  If so, this may be ideal for you, but if you are wanting something more multipurpose, I would leave the front as a 13T and maybe move up to a 52 or 53 on the rear.  This will give you the reduced speed/added torque on the low end and still leave you with some top end speed.

If you are still in question, use the gearing calculator on this site.

Just my $.02

Ben

[gwcrim]

I like to ride slow sometimes.  Yes in an almost trial bike way.  Up and down the creek bottoms.  I also ride with younguns and a crawler gear can be handy.  Sure don't care to go 80-90 on a dirt bike.

I just scored an 11t on ebay.  I'll toss it on with the 50 rear and see how I like it.  $13 shipped.  Can't pass that up.

50/13 = 3.85.  50/11 = 4.54.  That sounds like a good place to start.  Make a stump puller out of it. 

[don46]

On my hillclimb 450 I have run 12/56, its not stock and revs to the moon and works well. The sprockets are the same spline as a KX250 and I think a yamaha 450, the problem is the seal area rubs with the 250 sprocket. I have used a 250 sprocket and relieved it in the seal area. I do know that my dealer was able to get 12t sprockets for some of the guys and have seen sprockets as well, Vortex makes mine, I go from 42-59. 11 is pretty small, I'm suprised it will clear the seal lip.

good luck getting the sprocket off, whoever tightened the sprockets must have lost their torque wrench, the first one I did I had to use a 3/4 air wrench to get off

[gwcrim]

I got an 11t on this week.  Everything seems to fit well.  The new O ring chain didn't like to make the small turn but it broke in fine.  Is there anything I should look for in regard to rubbing seals, etc?

I like the gearing.  It idles along nicely but I could have gone with a bigger rear and been even more happy.  Still haven't been out in the woods yet but that sucka has LOTS of power.

[jonny500]

http://www.bandcexpress.co.uk/sprockets.html
this is  a company in the u.k they make sprockets and will make you any size you want i am sure shipping to the u.s will not be a problem. if you would like me to contact them to inquire let me know what sizes and materials you require and i will call them for a price ect