apex chain / change

[**sj**]

just making sure I dont pull a brainfart...changing top gear to a 22 which requires the 68 link chain.....go to my parts inventory and wallah' Ive got one...same width as stock...what else am I supposed to double check?

 

[rxrider]

Check what brand and model the chain is, if you're sure it's a Yamaha chain you're OK. Also check that the chain fits the sprockets 100%, if so you're good to go.

 

[**sj**]

well thanks for the reply...but I did screw up...turns out it was a 70 link...so I just ordered a 40 tooth bottom...

 

[Len Todd]

You may want to check the chain tension before putting on the cover. Especially with used chains. It could be that there is not much adjustment left, if any.

Speaking of used chains, if the chain is not an early takeoff, I would not use it on new gears. Speaking of gears, I personally would not change one gear. They should be changed in pairs and a new chain be used also. To not do that will cause premature wear in the chain and gears.

I know lots of guys do not follow these recommendations and seem to get away with it. But, if you got a couple years wear on the sled and you doing this mod., it is a really good idea to replace the chain and sprockets as a set.

 

[**sj**]

will be running a 23 and a new 40 bottom..with the chain the machine came with ...has about 1300 miles

 

[Firemann32]

What's the advantage of changing the gears. I ride sportbikes and understand the ratios but on a snowmobile what's the reasoning behind it? I'm guessing that the idea is to speed up the the track?

 

[**sj**]

just like rear axle gears on a truck or car...affect's performnce..

 

[Firemann32]

just like rear axle gears on a truck or car...affect's performnce..

Yes but how. What's the advantage of having the track spin faster or slower and "X" RPM?

 

[**sj**]

higher ratio with traction equals faster acceleration....lower ratio equals more top end...driveline drag is a factor as well I .E. longtrack etc.

 

[Firemann32]

higher ratio with traction equals faster acceleration....lower ratio equals more top end...driveline drag is a factor as well I .E. longtrack etc.

Cool Thanks. So what's the best setup for all around ride ability, stock?

 

[ahicks]

Um, let's not forget this is variable ratio tranny. As soon as the belt starts shifting out (almost immediately if geared properly) the belt height is going to seek it's own level - no matter your mechanical gear ratio...

So, IMHO, the bigger differences with this change (vs. stock) might be noticed most at the point you are first starting to get the sled moving (easier to get moving without blowing the snow out from under it is what I notice most), and at top end - with the potential for fully shifting out the clutches and overdrive.

If the sled is overgeared (way more gear than it has the potential to pull on top end) you'll see the belt must slip big time to get the sled moving and the sled will have to be moving much faster prior to the belt starting it's trip up the face of the primary - which it will never complete.

 

[**sj**]

good point ...gear ratio...traction...and inertia are all factors...too low and you run out of gear...too high and you could pull more gear (waste)
think of your clutches like a transmission...
clutch efficiency or inefficiency is considered a constant IMO...

from testing of others... for a standard 121-136 track..23/40 is the fastest on snow..