Need some advice on swapping sprockets

[coggonbrien]

Hi folks my blaster came with a second front and rear sprocket. Can somebody tell me the original tooth counts on a stock blaster to verify I have originals installed. As for the swap itself is there any major concern in removing the stator cover to get the front other than keeping things clean? As for the rear I don't think there's any real concern and if anybody is wondering I have a 22x11 rear tire on it currently.
Thanks!
David.

 

[99LRDblaster]

Hi folks my blaster came with a second front and rear sprocket. Can somebody tell me the original tooth counts on a stock blaster to verify I have originals installed. As for the swap itself is there any major concern in removing the stator cover to get the front other than keeping things clean? As for the rear I don't think there's any real concern and if anybody is wondering I have a 22x11 rear tire on it currently.
Thanks!
David.

Nope......no concerns. Stock is 13/40.......13 front, 40 rear. 14/40 is the most common change.

 

[York Racing]

Just remember, the larger in the front smaller in the back means top end or top speed. Smaller in front and larger in rear means torque.

 

[coggonbrien]

yeah i know gears i went from a 3.08 to a 4.10 in my tbird a few years ago. I just trail ride and ride from farm to farm so 60mph is plenty fast i need some low end grunt

 

[Blaner]

ya swap out the 13 tooth (if thats what u have) and put in a 14. i believe a 15 doesnt fit unless you edit your casings somewhat. more than that, you could go larger at the back but you could also put on 20/11/8's at the sacrifice of some ground clearance.

 

[coggonbrien]

anybody ever go to an 11 or 12 up front? i've got 22 inch rear tires so looking to compensate.

Thanks,
David

 

[1995blaster]

ive seen 12 never 11 tho id stick with 12 at the bottom i got a stockish blaster and dont weigh alot and can rip the front wheels up real good with just power and stock gearing.

 

[Luni]

Heres a blaster specific gearing calculator I made.

Gearing Calculator

A few things Ive theorized over the years of owning a blaster. Yamaha says the top speed of a blaster is ~58mph. Thats pretty spot on with the stock gearing of 13/40 with 22 inch rear tires at 8000 rpm. Keeping that in mind, Ive seen dynos of stock blasters revving past 9000 rpm, but I dont think that with a rider, with wind resistance the stock blaster has enough power to get up to 9000 rpm. I think 8000 in top gear is closer to realistic. However, things like porting, larger carb, top end pipe (like a Toomey, or LRD etc) can affect the target RPM in top gear, so you can play with that number accordingly.

The calculator is good at telling you how much of your top end youre turning into acceleration down low, because it will tell you what your top speed is in each gear, you can see what the sprockets are doing to your top speed in each gear.

Hope this helps.

 

[roger489]

just remember if you do go to a 12t in front that your gonna be over rev-ing alot to, i blew mine up with a 12t on it. it was mostly from it over rev-ing really quickly. since rebuld it a 14t and soon a 15t

 

[coggonbrien]

by over revving you mean running too high of rpm's for a sustained period of time? As i sit now 99% of my driving is through fields at slow speed (1st gear alot at near idle rpm's) I do drive down the gravel but i'm a far cry from maxed out rpm wise so I think i iwll be fine.

 

[roger489]

Well if your getting way up there doesn't take but a few seconds, especially if the motor has worn or has alot of time on it. I blew mine because it wound out each gear so quickly that it over rev-ed each time for a second, finally busted the skirt of the piston. My honest opinion is there no need to go to a 12t front. It's wasnt any more tourqe from what i noticed on mine. Just revs faster and cuts speeds down alot, that and I imagine it would wear out the engine faster