Useful Blaster gearing info

[Luni]

Primary Gear Reduction: 3.227

Gear Ratios:

1st gear: 3.091
2nd gear: 2.214
3rd gear: 1.667
4th gear: 1.250
5th gear: 1.056
6th gear: .905

Stock Rear Tire Size: 21x10x8.
Stock front sprocket size: 13t
Stock rear sprocket size: 40t


Stockish max RPM (without internal engine work - porting, balancing, etc) ~8000

And a pretty cool website you can plug different sprocket/tire combinations and see how it affects your gearing. My custom calculator can be found Blaster Specific Gearing Calculator



Hopefully this post helps. In fact, it MIGHT be worthy of a sticky? (assuming the information contained within is agreeed upon as being accurate)


**EDIT** Ive edited the code to the Blaster specifications, and Ive dropped max RPM down to 8000 in response to some discussions about it.

The original location of the calculator I edited the code for is here:
Gearing Calculator

 

[Sandking]

Good info Thanks

 

[Kieran]

thanks for that luni

 

[super noober]

omg this chart is saying im going to top out at 48mph tonight at the strip with 17" tires on lololol im gonna get laughed all the way home hahahaha

 

[sheeblast]

so a stock blaster tops out at 60mph???

 

[super noober]

i dont understand how your motor work plays into affect.. more speed by reaching higher RPM's?

 

[sheeblast]

with motor work, you can rev it higher.
plus to reach the higher speeds, you need more power to counteract the Cd (drag).

 

[Kungfutree]

If your engine can handle the higher RPMs with things such as better cooling, higher strength parts, balancing and what not then you will get more speed in the high end.
more RPMs = More speed!

 

[Luni]

Our engines dont have a physical rev limiter. Altitude, jetting, mods, rider weight, drag, wind, what youre riding on, tires, etc.

It all plays a role into how fast you go. Its not like a car where theres a physical rev limiter that cuts spark, it will spin as high as it is physically able to.

So, the more engine work you have, the more power you make, the more balanced your rotational assembly is, the higher its going to rev. The higher you rev, the faster you go.

 

[sheeblast]

there are "rev limiters."
like the pipe, the port work and stuff, that is the rev limiter. plus they can only rev so high before they blow, no matter what work you have done to it.

what people need to understand, this numbers are what you can hit.
like if you put in 8500rpm for the max, in 6th gear, you can go like 60mph. but, will the blaster actually rev to 8500 in 6th? most likely not.

 

[Luni]

I mean theres no electronic rev limiter dude.

On a car, on other motorcycle engines, theres a physical "fuel cut" or "spark cut" soft rev limiter, theres a computer that controls how high the engine can rev. Our engines dont have this system. They can rev to the sky if the physics of the rotating mass and volumetric efficiency will allow the engine to rev that high.

Dont call pipe, port work, etc a "rev limiter"

Its confusing to people and contradicts what I said about there not being a rev limiter in relation to my explaination of rev limiters in context to my initial post.

And yes, a blaster can probably rev to close to 8500 stock. Yamahas published top speed for a blaster is 55-60 so, based on that gear ratio calculator 8000 rpm would be 55mph and 8500 would be 59.

Pretty close.

 

[Luni]

Edited original post with a blaster specific calculator I edited the original code for.

 

[slickerthanyou]

I have a question, The front tire size doesn't matter? I think your calc are close. I'm going to use a GPS to see how fast I can go, not sure if they're acurate, but I swear a couple weeks back I had to be going close to 70. I could be wrong but I wish i could get timed.

 

[sheeblast]

that calculator is correct if you have the right info in it.
front tires do not matter one bit
also you have to take in to account rear tires are not alwys 20" tall when they say they are.
plus GPS's are not accurate enough to calculator MPH to the dot.

 

[Luni]

I had to search for this thread, and since the calculator is extremely helpful, Im bringing this thread back from the dead.

In fact, it would be nice if the calculator could be added to a sticky.

 

[99LRDblaster]

I had to search for this thread, and since the calculator is extremely helpful, Im bringing this thread back from the dead.

In fact, it would be nice if the calculator could be added to a sticky.

Touche. After some second thought, I might swap between 14/38 and 14/40 rear sprockets dependent on where I'm riding. Around the hometown here, a 1438 is more useful cruising between spots on the road, where as the 14/40 is nicer through the trails around the hometown. That calculator is a quick and easy tool.

 

[UncagedShadow]

this is a great tool i agree to the sticky. According to this if your running the 15/38 gearing that some people wanna run, and some 22 inch tires, and turning 9000 then you would just about be doing 80 miles per hour. Thats bada** but you better have the motor to pull that type of gearing lol.

 

[Antec1200X]

awesome find +rep

 

[PikledBeats]

Not trying to thread jack, but am extremely curious why so many decide to gear up. Almost all pipes for the blaster are somewhere in the mid-high range, most porting jobs extend top-end while losing in the low-end, I would think that gearing is the one successful way to get more low-end especially for trail riding (I guess I can understand if looking just for top speed). Just my opinion here, but it seems as gearing lower for instance 12/43 to compensate for lost low-end when modding is much better than gearing high when almost all blaster motor mods are mid-high based. I personally hated 14/40 and felt a noticeable loss in low end riding trails. After about five gearing choices 14/40, 14/41, 13/41, 13/43, then 12/43. I found the latter to be the best gearing for riding tight trails, especially when gaining elevation.

 

[99LRDblaster]

this is a great tool i agree to the sticky. According to this if your running the 15/38 gearing that some people wanna run, and some 22 inch tires, and turning 9000 then you would just about be doing 80 miles per hour. Thats bada** but you better have the motor to pull that type of gearing lol.

Getting 9000rpm is pretty unrealistic from the Blaster with typical engine work. Quite frankly in terms of peak power, anything above 8500 is pretty steep...between 7800-8300 is more realistic. It's been done on some builds, but the dyno's usually show otherwise.