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Gearing and speed are always common topics on any orv powersport board. In an effort to answer some broad questions I offer this post.

Stock Top Speed:

There are a lot of answers out there, but most are in the range of 68-77 on a flat patch of good ground. FME it's in the low 70's. Anyone claiming 80+ is either modified, going down a huge hill with a tail wind, or blowing smoke. Anything lower than 65 either has modifications (shorter gearing/smaller tires) or there's something wrong with it.

For most of us 70 is more than fast enough. At those speeds and higher the tires, twitchy handling and wind resistance start making things significantly less safe. If you're one of these people it's a good idea to shorten up the gearing to accellerate faster.

If you have a reason to go faster or a need to lower the rpms in top gear for a cruising speed then it's time to look into taller gearing.



Sprocket Sizes:

The 660 accepts front sprockets of 12-15 teeth with the oem shroud, 16 tooth will work without it. The rear sprockets can be sized from 39 teeth on up, with your ground clearance most likely being the limiting factor. Anything smaller than 39 and the chain will start to ride on the sprocket hub mounts instead of the sprocket.

For an idea on what sprockets do to top speed on a stock bike, I offer these calculators. In stock trim the 660 revs somewhere in the 7k-8k rpm range, but more on that in a minute.

Sprocket/Top Speed Calcuators
http://home.earthlink.net/~gellett/raptor02.htm
http://www.jandjcreativedesign.com/sprocket.php (Thanks to SandSquid for all his work on this one)



Higher Revs:
This is all keeping in mind that your bike is stock, meaning that it can only rev so high and only has enough hp to pull a certain gearing. But when you can rev higher the bike will go faster.

You'll notice in pipe comparison dynos that most aftermarket pipes not only increase the hp but also increase the peak rpm. Many of the modifications that you add to your machine will have a similar effect, including when you free up air intake. This also means that your top speed will increase, assuming as we will that you're not limited by wind resistance. So if you were able to go 70mph stock adding more hp might make that same bike go 75mph now. The more hp and higher revs you can get out of the bike, the faster the bike will go on that gearing.

But this also has an impact on gearing. If you only need to go as fast as you did stock and you modified the bike to reach higher rpms and therefore a higher top speed then you can change your gearing to keep that stock speed and get there faster at the same time.

The following numbers are for explanation purposes only. For instance, say your bike does 75 stock. You do some mods, now your bike goes 80. We all know that lower gearing (higher ratios) means less top speed, but we also know that it means increased accelleration. If you go from 13/40 down to 12/40 on your modified bike you'll have the benefit of greater accelleration and because your bike can rev higher than it did stock you can maintain the 75mph top end at the same time.

My 660 is a good example for me. Stock it did somewhere in the low 70's. I've made some modifications and now running 12/42 gearing and 20" tires my bike has the ability to rev high enough to exceed 78mph. My top speed hasn't gone up all that much, but with the shorter gearing I'm able to reach the original top speed significantly faster that I did when it was stock. And honestly it's still a little too fast on top so the 44 tooth is ready to go on for next year.


I've explained, at least in part, this topic as best as I understand it. If there are any discrepancies or questions please let me know. Hopefully it's able to clear some things up.
 

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great write up maddog thanks should stick this btw
 

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good thread man :thumbsup:

I've also noticed that stock I ran around 72-73 mph, but after putting a 12 tooth and a pipe/jetting I'm actually faster than stock by a few mph..I actually gained 2mph at the dragstrip with a pipe and 12 tooth.
 

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Awesome write-up Mike. 8)
 

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So given a stock 660, anyone know if it actually reaches max rpm in top gear or if load/resistance is the limiting factor. I guess weight is a big factor, so assume a 180lb person.
 

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Discussion Starter #7
gobeer net said:
So given a stock 660, anyone know if it actually reaches max rpm in top gear or if load/resistance is the limiting factor. I guess weight is a big factor, so assume a 180lb person.
Re-read the initial post, somewhere in the 7k-8k rpm range. Limiting factors include hp, airflow, and cam profile. Wind resistance plays a part as does weight but they aren't going to make dramatic differences for top speed on a stock bike.

Thanks guys, hope the post helps some people out.
 

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i weigh 230, when mine was stock i could hit the limiter in fifth.

can the raptor motor handle going 1000rpm over stock without handgrenading? I still run the stock cdi and still like the fact that my motor is reliable.
 

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danos660r said:
i weigh 230, when mine was stock i could hit the limiter in fifth.

can the raptor motor handle going 1000rpm over stock without handgrenading? I still run the stock cdi and still like the fact that my motor is reliable.
What kind of conditions were you in when you hit the limiter and what was the gearing setup? I ask because it's extremely unusual on a stock bike because of the mechanical and physical restrictions to hit it in lower gears, let alone top gear.

Can it handle it, yes but it won't last nearly as long as it should and I'd start looking for an oem rod through the cases. The long and short of it is if you're hitting the limiter you need to shift faster not raise the limiter. The engine is well past peak hp output if you've reached 9k rpm and adding the ability to rev higher can actually slow you down if you spend too much time in each gear.
 

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This may sound like a dumb question, but as you increase the torque output of the motor, won't you actually accellerate faster with taller gearing? What I guess I'm really asking is does traction become a limiter with the shorter gears - more wheelspin and less forward movement? I have been wondering this exact thing a lot lately, as I have now had my @$$ handed to me by two different DS650's, one bone stock and the other piped but not jetted/filtered. I run 12/41 gearing and have been beat on both my 20" paddles and my 22" dirt tires. Any input?
 

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Well you've actually posted 2 questions but they are related.

The first on tq vs accelleration, the second has to do with bike setup. Realistically it's important to understand what your goal is. You won't necessarily be running the same gearing and tires if you're looking for fast 300' times as you would for hill climbs or for xc racing and trails.

If your goal is to get as quickly as possible to 70mph in a straight line you'll have different gearing than if your goal is to get to get from one corner to another on a flattrack or xc course. So if you're trying to go faster then increased tq combined with the appropriate widening of the gear ratios will do the trick. But if you're shooting from corner to corner you just want to get to the highest speed possible in the straightaway instead of worrying about an extra 5mph you might not have the distance to reach with your engine output.

It's a lot of trial and error for different situations. Many of the top hill climbers are running 21 or 22" paddles w/ 6-8 paddles on 12/44 or similar gearing to keep wheelspeed high up the hill. If you're running on flat dirt you're going to go with shorter tires (18-20") and taller gearing to keep traction and speed.
 

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Hit the rev limiter on a stock 660?? Yeah right!!! Even with the airbox lid off and rejetted ON A DRY LAKE BED my best speed to date has been 69.4 MPH on my Trail Tech computer which is +- 1 MPH of my GPS. Someone do the math and tell us what 9000 RPM would give us in MPH on a 660 with stock rear tires. I would do it myself but I can't find a chart showing the drive ratio of 5th gear. That's not the rev limiter bud, it's water in the fuel, or a dirty air filter, or shorted wire, etc......................
 

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ok ?S i ride at cinders alot theres a big hill called $100 hill that people try to make it up .... my banshee flys up it with paddle geared 14/40. but my 660 with pipe jet kit and paddle wont even get half way up ... with 13/42 gearing the raptor runs good ... i have only seen 1 660 with tons of mods get up . anywho you think i should gear down more??? o ya i have 20 in paddle on both bike ... first gear just runs out of power ?????? my buddys 700 goes up fine and he has 14/38 ...
 

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banshee 388 said:
ok ?S i ride at cinders alot theres a big hill called $100 hill that people try to make it up .... my banshee flys up it with paddle geared 14/40. but my 660 with pipe jet kit and paddle wont even get half way up ... with 13/42 gearing the raptor runs good ... i have only seen 1 660 with tons of mods get up . anywho you think i should gear down more??? o ya i have 20 in paddle on both bike ... first gear just runs out of power ?????? my buddys 700 goes up fine and he has 14/38 ...
Your buddy also has a different set of internal trans gears so you can't compare sprocket teeth just overall gear ratios.

Never been to the cinders but from what I've heard that place can be hard on paddles and the paddles hook up quite a bit. You may be exceeding the bite that your gearing/power can handle, especially up long hills. Try dropping down to a higher gear ratio and air up your tires a bit more, you should pull better up the hill and get a bit more wheelspin to keep you going.
 

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Teraflx said:
Awesome write-up Mike. 8)
i have a 02 660 ... its piped jetted k&n i run a 12/42 and last year i dyno at 83mph and 43 hp.. this year i added a cdi box .. i hope to get up to 85 mph ..
 

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02yamrap said:
Teraflx said:
Awesome write-up Mike. 8)
i have a 02 660 ... its piped jetted k&n i run a 12/42 and last year i dyno at 83mph and 43 hp.. this year i added a cdi box .. i hope to get up to 85 mph ..
If you're trying for top speed you've gone all the way to the other end of the gearing spectrum, you're using the wrong gears. You're also asking a lot of your bike if you've got an OEM rod in there.
 

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i have an '03 raptor 660 with a big gun evo x, k&n, jets, ...minor toys, and ive been lookin at gearing up for more speed and adding a rev box for more rpm to play with and maybe even a stage 1 cam. i'm mostly stock (or so i tell whoever i race ;) and i have been clocked at 75 with a gsxr600 going up hill, not that the hill made a difference, i was on the limiter. Neways i was curious why the last guy was told he was "asking alot of his OEM rod"? I keep my machine super tight and clean and honestly it scares me to hear that a guy with similar mods might be stressin his rod. Ive seen a number of raptors with big dollar mods on, and still running the same bottom end and it holds. Are the stock rods prone to bustage, or is it just how hard you beat your machine?
 

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I'm curious as well. I've got an 04 raptor 660 with fmf q2, jets, pro flow, running 12/42 with Kenda Knarly XC Rear 22x11-9 and Kenda Klaw XC Front 23x7-10. I'm considering going down to 12/40 to stretch it out a bit but I'm not sure yet...any opinions would be helpful.
 

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My 05 with stock gearing , 22 inch rears, fmf slip on was clocked at 81 by the south dakota hiway patrol.This was after a 5 mile WFO run .I have GPS'd it at 78mph. Funny thing is When it still had the stock tires on it, I gps'd it at 77 So I am guessing it is just maxed out on power with the taller tires and Im not on the limiter?
 
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