# xr100 sprocket size

I have a 2003 xr100 with fmf power core 4 system and uni filter but i want to make it go faster now that I have the power to push it so stock gears are 14/50 so should I go 15/50 or 16/50 do you think 16t in front would be too much

you would lose a lot of power if you went 16/50. Mabey it would work on a super motard setup, but im assuming thats not your case... I tried 15/46 (which is basically 16/50) on my xr100 with a 120bbk and it didn't have the power for it. 15/50 sounds like it may do good though...

One up of the front equals 3 on the rear... For example

14/50 15/53 16/56 are so close in ratio you hardly notice a difference... Simple math

Divide 50 by 14 to get your ratio and so on.... I'm a big guy and I have elected to go witha large front sprocket... 16 and 17 and change the rear accordingly...

I figure the larger the sprocket on the front, the less work the motor has to do to turn it and it does not bind the chain as much thus, creating less wear...

This topic has been covered before, so I guess I'll throw a wrench into what's generally believed. There are two things going on math and physics. Everyone knows the math side, the simple ratio effect of the the the tooth size, but equally important is the increase in radius of the sprocket. With an increase of radius with either sprocket you have an increase of leverage, so a 16t/53 doesn't ride like 15/50, even though mathematically it should. As the front sprocket increases the countershaft has more leverage and as the rear increases in radius it spins the wheel easier, etc. Anyway, you have to test different sprocket sizes and get a set up that works for you with the way you ride. On my kx/xr120 I rode a 15/47 for years, but on my cr/xr120 I rode a 15/53. I still haven't figured that one out. So it all depends on a lot of factors. I tried a 16t setup and didn't like it, but I'm only a buck fifty, whereas the guy in the above post said he liked a 16t's, but he's a big guy. So it all depends.

I went one up on my front sprocket and it did wonders . I can still lug up hills easily, ride wheelies,and it seems to have quite a bit more speed:thumbsup: I did this to my ttr 125 btw.

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• I decided to compile a list of common modifications for the XR200 in hopes of eliminating some of the common questions asked on this forum. These modifications are intended to improve the overall performance of the bike, without sacrificing reliability. Feel free to suggest amendments or things to edit.
The XR200 is an excellent offroad machine; however, it was for the most part obsolete about 20 years ago. The bike can still be accredited to having probably the best reliability of any full size bike out there. When properly setup and modified, the "little XR" can run with the modern big bikes, especially in the tight and nasty technical terrain.
INTAKE: Remove the airbox snorkel on top of the airbox. It just takes a little prying and it's out. For \$20-\$40, you can get an aftermarket filter (UNI, TwinAir, No Toil), that will help increase airflow. Rejet one size up on the main and pilot.
Here are the stock jetting specs to give you a basline:
Stock jetting
XR200 (not XR200R)
main 102
pilot 35
Needle position 3rd groove
Pilot screw initial setting 1 3/4 turns out
XR200R (81-83 only)
Main 138
Pilot none
Needle position 3rd grove
Pilot screw initial setting 2 1/2 turns out
XR200R (86 and later)
Main 112 (86) 110 (87 and later)
pilot 38 35(98 and later CA only)
Needle position 3rd groove
Pilot screw initial setting 1 1/8 turns out
When these things are done, the bike will breath much better. This is the single greatest modification for a bike ridden at high altitude.
Overall cost w/out filter: about \$10 for jets; \$20-\$40 for the aftermarket filter
ENGINE: The greatest improvement to the XR200R engine is a big bore kit. Here are the 2 most common kits: http://www.powroll.com/P_HONDA_XR200.htm
Other options include porting and polishing the head, high compression pistons, hotter cams, etc. The more you do, the more reliability is reduced, but it is a trade off for power. Another option is an ’83 -’85 ATC200X cylinder head. It has a .5mm smaller bore, so it would need to be bored to 65.5mm, however, it has much larger cooling fins. For motors that are constantly being run in extreme temperatures, this is an option to consider.
Overall cost: Varies by modification, expect to drop \$200-\$1000
EXHAUST: There are several aftermarket exhausts on the market. These range from silencers to full systems. Prices range from \$80-\$500. Most aftermarket exhausts will give about the same improvement. The engine will rev quicker, which can be nice, but mostly they all just make the bike louder. For mild improvement to the stock system: grind the weld off of the inside of the header and remove the small cap held on by 2 8mm bolts at the exhaust tip.
Overall cost: 0-\$500
SUSPENSION: This is a major weakness with '92-'02 XR200s. The first option for the forks is to give the springs more preload by adding a larger spacer on top of the springs. The second, most common option is to swap out the entire suspension. '84-'91 XR200 forks and rear shocks will bolt right up, and ‘81-’83 XR200R forks will with the corresponding triple clamps. '84-'89 CR125/250 front ends will bolt up to any XR200R with the addition of a spacer. This particular swap is more complicated, but also adds a disc brake and improves the bike tremendously when used in combination with an '84-'91 XR200 rear shock. See this thread for more info on CR front ends: http://www.thumpertalk.com/forum/sho...1&parentpage=2 These parts frequently show up on Ebay and can be obtained very cheap. Also, a visit to racetech.com or similar suspension tuning company couldn't hurt with any setup. Emulators and progressive springs will get conventional forks nice and plush. Currently, XR250 rear shocks are in question as to what years will work; therefore, I do not recommend them at this point. Many people have them on their 200, however there is not a definitive answer for the years yet. Be sure to research before you buy.
Overall cost: Generally less than \$100; for Racetech tuning, expect to drop \$200+.
WHEELS: An 18" rear wheel from an '86-'89 XR250 will bolt right up. This can help because the 17" wheel spins too much sometimes, and tends to work its own spokes loose. There is also a much greater tire selection with the 18" rear wheel.
Overall cost: Generally less than \$100
LIGHTING/DUAL SPORT: Lights can easily be added to the 200 by tying into a pink wire that just comes up under the tank, then loops right back down to the stator. This wire has no purpose, and was left behind in the wiring harness, because the non-American XR200s had lights, and Honda didn't pay to change the wiring harness or the stator. I have personally tested it up to 75 watts, but I wouldn't recommend going much higher. From there it is simply a matter of wiring it the way you want it. In any application you will need a 12v voltage regulator. I would be happy to assist with any questions on the wiring you may have, since I have redone mine several times to change things. Also, please visit this thread for some diagrams (about halfway down the page): http://www.thumpertalk.com/forum/sho...d.php?t=431097 Each wiring job is different, so it is difficult to write a generalized way to do it. For dual sporting, there are kits from Baja Designs and similar companies, or you can be creative and pull parts together yourself, and in result save lots of money. The first time I had lights on my bike, it only cost me \$6. A speedometer cable can be attached to the speedometer port on the front brake hub, as long as you can find a way to mount the speedometer. TrailTech computers are the easy alternative to the manual speedometer.
Overall cost: Dependent upon creativity. Baja Designs kit runs around \$450