Gonna give off-road racing a serious try!

TriRacer27
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Edited Date/Time 10/20/2012 10:59am
First of all, gotta brag just a bit. This week has been one of the most fun weeks I've had all year! I just moved to a new house that has a huge public off-road area right behind my back yard. I have never been too much of a trail rider but one of the trails is just amazing with turn after turn after turn, rhythm sections out of natural dips and pretty tricky rock sections. I came back with a grin on my face like I haven't had in a while. It's not that it was that much more fun than going out to Nocona, but just with how convenient it is I could ride every day if time allowed! AND it's also a blast. I rode for a whole hour non-stop before I realized how long it had been and headed home out of fear of running out of fuel.

Now, of course, I've looked into local racing series and lo and behold, there's one in my area starting up next month! Time to get ready!

So off-road guys, what changes would you say are vital to an MX bike to get it ready for some woods racing? I'm down to just the YZ250 at the moment so it will have to serve double duty as an MX and off-road bike for now. I've already concluded that I need some better hand guards as the ones I used for MX don't work too well. How much does a heavier flywheel help? This area is pretty woodsy and I've always had to narrow my bars on the mountain bike for such trails, do off-road guys run narrower bars too?
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NeKawBoy
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10/19/2012 8:56am
Before switching to a KTM XC in 2011 I rode a KX250 in the woods for years. I did the mods in stages to see what helped it the most.
Bare minimum...a medium weight flywheel weight and hand guards...the MSR Evo handguards are great for the money but after trying 3 different types of hand guards I ended up with Cycra CRM's...they are super strong and they have a bend in the end that allows you to lay the bike over without rubbing the outside of your hand and wrist.
Next thing I would put in is ultra heavy duty tubes...I've run the Bridgestone ulta heavy duty tubes since the mid 90's with out a flat.
Next I would install a Gnarly pipe from FMF...it smooths out the power and they are more durable than stock. I run a FMF Turbine core spark arrestor where required and a FMF shorty silencer when I can get away with it.
I had my suspension revalved with lighter specs because i wasn't jumping very much...helped a bunch but, it's kind of pricey.
I also added the Scarey Fast power now and power now plus...great bang for the buck...they further smoothed out the power band and made throttle response noticably better.
Radiator braces can save you some serious cash if you ever tip over on a log or rocks.
As far as bars go i run the Pro Taper woods high Evo bar...they are narrower than stock and the metal in the Evo bar dampens vibration better than anything I've used...over a 3 hour race less vibration equals better control.
A mod that is rather pricey but worth it's weight in gold is a steering stabilizer...I tried 2 others before i ended up sticking with a Fastway System 5...it has highspeed and low speed dampening. I run very little low speed dampening and crank the high speed up so it steers easily until you hit something you shouldn't...such as a root or rock.
I run stock gearing in the woods that i ride in...on my KX I ran 13/49. When i head to Colorado I drop to a 12/51 with a quality oring chain.
headache
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10/19/2012 8:57am
Yeah most guys trim their handlebars down to help get through tight single track sections of woods. I would definetly look into a flywheel weight which will help smooth out the powerband and u might play with different size sprockets to get your gearing where u want it
TriRacer27
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10/19/2012 9:14am
Thanks guys, that's awesome advice.

I think I'm going to stage my upgrades by 1) durability, gotta finish the race first then later on 2) speed.

So on the list right now I have:

1) Hand guards
2) Heavier flywheel (less tiring)
3) heavy duty tubes
4) Maybe Evo bars. I've used those before but this bike has stock clamps and not sure the budget can handle all of this right now

Then later on if I still like it I'll look into more mods.

Either way I'm excited.

What about a larger tank? I'm probably going to be a C or B class rider and the races are 75min long.
PaleBlue
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Essex GB
10/19/2012 9:23am
We've used unmodified MX bikes in Enduro races here from time to time, with decent results. You might want to investigate the Tubliss tyre system. This would enable you to run lower tyre pressures, if you wanted to, without the problem of "snake bite" punctures to inner tubes.

Anyway, take a shot at it, don't go mad and above all enjoy yourself. Smile

The Shop

Wiley
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Placer Co., CA US
10/19/2012 9:26am
For a number of years I raced YZs in our district enduro series. I put flywheel weights on at one time, but don't think it was necessary. The changes that I found real necessary are these: suspension revalve, steering damper, shorter bars, "bark-buster" style hand guards, skid plate, pipe guard, over-sized fuel tank, 18" rear wheel, and a rear brake rotor guard.

The gearing is really up to the rider's preference. I would usually replace the chain with an x-ring type, change the counter-shaft to a 13 tooth and the rear to one tooth smaller than stock. I always reduced the size of the counter-shaft sprocket as so I wouldn't have to increase the rear to acheive the gearing I desired. I always felt that by increasing the size of the rear sprocket I would increase my chances of damage to the rear sprocket. Anything to reduce the chance of a mechical DNF was a no-brainer.

I also ran bibb mousse tire inserts to kill the chance of a DNF due to a flat, but that can get costly if you're not real serious about your efforts.

Enjoy the ride. That YZ is a champ off-road. I regret selling my last one, for I wish I still had it in my garage to ride trails with my buddies.
Moto Mofo
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10/19/2012 9:29am Edited Date/Time 10/19/2012 9:30am
There is no offroad series in Texas that is tight enough to necessitate trimming your bars down, except for maybe a few of the enduros. I wouldn't, and dont, do it.
TriRacer27
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10/19/2012 9:45am
Moto Mofo wrote:
There is no offroad series in Texas that is tight enough to necessitate trimming your bars down, except for maybe a few of the enduros. I...
There is no offroad series in Texas that is tight enough to necessitate trimming your bars down, except for maybe a few of the enduros. I wouldn't, and dont, do it.
Haha, you're probably right. However the definition of a tight trail is very different for someone who likes trials bikes vs. a typical WFO, feet-off-the-pegs, eyes closed moto joe like me. Those trees sure seem to want to suddenly jump out in front of me. Tongue
Kryan5
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10/19/2012 10:07am
I haven't ever made the switch, but a buddy of mine did and he said the most important thing he did was suspension. Not sure what kind of set up you have on your yz, but he had full mx suspension so it made a world of difference to him. He said before he got it redone it made one hour feel like 3hrs and now 3hrs feels like 1hr on his body!
Titan1
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Lehi, UT US
10/19/2012 10:21am
I've been racing desert races (Hare and Hound, and Hare Scrambles) on modified MX bikes for years (I prefer the MX platform over the offroad platform for building a race bike)...Here is what I do:

-Oversized tank
-Bark Buster Hand Gaurds
-Skid Plates
-Suspension Revalve
-Spark Arrestor

Those are the necessities...

If you've got the money, then go with a stearing stabilizer, and if you're in the technical stuff a rekluse clutch is very helpful. The little bits of energy that they save here and there over a 2 or 3 hour race make a huge difference.

I haven't seen much need for an 18 inch rear wheel...or a flywheel (though I ride 4 strokes...but haven't felt the need for one on 250 or 450 four strokes).
lucero10x
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10/19/2012 10:50am
#1 Steering stabilizer. After that it doesn't matter.
mx836
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10/19/2012 11:18am
I ran my RMZ 450 set up for the track in harescrambles with an oversize tank. Didn't even have hand guards. Always got the job done just fine.
10/19/2012 12:03pm
a skid plate. works connection makes a killer one that'll cover everything down there thats important.
tmauto769
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10/20/2012 5:33am
I say if it is wide open ie... quad wide trails, just throw some bark busters on, get a camel back and go see how you like it before you start throwing money at your bike. The 06+ yz's suspension is pretty good in stock trim offroad, in faster wide trails that is. If it is tighter single track, you may want a flywheel weight or rekluse, and a revalve. If you are coming from mx you should make it your goal just to finish, and not worry about where you are at. You will be suprised at where you will place just from guys dnf'ing.
dirtnasty
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10/20/2012 5:48am Edited Date/Time 10/20/2012 5:50am
lucero10x wrote:
#1 Steering stabilizer. After that it doesn't matter.
This. Stabilizer and body armor for the bike are the best ways to start off imo. And a larger tank would be a good investment.
10/20/2012 6:28am
Consider a wr250f. Issue with motox is the transmission. Runs out of gears on the top end. Apparently it is possible to swap cogs, but this requires a major teardown and purchase of new trans gears$$$.
10/20/2012 7:23am
unknownmxr wrote:
Consider a wr250f. Issue with motox is the transmission. Runs out of gears on the top end. Apparently it is possible to swap cogs, but this...
Consider a wr250f. Issue with motox is the transmission. Runs out of gears on the top end. Apparently it is possible to swap cogs, but this requires a major teardown and purchase of new trans gears$$$.
What are you talking about? He said he wants to give off road racing a serious try. Why would he go to such a corked up slow bike. No serious racer uses any of the japanese Off road models, they are awful race bikes but good trail bikes.

They YZ250 is a deadly Off road bike, with one of the best 2 stroke engines out there. Heres this list to make your bike a unreal bush bike. Skid plate, hand guards, Suspension re valve. I would suggest getting the new Rekluse EXP2.0. This way you dont have to go to a heaver fly wheel and your bike will still have that quick snappy throttle response and you can still use your clutch like normal. Oh and get a bigger gas tank. Your yz tank is to small for Off road racing.
CR250Rider
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10/20/2012 8:29am
Depends how serious you want to get.

I just have barkbusters, v-force reeds and fresh knobbies ( and a $20 walmart bike speedometer I rigged on there )

Riding every day can get expensive on the high wear items ! Smile
10/20/2012 9:11am
The single most important thing I can tell you is that you need is your suspension setup for sure! You can get by with a stock tank for a while so bark busters with plastic deflectors would be the next thing I would get. I know alot of people say run a flywheel weight but really that's all personal preference really. I have ridden bikes with flywheel weights and don't care for what it does to the motor. that would be the cheapest way to get into it with out spending an arm and a leg
10/20/2012 10:49am
Hare Scrambles > Moto

No waiting forever between motos, miles of different terrain. So fun.
Racerx930
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Stillwater, OK US
10/20/2012 10:59am
Just started doing some offroad stuff. I have an 09 CRF450 that's raced a lot of different stuff. It's been a motocrosser, a flat tracker, and now an offroad bike. With a 48 tooth sprocket on the rear it's so smooth that I don't feel the need for a flywheel weight. Right now I just have a big tank (this damn thing uses gas!) and some hand guards. I'm going to the Loretta Lynn GNCC on the 3rd and hope to have a rekluse before then.

Also my 450 gets hot fast in the woods. I'm actually sitting here with some 12v fans on my desk working on something to help with that.

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