What to do to a TTR-125

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#1
I have been looking at dirtbikes and am pretty sure the Yamaha TTR-125 is the one I will end up with. I want this bike to last for a few years and I want to keep this bike fun for a while. So my question is...

What are some things I can do to boost the performance, both low end and top end? (exaust, sprokets, etc.)

Can you please give links
 
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#3
Originally posted by js3350z
I have been looking at dirtbikes and am pretty sure the Yamaha TTR-125 is the one I will end up with. I want this bike to last for a few years and I want to keep this bike fun for a while. So my question is...

What are some things I can do to boost the performance, both low end and top end? (exaust, sprokets, etc.)

Can you please give links
Well, mini thumper trail bikes like the TTR/XR/KLX/DZR really don't respond to aftermarket parts as well as your probably thinking they will, like 2-stroke or 4-stroke MX bikes.

Things like aftermarket exhaust systems (ie: FMF Powercore 4 for the ttr) will increase 95% the sound of the bike, and maybe 5% powerwise. A friend of mine tried one on his XR 100 and it does hardly anything to help the power of the bike. Just louder. If you want the bike to sound cooler, you can remove the baffle from the end of the muffler and remove the spark arrestor peice, and the bike will sound louder, almost like a 4-stroke motocross bike.

Adding a new exhaust, new air filter, tuning the carb, etc will make minimal differences. Having the bike bored would be the best increase in performance though, but then you are looking at a very large amount of money.

If you want the bike to last for a couple of years, my advice wud be to go for a 2 stroke motocross bike. they are inexpensive, have suspension made for jumping (ttrs are NOT ment for jumping or riding motocross), are lighter, more fun to ride, and if you would compare lets say a TTR-125 and a YZ-85, the YZ will be more than twice as powerful every way you look at it. just a suggestion if you are looking to keep the bike for a long period of time, that would be the way to go. so at least look into it, and give it extreme consideration since the last thing your going to want is a ttr-125 that your going to outgrow its power quickly and wish you wud have gone with a two stroke!
 
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#4
First things, jet the bike with a 17.5 pilot and then according main to the mods.

Second, cut the top of the airbox out. Be sure to rejet as needed.

Third, shave the 22oz off the flywheel and at least install a Thrust Chamber if not full pipe.

After that you have like the BBR air filter, big bore kits, carbs, cams, etc. If you are racing the bike, get the frame craddle and swap out to the YZ front forks.
 

Jaybird

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#5
Dogman5 has made alot of good suggestions. If I were you, I'd take heed in what he is saying.

You can throw money all day long at it and hove nothing but an under-powered parade bike. One you will never get even close to your money back on....and you WILL get tired of the TTR soon.

Buy used for awhile....enjoy the sport....one day when you have a significant other that you want to get on the dirt, start shopping again for a TTR. Wives and first time riders love these bikes, but they get old fast.

Don't get me wrong, I think the TTR is a great place to start out on dirt bikes, they just aren't made to be a performance ride. Sinking $10,000 into one and still get scalded by an 80cc stock 2-stroke can't be fun.
 
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#6
Boy, you guys seem to really be down on the ttr. I just don't understant why. I've got a 2001 and I love it.
As far as dogman's comments on power I don't know where he's coming from. I swaped the stock pipe for a bbr, cut the top and sides out of the airbox, opened up the air filter plate and now it will stomp a stock ttr. I've also got an 86 XR100 that I put an FMF pipe on. It was so slow before that my buddies 93 XR left me in the dust. Now the roles are reversed he's behind me smelling the oil from my worn out rings.
If your looking for a fun bike to go out and play on the trails or in the woods the ttr is great, but it definately bennifits from modifications. I'd pick it over an 80 or kx100 to play in the woods any day. Even on small jumps it's great fun as long as it's set up to handle them.
As far as mods go beyond what I listed above mine has a bbr frame cradle, chain guide and front and rear springs and black aluminum rims (just because the look cool). I also put a set of Pro Taper bars on it with a universal mount kit which raised the bars up and made it a little more rommy.
The only weak link I've found on the bike is the rear hub (I've broken two now) and I'm spending the winter working on retro fitting a YZ80 rear wheel that should eliminate that problem.
 

Chili

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#7
I don't think anyone in this thread is down on TT-R's in fact several have stated they thought they were great beginner bikes. What they have pointed out was the inadequacies and limitations of the bike. When the original poster is already asking how to increase the performance of the bike it's not a far stretch to assume the poster will be disappointed with the power supplied by this bike.
As for your bike stomping a stock TT-R, I don't doubt there are performance gains to be had but even at the extreme end that bike is still going to get spanked by a bone stock 85 or 100cc 2 stroke.
 
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#8
Originally posted by tzracer46
Boy, you guys seem to really be down on the ttr. I just don't understant why. I've got a 2001 and I love it.
As far as dogman's comments on power I don't know where he's coming from. I swaped the stock pipe for a bbr, cut the top and sides out of the airbox, opened up the air filter plate and now it will stomp a stock ttr. I've also got an 86 XR100 that I put an FMF pipe on. It was so slow before that my buddies 93 XR left me in the dust. Now the roles are reversed he's behind me smelling the oil from my worn out rings.
If your looking for a fun bike to go out and play on the trails or in the woods the ttr is great, but it definately bennifits from modifications. I'd pick it over an 80 or kx100 to play in the woods any day. Even on small jumps it's great fun as long as it's set up to handle them.
As far as mods go beyond what I listed above mine has a bbr frame cradle, chain guide and front and rear springs and black aluminum rims (just because the look cool). I also put a set of Pro Taper bars on it with a universal mount kit which raised the bars up and made it a little more rommy.
The only weak link I've found on the bike is the rear hub (I've broken two now) and I'm spending the winter working on retro fitting a YZ80 rear wheel that should eliminate that problem.
I hardly doubt it will "stomp" a stock one, no offense. Changing exhausts wouldnt be that drastic when it comes to changes, expecially on 4-stroke minis. And even on a 125 or 250 2-stroke, putting a new silencer on one, and leaving the other one stock would never yeild in one stomping the other. Your probably thinking that the bike is going a whole lot faster, but its just louder. Its a psycological thing, whether you want to believe it or not. I'm not saying it wont gain any power at all, but not a whole lot.

And yeah, a TTR 125 would be a lot better to put around in some trails rather than an 80, but thats not what they are meant for and most likely not what a rider buying one of those bikes would intend to do. I wish you luck with your TTR, but the plain and simple fact is that you can put a bunch of money into the exhaust sysem, screw around with the carb, mess around with cutting things in different parts of the bikes, and changing the suspension, but in the end, you will see minimal differences, and money wise, the money you spent would be the difference between a TTR 125 to a YZ 85, and the 85 will still be twice as fast powerwise, bigger in size, and have better suspension.
 
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#9
what happens if you take out the spark arrestor? im told it can start a fire and stuff and you guys are talking about taking it out? i wouldn't mind having it louder so can i and it wont hurt anything?
 
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#10
Originally posted by DRZ125
what happens if you take out the spark arrestor? im told it can start a fire and stuff and you guys are talking about taking it out? i wouldn't mind having it louder so can i and it wont hurt anything?
I had mine off with my XR 100 for about 5 months without any problems. I don't think that it can do any real harm to the bike that I know of.

However, I ride with it back on now. I was informed that it is actually illegal to ride with it off, since tampering with the noise emmission is against the law. Not like a cop would nail you for riding without a spark arrestor or anything, let alone the 2% chance he will know what a spark arrestor is, but I just keep it on because it actually sounds really annoying after a while :p

It won't start a fire or anything. Chances of that happening are slim to none. Some of the aftermarket exhausts for the bike don't even come with spark arrestors.
 
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#11
from 7.9 up to 8.77 hp. My 6 year old boy's KTM 65 has 15hp stock, more when I put on the DEP Pipe and silencer.
 
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#12
I would go with a Pro Circut T-4 exhaust system and an oversized rear sprocket from patriotsprockets.com . They make excellent sprockets for a great price. They last forever. If you add a few teeth in the rear you will have a lot more snap out of corners and for wheelies and that kind of thing.

Oh, and if you do purchase, or even call Patriot Sprockets could you please say you heard about them from D.J. :thumb:
 
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#13
Originally posted by joereitman
from 7.9 up to 8.77 hp. My 6 year old boy's KTM 65 has 15hp stock, more when I put on the DEP Pipe and silencer.

In California that bike gets a red sticker so in the summer months you cant ride it...
 
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#15
Originally posted by DRZ125
what happens if you take out the spark arrestor? im told it can start a fire and stuff and you guys are talking about taking it out? i wouldn't mind having it louder so can i and it wont hurt anything?
not much will happen if you take it out.it will just get louder.and this should help you with some mods

Mod Edit - aedwards 07 in the future please don't cut and paste information from another site without first giving the other site FULL credit. Passing off someone elses post as your own isn't something we take lightly at DRN.

The following post was taken from the ThumperTalk TTR FAQ
Click to go to the original TT FAQ posting


1. Stock carb jetting
Mikuni VM20SS
17.5 pilot
110-120 main, (depending on mods)
The needle works best in the stock position, or middle clip.
Jets can be found here: http://www.sudco.com/ The mains are the N100.604 Large Round Type, and pilots are the VM28/486 Type.

2. Airbox Mod
Consists of removing the snorkle/plug from the top of the airbox and removing the screen from behind the filter. Every TTR should have this performed immediately upon delivery. Even more air flow can be achieved by cutting out the entire top section of the box and adding a high flow aftermarket air filter. This will require a richer pilot and main jet and tuning of the fuel screw to get the best response and power. However, it should be taken into consideration that the more extensive airbox mods may not be a good idea for someone who rides in extreme conditions often. With the top completely removed water or sand could easily get into the box and cause the bike to run poorly.

3. Flywheel mod
Basically, the flywheel creates rotating mass in your engine, keeping it spinning when you let off the gas. The "flywheel mod" involves machining material (up to 18oz.) from the flywheel, making it lighter, and in effect, allowing your engine to rev faster, or "spin up" quicker. The drawback is that the engine is easier to stall. Some internet companies charge over $100 for this service, but most local machine shops will usually do it for as little as $25. Overall opinion is that this is a very worthwhile mod for the money, but is better left to the more experienced riders.

4. BBR frame cradle compliancy
The BBR frame cradle is an essential item for the TTR. It adds much needed ridgidity to the frame and also protects the engine, while at the same time, being very light weight.

These pipes have been proven to fit well with the BBR frame cradle:

BBR (of course)
M4
Pro Circuit
GYT-R
FMF
DMC
Engines Only
Powroll
Big Gun

Pipes that have been proven not to fit:

Stock pipe (oddly enough)
Yoshimura
White Brothers

5. Handlebars and Handguards
Handlebars:
The stockers are weak, but there are many aftermarket bars to choose from in all shapes and sizes. However, most every rider prefers a slightly different setup, so you need to put some thought into how you like to feel and position yourself on the bike beforehand. The best thing to do is measure the stockers up, and compare those #'s to what's listed on the Renthal/TAG/ProTaper web sites. That way you can get a good idea of what you want, and what to expect. Oversized, 1-1/8" bars are great, but will require adapters or a new triple clamp. They damp out most of the vibration and resist bending like you wouldn't believe. Not to mention the fact that they look cool. But the extra thick 7/8" bars aren't bad either, and will bolt right up with no extra parts to purchase. You can buy your handlebars from a million different places, but look around for the best deals. TAG, Pro Taper, and Renthal all make oversized billet adapters for around $75, but remember, they raise the bar height 3/4 of an inch themselves, so keep that in mind when figuring out which bend you want. Triple clamps with oversized mounts can be found here: http://www.rswracing.com/ here: http://www.precision-racing-components.com/ and here: http://www.bbrmotorsports.com/Home.htm At prices from $100-200. I suggest the RSW triple clamp. Ron also makes a very nice and highly effective billet fork brace, which at $70, is probably the best deal on a performance accessory that you'll find anywhere.

Handguards:
The Acerbis Rally Pro's are the best thing goin' at $75. But reguardless of brand, the key is the sturdy reinforcing aluminum backbone. The plastic brushguards do little to protect your hands or the levers during a get off. If you are using oversized bars, you'll also need adapters for the handguards. Of course, all the major players can supply you with their version, and all seem to work well. With good bars and handguards your bike becomes almost indestructable. No more bent or broken levers. And no more fingers smashed between the bar and the ground.

6. Other Basic Mods
Sprocket changes are sometimes necessary. For more top speed go with a larger front sprocket or smaller rear. For more low end power do the opposite, smaller front or larger rear. The 14 and 15 tooth front sprockets work well and are readily available from Sprocket Specialists here: http://www.motorcyclesprockets.com/html/main.shtml They also have a wide selection of much lighter aluminum rear sprockets.

An actual chain guide is another well advised security mearsure for the TTR. There are many on the market, more popular versions being sold by BBR and PRC.

A stainless steel brake line is one of the best $$$ value mods available, and adds great feel and extra power to the TTR's front disc. I prefer Goodridge lines and have used them on all my bikes for a long time with great success, but there are several other brands available. Galfer, Speigler, Russell, ect... Most any manufacturer can make a custom line in any length you need with all the hardware in any configuration you want. Prices range from $50-90. Keep in mind, the stock rubber lines are supposed to be replaced every two to three years. Stainless lines are good for at least 10.

Brake pads can also be upgraded. The stock pads offer decent feel and power, but they overheat and fade quickly with the small rotor. Again, there are several brands on the market to choose from, and many times it comes down to personal preference.

7. YZ carb mod
The last generation of round slide carbs from the YZ80 make great improvements to the TTR for little $$$ and fit right up with no modification. (2.5mm can be milled off the engine side for a perfect fit, but is not necessary.) They are particular about jetting, but make very good power. Look on Ebay and in junk yards for a clean model from 1982 to 2001. They are all basically the same and can be had for as little as $20. Strait from a YZ, they will be very rich on top and bottom, and lean in the middle on the TTR. A good place to start with rejetting is a 20-22.5 pilot and 140-150 main. The best needle is still undecided, but any of the richest Mikuni 4 or 5 series needles could work. (The stock YZ needle seems to fall just on the rich side of the middle of the charts in the Mikuni catalouges.) Slide sizes could also be changed. The YZ's slide is a #3. A #2 or even #1.5 could work well? Many folks have opt'ed to replace the stock O-0 needle jet with a P-4 size and keep the YZ needle. This seems to work well too. But remember, jetting will be different on nearly everyone's bike, so what works great for one, may not work as well for another. These are all just generalized places to start. Getting your bike finely tuned is half the fun. But overall, the YZ80 carb mod is very much worthwhile for the added power and response. It also enables the use of a pod filter, which is impossible with the stock carb. All necessary jet's and needles can be found here: http://www.sudco.com/ and here: http://www.mikunioz.com/

8. Suspension mods
The best money you'll ever spend on any motorcycle is in getting the suspension dialed in. Not only will it enable you to go much faster, but you'll be doing it with less effort and more direct control of your bike. There are several routes that can be taken to upgrade the TTR's stock suspension. The easiest, and most common thing to do is add heavier aftermarket springs front and rear, thicker oil to the stock forks (10-15wt.), and purchase stronger billet triple clamps and a fork brace.

Those mods alone make terrific improvements over stock, but can still fall short for many larger and/or more aggressive riders. The ultimate suspension upgrade for the TTR125 is to replace the entire front end with an inverted forked, and much more ridgid, '94-03 YZ80/85 or KX80/85 front end. You'll need to change the springs to match the heavier bike and there's some simple adaptaion required, but a kit for the YZ-TTR swap can be found here: http://precision-racing-components.com/yamahaparts.html The YZ forks are much longer than the stock forks and can be shortened to maintain the stock ride height or a BBR swingarm can be purchased to raise the rear 1.5". They will also need to be matched up with a shock in the rear that can equal their performance level. The Works Performance shock seems to be the popular choice, but the newer generation TTR shocks with the remote resi can be rebuilt with a good deal of success.

9. Motard Conversion
The most common modification is to lace wider aftermarket 17 inch rims, such as Excel or Sun, to the stock hubs with heavy duty spokes. They are available here: http://www.buchananspokes.com/ and here: http://eastcoastwheels.com/

All year model TTR's with a stock or YZ/KX front end can run either a 2.5/17" or 2.75/17" front rim. The 2.5" is the prefered and standard 125GP size, but restricts your tire choices to full blown race tires if you want the proper profile to be maintained. The 2.75" rim is wider than necessary, but allows the more common 110/60 size sportbike front tires to be used without distorting their intended profile. Whether you are able to use the entire tire surface with that size has yet to be proven, though.

All '02 and older TTR's, and newer standard and "L" models without the aluminum swingarm, are restricted to a 2.75/17" rear rim with a 110/70 tire. The '03 and newer "LE" models with the wider aluminum swingarm have the choice between the 2.75/17", or the prefered 125GP sized 3.5/17", rear rims. The 3.5" wide rear rim allows you to run tires up to a 120/70 without any issues. 120/70 is the most common size of sportbike front tire, and they work great as rears if turned backwards. High performance street tires, DOT race tires, and full blown slicks are all available.

The 125GP setup (2.5"f, 3.5"r) is more restrictive as to front tire choice, but offers the best performing tires and sizes, and easily available rears in the most common size of all. Only three manufacurers make tires for the 125GP bikes, Michelin, Bridgestone and Dunlop, but they are all very good. A set at retail is expensive though. $200-300 front and rear. You do have the option of slicks or rains, and Dunlop and Michelin offer two compound choices. Much cheaper take-offs are out there to be had too. The Dunlops feel great and last a very long time, but are a harder compound rated for higher temps, so they take a while to "come on".. They also have a very stiff carcass so they tend to chatter more than slide sometimes. The Bridgestones and rated for a much lower optimum operating temp, so they heat up faster and work better at the lower temps that the TTR is likely to see. However, they are softer and don't last nearly as long as the Dunlops. They are cheaper though. The Michelin front tire doesn't suit my riding style, but I do like their rear tire.

The 2.75" setup has it's advantages in the fact that many decent tires are readily available, and can be had for cheap. However, it doesn't offer the all-out performance potential of the GP setup with slicks and a fatter rear. The steering is a little slower, and the response isn't as good with the wider tires. But there's plenty of grip to be had with good street tires. It also takes a lot more suspension to deal with the super grip of the slicks. Street tires may be just as fast, if not faster on some bikes.

10. Extreme Tuning
Of course, there are those that will never be satisfied with the amount of power their bike makes. Thankfully, I'm one of you.

The sickest power mods for the TTR begin with the camshaft. BBR, Powroll, PRC, and HotCam all make excellent cams for the TTR. I love my HotCam and Wiseco makes a drop in 11:1 high compression piston that works great with it.

Next up would be porting, polishing, and head and valve work. In this area it's really all about who you know and how good they are. I doubt you'll pry any secrets from the real competitors about the specifics here. Just have to find out for yourself. But the TTR's do have a good bit of power in there.

Big bore. What else needs to be said? There are several 150 kits on the market, and Powroll even offers the mac-daddy 170 stroker. And if you can't find enough juice for your TTR in 170ville then you've got the wrong idea entirely.

Links:
BBR
Powroll
PRC
RSW Racing
Sprocket Specialists
Sudco