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Project BBR TTR125

By Jerry Matta


         I've been putting off getting a TTR125 forever.  Well of course, since it was a Yamaha.  I had my little tricked out 120cc CRF80 that flew.  So why would I want any other bike?  I didn't, until all of the SoCal group were riding the track behind my house and I rode one of their TTR's.  My first thought was, "Holy Crap!! I don't feel any of the bumps that were killing me on my bike." I was pretty much sold at that point.  So my hunt was on for a TTR.  I was going to get a '06 when the '07's came out or maybe get a '06 from some dealership out here that sells them for $2499 OTD.  I figured that I would need about $1000 more to get it to work or at least be rideable. So I was going to have to sell my two CRF80's and all my after market parts.  Luckily, I have a friend that is a Harvard Psyche school mental case.  The type of guy who never has the right bike and gets a new bike every two months and three storage units worth of crap.  So I picked it up with a 1/2 a ride and with front and rear BBR springs, cradle, tall seat, and Renthals already installed for less than a new bike.  I couldn't pass it up.  And the good news was, the sale of my other stuff paid for everything.  So obviously, I would need to do some work to get it work for me.  This is where BBR comes in.  They are the only company that makes a full line of parts for the TTR125.  Every part I bought for this bike has nothing to do with "Bling", but everything to do with utility. I'll do a list with the purpose of the product.  In no real order. 

BBR Products:  Pipe, seat, shifter, rear spring, cradle, chain guide, foot pegs, free flow filter, carb intake, BBR Rev box.

1.Pipe -- We did a back to back test with the BBR pipe and it blew away every other pipe, including a factory Yamaha pipe.  
2. Seat -- For any adult rider, the tall seat is a must.  I couldn't even ride a TTR with a stock seat. In fact, that was one of the main reasons I never even thought about a TTR.  I rode one a long time ago with a stock seat and it felt so bad, I wrote the whole bike off.  It's night and day. 
3. Shifter --  The stock linkage system sucks. Under a heavy load it won't even shift.  You have to shut off.  Not good for battling.  I was thinking it might be the tranny, but when I put on the BBR shifter, I have missed a shift yet.  
4.  Rear spring --  The stock set up is just too soft for the average adult. It's not a permanent fix, but it will work until you can get it valved. 
5. Cradle --  Absolute must.  Your frame will stretch without it.  If you try to put it on and it doesn't line up perfect.  Your frame has already stretched some. Great skid plate too.   
6.  Chain guide --  It doesn't have a stock guide, just some piece of plastic.  Don't throw a chain on the trail because you don't have a real chain guide.  This is super important for trail riding and you're 10 miles from your tools and you can't get your chain back on.  
7. Foot Pegs --  Small foot pegs are worthless.  I can't even ride with them.
8. Free flow filter --  Probably the first engine mod you need to make.  You motor needs to breathe. 
9. Carb intake --  If you have a Kehien carb, it won't work without this adaptor. 
10. Rev Box -- The stock box has a limit of 9600 rpm, this gets rid of that and the bottom end hiccup.


For the forks, I got some YZ85 forks off ebay and with a spacer here and spacer there, they are pretty close to a bolt on as you can get.  The only issue is they soft, real soft.  So I took them over to Jason at Fineline Suspension in Huntington Beach and he valved them and got me some .44 springs.  Now they work. Other things I have are a CR85 master cylinder and brake line and some bar risers to get the forks a little higher.  Also, the stock carb is junk.  Some can work and some don't. Mine didn't.  So I replaced it with a 200x carb off my xr120.  It works twice as good.  Forget trying to jet the stock pile carb, just get a 200x carb.   I also had Dave Miller from DMC lighten the flywheel.  You can't take as much off a electric start flywheel as a non-electric start one, but still a good 8-12 oz came off.  I didn't have a scale to get the exact amount. About the only thing left to do is a BBR 150cc kit, which will be in next week.

On the track, it's night and day from stock.  Even though the motor hasn't been bored, it's still has more bottom and pulls the 14t front sprocket better than the stock motor pulled the original 13t.  The suspension is like real suspension, I can hit whoops now and not worry about the back kicking me side ways.  Overall, it just a solid bike.

Part 2:  Wheels

For part 2, I replaced the weak steal rims and spokes for a set of aluminum rims and heavy duty spokes.  It was kind of a chore, but it only took a day.  Plus, it enhances the look two fold.   I also wrote a "how to" on lacing up TTR rims. Click Here.

Part 3:  BBR 150cc Kit

There are definitely things to know ahead of time, if you haven't installed a big bore kit on a TTR before, which I haven't.

Tip 1:  Take the motor out.  I didn't, but it would have save me time and aggravation if I would have. 
Tip 2: Make sure the flywheel is TDC and cam lined up when you pull the head off.
Tip 3: Use a piece of wire to keep the cam chain up.  Do not let it fall and come off the lower gear. You'll need a flywheel puller if you do.
Tip 4: Be very careful taking the original cam chain adjuster gasket.  The kit doesn't come with one and if you tear it, you're screwed. They are only about $1.25, so you might want to buy one a head of time.  Luckily, mine didn't rip.
Tip 5: Do not use a screw driver to compress the valves to get the cam in and out.  Use a tire iron and place the head on the stock cylinder.  It will only take two seconds, if you do this. 

A) So how was this when I went to the track?? Well, I was a little disappointed. The set-up I was running ran great and I thought this would enhance it two fold.  Just like a 120kit does to an XR100.  It doesn't.  But I pretty much knew that before, since my old conversion pulled pretty much every other TTR.  What really disappointed my was the lack of bottom, but when I looked at the BBR catalog, it said it added mid to top, which is pretty much what it does. But I need more bottom to do jumps out of corners, which is what most of the tracks out here have.  It did help my lap times and let me clear a couple of jumps I couldn't before, so with that I was pretty happy. 

B) I went back to Elsinore and did a bunch of laps, then I swapped the 24mm to a 26mm carb. . . . Oh man, what a difference.  Bigger power everywhere and the jetting wasn't even perfect yet.  So am I disappointed any more??  Heck no.  This is the power I was looking for. BBR claims with this set-up somewhere about 11hp, which is what a good running XR120 puts out.  I would say, that's about spot on.

Project BBR TTR150 Final Word

Even with every trick part you can buy, a TTR with a stock frame isn't up to snuff even with a ton of gusseting.  So I picked up this kinda beat down BBR TTR for a relatively cheap price.  So after new wheels, complete brakes including CRF450 rear master cylinder and a front CRF450 Twin Piston caliper with steel braided brake line, plus a few odds and ends including my electric start motor, I have a pretty fun mx and trail machine.

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