More bottom end power on a 125
- Thread starter 123654
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handleme46
Member
- Apr 11, 2003
- 59
- 0
Sell it and get a 250!!!! lol j/p
Ive tried some stuff and am still trying, V-Force reed cage is a good investment, ive tried reed spacers without much change but i guess it really varies by model, what ive heard is really the best without over-sizing the cylinder is to have the head machined or get a aftermarket head with intercahgeable domes, and have the squish-band tightened. The downside is you will have to run race gas. I havent had this done to my CR125 yet, but am planning on it sometime. Another cheap thing to do is just go up a couple teeth on the rear sprocket, this will make your gears shorter which downsizes top speed, but isnt a big deal for MX because you can just shift, i doubt you will get the bike red-lining in 5th on any MX tracks. just some ideas.......
Ive tried some stuff and am still trying, V-Force reed cage is a good investment, ive tried reed spacers without much change but i guess it really varies by model, what ive heard is really the best without over-sizing the cylinder is to have the head machined or get a aftermarket head with intercahgeable domes, and have the squish-band tightened. The downside is you will have to run race gas. I havent had this done to my CR125 yet, but am planning on it sometime. Another cheap thing to do is just go up a couple teeth on the rear sprocket, this will make your gears shorter which downsizes top speed, but isnt a big deal for MX because you can just shift, i doubt you will get the bike red-lining in 5th on any MX tracks. just some ideas.......
Sorry, but unless you are an under weight Leprecaughn you are going to have to REV it to the heavens. 125's are ment to be run hot, not for grunting, think of a weed trimmer, it don't cut it unless you're on it. ;)
As the above poster suggested jokingly, if your searching for useable power, pony up to a 250. Other than that, get ready for some extensive modifications. It all depends on the application, I ride alot of woods where I am cranking for every bit of "get 'n go" that a 125 will produce. For sheer unadultirated thrills though, a 250 with the right combination on the sprockets and geared right is unbelivable! :aj:
As the above poster suggested jokingly, if your searching for useable power, pony up to a 250. Other than that, get ready for some extensive modifications. It all depends on the application, I ride alot of woods where I am cranking for every bit of "get 'n go" that a 125 will produce. For sheer unadultirated thrills though, a 250 with the right combination on the sprockets and geared right is unbelivable! :aj:
Nevada Sixx
Member
- Jan 14, 2000
- 1,033
- 0
i remember the magazines did a test with that bike to get bottom end and all they could come up with is a reed spacer. they are only about 25 bux i think.
i still think low gearing helped my bike best in the woods...try a smaller front sprocket and you wont believe the difference in tight woods.
i still think low gearing helped my bike best in the woods...try a smaller front sprocket and you wont believe the difference in tight woods.
My YZ is stock except for the gearing, it was the only change I had to make. 53teeth in the back did the trick, it works great for woods and track now. It'll never have bottom, so its not worth trying to make it so. The '01 YZ125 does have a more pipey behavior that many other 125's I've ridden. My buddies 2000 KX125 has a much fatter middle, but sacrifices on top. Same with a KTM 125 SX. I love the rediculous top end scream of the YZ though, so thats where I'm staying!
Can Can Kev
Member
- Feb 24, 2003
- 233
- 0
a fmf fatty might help it brings the power band down lower which helps on hills.....
This coming from an uncertified maniac that rides a 500. :scream:
Doc,
When I get the urge to poke the rabid beast that you ride in the dirt I will. I have no problems opening up a ZX-12 on the free way but not 500 cc's of adrenaline at a twist. Not yet.... too many trees here. ;) :thumb:
cactusreid
Member
- Jan 13, 2003
- 170
- 0
Try a flywheel weight-you will be very suprised at how much more bottom end grunt they give you!!
nikki
Moto Junkie
- Apr 21, 2000
- 5,802
- 1
Wow... I spent two years trying to boost the bottom end power on my '01 YZ 125!! Unfortunately, the '01 YZ had the least bottom (and most top) out of the '96-'03 YZ 125's because it was the first year of the 38mm carb (bigger than the previous 36mm) and the cylinder porting and everything else was designed for mid-top expert power.
After having the bike for a year and trying everything under the sun... I sent my cylinder/head off to Wes Gilbert at Boyesen and he did wonders with the bike!!! Basically he took some off the base of the cylinder and matched the head to keep stock-like compression levels. Lowering the cylinder/ports made the power come on sooner and gave a huge boost to the low end! The bike became an instant wheelie machine with a 250-like power band. My first race after the motor work was on the SX track at Gatorback in Gainesville, FL. Motor work and a fresh set of Maxxis tires and I got awesome starts and had a hard time keeping the front wheel down outta the turns. The bike was a throttle response beast!!
But here is everything I tried in the year before the motor work:
First thing I did (stock) was tune the jetting. First, I switched to a BR8ES plus to avoid fouling the stock BR9EGV. The 8 plug is hotter. Then dropping the needle/raising the clip (leaner) one position (to 2nd from top) will help the mid range. I also played with a 22.5, 25 (stock), and 27.5 pilot jet and the air screw (depending on conditions) to get the bottom end response as crisp and clean as possible. I also had the float height on the carb reset to... I want to say 13.5mm above the float bowl mating surface. I read somewhere that the low end off idle bog was due to the float bowl heights being set too low at the factory. I can't remember if 13.5mm was the correct setting or not though... but whatever it was, it made a small difference.
I bumped up the rear sprocket 2 teeth over stock (to a 51 I believe) and it helped acceleration out of the corners but made the gearing a little funny. You had to shift more often as you'd go through the gears really fast and I'd be in 4th gear a lot - even in some faster turns. I never used 1st and rarely used 2nd. (After the motor work I had to go back down to a 50 sprocket - 1 tooth bigger than stock to tame things out - but the gearing was similar).
When the bike first came out, all the mags recommended a Mossbarger reed spacer to help low end. It was like $25-$30. I bought one and tried it but couldn't tell a difference either way. I think it eventually became a paper weight in the tool box.
Then I played with different pipes/silencers to try to boost the bottom end. I was the happiest with the stock pipe and a Pro Circuit R304 shorty silencer although the stock silencer was good too.
Then I went to a V-force reed cage with the reeds set on low tension. The low tension setting will give you a boost to the throttle response and low end power that you'll notice but the reed life will be shorter because the reeds open sooner and more. The V-force was definately an improvement.
So to sum it up... Wes Gilbert/Boyesen cylinder/head mods, V-force reed cage (low tension setting), decent jetting, and a tooth on the rear sprocket will do wonders to the '01 YZ 125 powerband.
Or like handleme said - get a 250 (or 250F)! ;)
After having the bike for a year and trying everything under the sun... I sent my cylinder/head off to Wes Gilbert at Boyesen and he did wonders with the bike!!! Basically he took some off the base of the cylinder and matched the head to keep stock-like compression levels. Lowering the cylinder/ports made the power come on sooner and gave a huge boost to the low end! The bike became an instant wheelie machine with a 250-like power band. My first race after the motor work was on the SX track at Gatorback in Gainesville, FL. Motor work and a fresh set of Maxxis tires and I got awesome starts and had a hard time keeping the front wheel down outta the turns. The bike was a throttle response beast!!
But here is everything I tried in the year before the motor work:
First thing I did (stock) was tune the jetting. First, I switched to a BR8ES plus to avoid fouling the stock BR9EGV. The 8 plug is hotter. Then dropping the needle/raising the clip (leaner) one position (to 2nd from top) will help the mid range. I also played with a 22.5, 25 (stock), and 27.5 pilot jet and the air screw (depending on conditions) to get the bottom end response as crisp and clean as possible. I also had the float height on the carb reset to... I want to say 13.5mm above the float bowl mating surface. I read somewhere that the low end off idle bog was due to the float bowl heights being set too low at the factory. I can't remember if 13.5mm was the correct setting or not though... but whatever it was, it made a small difference.
I bumped up the rear sprocket 2 teeth over stock (to a 51 I believe) and it helped acceleration out of the corners but made the gearing a little funny. You had to shift more often as you'd go through the gears really fast and I'd be in 4th gear a lot - even in some faster turns. I never used 1st and rarely used 2nd. (After the motor work I had to go back down to a 50 sprocket - 1 tooth bigger than stock to tame things out - but the gearing was similar).
When the bike first came out, all the mags recommended a Mossbarger reed spacer to help low end. It was like $25-$30. I bought one and tried it but couldn't tell a difference either way. I think it eventually became a paper weight in the tool box.
Then I played with different pipes/silencers to try to boost the bottom end. I was the happiest with the stock pipe and a Pro Circuit R304 shorty silencer although the stock silencer was good too.
Then I went to a V-force reed cage with the reeds set on low tension. The low tension setting will give you a boost to the throttle response and low end power that you'll notice but the reed life will be shorter because the reeds open sooner and more. The V-force was definately an improvement.
So to sum it up... Wes Gilbert/Boyesen cylinder/head mods, V-force reed cage (low tension setting), decent jetting, and a tooth on the rear sprocket will do wonders to the '01 YZ 125 powerband.
Or like handleme said - get a 250 (or 250F)! ;)
I'd keep the power the way it is on my '01 YZ... does it EVER stop pulling? Once your in, your in... it'll pull a gear longer than you can imagine, just keeps building and screaming. Sure its got nothing down low, but unless your going under 5 mph the whole time, your fine!
nikki
Moto Junkie
- Apr 21, 2000
- 5,802
- 1
Ha!! I tried that too and over 2 years I shattered maybe 6 sets of clutch plates (some Hinson and some stock), went through 2-3 sets that didn't shatter, trashed 5-7 stock inner hubs and 1 Hinson inner hub, a few pressure plates, many gaskets, one clutch cover, and the stock basket (however the Hinson basket lasted). :eek:
Clutching... the #1 reason I got a 250F!
Nikki, that is insane... 9 sets of plates in 2 years? Wow. You must give new meaning to the term clutch artist! Gotta clutch it to make it fly though... somebody burned up a clutch at Bud's Creek the other week at the national... it was a factory YZ 250. I guess if your really really pushing it, its possible to eat through that many. And you don't get to be the champ without pushing it, huh? :)
nikki
Moto Junkie
- Apr 21, 2000
- 5,802
- 1
Actually... the 6 sets of shattered plates all happened in the second year. I think something must have been outta whack cuz it got really freakin hot in there. Either than or my pointer finger on my left hand got a little heavier in the second year ;) I remember one day at Casey last year where I shattered a plate in practice and Red swapped out my inner hub, plates, and springs in a matter of about 4 motos (maybe 40 minutes).
I was so happy to pop off my clutch cover on my 250F a month or so ago and to see brand new looking baskets and plates! I think I might use the clutch in 50% of the turns on a track on the F compared to using it 50% of the total track on the 125 :confused:
I was so happy to pop off my clutch cover on my 250F a month or so ago and to see brand new looking baskets and plates! I think I might use the clutch in 50% of the turns on a track on the F compared to using it 50% of the total track on the 125 :confused:
I havent had much experience riding two stoke 125's, but everyone says hold the clutch in give it gas and let it go...pop the clutch to keep the power on. This seems like it wears everything out like it did to nikki. Why not just shift down to a lower gear? Downshifting would keep the rpms up and keep you close to the power. I could be wrong though
Micah... being in the right gear helps a lot with clutch wear... isn't not really neccisary to beat on the clutch, slipping it out of every turn, unless you can ride the bike to its full capacity. IF you can ride a 125 to its full capacity, and not too many people actually can, then a bigger bike is appropriate. In some situations though, you'll enter a turn in a certain gear, the next gear down is going to require an immediate shift back up, so you keep your present gear and just use a bit of clutch... makes for less shifting, and smooth transitions out of the cornor. Your right Nikki, something must have been very wrong to shatter so many plates. I'm still on my Original clutch... and many many hours have gone on it. Gear did most of the trick for me on the YZ, adjusting my riding style did most of the rest... and the clutch is always there to help out when the first to solutions don't work . :)
SterlingYZ
Member
- Mar 19, 2003
- 86
- 0
I've got to agree, on my '97 YZ 125, Clutching keeps it on the pipe. I always try to get in the appropriate gear anyway, but the clutch brings it on harder. I would think that being a gear or 2 too high THEN trying to clutch the hell out of it would really hurt something in the gears, but who knows. In all my years of riding, I have never burned up clutches like that, using stock clutches too.
I use the reed spacer. Not sure if I tell a difference as well, but it's still on there. I went up one tooth in the rear, and that helped out a lot. I ride trails, and am practicing to get to a track, so my bike has to perform both duties (just like my Giant AC freeride mountain bike, which I am NOT afraid to climb on) so I look for low end, but to be honest, the YZ 125 engine is awesome, and I have learned how to ride it, tight trails OR wide open tracks. I very RARELY foul plugs. Also, if I am not mistaken, I thought the higher number on a plug meant a hotter range... isn't a "9 plug, hotter than an 8"? If I am incorrect, please correct me, I may have it backwards.
I can't wait to make it to the track, I've spent most of my summer rebuilding it... Hey, what can I say, it's paid off, so it's ALL upgrades at this point. :)
I use the reed spacer. Not sure if I tell a difference as well, but it's still on there. I went up one tooth in the rear, and that helped out a lot. I ride trails, and am practicing to get to a track, so my bike has to perform both duties (just like my Giant AC freeride mountain bike, which I am NOT afraid to climb on) so I look for low end, but to be honest, the YZ 125 engine is awesome, and I have learned how to ride it, tight trails OR wide open tracks. I very RARELY foul plugs. Also, if I am not mistaken, I thought the higher number on a plug meant a hotter range... isn't a "9 plug, hotter than an 8"? If I am incorrect, please correct me, I may have it backwards.
I can't wait to make it to the track, I've spent most of my summer rebuilding it... Hey, what can I say, it's paid off, so it's ALL upgrades at this point. :)
- Jun 15, 2001
- 2,551
- 0
Yeah, Nikki. But everyone knows all women ride the clutch. ;) :eek: :eek:
Just kidding...you're obviously a hell of a lot harder (better rider) on a bike than the average joe.
If I remember right, it was Nick Wey that burned his YZ250 clutch up at either Budd's or Southwick.