Two Stroke Motocross
Two Stroke Motocross Forum => Technical => Topic started by: Hondacrrider on August 23, 2010, 10:59:53 PM
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As many of you know, I ride a 2001 cr 125, and it happens to be one of the slowest 125's(in terms of power, has a good frame though) out there. I have now decided to send my cylinder and carburetor to HP bikes as told to do so in the budget racer build up on the main site. Derek Harris is also offering me a 1999 cr 125 ignition module that will allow me to rev higher. My question for you guys is what bolt ons should I buy to make the best, most hard hitting top end ever! I am planning to save up through the winter and buy bolt ons that will compliment the new engine. I have already asked him to put as much punch up top as physically possible. I am thinking an fmf(no pro circuit) fatty will get me the most top, but, I hear the shorty brings more bottom, what silencer would increase top? Also, what reeds? Boysen, or Vforce? What about this power now plus that fits in your carb, and supposedly increases hp, what jet kit? what about this boyesen quick shot cover for the carb? Do you guys know of any bolt ons? I will have roughly a grand to spend. I want this thing to be a fire breather for the 2011 season. I will by the way send the cylinder off in winter, as I have one last race in september, thanks guys! ;D
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Unfortunately you probably don't want to hear this but bolt ons are just that bolt ons. To make good top end power you have to make a few simple changes like adding a base gasket and 1 extra gasket between the reed cage and the cylinder.However the biggest change can come from you. For example if a AMA Pro level rider rode your bike as is would it go round the track quicker? Can you cope with a a peaky engine? Do the gearbox ratios suit a peaky engine?
To make a good modified engine, everything has to work together and you start to move away from bolt on to custom this and that.
Spend the grand on a ride school and some suspension.
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I didn't really think of that, though I will still be sending my cylinder off to HP bikes, because the bike is still very slow, any suggestions for suspension companies?
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I have a pal that raced a 01 cr125 totally stock,pipe,silencer,everything in 05. He got top 3 starts sometimes and won alot, ended up 1st in Northern Cup series, that was highly contested, ave. 30 or so in 125b. He,s 6 ft. 1 or 2 175 or so. I have a 04 cr125 and 2 months ago picked up a 06 cr125. The 04 is slower than the 01 stock,until jm racing ported it and borred the carb to 40 mm, it pulls a YZ 144 on hills with a 35 lb. lighter rider on the yz. If your going nuts and want to mod your bike a little get the rad valve, take it apart polish the internals, on my 06 it made an instant diff. On my 04 before the porting, I installed the vforce and was disapointed,very little diff. On my 04 my engine guy endorses FMF, I told him I hv. a PC on it,whats the diff.anyway he said the fmf hits harder, the mod motor hits hard already, the pc pipe has better over rev. On a hard pack track I took the pc silencer off, put the stock silencer on with the pc pipe, it was smoother delivery,lost top end. It really comes down to riding as much as you can, or if you only have time for 20 laps, brake late smooth in threw and out of the corners, be precise everywhere, be aggressive on every inch on the track, then every mm, no cruising. Maintain your bike, if you want to become a really great 125 rider, have a practise 125. What you want on a 125 is a smooth flow, with your wheels on the ground it feels like your flying, in and out of corners it will feel like your in the air,because your so dam smooth.
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I just did a complete overhaul on a late model Honda CR125 for a friend's wife. Man was that thing slow. At the same time I was restoring a 35 year (!) year old hotrodded Sachs 125 that made WAY more power.
I would do the same mods as in an article that was featured here at TSM a little while back. Otherwise you won't stand a chance.
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I just did a complete overhaul on a late model Honda CR125 for a friend's wife. Man was that thing slow. At the same time I was restoring a 35 year (!) year old hotrodded Sachs 125 that made WAY more power.
I would do the same mods as in an article that was featured here at TSM a little while back. Otherwise you won't stand a chance.
I am doing all the mods on the article shown on this site, this is where I got the idea. Do you know why this particular bike can not make power?
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I have a pal that raced a 01 cr125 totally stock,pipe,silencer,everything in 05. He got top 3 starts sometimes and won alot, ended up 1st in Northern Cup series, that was highly contested, ave. 30 or so in 125b. He,s 6 ft. 1 or 2 175 or so. I have a 04 cr125 and 2 months ago picked up a 06 cr125. The 04 is slower than the 01 stock,until jm racing ported it and borred the carb to 40 mm, it pulls a YZ 144 on hills with a 35 lb. lighter rider on the yz. If your going nuts and want to mod your bike a little get the rad valve, take it apart polish the internals, on my 06 it made an instant diff. On my 04 before the porting, I installed the vforce and was disapointed,very little diff. On my 04 my engine guy endorses FMF, I told him I hv. a PC on it,whats the diff.anyway he said the fmf hits harder, the mod motor hits hard already, the pc pipe has better over rev. On a hard pack track I took the pc silencer off, put the stock silencer on with the pc pipe, it was smoother delivery,lost top end. It really comes down to riding as much as you can, or if you only have time for 20 laps, brake late smooth in threw and out of the corners, be precise everywhere, be aggressive on every inch on the track, then every mm, no cruising. Maintain your bike, if you want to become a really great 125 rider, have a practise 125. What you want on a 125 is a smooth flow, with your wheels on the ground it feels like your flying, in and out of corners it will feel like your in the air,because your so dam smooth.
I am thinking that that is what I need to do, practice, be smooth, get some lessons from a pro, I really do enjoy riding my 125, it is a lot of fun, and boy do you ever have to be on the pipe, it really builds skill. I can't imagine what it would be like riding my friends' 250f now! My friends are telling me, "You are beating us on a slow cr125, imagine what you would be like on an rm125 or a 250f". So... my other question, should I just buy a different 125, I will not buy a 250f though, you guys think it's possible for me to do good in the school boy, 125 beginner class on a stock 125 cr?
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The 90's Honda CR125s were the bikes to beat, so what happened to the last ones I do not know. Did the other 125s get faster, or the CR125 slower? The last KTM SX125 I rode sure was fun.And why did Honda put the 5 speed gearbox in the last CRs as well?
I think your CR125 has excellent potential for very little money. While the 250f guys will be sweating every moto, wondering how they will pay for it all, you'll be getting faster and faster and having more fun.
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Yeah you can do well on a 01 cr125 in beginner and competitive in 125 jr. The so called slow years of the cr125 2000 to 04 have a good mid range, they rev out but theygo flat on top, most 125,s stock are this way. The 90,s cr125,s made a peak of 27 hp, a 2000 is over 32, a 04 is 30.7, a 05-07 34.8 and has great throtle response. Even if you had a 40 hp mod 125 that motor will have a sweet spot, prob. in the upper mid,that,s where you would ride it,every motor has a sweet spot,your bike is no diff.
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The 90's Honda CR125s were the bikes to beat, so what happened to the last ones I do not know. Did the other 125s get faster, or the CR125 slower? The last KTM SX125 I rode sure was fun.And why did Honda put the 5 speed gearbox in the last CRs as well?
I think your CR125 has excellent potential for very little money. While the 250f guys will be sweating every moto, wondering how they will pay for it all, you'll be getting faster and faster and having more fun.
I am wondering all the same things...
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Yeah you can do well on a 01 cr125 in beginner and competitive in 125 jr. The so called slow years of the cr125 2000 to 04 have a good mid range, they rev out but theygo flat on top, most 125,s stock are this way. The 90,s cr125,s made a peak of 27 hp, a 2000 is over 32, a 04 is 30.7, a 05-07 34.8 and has great throtle response. Even if you had a 40 hp mod 125 that motor will have a sweet spot, prob. in the upper mid,that,s where you would ride it,every motor has a sweet spot,your bike is no diff.
Why did the 2004 bike lose power?
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That was the 1st yr. honda built the 250f. It was a surprise that the 125 got any improvements at all, but it was a rush job with the new cylinder with the eletronic power valve. The transfer ports- the little ports inside in the middle, are too high. Quick fix deck the cylinder-machine quite a bit off the bottom, widen the exhaust port, very little other porting, bore carb to 40mm, icat, 110 leaded fuel,pc pipe,silenser, head mod. And then it,s 37hp or so. Now it,s stroked and borred 2mm, I didn,t want the ovr bore,but it,s done and it,s quicker and faster than a 150 KTM easily. The bad the 110 leaded fuel in 5 days can not be used, that,s the cheap stuff 6.50 a gal., I need to use vp112 and that,s more than 10 a gal. My back and hip is still hurting, never should,ve flagged the race sunday.
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Spending all that money to make an old bike go a little faster, doesn't make sense to me.
Why not sell it and use the extra $$ you where going to spend on hot up's, to buy yourself a later model yz or ktm.
Guarenteed to be faster and still standard (read reliable) Big mods turn bikes into time bombs.
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It,s easier to make a slow bike fast,than a poor handling bike handle better. You can make any bike faster,but you can,t improve the handling much.
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It,s easier to make a slow bike fast,than a poor handling bike handle better. You can make any bike faster,but you can,t improve the handling much.
But you sure can make a fast, good handling bike even faster. ;)
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It,s easier to make a slow bike fast,than a poor handling bike handle better. You can make any bike faster,but you can,t improve the handling much.
But you sure can make a fast, good handling bike even faster. ;)
Which would mean a ktm, or yz 125, and i haven't found a bike that handles like mine, I am thinking i am going to go ahed with the mod and buy a practice bike that I can keep stock
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O.K., I'm stil not getting it. You have enough cash to hypermod one old bike, then buy a second practice bike.
Why not just get a 2010 yz or ktm 125 .........no more power issues and a new bike.
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O.K., I'm stil not getting it. You have enough cash to hypermod one old bike, then buy a second practice bike.
Why not just get a 2010 yz or ktm 125 .........no more power issues and a new bike.
And definately no handling or reliability issues.........both of them are awesome little bikes..
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O.K., I'm stil not getting it. You have enough cash to hypermod one old bike, then buy a second practice bike.
Why not just get a 2010 yz or ktm 125 .........no more power issues and a new bike.
Yes, I would love a 2010 bike, but a 2010 bike around here is 8000 plus tax. My practice bike would be an 89, and I am just going by what this site has told me to do http://twostrokemotocross.com/2009/05/budget-racer-2001-honda-cr125/ (http://twostrokemotocross.com/2009/05/budget-racer-2001-honda-cr125/)
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I actually don't know what to do at the moment you see... This was my first motocross bike, but i am definitely searching for more power now, especially on hillclimbs, but, I have a brand new engine in the thing, and, the bike didn't change too much by 2007, I do know that the yz 125 and ktm have a lot more power, but who knows if I will have enough money. I can sell my cr125 for around 2300 dollars in my area, and if I travelled a little bit, I could pick up a good 125 for an extra 500 dollars, what do you guys think?
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I am HP.
That bike stock is just sad - never ever quite ran right.
IF and that's and IF you can sell it for 2300...by all means DO so.
Pick up a newer bike - these days good yz125's can be had cheap.
Even the 05 honda was quite good stock (finally made revisions to motor that paid off)
But if you cant - and you even want to have fun - that motor needs help! First thing you need to do is jet it a little more aggressively now - but this requires some expertise and patience. Plus fuel choice factors in.
I ALWAYS agree lessons will pay bigger dividends in lap times than ANY amount of motor work for non pro rider.
Somtimes when you find a couple horses - but find out how little dividends it pays off in a drag race in actual distance you can be discouraged. I actually wanted to quit this business one day when I found the real difference in acceleration between a bike with 5 more horses than another - but I finally came to terms with the fact that I would much rather be the guy that gap ahead than behind after the start of straight!
That said - that motor is NO fun IMHO stock. But run stock pipe for a while and see what you think of that - save you some dough - and it's quite decent in breadth. Honda made good pipes stock!
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I am HP.
That bike stock is just sad - never ever quite ran right.
IF and that's and IF you can sell it for 2300...by all means DO so.
Pick up a newer bike - these days good yz125's can be had cheap.
Even the 05 honda was quite good stock (finally made revisions to motor that paid off)
But if you cant - and you even want to have fun - that motor needs help! First thing you need to do is jet it a little more aggressively now - but this requires some expertise and patience. Plus fuel choice factors in.
I ALWAYS agree lessons will pay bigger dividends in lap times than ANY amount of motor work for non pro rider.
Somtimes when you find a couple horses - but find out how little dividends it pays off in a drag race in actual distance you can be discouraged. I actually wanted to quit this business one day when I found the real difference in acceleration between a bike with 5 more horses than another - but I finally came to terms with the fact that I would much rather be the guy that gap ahead than behind after the start of straight!
That said - that motor is NO fun IMHO stock. But run stock pipe for a while and see what you think of that - save you some dough - and it's quite decent in breadth. Honda made good pipes stock!
While, you are right, the bike doesn't have the same snap as the others, i still do enjoy riding it, heck, I loved riding my old xr, but, yes, I would like more power, so, I think I will finish up the season on my cr, and I will look for a yz in the winter.
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Thanks for the help
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Honda
We just finished our season on our 2001 cr125 and we took 4th place in the series out of about 45 riders. It was our first year on a big bike in the 250C class with alot of highly modified 250Fs and most of them new. I usually take pictures of Jakes starts and he is usually about 4th to 7th out of about 20 riders and he usually backs off so we are working on his starts. In Feb. he rode in two beginer class races and got the hole shot in both of them. Last week end he finally figuered out how ride a 125 ( wide open) He was fighting with two 250 two strokes for 11th place out of 24 riders and was passed and he repassed them and held them off very close racing. Its more the rider than the bike. I've done mods to the bike Jetting was huge 380 to 340 !!! and I think I could still go down one more size!! We have the oldest race bike out there and we are in the thick of things at a fraction of the price. By the way (knock on wood) we had no breakdowns!
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Keep up the good work luther. ;D
Thats what it's all about. Having fun at an affordable price.
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Thats part of my point unless your a A class or B class rider you may be better off with out having a rocket ship. When I raced I had a 1976 CR125 I DG port the cylinder and the big carb and it ruined the bike it was like a switch all on or all off. I was not capable of ride wide open. Here are a few pics.
(http://i885.photobucket.com/albums/ac60/luthier269/R1-24.jpg)
(http://i885.photobucket.com/albums/ac60/luthier269/R1-9.jpg)
(http://i885.photobucket.com/albums/ac60/luthier269/Jake2.jpg)
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Honda
We just finished our season on our 2001 cr125 and we took 4th place in the series out of about 45 riders. It was our first year on a big bike in the 250C class with alot of highly modified 250Fs and most of them new. I usually take pictures of Jakes starts and he is usually about 4th to 7th out of about 20 riders and he usually backs off so we are working on his starts. In Feb. he rode in two beginer class races and got the hole shot in both of them. Last week end he finally figuered out how ride a 125 ( wide open) He was fighting with two 250 two strokes for 11th place out of 24 riders and was passed and he repassed them and held them off very close racing. Its more the rider than the bike. I've done mods to the bike Jetting was huge 380 to 340 !!! and I think I could still go down one more size!! We have the oldest race bike out there and we are in the thick of things at a fraction of the price. By the way (knock on wood) we had no breakdowns!
This is why I love this bike, I got it for a good deal, and it is a good bike to learn on, and I love riding it in all situations except for sandy hill climbs. This is why I have decided to do the spring series on my stock cr125(although I do think I am going to get to that jetting one of these days) and eventually get a new bike in time for the fall series, because I would like to be somewhat competitive on the hill climbs. Thanks for the tips!
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Listen to Luthier269 , it,s way more rider than bike at the b,c level. The cr125,s are built more durable than other bikes, you can put mega hrs. on them and they feel like a new bike yet, tough trans.clutch,etc. For hill climbing a 2011 won,t impress you much either, unless you mod the motor and then the fuel is 10 per gal. A 04 cr125 has the cases fixed,just deck and port, a cr 05-07 is just as fast as a 2010 YZ, and the CR doesn,t blow tranny,s and handles alot better. A pal of mine works at a KTM dealer, and told me the top am. and pro,s were surveyed on what is the best chasis ever built, the CR125 won handes down.
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:D