Two Stroke Motocross
Two Stroke Motocross Forum => General Two Stroke Talk => Topic started by: Scooter T on March 28, 2012, 01:46:59 AM
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To make a long story short, I am trading a mini bike project for a 2001 CR125 roller. I was wondering what my engine options are for this chassis. What engines, from previous years, will bolt into this chassis? I know some years have been better than others. Any thoughts?
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Go To Eric Gore's web site he has big bore service for this bike. We have been racing a 2001 cr125 for almost 3 years in the 250C class won two races on it and handles well. Also there is an artical on this web site for this bike look in the arcives.
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I've heard you can bolt in the famous 97 cr125 motor. this was the BEST motor honda put out on the tiddler and has been crap compared to everythin else since 98. id try to find out if this would be possible then get some custom work if necessary or it was the cylinder that was compatible with the newer cases not sure. that or just get the newest motor you can and slap a 144 in it. the newer cr's respond really well compared to others as the cases are kinda big for the motor. i talked to a tuner about then you could only go one way or the other meaning all top(pros on mx tracks) or all bottom (for sx) it wouldnt do any in between. however i have heard that some tuners figured out by using epoxy they could "close" the motor up to get a better tune
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The 1990-97 motors where good,the 05-07 has a stronger motor 5 more hp,and has the same peak hp as a 2012 ktm 125. All depending on what kind of tuned motor you want, a 2mm ovr borre should have good torque #,s or porting for mid-top and carb borring should have a strong mid to topend with a weak bottom end. There,s a youtube vid of a 01 with a pc motor-blackfoot xpro bike, imo I would go with porting mid-top,borre carb, that would be cheaper than a bigborre and would sound alot better.That would,nt be anygood for trail riding tho.
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I've always wondered about the 5sp vs 6sp thing with the 125s.
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apparently shifting gears and powerbands are just too much for todays riders, as they are now literally racing semi-automatic (rekluse) 4 strokes in SX.
just lets you know how awesome guys like McGrath really were.
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apparently shifting gears and powerbands are just too much for todays riders, as they are now literally racing semi-automatic (rekluse) 4 strokes in SX.
Just wait until they add another 50 pounds to the fooper pigs by adding an automatic transmission 
But I would say if the 96 cr125 engine would fit into the chassy, then go for it.
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What's wrong with rebuilding the stock motor? Nothing you're going to bolt in there short of a 250 is going to make it significantly faster. The main issue with the aluminum frame Honda's is the air flow is choked. I had and raced new CR125s from 94 through 98. I can tell you the 97 motor wasn't anything more special than the previous years. The bike went down hill with the twin spar frame.
Not to get drawn into another 4-stroke debate on a 2-stroke site but what riders in SX even run a rekluse? I don't see a single top rider running rekluse stickers. But the entire track can be ridden in pretty much 1 gear, especially with a factory transmission and their longer 2nd gear. It wasn't THAT much different with 2-strokes either, on a 250 you only needed 2nd and 3rd.
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Not to get drawn into another 4-stroke debate on a 2-stroke site but what riders in SX even run a rekluse? I don't see a single top rider running rekluse stickers. But the entire track can be ridden in pretty much 1 gear, especially with a factory transmission and their longer 2nd gear. It wasn't THAT much different with 2-strokes either, on a 250 you only needed 2nd and 3rd.
Here you go, holmes.
http://www.vitalmx.com/features/Auto-Clutch-for-Supercross,3257
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Ehhh.. I get your obvious point that you think riders and bikes aren't what they use to be but that's reaching. I'm not going to assume your experience level or speed but on a 250F a SX track is still tough ****. You need all kinds of clutch to make new style rhythms and triples that are right out of turns. The only advantage that gives Lemoine is if he falls the bike will free-wheel. Even on a 450 you need the clutch to seat bounce over some things.
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The 1990-97 motors where good,the 05-07 has a stronger motor 5 more hp,and has the same peak hp as a 2012 ktm 125.
the 05-07 or 2002 or newer did make about 34 hp on top. but dont get too excited just because it makes as much as a new KTM its like saying a dolled up girl is better than a model with out makeup. The old cr only made good hp in a very small range. like 10,000-11,000 type range meaning you had to tap dance on the shifter and clutch. the Older ktms like 03-08 made 35 up to 38hp! thats what 250fs make NOW. the newer KTM is possibly the absolutly best 125 motor in that its a mini 250 in the way a YZ is but with more grunt. true it only makes 34 hp but it makes so much more bottom and mid.
as far as a rekluse clutches a pro would very smart to run them so that when they do fall over they dont have to drop a few laps tryin to restart
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ST I didn,t know you had a roller. I tried to find out if my 06 cr125 engine would fit into my 04 cr125, I never got an answer. So I looked everything over,it looks like it would work.I did forget to measure the swingarm mount tho. Until I swap motors,don,t know if it will work. The pc pipe on the 04 bolts on the 06, strange but the 06 pipe will not work on the 04. FYI you will need the ignition also,with the stator. There could be a problem with the airboot, the swingarm mount is the engine mount that you can,t change,I would check that 1st. The next time I,m at my bikes,I,ll get that measurement for ya,the weather here is bad right now.
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Go to on the pipe racing he knows all about cr125's his son raced a 2001 for years. To bad he sold the spare motor out of it cheep! http://www.onthepiperacing.com/
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Lee from on the pipe racing, is a trip and a huge 2-stroke nut. His kid got alot faster, the last 2 years he,s been on a yz 250 in expert class.
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I see steel framed 95-97 CR125s on CL all the time for less than a grand. Why dont you just get one, rebuild it, and put your newer forks/triples on it? then you could use the front wheel/brake too. You'd be just like Steve Lamson, only with more stopping power.
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I called Lee today. He informed me that any engine from 98 up will be a direct bolt in for this chassis. So now the question will be finding the best value for this bike. My goal is to build the bike up without spending a lot of money on extras.
I currently ride a KTM 200xc in the woods. This will be my track bike this year?
I will be picking up the bike tomorrow morning and I will start documenting my progress for a build thread?I look forward to asking a lot of questions?
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for what i know, all the cases from 94 to 07 are the same and share the same bolt pattern, so it will bi a straight fit.
i own a 01 cr 125 and i broke the loeft side case because the chain broke up, and the engine case has the same part number for all those years.
i'd like to get old at least of a 94/97 gearbox to swap the 5speed to 6..
check this conversion http://metal-matrix.com/s/index4.html
you'll get a bike such competitive as a 90's cr with better handling, and you can find 94/97 tranny's pretty cheap on ebay, most of them in the states. to bad for me that they don't ship overseas..
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I would just stick with the 5 speed if your trying to keep the money down, the 5 speed is a tougher trans. I hope Lee is right about the 98 and up motor working, he said a 03 and up KX pipe fit 04 cr125,s and up, the 03 KX pipe is not even close to fitting on a 04 Cr 125. I went out and bought 2 2003 KX pipes, Doma and HGS BUd, hope you have better luck. The head stay from another year will prob be different too.
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Thanks for all of the replies to my Newbie post?.I picked up the bike last weekend and later missed out on a motor for the bike. Well I found a 99 that is complete and recently rebuilt. The best part is that it is close to home. Hopefully Lee is correct and this will bolt into my chassis. The only question is about the carb and radiator fitment. So I guess I will find out if this motor is still available?
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I wonder if the 98 YZ 6 speed will go into the 02+....
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Miedosoracing has a lot of time on CR rebuilds and deals with the air flow issue on the alum framed CR125s. Shawn36 is right, the engines after '97 weren't that much different, the problem was the air flow was restricted on the alum frames. Like I said, miedosoracing.com has everything you could need to make your '01 rip.
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My vote is still for the Steve Lamson model.
