I did the same thing to my MT125 but all I changed was the barrel and piston, at first. I added a CR125 expansion chamber and got a beast to ride instead of a slug. Running on premix was the only option as the CR barrel didn't have an oil injection port. I took out the oil pump but left the oil tank in as an emergency reserve if I ran low on gas and had to buy some from a farmer in the boondocks. I raced my bike occasionally and could compete with RM125's if there weren't too many jumps. I did lay down the shocks and got 7" on the rear but it wasn't perfect. But, there wasn't a stock trail bike on the market that could keep up with me. Great times.
Hi, before the conversion I had taken the bike to approximately 70 MPH. With over 30 year old trials tires it was not a comfortable ride and I was a little nervous but wanted to see what it could do. The whole point of the conversion was to make the bike quicker and improve throttle response which it did. I was not looking to increase top speed. Before the conversion this bike was sort of a dog as far as I'm concerned but now I can brag that this old piston port 2 stroke can hold it's own!
Even with the rather small MT rear sprocket the bike will lift the front wheel in first and second gear on the road at about 5,000 RPM and thats with me at 215LBS laying on the tank! I could put CR sprockets on it and lift the wheel every gear but I am only going to cruise on the road with this bike. It is way too nice to beat on it off road!
@@louisavondart9178 According to period road tests they weren't gutless. The engines had a lot of low-end grunt and heavy flywheels for tractability. The real problem was weight and a heavy front end.
Hi I have a 1977 dt 100d with the oil injection removed, gear still in the motor. Runs great but do I have remove the gear or can I leave it in?Will it burn up the motor if I don't put oil in the reservoir? Many thanks my brother has the same bike, it's a beauty like yours. Thanks again. Andy
hi! thanks for the vid! minus the compression released, did you need to machine anything on the cylinder? can anyone do this with a CR top end? if so, I'm off to ebay! thanks!!!
It's a bolt on mod. You can use the MT head and carb too. Just put in a bigger main jet. You'll have to run it on premix as the CR barrel does not have an oil injection port.
Hi Lee, I'm getting ready for a lower end rebuild and have my CR top end ready to go. Did you use a Mukuni VM34? What Fernco fitting did you use? Thanks, Mike
Got a low mileage MT 250....MT should stand for "empty" of horsepower....Got an MR250....great motor and power, but poorly spaced 5 speed gearbox....needs better gearing or six speeds....I have not really been into either motor, but I would think that the MR/CR cylinders would not mate up easily to an MT bottom end....any difficulties in that respect and if so how did you over come them???
Put a aftermarket pipe on the stock MT250 engine like a Jemco pipe and it wakes them up some. to do the CR 250 top end swap on a MT 250, you need a 1973-74 CR250M top end. the 1975-76 CR250 and MR250 cylinders will not bolt on to a 1974-76 MT250 or 1973-74 CR250 because the later cylinders have 4 larger and shorter studs and the MT and Early CR250 engines have 4 long slender studs that pass through the cylinder and into the head. as far as power goes on a MT250, it will run with the Suzuki, Yamaha and Kawasaki Dual purpose 250s of the time. that and it does way better on fuel than a MT250 that had a CR250 conversion done to it.
I did the same thing to my MT125 but all I changed was the barrel and piston, at first. I added a CR125 expansion chamber and got a beast to ride instead of a slug. Running on premix was the only option as the CR barrel didn't have an oil injection port. I took out the oil pump but left the oil tank in as an emergency reserve if I ran low on gas and had to buy some from a farmer in the boondocks. I raced my bike occasionally and could compete with RM125's if there weren't too many jumps. I did lay down the shocks and got 7" on the rear but it wasn't perfect. But, there wasn't a stock trail bike on the market that could keep up with me. Great times.
Hi, before the conversion I had taken the bike to approximately 70 MPH. With over 30 year old trials tires it was not a comfortable ride and I was a little nervous but wanted to see what it could do. The whole point of the conversion was to make the bike quicker and improve throttle response which it did. I was not looking to increase top speed. Before the conversion this bike was sort of a dog as far as I'm concerned but now I can brag that this old piston port 2 stroke can hold it's own!
Nice bike!. I have a 1974 XL 350 that I restored.
Even with the rather small MT rear sprocket the bike will lift the front wheel in first and second gear on the road at about 5,000 RPM and thats with me at 215LBS laying on the tank! I could put CR sprockets on it and lift the wheel every gear but I am only going to cruise on the road with this bike. It is way too nice to beat on it off road!
Very nice conversion, honda detuned the mt models for street use.
That's an understatement. They were gutless.
@@louisavondart9178 According to period road tests they weren't gutless. The engines had a lot of low-end grunt and heavy flywheels for tractability. The real problem was weight and a heavy front end.
Wow you sound like your from RI!
is there a cdi box behind the key ignition or somewhere on the bike
if you ride at 55+mpr often then I strongly suggest you keep a 44-45 on the rear(44s arn't made) I put a 48 on and its windes out at 55.
Hi I have a 1977 dt 100d with the oil injection removed, gear still in the motor. Runs great but do I have remove the gear or can I leave it in?Will it burn up the motor if I don't put oil in the reservoir? Many thanks my brother has the same bike, it's a beauty like yours. Thanks again. Andy
you must take off the oil pump and put a blank plate on there or it will suck air through the pump.
hope your running properly mixed oil in your tank .....sound pretty new to this. ....yes you need to blank off oil pump
what was the top speed before and after the conversion?
A good question. 🙂
hi! thanks for the vid! minus the compression released, did you need to machine anything on the cylinder? can anyone do this with a CR top end? if so, I'm off to ebay! thanks!!!
I have the same question. My MT250 has a scored cylinder, I can either bore it or replace it.
It's a bolt on mod. You can use the MT head and carb too. Just put in a bigger main jet. You'll have to run it on premix as the CR barrel does not have an oil injection port.
Hi Lee, I'm getting ready for a lower end rebuild and have my CR top end ready to go. Did you use a Mukuni VM34? What Fernco fitting did you use? Thanks, Mike
Same year top end?
LOL!!! Yeah, where I come from (Northern RI) even though you divorce your wife shes still your sister!! LOL!!!
Got a low mileage MT 250....MT should stand for "empty" of horsepower....Got an MR250....great motor and power, but poorly spaced 5 speed gearbox....needs better gearing or six speeds....I have not really been into either motor, but I would think that the MR/CR cylinders would not mate up easily to an MT bottom end....any difficulties in that respect and if so how did you over come them???
Put a aftermarket pipe on the stock MT250 engine like a Jemco pipe and it wakes them up some. to do the CR 250 top end swap on a MT 250, you need a 1973-74 CR250M top end. the 1975-76 CR250 and MR250 cylinders will not bolt on to a 1974-76 MT250 or 1973-74 CR250 because the later cylinders have 4 larger and shorter studs and the MT and Early CR250 engines have 4 long slender studs that pass through the cylinder and into the head. as far as power goes on a MT250, it will run with the Suzuki, Yamaha and Kawasaki Dual purpose 250s of the time. that and it does way better on fuel than a MT250 that had a CR250 conversion done to it.
they bolt right on
Did you use the mt throttle cable?
Yes I was.
Does it have a key???? do start it
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