CR125 engine change, is it possible?

[bandito]

Hi, here we go. :ahhh:

I've got a CR125RP 1993 model as a project. The engine is completely SHAFTED... Where do i start, the clutch basket has one of the fingers missing, the shift drum has a chunk missing out of it, the dogs on the 1st gear are completely bashed. It has been rebored at sometime but with the wrong plating for gods sake... The impeller rod is leaking coolant into the gearbox. Basicly the engine has had it's day unless i want to just throw cash at it...

I've been told it's not possible to swap the engine for a later model and it would have to be a 1993 CR125RP. Is this true? What stands in the way of using a later model engine. Could i use a 98 CR125R engine? The RP models seem very rare and i don't think i stand a chance of getting one.

Please help! :bang:

 

[jim f.]

I your willing you can have new motor mounts welded on frame if you have to.

 

[YZ165]

Anything is posiible given enough time, money and desire. The motor mounts will probably be diffrent, the exhaust might not fit, the electronics prolly won't work, and the airbox to carb junction might not line up, but other than that, I don't see why you couldn't make it work. But, by the time you get all the stuff together to swap the new motor in, you probably could have just replaced the broken parts in your motor and put it together. Just my .02, YZ165

 

[SirHilton17]

What is a cr125rp... i have never seen a P in a crs name before??

 

[MXP1MP]

I don't see why not honda used the same motor from like '90 thru '99! Especially from like the mid 90's, stuff like chassis parts I can see not swapping but the motor I bet they swap right out, check out part #'s there might be a difference in the like 93 thru round 96 due to a color change (non painted cases for once) you'll find that nearly all parts from like 93 thru 97 in the motor inter change parts like cylinders but heads might be alittle different in respect to piston dome or flat top design on some motors. Do some part # diagram searching dimensions I recommend spending time at serivce honda's site. As far as the electronics if you get one year motor and stick with it's electronic's they will mount up. I think the only think that you might need to use if you get an '98 motor into a '93 frame is the rubber manifold from the cases to the carb for the right angle fit. Use the air box/boot stuff from the year you have should fit fine and use the style pipe/silencer for your steel frame chassis. Other than maybe the area between the center cases and swing arm pivot but if they didn't change the center cases good bet that didn't change either.

 

[flattie]

93-02 will bolt up, i'm running a 00 model cylinder on my 96 cases, all engines in those years will bolt up with very little mods

 

[bandito]

Thanks for the advice guys. You've helped me make the decision not to scrap for spares, and spend some time making a new motor fit. From what some of you have said it might not be *so* hard, and need little in way of modifications.

The current engine is a lost hope i think, by the time i bought everything it needed it would've been cheaper to buy a whole new engine unit.(i've been told) It needs new clutch basket, new counter shaft, new shift drum/forks, new 1st gears, new impeller rod, needs rebored with correct plating + alot more horrors i'm sure. And i'm not sure i'm competant enough yet/have the equip to do the work myself.

I'm not really that experienced with the inside of the motor, but at least i have a knackered one to get familiar with now.
I'm gonna spend some time checking out dimensions and part #'s as MXP1MP suggested.

Again, thanks for the advice guys, and any other insight into my plans or the old motor would be great. :cool:

 

[22703]

you never know unless you try it.what the heck give it a wirl if worst comes to worst than get an 1993 motor of **** or salvage yard.