found an 1125CR engine for a spare. Is there differences between the R and CR engines besides trans ratio's?
differences?
- Thread starter mrlogix
- Start date
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Engines are the same. I believe the output ratios were changed by the output sprocket and rear wheel sprocket so just use your sprockets if you ever swap to this engine. Oh and the sticker on the cluch cover says 1125cr
Just looked it up to verify the transmission ratios are the same R and CR its the output ratios that were changed requiring different sprockets belts and I believe swingarms.
Just looked it up to verify the transmission ratios are the same R and CR its the output ratios that were changed requiring different sprockets belts and I believe swingarms.
heagachongoose
Well-known member
Affirmative. Sprocket ratio is the only gearing difference. The cr has a slightly shorter swing arm to compensate for belt length lost from the gearing difference.
thanks guys 
yep
heagachongoose
Well-known member
Doooo eeeet. If I had the cash on hand I would have already done it.
this will be my winter project
still trying to determine all the differences between the 1125 and the 1190. I realize that there are internal differences between the engines that may not be able to be accounted for, but still trying to figure out stuff like head differences, cams, valvetrain, etc., etc. I know the fuel injection system now uses a showerhead style aux. injector and the wiring harness differences and ecm stuff. May be a little longer project than just the 3-4 winter months, but I have a lot of resources as far as manufacturing and machining, and experience with modifying euro sport cars for endurance racing. We will see where it ends up.
Doing just the cylinder/piston swap isn't that big of a job. It will work with everything else on the 1125 from what I've been told. You'd need their race ecm matched to the big bore kit, the pipe you have should flow enough to work well with it. Secondary injectors on the 1125 based engine is most likely not needed, but if you go that route, the stock 1125 ecm has the data/cells to do it. Wiring it up should be relatively straight forward, it's just a matter of sorting out the pins on the ecm. Mounting them to the throttle bodies on the other hand, that will take a little bit of creative work. I can post pics of mine if you like, but it's a rat's nest inside the 1190 airbox.
If you need/want cams, I'd look up Crower cams, they have some 1125 RR cams already done, this was mentioned just recently in another thread.
If you need/want cams, I'd look up Crower cams, they have some 1125 RR cams already done, this was mentioned just recently in another thread.
I seen the thread on the Crower Cams just don't know the profiles to compare with the 1190RX profiles or if the 1190RX cams are a bolt in replacement or does it require machine work/ new design heads. I have rapid prototype printers at my disposal to mock up a lot of stuff before I make anything. I also have access to EDM's, Grinders (OD, ID and surface) mills, lathes, 5 axis machining centers and 3-D modeling/CAM software (Unigraphics NX 7.5). Like I said the resources are there, Just a lot of engineering work in the beginning.
looking at the spec's for the RX it looks like they changed the steering geometry also.
For the amount of time and money and possibly losing reliability you can buy a brand new Ktm RC8 here in Spfld, MO for 14,000. Sell Betty and save yourself the hassle and pick up the beast. Of course, unless you just like to spend every waking moment thinking about what your building.
lol, not every moment, only about half.
if you have to ask, you won't understand. It's not about the destination, it's about the journey.
just read your tunepro thread, from some of your questions and the replies, your way ahead of me on ecm re-programming/fuel maps. I'm just going to do some old school mods to the engine that should be good for a couple of horses. If I do it right, it should be mechanically reliable. But I will be having to make some changes to the ecm, and I'm learning a lot
question, does anyone have a 1190RX service manual or a link where to buy one?
