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  1. #1

    Xlt1200 Mr-1 conversion

    After years of research and several blown 1200pv motors I've finally started my Mr-1 conversion and chunked the 1200 in the scrap pile. This is a 05 Yamaha Xlt1200 the donor is a 05 Yamaha Fxho with only 31.7hrs I picked up from a local auction for $2500. So far I have installed the Fxho fuel tank, Fxho midwall bearing/coupler, and mocked up the Fxho seat plate to be able to easily access the rear of the motor and the coupler.

    Everything I've read up until now has said its necessary to clearance to starboard stringer to make room for the ho exhaust. But during mock up I found the exhaust has a little over an inch and a half of clearance which I would think should be more than enough without cutting it. So I believe I'm just going to bolt the engine right in as it is and see how it turns out.

    Next up I will be installing the Fxho transom plate/pump, Fxho cables/hoses, full oil change on the motor, and install the motor. Here are pictures of the donor and my current progress.Click image for larger version. 

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  2. +1 by:

  3. #2
    This is the ski I'm performing the conversion on. Spent a lot of time and money on customizing it before the last 1200 blew so I couldn't help but stick with it and just do the conversion instead of replacing the ski.
    Click image for larger version. 

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  4. #3
    raiderteen's Avatar
    Join Date
    Nov 2007
    Nice looking ski. Could you get a measurement of the complete MR-1 from coupler to furthest forward point? Looks like you've made good progress already. Keep it up!

  5. #4

    Join Date
    Jul 2015
    Chattanooga, TN
    Any update?

  6. #5
    Well apparently I got side tracked and forgot I even started this thread, but here I am with an update. The ski is completely done now and has been out on the water a few times now, all I can say is, WOW!! This conversion has completely renewed my love for this ski. Way better fuel mileage, runs way smoother, and the sound from this engine is intoxicating. Haven't got a good top speed run from it yet because everytime I've been out lately it has been choppy. Fastest ive gone on it so far was 68 mph and it seemed like it had a bit more left in it. As for the remaining details of the install, everything from the Fxho literally bolted right in, I even decided to run the Fxho steering column due to the steering cables being different and wanting to retain the steering sensor. The only hull modifications I had to do was cut the factory seat plate out to use the Fxho seat plate, cut a couple extra holes in the pump tunnel for water lines, re-drill a couple hole for the steering column, re-drill holes for ecm mounting/nozzle trim mechanism, and trim the dash to fit the cluster. The factory seat plate had to be cut out to allow the motor to drop in the engine compartment and allow use of the removeable Fxho plate to be able to access the oil fill cap which sits inconveniently right under the seat plate in this application. But with some modification to the Fxho seat plate the fill cap can still be removed with the plate still bolted on to check oil level. Just have to remove the plate to change the oil which really isnt a big deal. For the motor mounts I used the XLT motor mounts and the Mr-1 mount brackets fell right into place over the mounts like it was meant to bolt in there and the exhaust cleared the stringer by about 2.5-3 inches. For the exhaust I used a second Mr-1 exhaust outlet pipe to get the exhaust to pass through the factory exhaust hole in the midwall and meet up with the XLT's waterbox. Have been running it without the airbox because I didn't feel like modifying the seat and the factory stacks with the intake ribbons do a good enough job of keeping any hazardous debris out of the intake if anything were to ever find its way in there. The nozzle trim mechanism had to be moved from the XLT's factory location back to the rear of the midwall because the Fxho pump is longer and the XLT's trim cable is to short to reach. But all the Fxho cables swapped right over and the only things that needed to be done was redrill a few holes for the trim mechanism. I decided to swap in the Fxho steering column as well because I needed the longer steering cable to reach the steering nozzle and the cable mount on the column end of the cable was different than the XLT so it was less headache just to swap over the column as well. To mount the column the mount holes had to be redrilled and the plastics had to be trimmed around the glove box hinge to clear the larger Fxho column tilt handle. And finally the transom plate from the Fxho was used because the cooling water port is larger than the XLT plate. This swap is insanely easy I feel just about anyone should be able to pull this off within a weekend with any decent knowledge mechanics. Knowing what I know now about this conversion I will never rebuild another one of the 2-stroke PV motors if the 800 im my wife's XL800 let's got it will get an Mr-1 swap as well or maybe even a 1.8 swap.Click image for larger version. 

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  7. #6
    TimeBandit's Avatar
    Join Date
    Jun 2016
    Tampa Bay
    Good job! I dropped a 1.8L NA in a 2005 FXHO hull (see sig-line links), so I have an appreciation for the level of effort here.
    BTW, I really like the 1.8 over the MR1 any day! Plus more roomy in the hull and no stupid oil sump or reduction gear - my 2 cents.

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