Home Forums TaG Rotax Max Rotax Jr. To Rotax Sr. Switch – How To?

This topic contains 7 replies, has 4 voices, and was last updated by  Ken Marcotte 3 years ago.

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  • #37177

    Ken Marcotte
    Participant

    Hello, ive located a low hour complete Rotax FR125 Junior engine and was wondering exactly what it takes to upgrade it to a Senior engine package?  Is this cost effective to get this done and who can do the work? Any idea of what it can cost within the USA?

    Thanks for the help!

    #37180

    Eric Alexander
    Participant

    The only difference is the RAVE power valve. But to add that you need a Senior cylinder block. New, the items run about $900 in parts. Now you can find these used. RAVE assemblies run between $75 and $150. Cylinder blocks anywhere from $150 to $400. I’ve recently heard that Rotax has relaxed the cylinder block casting serial number rules, so you should be able to use any year.

    Now add to this labor and resealing costs. Thats going to run you another hundred or two. At this point you might consider a top-end rebuild just to match a new cylinder to the new block I.D. That will probably only cost you a hundred more.

    #37185

    Steve piggott
    Participant

    Thumps up to Eric, I have gone both ways, senior to micro and back, pricey but you get a fresh motor out of it!

    #37190

    Ken Marcotte
    Participant

    Thanks for the reply. Its sounding like i will have quite a bit of money into this engine. Im not sure it will be worth it. It would be different if it came with the senior cylinder.

    Thanks for the help!

    #37205

    Mike Bray
    Participant
    #37208

    Ken Marcotte
    Participant

    Thanks for passing that along. Ive noticed these parts get listed and move pretty quick, are they fairly common? If i could get a complete SR. cylinder at this price i might be able to get the JR. engine switched over for a reasonable amount of money.

    #37233

    Ken Marcotte
    Participant

    What does it cost to freshen the top end and re-seal one of these engines if it was purchased with a broken manufacturer seal?

    Thanks for all the help!

    #37281

    Ken Marcotte
    Participant

    Well folks, ive got the price down on the Jr. Engine to a point i could probably be into a fresh Sr. Engine for a coupls hundred bucks less than what i could just purchase a decent Rotax sealed engine with papers. Im just not thinking the deal is good enough and could be problematic down the road. Ive learned before that most of the time you get what you pay for, i think im better off holding out for a decent engine package without all the guesswork.

    Thanks for all your help!

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