Home Forums TaG Rotax Max Thinking about getting a Rotax Jr

This topic contains 17 replies, has 5 voices, and was last updated by  Samir Shah 3 years, 4 months ago.

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  • #47373

    Samir Shah
    Participant

    As if I don’t have enough to learn with the Leopard and the chassis, I am also thinking of building up a second chassis as a Rotax Jr.

    Last week was our first time at OVRP. We ran a Leopard Jr, and my son totally took to the track and was fast. However, the class was tiny, whereas there was a huge Rotax Jr class.

    If we drive the Leopard at OVRP, it’ll be mostly as a test session. It does not tell us anything to have a Jr race with a mixed group of seniors and juniors, or varying abilitiies.

    So, instead I am thinking of getting a Rotax and letting him race in Rotax Jr at OVRP. With a rental priced around $350-$450/day, it makes more sense to get our own equipment.

    As I read more about it, I am getting more and more confused. A new engine is out of the question from a budget perspective, so I have get a used one. A new Jr cylinder is also out of the question. So I need to find a good used Jr motor.

    What are the questions to ask to identify a good Jr motor? Does the age of the motor matter at all? Number of times its been rebuilt? What else?

    Can a swap from Senior engine to Junior be done by myself? Or does it need to be sealed with an authorized center doing the work?

    If I get a used Jr cylinder, and a used senior engine, are there other constraints? Do numbers or vintages need to match for example?

    And what is this business w/ the EVO?

    Any FAQs or technical docs I should read to understand this stuff better?

    Would appreaciate all advice. If anyone has a usable JR engine package for sale, please let me know. Thanks.

    Samir.

  • #47393

    Christian Fox
    Participant

    Glad you had fun at OVRP. It’s our home track and a great place. Rotax is where it’s at if you want good size fields to race. No engine package is perfect, but Rotax motors are tanks and very reliable. That said, this is a tricky time to get into Rotax, especially on a limited budget. There are a lot of changes to the engine package for this year. That’s what EVO is; it’s a new carb, coil/e-box, exhaust manifold and wiring harness. The changes improve the performance to the point that you won’t be competitive without them. Also, for 2016, cylinders manufactured before 2011 will not be allowed, so if you look for a used motor, it would be wise to find one with a newer cylinder (2011 and newer cylinders are denoted by a two letter code stamped on the intake side of the cylinder, pre-2011 have a number stamped there). Vintages don’t need to match, in fact the best Rotax motors are a hodge-podge of different parts from different motors. It’s not hard to find decent used motors, but look for one sold bare without a carb or coil; there is no reason to pay for the older stuff when you will need the Evo parts anyway. You can expect to pay around $1,000 to $1,500 for a decent bare motor and another $1,000 or so for the Evo parts. I can’t see it being done for less than that.

    The guys at OVRP are super helpful and know a ton. Just speak with Tim, Peter, or Chris and they will get you headed in the right direction.

     

     

  • #47562

    Samir Shah
    Participant

    Thanks. Maybe we hold off on Rotax this year.

  • #47586

    Christian Fox
    Participant

    Samir, don’t give up on the Rotax idea until you’ve spoken to the guys at OVRP, they’ll help you figure something out

  • #49215

    Samir Shah
    Participant

    Christian, you must be Aiden’s dad. I noticed him at OVRP last weekend.

    We rented a non-EVO Rotax Jr Birel RY30 from Peter at OVRP, and ran in Rotax Jr. Spent the first 2 sessions jetting and gearing the engine to get rid of flat spots and bogging. And the new 11T sprockets were defective, and kept tossing the chain. So we missed a practice as well. Then it rained, and that was a new experience as well, to compound the Rotax experience.

    Up to that point, my son did not like driving it, and he was ready to give up, as was I, due to the gearing hassles.

    About halfway into the feature, while running last, he suddenly got the hang of the throttle, and started pushing and managed to pass 2 other kids, and now likes Rotax. Both of us think we need the EVO though.

    So, I’m trying to decided on whether we try and rent an Jr EVO engine next, or just buy one. Of course, the EVO upgrade special has expired, and now they cost a bomb!

    Know anyone with an EVO Jr kit that they got at the special price that they are not using and would sell?

    Samir

     

     

  • #49219

    Christian Fox
    Participant

    Hi Samir, yup, that’s me, Aidan’s Dad. I’m glad you guys gave the Rotax a shot. You certainly had a challenging start with the weather; that was some nasty rain. Rotax is a really good package, with big, competitive fields in the Northeast. Like I wrote before, they are tanks and easy to deal with when you figure them out.

    It won’t be easy to find people selling upgrade kits at cost per se, but a lot of people who were planning to sell their motors waited until they got the upgrade kit before listing them. You should be able to hunt around classifieds (here or other karting sites) or ebay and find a decent used motor with an upgrade kit. I’ll keep an eye out. Stop by and say hello if you guys are at the next race.

  • #49237

    Samir Shah
    Participant

    We’ll be back at OVRP this coming Sat to practice and set up w/ the iKart/Leopard if you are around. #3 kart. Should be at the next race again, either w/ a Rotax, or a TAG Leopard.

    Yup, I’m shopping around for Jr engines and upgrade kits.

    Samir.

  • #49238

    Ambrose Buldo
    Participant

    I should be at OVRP Sat with my IKart+Rotax Sr, #27. Just did a front end alignment, looking so see impact. I’ve ordered the Rotax EVO Upgrade Kit, still waiting.

    The Rotax Motors run reliabibly, but when you need parts they are costly. I just noticed I have a cracked exhaust and they want $500 for a new replacement. It’s outragous what they can charge.

    Started using a jetting app this year, love it as having the jetting, pin or plug wrong can easily cost you a second or more.

  • #49243

    Wesley Legaspi
    Participant

    Ambrose, do you mind sharing what jetting app you are using?  Thanks!

    • #49244

      Ambrose Buldo
      Participant

      Using KartMaxPro by Uranus Software, for iPhone.

  • #49246

    Wesley Legaspi
    Participant

    Ok, thanks Ambrose. Will wait to purchase when evo’s are supported as well.

  • #49449

    Samir Shah
    Participant

    Hi. So today I’ll be pulling the trigger on buying one of 5 used/rebuilt Rotax Jr. Engines I’ve identified. I’ve also lined up an Jr EVO kit and will be installing that. The goal is to get the engine during the coming week, and be ready to race at the NE Regional at OVRP next Sat and Sun.

    What other Rotax parts and tools will I need? Here are some that I’ve identified. Anything else?

    – Battery: can I use an equivalent battery, or do I need to use the spec -Yuasa or Rotax branded batteries?

    – Is there a spec oil for Rotax? Or can I use the Motul 2T I have for my Leopard?

    – Mojo D1s

    – Engine sprocket locker thing to lock the flywheel and allow the clutch drum and front sprocket to come off?

    – Exhaust springs – they need to be Rotax?

    – Rules specify a rear tire protection system? What is this?

    ” ROTAX rear tire protection system is mandatory to be used. Either 2-tube version or 3-tube version, third tube might be mounted above or below the two main tubes. No part shall be added or removed from original content (except safety wire or bolt connection between pos. 1 and pos. 2 as well as number plate with support). Only orange or red ROTAX original tyre-protection rollers are allowed to be used.”

    Would appreciate and tips and knowledge about tools and setup issues and things to watch out for. Thanks, Samir.

     

  • #49461

    Christian Fox
    Participant

    Hi Samir, glad you found a motor. To answer your questions:

    -You need to use the Yuasa/Rotax battery

    -You can use Motul 2T at 50:1 ratio for NE Regionals or clubs, national Rotax events require Rotax XPS

    -93 pump gas from the gas station down the road (O’Dell’s) is the spec fuel. Use 93; anything lower octane won’t pass tech

    -Mojo D1, must be purchased from OVRP for the regional event (this is standard practice)

    -drive sprocket lock is very handy

    -exhaust springs do need to be Rotax. Black for old package, Evo springs are silver

    -The tire protection system you are referring to s for DD2 only. All other classes use the regular black, plastic CIK bumper.

    Good luck! We’ll be there tomorrow so Aidan can practice in his Mini Max.

  • #49503

    Samir Shah
    Participant

    What is involved in swapping out a numbered cylinder for a lettered cylinder on a JR motor? Does the engine seal get broken in the process? Can this be done at home, or does it require special tools, or is it required that a Rotax center perform this swap?

    Thanks, Samir.

  • #49542

    Mark Traylor
    Participant

    Samir,

    Yes, the cylinder swap must be done by a service center.   it requires cutting the top end seal.   Do not buy any engine that does not have a lettered cylinder already They will not be legal and you will have to replace it at a potentially very high cost.   A good rotax cylinder can cost well over $1000.  I have seen them sell for $3000 to $5000.  That is for a cylinder only.   I do have a very good engine that I have been on the fence about selling.   If you have not purchased one yet contact Christian Fox.  He and I talk a lot about our engines and tuning so he can vouch for me.

  • #49667

    Samir Shah
    Participant

    OK, got my lettered JR cylinder rotax engine! Got to convert it to EVO tomorrow and install it and get the kart ready for transportation on Friday.

    I am hearing that the EVO jetting is different from the jetting for the PREVO. Any suggestions for JR EVO jetting and gearing for OVRP? Saturday is scattered T-storms, similar to the last time when we rented a Rotax JR. The jetting we used on the PREVO that time was 152.

    Thanks, Samir.

     

  • #49672

    Ambrose Buldo
    Participant

    Samir – Nice meeting you and your son Sat.

    You may want to ask Tim on recommended Jetting. He is installing our EVO Upgrade on SR Engine this week. On the SR motor I think he said we’d end up with a 122ish main jet, verses 160 on current setup with 12/82 gearing. Jr motor may be totally different.

  • #49679

    Samir Shah
    Participant

    FYI, all – the EVO Jr carb comes with a 130 jet and the needle at the 2nd position from the top.

    I assume the 2 pins on the floats both need to be below the lever. One of them was above the lever on mine.

    I made a throttle cable by grinding narrower (with a Dremel) the head of a Shimano bike shift cable!

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