rotax break in

[william keyes]

I have purchased a recently rebuilt Rotax JR that will need break in time, what is the procedure for this?

Will the Pro Shop be operating this weekend? In particular I will need restrictors for Micro Max. I realize it is a new class but I hope you have the parts in stock.

Last of all referring to your "Pit Kit", had you ever considered assembling this and marketing the actual kit, this would helpful to us new guys. Maybe even a crash kit expanded with other items like cable clips, exhaust springs, throttle and brake springs, etc. With your experiance I'll bet you know the high percentage needs. If you already provide something like this , what is MRPs' MSRP on such a kit.

Thaks to all

[Steve Miller]

Bill send me your e-mail at work and I'll e-mail you a nice document on Rotax break in procedures. As for the pit kit, we have one. Each kart needs different items such as king pins etc. We can tailor one for any kart.

[Marc Miller]

William,

Typical break-in procedure is to not start engine on stand. Use 4 oz of oil per gallon. First 10 minute session, do not exceed 8000 RPM but vary your RPM's below that. Let cool down. Next 10 min. session, do not exceed 10,000 RPM's using the same method. Cool down. Next session, Do not exceed 11,500 - use the same procedure.

You can then mix fuel/oil between 3 to 3.5 oz per gallon and should be good to rev engine however it desires.

You don't want to fire on stand as you want to make sure the engine has a load on it.

As far as MICRO class, you will need more than just the restrictor to convert your Rotax Jr. to Micro Max. You will need to have Tim cut the seal and put a spacer to raise your cylinder up - plus you will need a different pipe. We have USED kits available (no new ones) so you might want to try to call Tim Lobaugh at 269-756-9133 to make arrangements (call Thursday) for this.

[Bruce Woodrow]

William,

This is straight from the operator's manual:

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8. Running-in procedure for the engine

Attention: Pay attention to safety advice of the kart manufacturer.

To ensure that components have the longest possible life span, the engine must be subject to a defined running-in period at first operation of engine or after a repair of the crankshaft or displacement parts.

To warrant the best running-in conditions we recommend to fill the fuel tank the first time with slightly oil-enriched gasoline/oil mixture of 1 : 33 (3 % oil). After the end of the running-in period run the engine without fail on the specified oil/gasoline mixture of 1 : 50 ( 2 % oil), to prevent trouble like coking of the exhaust valve.

Attention: A fully synthetic 2-stroke oil must be used.

Start the engine and run the kart for 15 minutes on a race track changing load and engine speed up to

• 7.500 r.p.m

Then run the kart for 15 minutes with load and speed changes up to

• 9.500 r.p.m.

Load and speed changes mean:

Fully open the accelerator until the engine reaches the r.p.m. mentioned above – lift off the accelerator completely – until the r.p.m. comes down to 5.000 r.p.m. and accelerate again.
After this running-in period the full power of the engine may be used.

Warning: The engine may never be operated without load. Is it operated (i.e. on the trolley)
r.p.m. over 14.000 1/min are possible, this dramatically shortens the lifetime of components (conrod, big end bearing etc.)
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In addition, I would recommend using the K27 Needle in the carb. for break-in, as it gives a richer (safer) mixture at part throttle conditions.

Bruce

[pskjerven]

Sorry - I'm new to rotax. Will a new Micro rev up that high with its restrictors? If not, how do you recommend breaking in a Micro?

[Marc Miller]

A micro will not rev as high - however similar break in procedures should be used. The first couple sessions you want to keep the motor "off the pipe" - and you will know when the power delivery of the pip comes in to play.