[tony zambos]

There are many ways the kart, tires and the track could be slowing you down. Trying reaching out to your engine builder for help.

[tony zambos]

There are two gear and chain types, 219 and 35. You might have a 219 chain and a 35 sprock or the reverse. Make sure you have the same gear type on the clutch and axle gears plus the matching type.

[tony zambos]

Tom,
Double check the pulse line between the crankcase and carb for a tight fit.

[tony zambos]

Tom,
First of all, thanks for the update. On the carb with the issue, you’ve had it apart and found dirt in the screen, but did you rebuild it? That would be a starting point. Pay attention to the tips of the low & hi speed needles for any deformations or if they’re broken off. Also check the inlet needle valve. Finish up by testing the pop-off. 9 psi is usually good.

[tony zambos]

You had the right idea, but maybe you took too big of a swing at fixing the problem. To get 50 MPH with 14/54 gearing, your engine had to be turning about 6200 RPM. With an 18/54 gearing and turning the same 6200 RPM would get you to 65 MPH. But that’s if you could still turn 6200 which you may not be able to do with the loss of the mechanical advantage of the first ratio you used. Going from the 14t driver to the 18t was equivalent to dropping twelve teeth on the axle. Try dropping a couple of teeth at a time on the axle gear and see what happens.
All of your speed does not come from the engine. Chassis setup and drive technique play a big roll in top end speed.

[tony zambos]

Your engine may not have enough power for that ratio. Add four teeth to the axle gear and see what happens.
Also go over the kart. About zero toe in/out with the driver in the kart and on the ground. The gears should be in the same plane. No bad links in the chain and the axle spins freely w/o a chain.

[tony zambos]

On rolling starts and down the straight a ways, how does your kart compare? Are the other engines EVO? What rpm does your clutch stall at?
FYI- The new style clutches came out a few years ago. Along with the new clutch and drum came metal gears to replace the nylon ones. IMO you should have upgraded the clutch along with the EVO mods.

[tony zambos]

The carb settings sound good. Keep blipping the throttle on the formation lap to keep the engine cleaned out. At 5K, you should be way below the stall speed on the clutch. Wouldn’t close down the low end needle. As you know it gets busy on the first lap and you might forget to open the needle back up.

[tony zambos]

Matt,
Guessing that if you have an axle sensor, the gauge could determine how far away from start/finish you were.

[tony zambos]

Dan,
update your gauge to the latest version of firmware. That should resolve your issue. If that doesn’t, call AIM.

[tony zambos]

Matt C.,
Let me know what your thoughts on predictive lap times. tony

[tony zambos]

The option to enable Predictive Lap Times can be found under MENU > CONFIGURATION > SYSTEM SETUP. Never used it.

[tony zambos]

Call Franklin Motorsports or Comet Kart Sales or an OTK kart distributor near you in the morning. You’re not going to find that bolt at a hardware store. Order the locking bushing and nut as well.

[tony zambos]

Going to a better will never hurt. Bring a voltmeter with you to the track and measure voltage before and after a session. But you’ll not be able the measure the amperage which also is important. A better battery should get you amps as well.
With that said, the battery might not be the cause of your engine getting past 12600. Check your plug and exhaust colors for a jetting issue. If you haven’t changed the exhaust matting in a while, that could be your cause.

[tony zambos]

Larry,
You know you can’t have both speed and acceleration out of the Rotax. For faster acceleration, go smaller on the clutch gear. There are 11 and 12 tooth sprockets. Going down to a 11 tooth on the clutch sprocket is going to change your top end from 72 to 61 mph at 13.5k using the same 79 on the axle. But off the line you should be pretty good.
Keep in mind that the Rotax isn’t going turn much more the 13.5 and have any power behind it. A shorter track is going to help you out.

[tony zambos]

Ty,
thanks for the reply. Tried vigorlessly at tapping them on a kitchen counter without success. But will try that again in the morning when it’s cooler.

[tony zambos]

Look for a local kart shop to help you out. The clutch will not fall off on its own. It requires special tools.

[tony zambos]

First suggestion would be to call Comet. Can’t see how the key would fall off if you can’t get the starter nut off. Using the Comet clutch tool, secure the clutch and use an impact wrench to loosen the starter nut. Next use the puller. See this post for additonal help.https://new.ekartingnews.com/forums/topic/stuck-hortsmen-2disc/

[tony zambos]

Amber and green are only the colors for the back lighting. Typically the gauge will not be illuminated during the day. We’ve never used the back lighting at the track. Gets used when I have to read or configure the gauge in the garage. We have the green and maybe the amber would be easier to read in low situations. Lets hear from an amber M4 user.

[tony zambos]

Richard,
start out with using the blue Loctite on the grub screws in the axle bearings that hold the axle in place. Also Loctite the bolts that hold the axle bearing cassettes to the chassis. You can omit this if the cassette bolt heads are drilled for a safety wire.
All of the steering hardware should be cotter keyed or safety wired, i.e., the bolts thru the steering wheel to its hub, the bolt thru the upper steering shaft support, the bolts at both ends of the tie-rods, the pivot for the brake pedal. More than likely there are E-clips at the bottom of the steering shaft and at the ends of the front spindles.
Get in touch with the organization you are going to race with and acquire their rule book which spell out all the safety procedures. Also check with your local kart shop.

[tony zambos]

Know zippo about EVO’s. Start with what you know is wrong, the fuel pump.

[tony zambos]

Yes and enjoy.

[tony zambos]

John,
If my memory severs my right, there should be a metal washer under the bleeder plug. The washer could be missing. If that’s not the case, try a rubber O-ring. Carefully make sure there is no debris trapped under the bleed screw.

[tony zambos]

Guess all the laws of physics are applied equally to everything in the universe EXCEPT for karts.

[tony zambos]

Remove the nut circled in GREEN, attach the lug circled in RED and reinstalled the nut. The engine is now grounded to the wiring harness. Because the coil is mounted to two rubber isolators, the jumper wire is necessary to bring the ground over to the coil.
If you have a harness with a second ground, just coil it up and secure it to something. It’s used with a DD2 engine.
Safe link to operator’s manual: http://www.spellfame.co.uk/acatalog/rotaxrepairmanual.pdf

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