[tony zambos]

Ed,

Think you’re out of luck on trying to get it repaired.  Try searching for one on E-Bay or Amazon.  You might not find one that’s RMAX legal, but you’ll have a spare.  That would be better than having a short day at the track.

 

[tony zambos]

Good to see that our doing a lot of homework. The most common 2-cycles, like the Yamaha KT-100 and the Rotax, have external pulse lines attached from the crankcase to the carb.  The Leopard has a passage through the reed cage, eliminating the problems of dried out or pinched line.

Your theory on carb operation is a little off.  The pulse pressure only affects the pump side of the carb, raising and lowering the pump diaphragm.  This action pumps fuel into the carb chamber, similar the float bowl on a car.  None of the pulse is felt at the tank.  The amount of fuel in the chamber is regulated by the needle valve.  You saw in the video, that he tested the pop-off of the needle valve with a pressure gauge. The more tension on the spring, the more fuel in the chamber and vice verse.  also in the video, he set the pop-off to 10 psi, + or – 1, and that’s a good place to start.  IMO, compressing the spring will get the proper pop-off for now but will eventually go back to it original tension. If you have the patience, you can cut little pieces of the spring off to lower the proper pop-off.  I think the best way is to purchase a kit with several springs of different tension. If you don’t have a pop-off gauge, get one. Eventually you’ll need one.  But to get your engine to started start, just about any pop-off will do so long as it not too high or low.

Also look at the gasket between the crankcase and the reed cage to make sure the pulse port hasn’t been blocked off.  And hate to asked this, but does the engine have compression?  It’s a 2-cycle engine. All you need is fuel and air plus spark at the right time and compression.

Keep plugging away on this.

[tony zambos]

Check your PM’s

[tony zambos]

Paul,

Welcome to karting.  When you say you’re a big guy, you mean taller the average.  The pedals are designed to keep feet from sliding off during turns and behind the nerf bar.  Think your best solution is a porch extension.  Call CRG and ask for their opinion

[tony zambos]

Chris,

IMO, in this one instance, the manual is incorrect when it comes to a Rotax.  Even two wraps of the rpm lead around the spark wire may not be sufficient.  I have three.  The rpm lead is only measuring flux changes as the coil discharges.  Don’t quote me on this, but the Rotax coil wire may have better insulation, hence a weaker signal to detect.  If your engine is stumbling at high rpm’s, you might have a marginal coil, but doesn’t seem to be the case.

There must be other Rotax guys out there running a MyChron on the Forum.  It would be nice to here from you on how you have the sensor attached.

 

[tony zambos]

Chris,
Here’s a link to installing AIM sensors.

http://www.aimsports.com/support/faq.html#sensors

[tony zambos]

Chris,

First, Bill has a good idea.  Won’t argue with your shop’s logic but it should have given you a place to start.  I’ve had this happen to me.  After downloading the data from a MyChron4 at the end of the day, noticed that I had one more session stored than the number of times on the track.  Found that the gauge thought it saw zero RPM’s during a 25 minute race. The only change made for the next race was to wrap the RPM sensor tighter around the plug wire.  Ran the rest of the season without a problem.

You could try to tighten the lead around the plug wire and you could add an extra wrap of the lead around the plug wire.  There is the possibitity that the RPM wire is damaged or theere is problem with the guage.  Call AIM.  Their service is excellent.

Don’t think it could be the on/off switch unless your engine is cutting out. From your description your engine is running and just the gauge is giving a false RPM reading.  The spark plug wire is part of the coil. Now you’re talking bucks.

[tony zambos]

Last idea except for calling Jim Russell Jr. Is the starter turning the motor fat enough?

[tony zambos]

If you don’t have fresh fuel in the tank, replace it.  Try to borrow a working carb.  Check the ground to the motor from the box and the ground that jumpers over the vibration mounts for the coil.  Open both needle valves for the carb roughly a turn & a quarter. Try starting the motor without the air filter and a hand over the carb inlet. Crank it briefly. Should have some fuel spill out of the carb.  If you’ve taken the carb off, did you pay attention to installing the gasket so it doesn’t block the pulse port in the block and the carb.  good luck.

[tony zambos]

Brian,

First, I don’t claim to know a lot about the DXL clutch.  Have you checked the clearance between the friction and floater disks? It appears that you have enough end play. Pull the spark plug and rock the rear wheels. If the piston moves, the clutch is engaging.  Assuming that the clutch and rear gears are in line.  And you could try installing the clutch without the key. Other than that, hopefully someone knowledgeable will chime in or you could call Hosrtman.

Word of advice, used the Horstman clutch tools to remove and install the clutch.

[tony zambos]

Eric,

Sorry, never considered you might have a bottom pickup. Hopefully someone with a similar tank will post.  If you look into the tank, are there walls around the pickup area? If not, would you consider installing a short piece of fuel line with a weighted end?

[tony zambos]

John,
Thanks for the update.

[tony zambos]

Eric,

Have no expirence with fuel cell foam and don’t anyone that does. Suggest that you pull the pickup line out of the tank. There should be a weighted end and the line should be flexible. The weighted end should almost reach the bottom of the tank and that should be long enough to pick up fuel when it sloshes to the far side of the tank. Will adding more fuel help?

[tony zambos]

John,
since this topic reoccurs periodically, would you mind sharing the solution that worked for you?

[tony zambos]

We’ve had this problem after a couple of years running the three pin rotor. Ours broke during a road race. Fortunately we had front brakes and no one was hit by the flying rotor. Your rotor is worn and also broken. Still suggest you upgrade to a six pin unless this is a fun kart.

[tony zambos]

Steve,
what ever rotor you decide on, consider going from a 3 bolt to a 6 bolt. They are less likely to break as yours did.

[tony zambos]

Steve,

I have a Mychron EVO-3 with an Mychron 3 dash. It’s similar to a Mychron 3 Gold. The E-Box has inputs for two temp sensors plus beacon, display, speed and RPM. Internal battery in the E-Box. Have the sensors and cables for the IR beacon and CHT. Track mapping can be done as the E-Box has two accelerometers. If interested, I’ll get you a price.

<img src=”http://[URL=http://s1139.photobucket.com/user/backlite/media/EVO-3_and_Dash/IMG_0012.jpg.html%5D%5BIMG%5Dhttp://i1139.photobucket.com/albums/n546/backlite/EVO-3_and_Dash/IMG_0012.jpg%5B/IMG%5D%5B/URL%5D&#8221;

[tony zambos]

A minimun of every two years and yearly if I can.  Besides replacing the seals in the calipers and master cylindars, also replace the pistions in both.

[tony zambos]

Rick,

Can’t see that rod acting as a torque tube.  It has a heim joint on both ends.  Guessing that it could only be keeping the distance between the front tab and the rear tab at the same distance.  Maybe it’s designed to keep the rear end of the kart alinged with the front during hard acceleration out of a corner.

 

[tony zambos]

Thanks Jeff.  I’ll bookmark that address before Dave gets annoyed with me.  When I tried doing a search, all I come up with were the tags that were available from Stapels.

[tony zambos]

John, check your PM’s

[tony zambos]

John,

I live in the western suburbs of Chicago. Suggest that you start by contacting these Chicago area kart shops, L.A.D Specialties at http://www.ladspec.com/   or Viking at    http://www.vikingkartingproducts.com/.  Dave Larson had a kart shipping service but could not find a web site.  I can PM you his phone number if you wish to contact him.

[tony zambos]

Used shot in my son’s kart when he was a novice.  Wouldn’t do it today.  Beside the fact that it might alter the way the chassis flexes, consider what woulld happen if you lost your rear bumper and dumped little round balls on the track.

 

[tony zambos]

Patrick,

It is the off season here in Chicago as it is in Ohio and it’s too cold here to work in an unheated garage.  If people are not working on their karts maybe karting is not on their minds, hence the fewer.   I’m sure there will be more people on the EKN forums as the racing season approaches.   There seems to be a fair number asking questions and getting good answers.  While it’s a shame that EKN lost some if its participants because of the new forum format, it is still the best source of information next to your local kart shop and a lot easier to go to.

[tony zambos]

Dave, are those negative one inch spacers?

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