Sneevly

I have a variety of questions that I would like answered, and this seemed to be the best spot to start. The story here is my brother built my XXX-T about 3 or some years ago, raced it about 2 times and quit. I'm starting back up now, and he's not too willing to help out any more. I noticed there are some problems with the car.

1. Any thing past 20 feet, the cars throttle skips in and out while going full throttle, as if the reception was going out. Wildly turns around 60 feet.

2. Full throttle from a standstill, and any time there is heavy resistance to the back tires such as rough terrain causes the back end to make a screeching sound, and I've got the slip clutch just about as tight as it goes.

I think number one is just due to old crystals. Should I honestly go out and buy a whole new set of radio equipment, or is this a cheap and easily diagnosed problem where I can just buy new crystals? My controller says "74 75.670Mhz", and it's one of the yellow band ones. I've been told by one of the the hobby stores that they are old, and they stopped selling those.

Oh yea, and what's up with that capacitor crap that you solder onto the motor? Could that just be my problem? Not having those?

With the screeching, can that be caused by dirt and what not, or am I honestly stripping the crap out of the gears in the back end? I've tightened and loosened my slip clutch all around the place, it has 0 effect on it.

RocketRob40

Anytime anyone digs out an old car they oftentimes make the fatal error of not cleaning the car throughly, reoiling the bearings, and freshening the batteries through, and making sure everything is operating as it was designed. Start there.

Have you replaced the batteries in the controller?
Usually poor radio reception, regardless of the age of the radio, is due to low power and low battery levels can reduce the output transmission power of the transmitter.

Having the slipper set too tight can cause this as the slipper is supposed to slip, that's what it's designed to do and why they call it a slipper - to slip. Or is the car dirty, and dirt has gotten between the slipper pads? Or it could be that the bearings need oil. It could be a lot of things. Take the car apart, check everything and then check back in.

Old crystals don't mean a thing. And if a hobby shop told you that it was because they were trying to make a sale. They might not sell them, but somebody does, and just because they're old doesn't mean they won't work. I have 20yo crystals that work fine to this day.

If it wasn't a problem before it shouldn't be a problem now.

As I said, it could be all sorts of things - including having too tight a gear mesh.
Clean the car and start fresh.

Dave H

Not sure about #1, I don't think old crystals are the problem, I use 20 year old ones myself on some stuff. Does the transmitter have good batteries?

#2 is almost certainly the differential slipping. Generally sounds like barking. You need to tighten the diff, probably needs a rebuild by now as well. Tightening the slipper has just made things worse, the slipper is there in large part to protect the diff. So start be loosening the slipper.

To tighten the diff, you put a thin wrench, say a small allen wrench, across/through the slot on the left output of the tranny where the dogbone rides. Push the wrench towards the tranny, then turn the right tire clockwise. The wrench will catch in a screwdriver like slot, then as you turn the wheel it will tighten the diff. Don't overdo it or force it, if it seems to bottom out back off 1/8 to 1/4 turn. The slipper should give first, you can turn the spur gear by hand to confirm.

If the diff feels gritty or notchy when you turn the tires in opposite directions, the diff needs rebuilt. New diff balls, possibly new diff washers, but you might be able to flip the washers over and use the other side. If you don't have the manual it is available on the Losi site.

little man

clean and oil the motor to get rid of the noise do the rest of the bearing or bushings while you are there,the reception sounds like a broken wire.the ariel wire ,the one that goes up the hollow tube measure and replace the wire just solder another one on at thereciever if you cant do this get a friend to do it its easy
the capacitors are there to supres electrical noise from interfering with the radio reception and operation.
lay a towel on the table sit down pull the car apart and inspect everything clean it re oil it then put it back together. you will find a lot more problems but they will be easy to fix and you know the job is done properly by you ,you also learn how the car goes together .if you get stuck go to the losi web site

Sneevly

Only thing I've tried already so far was changing the batteries in the transmitter, no improvement. But I'd like to thank all of you for your suggestions, I'm going to do some of the things you guys said later on today when I get more time. I appreciate it, I'll be back on here yapping if I'm still running into the same problems.

Sneevly

Ok, update time. I tightened that screw in the diff., stopped screeching all together. Now I'm just dealing with radio problems, I haven't tried any thing with that yet. For soldering on the wire to the receiver, am I opening up the case and soldering from there? Or should I just cut about 1/2 an inch from what's sticking out and solder from there? I didn't see any tears or points that could be broken, probably just going to drop 40 bucks and solve the problem the easy way if a new wire doesn't work.

Oh yea 1 more silly question, I'm using a Midnight 2 for my motor. Does any one still use those? I don't really care I think mine kicks ass, I just want to know how old this stuff is.

Dave H

I would only try to replace the receiver antenna if there was evidence of damage. Generally they don't just quit working, and the length is important.

I would try and find a similar radio, say at a local hobby shop, to try and cross test it with. Your transmitter, another receiver, and vica versa. With a matching set of crystals of course.

Not having the capacitors could be the problem, but I've had them knocked off and didn't have that much trouble. Also be aware that many newer motors have the caps built in.

Good Luck

little man

you solder at the board,just make sure the wire lengths are the same.the reason is the wire might have cracked in the heatshrink casing overtime.
its happened to me before