XRAY - Model racing cars

Hi All,

I have an issue where the car won't move from a stopped/idle position. I tried to warm it up to temp, slowly open the throttle, punch it, etc. The car just won't move.

At low RPMs, I can see the clutch shoe move forward and connect with the clutch bell. This causes the pinion gears to spin counter-clockwise which in turn spins the spur gears clockwise (when looking at the car from the right side). When this happens, the car is suppose to move but it does not. It seems like the one-way bearing on the 49t spur gear is slipping.

When I let off the throttle, the spur gear and pinion gears are still spinning. As it winds down to almost where it is going to stop, the car jerks forward 1/4 of an inch. It seems like at that point is when the one-way bearing locks on to the shaft.

The above makes me think the one-way bearing is slipping.

I checked the following:
1. i turned off the engine. Put the car on a pit stand so the wheels are off the ground. I moved the large 49t spur gear (with the one-way bearing) clockwise. This causes the wheels to spin like it should.

2. Then i took the car off the pit stand and manually moved the car forward. The spur gear turns clockwise like it should. If I hold the spur gear, the car won't move forward.

The above makes me think the one way bearing is working.

But as stated above, when I start the engine and hit the throttle, the pinion and spur gears move but the car stays still.

Also, this problem did not just happen. There has been something wrong for the last few times I ran it. For the first time it happened, I ran the car for 20-30 minutes. All was fine until I slowed the car down until it stopped and then tried to open the throttle half way to get the car moving again. At which time, the car won't move from a start position. I had to slowly open the throttle before the car would move. After the car moved, the car was fine. I could hit the brake, make a turn, and throttle out of a turn without any issues. The only issue was moving the car from a stopped position. This problem continued for the next few times i ran it and the problem just progressively got worst. I thought it was the clutch shoe or the clutch gap and end play, so I put in a new yellow shoe and re-checked the gaps. The problem just got worse. Now, the car won't even move when slowly opening the throttle.

FYI: I did not put any one-way lube on this gear when I built the car. Do you think I damaged the bearing as a result?

god job to all xray drivers that that attended the 1/8th euros

It can only be that the one way bearing is damaged.

Please clean the the one-way with brake cleaner and check if you see any damages to the bearing or the plastic springs inside the bearing that keep the pins in place. If you dont see damages put enough one-way oil on the bearing and re-assemble the one-way on the 2-speed shaft.

Thanks jermen. I cleaned it with non-chlorinated brake cleaner, wiped down the inside of the bearing and then inspected it. It all looked fine to me. I put some Hudy one-way in there and then took it to the Rose Bowl to try out. It ran fine for one tank and then started to slip completely. I have a new one-way and shaft coming tomorrow afternoon so I will just change it out. I will remember to put one-way lube in this time.

Stupid question but I assume I need to clean and lube the front one way as well?

MC

always clean and lube one way bearings after each racing day.

the oil in the front oneway stays better in place than in the gearbox because the are more closed. but its always good to give it some oil.

When you punt the new one in clean out all the grease of the bearing before lubing it. You should be good to go!

regards,
John

Bad oneway bearings can lock themselves on the shaft...

Hi All,

It was the one way bearing. Sorry for the confusion. Basically the one-way would work as intended when the car was off. It would only slip when I would run the car with the engine on. i replaced the one-way and all was good again. I've been cleaning and lubing it each time now.