Strange sound XX4.

[zaquiz]

Hi there,

I know many of u guys over in the UK run the XX4, or had run it in the passed. Here in Spain i am compleatly alone with XX4, but doing quite good since i got back from 15 years abcence in this hobby.

At the last spanish championship a strange sound started in my XX4. Finally the mid-belt broke. I got help from experienced drivers, but none could locate de problem.

It sounds like one of the belts are "jumping" over some tooth. Like someting is vibrating inside of the "belttrain". You can only hear the sound when car is running on the ground. And it gets worse the more thorttle.

When I opened it up, i could see that one of the pulleys were a little damage, but very little. Could it be that?

I am running a 4.5R Novak. Could it be to much motor for beltdriven car?

Hope to hear form you soon.
Z

[Southwell]

If the pulley is damaged i would expect that to be the problem, especially with a powerful motor like a 4.5, change the pulley, their not expensive, if only for a process of elimination.

[zaquiz]

Thnx mate, yes I have allready ordered pulleys which are arriving soon I hope. Just wanted to check if it could be some other known problem with XX4.

[Gayo]

And always use some slipper, specially with such a powerful motor.

[Slimboyfat]

yes setting the slipper is VERY inportant especially with the mega high power these brushless things seem to provide!

[P_B]

Whenever I replace a belt in the XX-4 I also replace the pulleys it ran on. This is especially important for the fine-pitched mid and front belts, as even a slightly damaged pulley will ruin a new belt in no time.

Also, like everyone else says, the correct slipper setting is crucial too.

[zaquiz]

Should I follow the slipper-adjustments that are indicated in manual?

[zaquiz]

One more question, where can I find a motor mount clamp for the XX4? I am using the standard one, and its useless!

[Southwell]

They are like gold dust! I had three but sold them all

Slipper is normally around 2 foot i think? Im not 100% as i don't run much slipper myself.

[zaquiz]

I think Trinity had one b4 right? But not anymore... anyone else?

[anoolite76]

I am having the same problem with my xx-4 w/ Novak 6.5 with the stock spur and a 13t pinion. After the rear drive belt started skipping like crazy, I switched the "A" spacer for the rear diff to the tightest setting, and I wasted the belt. So I changed it out and went to the "B" spacer with the arrows pointing aft. The car was fine for about fifteen minutes. Everyone knows who I am because my car is "the one that makes that loud clicky sound". My slipper is tight, but GEESH, I keep wondering if this car does this to everyone. I'm changing out the pulleys ASAP and I'll get back to tell you if this helped. Anyone have a comment about the skipping? Is this a problem with everybody's XX-4 who runs brushless?

[Southwell]

The pulleys sorted my car out. I also run my rear belt on A forwards, the loosest setting with no problems.

[super__dan]

I'm surprised you could hear the belt skipping over the sound of a 13t pinion trying to mesh correctly????

[anoolite76]

Hmmm....There is definitely a loud gear whine coming from the car, but I figured that was just from the belts being belts. Thanks for pointing that out.

[anoolite76]

And the verdict is that the thing still skips under full take off speed with no slipper. I would never run it with no slipper for a race, but it would be nice to know that the car could handle it. The main belt had a pack run on it before I gave the car new pulleys. I'm sure that's hardly enough time to make a difference. XX-4: -1 point for being lame. See me after class.

[Southwell]

Did you replace the belts too?

[anoolite76]

Well, the main belt had about a pack or two run through it on the old pulleys, but I pulled the belt out, washed it with soap and water and checked for wear and did not see ANY, so I put it together.

[Southwell]

Mine didn't show any wear but were stretched, you are best off replacing them.