XXX-4 slipping a lot
 

Hi, I just took my XXX-4 out for its first proper run.

It is slipping a lot, I can't get any grip, or any speed. I don't think it is the tyres as I have tried 2 different sets, and it slips on carpet, tarmac and grass.

I don't have the tool to adjust the slipper, I will get one, but I am guessing it's either the slipper clutch, something to do with the belt, or the diffs.

How can I check all the above are fine? I have no experience with belt drive, and very little to no experience of slipper clutches.

Any advice would be hugely appreciated, thanks,
Alexi

PS, almost forgot to mention, I am running a mamba max 5700 on 10 cells, so I do have too much power. However I am getting more that a bit of wheel spin, on grass the car wont hit 15mph.

If you can hear a barking or chirping noise, then i may be one of your diffs, but if it sounds smoother then it will probably justg be the slipper. Anyway you can tighten the slipper eaisily with a set of pliars if you take it out, that is what i do with my dads and i dont hear him making any comments on it.

I cant hear any clicking, and it all sounds quite smooth, just a lot of whirring noise (as I said, I'm not used to belt drive :D), I'll try the slipper, thanks for the tip.

can you move/turn the spur gear with your thumb when all 4 wheels are on the ground?

if it moves freely then the clutch needs adjustment

Nope, and I know that points to the slipper being fine :(

Anyway, here's a (poor) video that might help:

http://i28.photobucket.com/albums/c2...8062007019.jpg

did you get it new or used?
who built it?

maybe the diffs need to be tightened or are in the wrong way round

diff screws need to go in from the off-side front & rear according to the online Manual

Yep that deffinately sounds like the slipper is well loose and could do with a tighten, But if yopu want to be on the safe side then you could check the diffs by tightening then all the way then backing off about half a turn, then you will just have to fine tunr it then.

That's almost certainly the slipper. The belts make a noise like a machine gun and the diffs a distinctive bark as has been said.

The slipper is a bit of a swine to adjust and it's essential you build it correctly with all the shims in the centre part exactly right. It was well known that unless you totally locked it up it used to slacken off during a run.

Paul Worsley made a mod where you could set it with some slip and set it with a set screw but I ran mine tight and never had any problem.

If you use pliers be carefull as the bit you tighten is quite thin and easy to mash up. The slipper tool is the best thing to use to be honest.

CFR, I got it used on Friday, I'm now it's 3rd owner. Apparently the first owner didn't give the guy I bought it off the slipper tool, and that it ran fine. This may be the case, and my brushless has just worked it loose.

I will also give the diffs a look (may as well, seeing as it's used), so thanks for that Legend.

Super__dan, thanks for all that info, I will buy the slipper tool when I can, but I have the spare parts to rebuild it if the pliers do damage, and it means it can try it now. I will probably run it nearly locked. I locked my mini inferno, and prefer the feel of an immediate kick so to speak :D
I have a spare belt anyway, so if I get excessive wear I can always back off the slipper clutch and fit the new belt.

Thanks for all the help, hopefully you've found the problem!

can we take it the belt in the car has got some teeth on it?

Haha, good idea, but yeah it does ;)

Had a look, found the problem. The slipper clutch is fine, the diffs...aren't. The pulley gear in the diff rotates, but doesn't turn the outdrives. Hopefully they just need tightening up. I am cleaning the bearings first, they are filthy...

So anyway, well done to Chequered Flag Racing, today's winner who correctly guessed it was the diffs! :p

Possibly the only time I'll get to the Chequered Flag 1st as I can't do it when Racing :p

Glad you've found the problem :)

lol, yeah I've found the problem :(

http://i28.photobucket.com/albums/c2...8062007086.jpg

That should all be one piece... It's not :D

Fortunately, the seller included a new set of pulleys. Do I need any particular grease? I have some left over from when I built some diffs for a Yokomo TC, will that be ok?
Thanks

any regular white/opaque diff grease will be OK

I use AE as I seem to have plenty of it.

I tried to put it back together last night, and after 2 hours realised the nut had lost its thread. Annoyingly I checked it when I first had problems putting it back together and it looked fine, but upon further inspection, it screws in, and then when enough pressure is applied, slips out (rather like a WORKING diff should :D).

Also, it looks to me like the front diff is in the rear, although I haven't checked the front yet. Is there any problem with leaving it like this?

Does anyone have a spare diff nut lying around? Actually, if anyone has a complete diff I may be interested, so I have spares as well.

Thanks in advance
Alexi

No-one else has passed coment on this, so I'm probably wrong but if I did this in my car, it would tear itself to peices. Maybe the 10 cells are the problem?

(how do you fit 10 sub-c cells in there anyway?!?)

The problem of the slipping was there from the very first run I gave the car, so I don't think the power broke it. Maybe it will in future, but it wasn't the cause this time. To be honest I've run this setup in my (custom) Mad Bull with the stock transmission holding up, so I am confident the XXX-4 should hold up for a fair while.

I got the 10 cells in with a bit of imagination, and a small amount of dremeling. If anyone's interested I'll put up a thread. Basically I love a project, and so it's quite a neat job I've done :D