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Discussion Starter #1
Hello,

Upon assembly of my xxx-4 I noticed something that doesn't seem right. I double checked assembly and everything is put together properly. When installing my slipper assembly with the kevlar spur gear it spins very freely in the chassis. Upon installation of the belt tensioner things seem to tighten up a bit. When I say that it tightens up a bit it's not due to the drag of the drivetrain through the belt. It seems to be due to the side load of the tensioner assembly on the slipper. If I tighten the screws for the slipper to "tight" it seems to be worse.

Has anyone come across this before? Do you leave your slipper screws on the "softer" side of tight and use some blue loctite on them for safety? Could it be due to my slipper being set at "handtight" and not adjusted properly? ( I haven't installed a motor or done any diff breakin as of yet)

Note: It's not overly tight where I'm really worried. I just don't want to have any drag on the drivetrain as I love that freewheeling coast that the novak BL offers and with the current setup it seems like it will slow itself down.

I'll be building my son's rc10b4 tonight and won't be back at the Losi until this weekend. Any help or insight would be greatly appreciated.

Thanks,

-Ryan
eri3f0g
 

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I know you said you rechecked everything, but... the small 'top hat' shaped spacer that the tension arm fits onto is directional, and if installed wrong can cause drag...

Also -- on my XXX-4, I "played" with the thin shim washers (moving them around on the slipper/gear shaft assembly) to help fine tune the drag in my system... My problem was in two areas...
1) If I wasn't carful, it was possible for the belt to ride up on the hex 'nut' that adjusts the slipper tension, and that created drag. I even played around with using shims on the sides of the rear diff to get the belt to not ride up on that hex...
2) If the idler pulley assembly is not installed correctly, the idler can drag on the tensioner arm or on the spur gear -- check this assembly too...

Sorry I cannot be of more help.
 

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Discussion Starter #3 (Edited)
no need to apologize, you are excellent help. I'm going to double check that tensioner assembly as well. I did double check that "top hat" shaped spacer and it's correct. That was my first guess was that I spaced something out wrong in the slipper assembly and that was why it was dragging.

I feel that the drag is likely your #2 culprit. It seems like the idler is slightly dragging on the spur gear. I'll post more feedback upon more disection.

Thanks again!

EDIT: Upon further checking it really does appear to be the idler dragging slightly on the spur. I held the tires in place and spun the spur gear and it "slips" very easily. I did a quick remove, inspect, install and from there I tightened up the slipper per the manual. I rotated the front tire quite a few revolutions to get tension on the spur gear and as I did that it seemed to reduce the drag on the idler. Now I only have a very small section (near the word LOSI on the kevlar spur) that rubs. I can still hold the tires and move the slipper by hand but I've not had a motor in it to set the proper slip. My hopes are that the slipper is still to loose and upon tightening it to it's proper tension the drag will go away.

When your slipper is properly adjusted is it relatively easy to hold the car down (no tire movement) and rotate the spur gear forward? Basically making the slipper slip so the spur is moving but the plates holding it are stationary. I have no basis to go by so I'm just wondering if I'm close on my adjustment. I also notice that you have to rotate the tire quite a few times to make a noticeable difference in slipper tension, do you agree?

Thanks all!
 

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It shouldn't be "easy". When you hold the car down and turn the spur with your thumb it should be very firm to the point that it almost hurts to turn it with your thumb.
 
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